U.S. patent application number 14/854779 was filed with the patent office on 2016-01-28 for fluorescent probe.
This patent application is currently assigned to THE UNIVERSITY OF TOKYO. The applicant listed for this patent is THE UNIVERSITY OF TOKYO. Invention is credited to Takahiro EGAWA, Kenjiro HANAOKA, Kazuhisa HIRABAYASHI, Yuichiro KOIDE, Tetsuo NAGANO.
Application Number | 20160023988 14/854779 |
Document ID | / |
Family ID | 46515837 |
Filed Date | 2016-01-28 |
United States Patent
Application |
20160023988 |
Kind Code |
A1 |
NAGANO; Tetsuo ; et
al. |
January 28, 2016 |
FLUORESCENT PROBE
Abstract
A compound represented by the formula (I) (R.sup.1 represents
hydrogen atom or a monovalent substituent; R.sup.2 and R.sup.3
represent hydrogen atom, an alkyl group, or a halogen atom; R.sup.4
and R.sup.5 represent an alkyl group or an aryl group; R.sup.6 and
R.sup.7 represent hydrogen atom, an alkyl group, or a halogen atom;
R.sup.8 represent hydroxy group or a dialkoxyboranetriyl group; and
X represents silicon atom, germanium atom, or tin atom), which is a
novel fluorophore usable as a mother nucleus of an off/on type
fluorescent probe not utilizing the intramolecular photoinduced
electron transfer.
Inventors: |
NAGANO; Tetsuo; (Tokyo,
JP) ; HANAOKA; Kenjiro; (Tokyo, JP) ; KOIDE;
Yuichiro; (Tokyo, JP) ; EGAWA; Takahiro;
(Tokyo, JP) ; HIRABAYASHI; Kazuhisa; (Tokyo,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
THE UNIVERSITY OF TOKYO |
Tokyo |
|
JP |
|
|
Assignee: |
THE UNIVERSITY OF TOKYO
Tokyo
JP
|
Family ID: |
46515837 |
Appl. No.: |
14/854779 |
Filed: |
September 15, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13980215 |
Jul 17, 2013 |
9187499 |
|
|
PCT/JP2012/051122 |
Jan 19, 2012 |
|
|
|
14854779 |
|
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Current U.S.
Class: |
556/87 ; 556/406;
564/330 |
Current CPC
Class: |
C07F 7/10 20130101; C09B
69/008 20130101; C07C 211/44 20130101; C07F 7/0816 20130101; G01N
2021/6439 20130101; C09K 2211/1011 20130101; C09K 11/06 20130101;
H05B 33/10 20130101; G01N 21/6428 20130101; C07F 7/1804 20130101;
C09B 11/24 20130101; G01N 33/84 20130101; C07C 211/52 20130101;
C07F 7/30 20130101; C07F 7/081 20130101; C07F 7/2208 20130101; C09K
2211/1096 20130101; C09K 2211/1007 20130101 |
International
Class: |
C07C 211/44 20060101
C07C211/44; C07F 7/22 20060101 C07F007/22; C07F 7/30 20060101
C07F007/30; C07F 7/10 20060101 C07F007/10 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 20, 2011 |
JP |
2011-009577 |
Feb 18, 2011 |
JP |
2011-033395 |
Claims
1. A compound represented by the following general formula (III):
##STR00036## wherein, in the formula, R.sup.2 and R.sup.3
independently represent hydrogen atom, an alkyl group having 1 to 6
carbon atoms, or a halogen atom; R.sup.6 and R.sup.7 independently
represent hydrogen atom, an alkyl group having 1 to 6 carbon atoms,
or a halogen atom; and R.sup.12 represents a halogen atom, or a
salt thereof.
2. An N,N,N',N'-tetrallyl-diamino-X-xanthone compound represented
by the following formula: ##STR00037## wherein, in the formula,
R.sup.2 and R.sup.3 independently represent hydrogen atom, an alkyl
group having 1 to 6 carbon atoms, or a halogen atom; R.sup.4 and
R.sup.5 independently represent an alkyl group having 1 to 6 carbon
atoms, or an aryl group having 1 to 6 carbon atoms; R.sup.6 and
R.sup.7 independently represent hydrogen atom, an alkyl group
having 1 to 6 carbon atoms, or a halogen atom; and X represents
silicon atom, germanium atom, or tin atom, or a salt thereof.
3. A diamino-X-xanthone compound represented by the following
formula: ##STR00038## wherein, in the formula, R.sup.2 and R.sup.3
independently represent hydrogen atom, an alkyl group having 1 to 6
carbon atoms, or a halogen atom; R.sup.4 and R.sup.5 independently
represent an alkyl group having 1 to 6 carbon atoms, or an aryl
group having 1 to 6 carbon atoms; R.sup.6 and R.sup.7 independently
represent hydrogen atom, an alkyl group having 1 to 6 carbon atoms,
or a halogen atom; and X represents silicon atom, germanium atom,
or tin atom, or a salt thereof.
4. A dihydroxy-X-xanthone compound represented by the following
formula: ##STR00039## wherein, in the formula, R.sup.2 and R.sup.3
independently represent hydrogen atom, an alkyl group having 1 to 6
carbon atoms, or a halogen atom; R.sup.4 and R.sup.5 independently
represent an alkyl group having 1 to 6 carbon atoms, or an aryl
group having 1 to 6 carbon atoms; R.sup.6 and R.sup.7 independently
represent hydrogen atom, an alkyl group having 1 to 6 carbon atoms,
or a halogen atom; and X represents silicon atom, germanium atom,
or tin atom, or a salt thereof.
5. A compound represented by the following general formula (IV):
##STR00040## wherein, in the formula, R.sup.2 and R.sup.3
independently represent hydrogen atom, an alkyl group having 1 to 6
carbon atoms, or a halogen atom; R.sup.4 and R.sup.5 independently
represent an alkyl group having 1 to 6 carbon atoms, or an aryl
group having 1 to 6 carbon atoms; R.sup.6 and R.sup.7 independently
represent hydrogen atom, an alkyl group having 1 to 6 carbon atoms,
or a halogen atom; R.sup.13 represents a protective group of
phenolic hydroxy group; and X represents silicon atom, germanium
atom, or tin atom, or a salt thereof.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a divisional application of U.S.
application Ser. No. 13/980,215, which is a National Stage of
International Patent Application No. PCT/JP2012/051122, filed Jan.
19, 2012, which claims priority of JP 2011-009577, filed Jan. 20,
2011 and JP 2011-033395, filed Feb. 18, 2011. The entire
disclosures of U.S. application Ser. No. 13/980,215 and
International Application PCT/JP2012/051122 are expressly
incorporated by reference herein.
TECHNICAL FIELD
[0002] The present invention relates to a fluorescent probe having
a novel fluorophore.
BACKGROUND ART
[0003] Fluorescein is a molecule reported in 1871, and has been
widely used as a pH indicator or a labeling dye because of the high
water solubility and high fluorescence quantum yield thereof. Since
a calcium probe containing fluorescein as a mother nucleus was
developed, there have been provided a large number of highly
sensitive fluorescent off/on type probes utilizing intramolecular
photoinduced electron transfer (PET), decyclization or cyclization
of spiro ring, and the like. However, plural dyes containing
fluorescein as a parent compound cannot be simultaneously used in
molecular imaging, since fluorescence wavelengths thereof overlap
with each other. Moreover, the probes utilizing the intramolecular
photoinduced electron transfer suffer from a problem that such
probes require precise design of the oxidation potential of the
benzene ring, and therefore modification of the chemical structure
is strictly limited.
[0004] Further, almost no reports were made as for structural
modification of fluorescein at the oxygen atom of the 10-position
of the xanthene ring, and optical characteristics of such
compounds, wherein the oxygen atom at the 10-position of the
xanthene ring is replaced with another type of atom, are not known
so far. Although a compound corresponding to the basic structure of
rhodamine, pyronin Y (PY), of which oxygen atom is replaced with
silicon atom (TMDHS) and application of this compound as a
fluorescent probe have already been reported (Best, Q et al.,
Pacifichem 2010, subject number 2335, Dec. 19, 2010; Yuichiro KOIDE
et al., Fourth Convention of The Japanese Society for Molecular
Imaging, subject number P8-9, May 14, 2009), this fluorescent probe
having TMDHS as the basic structure is basically a probe utilizing
the intramolecular photoinduced electron transfer, or decyclization
or cyclization of spiro ring. In addition, any compound
corresponding to fluorescein, of which oxygen atom at the
10-position of the xanthene ring is replaced with silicon atom, has
not been reported so far, and fluorescent characteristics of such a
compound are also not known.
PRIOR ART REFERENCES
Non-Patent Documents
[0005] Non-patent document 1: Best, Q et al., Pacifichem 2010,
subject number 2335, Dec. 19, 2010 [0006] Non-patent document 2:
Yuichiro KOIDE et al., Fourth Convention of The Japanese Society
for Molecular Imaging, subject number P8-9, May 14, 2009
SUMMARY OF THE INVENTION
Object to be Achieved by the Invention
[0007] An object of the present invention is to provide a
fluorescent probe having a novel fluorophore.
[0008] More specifically, the object of the present invention is to
provide a compound which can be a novel fluorophore usable as a
parent compound of a fluorescent off/on type probe not utilizing
the intramolecular photoinduced electron transfer by chemically
modifying the fluorescein structure, and provide a fluorescent
probe utilizing such a compound.
Means for Achieving the Object
[0009] The inventors of the present invention conducted various
researches to achieve the aforementioned object. As a result, they
found that, as for a compound having the fluorescein structure in
which the oxygen atom at the 10-position of the xanthene ring was
replaced with silicon atom, the maximal absorption wavelengths of
the non-dissociated form (neutral form) and dissociated form (anion
form) of such a compound significantly deviated, and the difference
of the wavelengths was about twice or more larger than that is
observed in the non-dissociated form (neutral form) and dissociated
form (anion form) of a fluorescein derivative (the oxygen atom at
the 10-position of the xanthene ring is conserved). They also found
that, by utilizing this characteristic, a fluorescent probe,
capable of highly sensitive measurement of pH, various enzymes, and
the like, was successfully provided without utilizing the
intramolecular photoinduced electron transfer. The present
invention was accomplished on the basis of the aforementioned
findings.
[0010] The present invention thus provides a compound represented
by the following general formula (I):
##STR00001##
wherein, in the formula, R.sup.1 represents hydrogen atom, or the
same or different 1 to 5 monovalent substituents existing on the
benzene ring; R.sup.2 and R.sup.3 independently represent hydrogen
atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom;
R.sup.4 and R.sup.5 independently represent an alkyl group having 1
to 6 carbon atoms, or an aryl group having 1 to 6 carbon atoms;
R.sup.6 and R.sup.7 independently represent hydrogen atom, an alkyl
group having 1 to 6 carbon atoms, or a halogen atom; R.sup.8
represents hydroxy group, or a dialkoxyboranetriyl group; and X
represents silicon atom, germanium atom, or tin atom, or a salt
thereof.
[0011] According to a preferred embodiment of the aforementioned
invention, there is provided the aforementioned compound or a salt
thereof; wherein R.sup.1 represents hydrogen atom, or 1 to 3
monovalent substituents existing on the benzene ring (the
substituents are selected from the group consisting of an alkyl
group having 1 to 6 carbon atoms, an alkenyl group having 1 to 6
carbon atoms, an alkynyl group having 1 to 6 carbon atoms, an
alkoxy group having 1 to 6 carbon atoms, hydroxy group, carboxy
group, sulfonyl group, an alkoxycarbonyl group, a halogen atom, and
amino group), R.sup.2 and R.sup.3 independently represent hydrogen
atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom,
R.sup.4 and R.sup.5 independently represent an alkyl group having 1
to 6 carbon atoms, R.sup.6 and R.sup.7 independently represent
hydrogen atom, or an alkyl group having 1 to 6 carbon atoms,
R.sup.8 represents hydroxy group, or (pinacolato)boranetriyl group;
and X represents a silicon atom. According to a further preferred
embodiment, there is provided the aforementioned compound or a salt
thereof, wherein R.sup.1 represents hydrogen atom, or 1 to 3
monovalent substituents existing on the benzene ring (the
substituents are selected from the group consisting of an alkyl
group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6
carbon atoms, hydroxy group, carboxy group, a halogen atom, and
amino group), R.sup.2 and R.sup.3 independently represent hydrogen
atom, or a halogen atom, R.sup.4 and R.sup.5 independently
represent an alkyl group having 1 to 3 carbon atoms, R.sup.6 and
R.sup.7 are both hydrogen atoms, both chlorine atoms, or both
fluorine atoms, R.sup.8 represents hydroxy group; and X represents
silicon atom.
[0012] From other aspects of the present invention, there are
provided the aforementioned compound represented by the general
formula (I) or a salt thereof, which is for use in manufacture of a
fluorescent probe, and use of the aforementioned compound
represented by the general formula (I) or a salt thereof for
manufacture of a fluorescent probe.
[0013] The present invention also provides a compound represented
by the following general formula (II):
##STR00002##
wherein, in the formula, R.sup.1, R.sup.2, R.sup.3, R.sup.4,
R.sup.5, R.sup.6, R.sup.7, and X have the same meanings as those
defined above, and Y represents OR.sup.11 (R.sup.11 represents
hydrogen atom, or a monovalent group that is cleaved by contact
with an object substance for measurement) or a dialkoxyboranetriyl
group, or a salt thereof.
[0014] According to preferred embodiments, there are provided the
aforementioned compound or a salt thereof, wherein R.sup.1
represents hydrogen atom, or 1 to 3 monovalent substituents
existing on the benzene ring (the substituents are selected from
the group consisting of an alkyl group having 1 to 6 carbon atoms,
an alkoxy group having 1 to 6 carbon atoms, hydroxy group, carboxy
group, sulfonyl group, an alkoxycarbonyl group, a halogen atom, and
amino group), R.sup.2 and R.sup.3 independently represent hydrogen
atom, an alkyl group having 1 to 6 carbon atoms, or a halogen atom,
R.sup.4 and R.sup.5 independently represent an alkyl group having 1
to 6 carbon atoms, R.sup.6 and R.sup.7 independently represent
hydrogen atom, or an alkyl group having 1 to 6 carbon atoms, or
they are both chlorine atoms or both fluorine atoms, X is silicon
atom, and Y is OR.sup.11 (R.sup.11 is a monovalent group that is
cleaved by an enzyme), or (pinacolato)boranetriyl group; the
aforementioned compound or a salt thereof, wherein R.sup.11 is
hydrogen atoms, or a monovalent group that is cleaved by a
reductase, an oxidase, or a hydrolase; and the aforementioned
compound or a salt thereof, wherein R.sup.11 is hydrogen atom, or a
monovalent group that is cleaved by an enzyme selected from the
group consisting of .beta.-lactamase, cytochrome P450 oxidase,
.beta.-galactosidase, .beta.-glucosidase, .beta.-glucuronidase,
.beta.-hexosaminidase, lactase, alkaline phosphatase, matrix
metalloproteinase, and glutamyl transferase.
[0015] As another aspect, the present invention provides a pH
fluorescent probe containing a compound represented by the
aforementioned general formula (II) (in the formula, R.sup.1,
R.sup.2, R.sup.3, R.sup.4, R.sup.5, and X have the same meanings as
those defined above, and Y represents hydroxy group) or a salt
thereof.
[0016] The present invention also provides a method for measuring
pH, which comprises the step of measuring pH by using a compound
represented by the aforementioned general formula (II) (in the
formula, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, and X have
the same meanings as those defined above, and Y represents hydroxy
group) or a salt thereof as a fluorescent probe, and a method for
measuring pH, which comprises the step of contacting a cell,
tissue, or body fluid with a compound represented by the
aforementioned general formula (II) (in the formula, R.sup.1,
R.sup.2, R.sup.5, R.sup.4, R.sup.5, and X have the same meanings as
those defined above, and Y represents hydroxy group) or a salt
thereof, and then measuring fluorescence.
[0017] From still another aspect, the present invention provides a
fluorescent probe containing a compound represented by the
aforementioned general formula (II) (in the formula, R.sup.1,
R.sup.2, R.sup.3, R.sup.4, R.sup.5, and X have the same meanings as
those defined above, and Y represents OR.sup.11 (R.sup.11
represents a monovalent group that is cleaved by contact with an
object substance for measurement), or a dialkoxyboranetriyl group),
or a salt thereof.
[0018] The present invention also provides a method for measuring
an object substance for measurement, which comprises the step of
contacting the object substance for measurement with a compound
represented by the aforementioned general formula (II) (in the
formula, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, and X have
the same meanings as those defined above, and Y represents
OR.sup.11 (R.sup.11 represents a monovalent group that is cleaved
by contact with an object substance for measurement), or a
dialkoxyboranetriyl group, or a salt thereof, and then measuring
fluorescence.
[0019] From still another aspect, the present invention provides a
method for preparing a compound represented by the aforementioned
general formula (I) or a salt thereof, which comprises:
(a) the step of preparing a compound represented by the following
general formula (III):
##STR00003##
(in the formula, R.sup.12 represents a halogen atom, and R.sup.2,
R.sup.3, R.sup.6, and R.sup.7 have the same meanings as those
defined above) from a 3-halogenated N,N-diallylaniline, which is
prepared from a 3-halogenated aniline and an allyl halide, and
formaldehyde, (b) the step of reacting the compound represented by
the aforementioned general formula (III) with
X(Halo).sub.2(R.sup.4)(R.sup.5) (Halo represents chlorine atom or
bromine atom, and X, R.sup.4, and R.sup.5 have the same meanings as
those defined above), and then subjecting the resultant to an
oxidation reaction to prepare an
N,N,N',N'-tetrallyl-diamino-X-xanthone mentioned below,
##STR00004##
(c) the step of subjecting the
N,N,N',N'-tetrallyl-diamino-X-xanthone to deallylation to prepare a
diamino-X-xanthone mentioned below,
##STR00005##
(d) the step of converting the amino groups of the
diamino-X-xanthone into hydroxy groups to prepare a
dihydroxy-X-xanthone mentioned below,
##STR00006##
(e) the step of protecting the hydroxy groups of the
dihydroxy-X-xanthone with protective groups to prepare a compound
represented by the following general formula (IV):
##STR00007##
(in the formula, R.sup.13 represents a protective group of phenolic
hydroxy group, or a dialkoxyboranetriyl group), and (f) the step of
preparing a compound represented by the aforementioned general
formula (I) or a salt thereof from the compound represented by the
aforementioned general formula (IV) and a halogenated benzene
derivative.
[0020] R.sup.2, R.sup.3, R.sup.6, and R.sup.7 are preferably
hydrogen atoms, Halo is preferably chlorine atom, and R.sup.4 and
R.sup.5 are preferably methyl groups.
[0021] The present invention also provides the aforementioned
method for preparing a compound represented by the general formula
(I) or a salt thereof, which comprises the aforementioned step (f);
the aforementioned method for preparing a compound represented by
the general formula (I) or a salt thereof, which comprises the
aforementioned steps (e) and (f); the aforementioned method for
preparing a compound represented by the general formula (I) or a
salt thereof, which comprises the aforementioned steps (d), (e),
and (f); the aforementioned method for preparing a compound
represented by the general formula (I) or a salt thereof, which
comprises the aforementioned steps (c), (d), (e), and (f); and the
aforementioned method for preparing a compound represented by the
general formula (I) or a salt thereof, which comprises the
aforementioned steps (b), (c), (d), (e), and (f).
[0022] The present invention also provides the aforementioned
method for preparing a compound represented by the aforementioned
general formula (I) or a salt thereof, wherein a compound wherein
R.sup.6 and R.sup.7 are both hydrogen atoms is used as a starting
material in the step (a), the resultant of the step (d) is reacted
with a chlorinating agent or a fluorinating agent to prepare a
compound wherein R.sup.6 and R.sup.7 are both chlorine atoms, or
R.sup.6 and R.sup.7 are both fluorine atoms, and this compound is
used as a starting compound to perform the steps (e) and (fl and
thereby prepare a compound represented by the general formula (I)
wherein R.sup.6 and R.sup.7 are both chlorine atoms or both
fluorine atoms. The present invention also provides a method for
preparing the dihydroxy-X-xanthone compound wherein R.sup.6 and
R.sup.7 are both chlorine atoms, or R.sup.6 and R.sup.7 are both
fluorine atoms, which comprises reacting the dihydroxy-X-xanthone
compound mentioned in the aforementioned step (d) wherein R.sup.6
and R.sup.7 are both hydrogen atoms with a chlorinating agent or a
fluorinating agent.
[0023] Further, by reacting 2,7-substituted or 2,7-unsubstituted
3,6-dihydroxyxanthone with a chlorinating agent or a fluorinating
agent, 2,7-substituted or 2,7-unsubstituted
4,5-dichloro-3,6-dihydroxyxanthone, or 2,7-substituted or
2,7-unsubstituted 4,5-difluoro-3,6-dihydroxyxanthone can be
prepared. Furthermore, by protecting the hydroxy groups at the 3-
and 6-positions of 2,7-substituted or 2,7-unsubstituted
4,5-dichloro-3,6-dihydroxyxanthone, or 2,7-substituted or
2,7-unsubstituted 4,5-difluoro-3,6-dihydroxyxanthone with
protective groups, then reacting the protected compound with a
halogenated benzene derivative, and removing the protective groups
of the hydroxy groups, 2,7-substituted or 2,7-unsubstituted
4,5-dichloro-3,6-dihydroxyxanthen-9-yl, or 2,7-substituted or
2,7-unsubstituted 4,5-difluoro-3,6-dihydroxyxanthen-9-yl to which a
substituted phenyl group is bound at the 9-position can be
prepared.
[0024] As a particularly preferred embodiment of the aforementioned
method, there is provided a method for preparing a compound
represented by the aforementioned general formula (I) (in the
formula, R.sup.2, R.sup.3, R.sup.6, and R.sup.7 are hydrogen atoms,
R.sup.4 and R.sup.5 are methyl groups, and R.sup.8 represents
hydroxy group) or a salt thereof, which comprises:
(a) the step of preparing a compound represented by the following
general formula (IIIa):
##STR00008##
(in the formula, R.sup.12 represents a halogen atom) from a
3-halogenated N,N-diallylaniline, which is prepared from a
3-halogenated aniline and an allyl halide, and formaldehyde, (b)
the step of reacting the compound represented by the aforementioned
general formula (IIIc) with dichlorodimethylsilane, and subjecting
the resultant to an oxidation reaction to prepare
N,N,N',N'-tetrallyl-diamino-Si-xanthone mentioned below,
##STR00009##
(c) the step of preparing diamino-Si-xanthone mentioned below by
subjecting the N,N,N',N'-tetrallyl-diamino-Si-xanthone to
deallylation,
##STR00010##
(d) the step of converting the amino groups of the
diamino-Si-xanthone into hydroxy groups to prepare
dihydroxy-Si-xanthone mentioned below,
##STR00011##
(e) the step of protecting the hydroxy groups of the
dihydroxy-Si-xanthone with protective groups to prepare a compound
represented by the following general formula (IVa):
##STR00012##
(in the formula, R.sup.13 represents a protective group of phenolic
hydroxy group), and (f) the step of preparing a compound
represented by the aforementioned general formula (I) (R.sup.2,
R.sup.3, R.sup.6 and R.sup.7 are hydrogen atoms, R.sup.4 and
R.sup.5 are methyl groups, and R.sup.8 represents hydroxy group) or
a salt thereof from the compound represented by the aforementioned
general formula (IVa) and a halogenated benzene derivative.
[0025] The present invention also provides the aforementioned
method for preparing a compound represented by the general formula
(I) (in the formula, R.sup.2, R.sup.3, R.sup.6 and R.sup.7 are
hydrogen atoms, R.sup.4 and R.sup.5 are methyl groups, and R.sup.8
represents hydroxy group) or a salt thereof, which comprises the
aforementioned step (f); the aforementioned method for preparing a
compound represented by the general formula (I) (in the formula,
R.sup.2, R.sup.3, R.sup.6 and R.sup.7 are hydrogen atoms, R.sup.4
and R.sup.5 are methyl groups, and R.sup.8 represents hydroxy
group) or a salt thereof, which comprises the aforementioned steps
(e) and (f); the aforementioned method for preparing a compound
represented by the general formula (I) (in the formula, R.sup.2,
R.sup.3, R.sup.6 and R.sup.7 are hydrogen atoms, R.sup.4 and
R.sup.5 are methyl groups, and R.sup.8 represents hydroxy group) or
a salt thereof, which comprises the aforementioned steps (d), (e),
and (f); the aforementioned method for preparing a compound
represented by the general formula (I) (in the formula, R.sup.2,
R.sup.3, R.sup.6 and R.sup.7 are hydrogen atoms, R.sup.4 and
R.sup.5 are methyl groups, and R.sup.8 represents hydroxy group) or
a salt thereof, which comprises the aforementioned steps (c), (d),
(e), and (f); and the aforementioned method for preparing a
compound represented by the general formula (I) (in the formula,
R.sup.2, R.sup.3, R.sup.6 and R.sup.7 are hydrogen atoms, R.sup.4
and R.sup.5 are methyl groups, and R.sup.8 represents hydroxy
group) or a salt thereof, which comprises the aforementioned steps
(b), (c), (d), (e), and (f).
Effect of the Invention
[0026] The compounds represented by the general formula (I) and
salts thereof provided by the present invention show significantly
deviated maximal absorption wavelengths between the non-dissociated
form (neutral form) and dissociated form (anion form) of the
compounds, of which difference is about twice or more larger than
that of a fluorescein derivative. Therefore, when this property is
utilized, they are useful as a parent compound for manufacture of a
fluorescent probe that is capable of highly sensitive measurement
of pH, reactive oxygen species, various enzymes and the like
without depending on the intramolecular photoinduced electron
transfer or control of cyclization of spiro ring. The compounds
represented by the aforementioned general formula (II) and salts
thereof are also useful as a fluorescent probe that successfully
achieves highly sensitive measurement of pH, reactive oxygen
species, various enzymes and the like without depending on the
intramolecular photoinduced electron transfer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 shows results of measurement of absorption spectra
and fluorescence spectra of 2-Me TokyoMagenta, which is a typical
example of the compound of the present invention (in this
specification, "TokyoMagenta" represents a compound of the general
formula (I) wherein R.sup.1 is hydrogen atom, R.sup.2 and R.sup.3
are hydrogen atoms, R.sup.4 and R.sup.5 are methyl groups, R.sup.6
and R.sup.7 are hydrogen atoms, R.sup.8 is hydroxy group, and X is
silicon atom, and this compound may be abbreviated as "TM"). The
measurement was performed with changing pH. In this specification,
Me means methyl group. The upper graph shows absorption spectra and
the lower graph shows fluorescence spectra (excitation wavelength,
550 nm). The measurement was performed by using a 1 .mu.M solution
of 2-Me TokyoMagenta dissolved in a 0.1 M phosphate buffer
containing 1% dimethyl sulfoxide (DMSO).
[0028] FIG. 2 shows results of comparison of absorption wavelengths
of 2-Me TokyoMagenta, which is a typical example of the compound of
the present invention, and 2-Me TokyoGreen
(9-(2'-methylphenyl)-xanthen-3-one) having an oxygen atom at the
10-position of the xanthene ring.
[0029] FIG. 3 shows absorption spectra (upper left graph), and
fluorescence spectra (upper right graph (excitation wavelength, 582
am) and lower left graph (excitation wavelength, 448 nm) of 2-Me
TokyoMagenta .beta.gal, designed as a fluorescent probe for
measurement of .beta.-galactosidase. The spectra were measured
before and after a treatment with an enzyme.
[0030] FIG. 4 shows results of measurement of fluorescence
intensity over time, indicating advance of the hydrolysis reaction
of 2-Me TokyoMagenta .beta.gal with .beta.-galactosidase. As a
control, 2-Me-4-OMe TokyoGreen .beta.gal was used, which had been
already widely used as a fluorescent probe for .beta.-galactosidase
measurement.
[0031] FIG. 5 shows results of measurement of intracellular
.beta.-galactosidase using 2-Me TokyoMagenta .beta.gal as a
fluorescent probe. The bars shown in the photographs indicate 30
.mu.m.
[0032] FIG. 6 shows results of measurement of fluorescence spectra
of 2-Me TokyoMagenta, which is a typical example of the compound of
the present invention. The measurement was performed with changing
pH (excitation wavelength, 471 nm) by using a 1 .mu.M solution of
2-Me TokyoMagenta dissolved in a 0.1 M phosphate buffer containing
1% dimethyl sulfoxide (DMSO).
[0033] FIG. 7 shows absorption and fluorescence spectra of 2-Me TM
(a), 2-Me Ge-TM (b), and 2-Me DiEtTM (c). The measurement was
performed at pH 9.
[0034] FIG. 8 shows pH-dependent change of absorption spectrum of
2-Me Ge-TM (concentration was 1 .mu.M in a 0.1 M phosphate buffer
containing 1% DMSO).
[0035] FIG. 9 shows pH-dependent change of absorption spectrum of
2-Me DiEtTM (concentration was 1 .mu.M in a 0.1 M phosphate buffer
containing 1% DMSO).
[0036] FIG. 10 shows reactivity of 2-Me Ge-TM (blue), 2-Me TM
(green) and 2-Me DCTM (red) with GSH in a phosphate buffer (pH 7.4)
containing 1% DMSO.
[0037] FIG. 11 The upper graph shows pH-dependent change of
absorption spectrum of 2-COOH TM (concentration was 1 .mu.M in a
0.1 M phosphate buffer containing 1% DMSO), and the lower graph
shows pH-dependent change of absorption spectrum of 2-COOH TM at
580 nm. Curve fitting was performed on the basis of single-phase
normalization (red) and two-phase normalization (blue), and
.chi..sup.2 values were 0.041 and 4.4*10.sup.-4, respectively.
[0038] FIG. 12 shows optical characteristics of 2-MeDCTM, 2-COOH
DCTM, 2-Me DFTM, and 2-COOH DFTM, and shows pH-dependent change of
absorption spectrum (left) and change of fluorescence (right) at a
concentration of 1 .mu.M in a 0.1 M phosphate buffer containing 1%
DMSO.
[0039] FIG. 13 shows results of measurement of fluorescence
intensity change performed by loading 3 .mu.M of each probe on HeLa
cells at 37.degree. C., washing off the probe, and then measuring
fluorescence intensity under a microscope at 37.degree. C. for 60
minutes. The probes were 2-Me TMAM (2000.4000), 2-Me TMCOOAM
(1100.5000), 2-Me TMIDAAM (1000.5000), and 2-Me TMIDAIDAAM
(550-800), exposure time was 30 ms, and ND means 6%.
MODES FOR CARRYING OUT THE INVENTION
[0040] In the specification, "an alkyl group" or an alkyl moiety of
a substituent containing an alkyl moiety (for example, an alkoxy
group, and the like) means a linear, branched, or cyclic alkyl
group, or an alkyl group consisting of a combination thereof,
having, for example, 1 to 6 carbon atoms, preferably 1 to 4 carbon
atoms, more preferably 1 to 3 carbon atoms, unless specifically
indicated. More specifically, examples of the alkyl group include,
for example, methyl group, ethyl group, n-propyl group, isopropyl
group, cyclopropyl group, n-butyl group, sec-butyl group, isobutyl
group, tert-butyl group, cyclopropylmethyl group, n-pentyl group,
n-hexyl group, and the like. The "halogen atom" referred to in the
specification may be any one of fluorine atom, chlorine atom,
bromine atom, and iodine atom, preferably, fluorine atom, chlorine
atom, or bromine atom.
[0041] In the compound represented by the general formula (I),
R.sup.1 represents hydrogen atom, or the same or different 1 to 5
monovalent substituents existing on the benzene ring. When R.sup.1
represents the monovalent substituents existing on the benzene
ring, it is preferred that the same or different about 1 to 3
substituents exist on the benzene ring. When R.sup.1 represents one
or two or more monovalent substituents, the substituents can
substitute at arbitrary positions on the benzene ring, but it is
preferred that, for example, one substituent exists at the
ortho-position with respect to the binding position of the
condensed ring containing X on the benzene ring. When two or more
substituents exist on the benzene ring, it is preferred that one of
the substituents exists at the ortho-position with respect to the
binding position of the condensed ring containing X. It is
preferred that R.sup.1 represents hydrogen atom, or one substituent
existing at the ortho-position with respect to the binding position
of the condensed ring containing X. It is also preferred that, for
example, R.sup.1 represents two monovalent substituents.
[0042] Although type of the monovalent substituent as R.sup.1 is
not particularly limited, it is preferably selected from, for
example, the group consisting of an alkyl group having 1 to 6
carbon atoms, an alkenyl group having 1 to 6 carbon atoms, an
alkynyl group having 1 to 6 carbon atoms, an alkoxy group having 1
to 6 carbon atoms, hydroxy group, carboxy group, sulfonyl group, an
alkoxycarbonyl group, a halogen atom, and amino group. These
monovalent substituents may further have one or two or more
arbitrary substituents. For example, the alkyl group as R.sup.1 may
have one or more of substituents selected from a halogen atom,
carboxy group, sulfonyl group, hydroxy group, amino group, an
alkoxy group, and the like, and the alkyl group as R.sup.1 may be,
for example, a halogenated alkyl group, a hydroxyalkyl group, a
carboxyalkyl group, an aminoalkyl group, or the like. The amino
group as R.sup.1 may have one or two alkyl groups, and the amino
group as R.sup.1 may be, for example, a monoalkylamino group or a
dialkylamino group. Further, when the alkoxy group as by R.sup.1
has a substituent, examples thereof include, for example, a
carboxy-substituted alkoxy group, an alkoxycarbonyl-substituted
alkoxy group, and the like, more specifically, 4-carboxybutoxy
group, 4-acetoxymethyloxycarbonylbutoxy group, and the like.
[0043] When R.sup.1 represents two monovalent substituents, they
are preferably selected from, for example, the group consisting of
an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1
to 6 carbon atoms, and carboxy group, and they are more preferably
selected from the group consisting of an alkyl group having 1 to 6
carbon atoms, and an alkoxy group having 1 to 6 carbon atoms. In
this case, it is preferred that an alkyl group having 1 to 6 carbon
atoms exists at the ortho-position with respect to the binding
position of the condensed ring containing X, and an alkoxy group
(for example, an unsubstituted alkoxy group, a monocarboxy
group-substituted alkoxy group, a monoalkoxycarbonyl-substituted
alkoxy group, 4-acetoxymethyloxycarbonylbutoxy group and the like)
exists at another position on the benzene ring.
[0044] R.sup.2 and R.sup.3 independently represent hydrogen atom,
an alkyl group having 1 to 6 carbon atoms, or a halogen atom. When
R.sup.2 or R.sup.3 represents an alkyl group, the alkyl group may
have one or two or more substituents selected from a halogen atom,
carboxy group, sulfonyl group, hydroxy group, amino group, an
alkoxy group, and the like, and the alkyl group as R.sup.2 or
R.sup.3 may be, for example, a halogenated alkyl group, a
hydroxyalkyl group, a carboxyalkyl group, or the like. It is
preferred that R.sup.2 and R.sup.3 are independently hydrogen atom
or a halogen atom, and it is more preferred that R.sup.2 and
R.sup.3 are both hydrogen atoms, or R.sup.2 and R.sup.3 are both
chlorine atoms or fluorine atoms.
[0045] R.sup.4 and R.sup.5 independently represent an alkyl group
having 1 to 6 carbon atoms, or an aryl group having 1 to 6 carbon
atoms. It is preferred that R.sup.4 and R.sup.5 are independently
an alkyl group having 1 to 3 carbon atoms, and it is more preferred
that R.sup.4 and R.sup.5 are both methyl groups. The alkyl group as
R.sup.4 or R.sup.5 may have one or two or more substituents
selected from a halogen atom, carboxy group, sulfonyl group,
hydroxy group, amino group, an alkoxy group, and the like, and the
alkyl group as R.sup.4 or R.sup.5 may be, for example, a
halogenated alkyl group, a hydroxyalkyl group, a carboxyalkyl
group, or the like. When R.sup.4 or R.sup.5 represents an aryl
group, the aryl group may be a monocyclic aromatic group, or a
condensed ring aromatic group, and the aryl ring may contain one or
two or more ring-constituting heteroatoms (for example, nitrogen
atom, sulfur atom, oxygen atom and the like). As the aryl group,
phenyl group is preferred. The aryl ring may have one or two or
more substituents on the ring. As the substituents, for example,
one or two or more substituents selected from a halogen atom,
carboxy group, sulfonyl group, hydroxy group, amino group, an
alkoxy group, and the like may exist.
[0046] R.sup.6 and R.sup.7 independently represent hydrogen atom,
an alkyl group having 1 to 6 carbon atoms, or a halogen atom, and
these are the same as those explained for R.sup.2 and R.sup.3. It
is preferred that R.sup.6 and R.sup.7 are both hydrogen atoms, both
chlorine atoms, or both fluorine atoms.
[0047] X represents silicon atom, germanium atom, or tin atom. It
is preferably silicon atom or germanium atom, and it is
particularly preferably silicon atom.
[0048] R.sup.8 represents hydroxy group, or a dialkoxyboranetriyl
group. The carbon numbers of two alkoxy groups existing in the
dialkoxyboranetriyl group are, for example, about 1 to 6, and these
alkoxy groups may combine together to form, for example, a
5-membered ring or 6-membered ring. This 5-membered ring or
6-membered ring may have about 1 to 4 substituents, for example, an
alkyl group having about 1 to 6 carbon atoms. The dialkoxy group
can also be introduced by reacting a diol compound with boron atom,
and examples of such a case include, for example, binding a diol
compound such as ethylene glycol, propylene glycol, pinacol,
neopentyl glycol, and catechol, with boron atom. Examples of the
dialkoxyboranetriyl group include, for example,
dimethoxyboranetriyl group, tetramethylethylenedioxyboranetriyl
group, ((pinacolato)boron), o-phenylenedioxyboranetriyl group, and
the like, but it is not limited to these examples. Among them,
(pinacolato)boron is preferred.
[0049] In the compound represented by the general formula (II),
R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, and
X have the same meanings as those defined above. Y represents
OR.sup.11 (R.sup.11 represents hydrogen atom, or a monovalent group
that is cleaved by contact with an object substance for
measurement), or a dialkoxyboranetriyl group. As R.sup.11 in Y,
besides hydrogen atom, a group having a property that it is cleaved
by contact with an object substance for measurement can be used.
The dialkoxyboranetriyl group as Y is also the same as that defined
above.
[0050] Type of the object substance for measurement is not
particularly limited, and it may be any of, for example, an enzyme,
a metal ion (for example, alkali metal ion such as sodium ion and
lithium ion, alkaline earth metal ion such as calcium ion,
magnesium ion, zinc ion, and the like), a nonmetallic ion
(carbonate ion and the like), reactive oxygen species (for example,
hydroxy radical, peroxynitrite, hypochlorous acid, hydrogen
peroxide, and the like), and the like. The substance is preferably
an enzyme.
[0051] Examples of the enzyme include, for example, reductase,
oxidase, hydrolase, and the like. For example, examples of the
enzyme include enzymes useful for diagnosis of infectious diseases
and cancers, such as .beta.-lactamase, cytochrome P450 oxidase,
.beta.-galactosidase, .beta.-glucosidase, .beta.-glucuronidase,
.beta.-hexosaminidase, lactase, alkaline phosphatase, matrix
metalloproteinase, glutamyl transferase, and the like, but the
enzyme is not limited to these examples. Among the enzymes,
hydrolase is especially preferred. Typical examples of the
hydrolase include, for example, .beta.-galactosidase,
.beta.-lactamase, alkaline phosphatase, matrix metalloproteinase,
glutamyl transferase, and the like, but the hydrolase is not
necessarily limited to those mentioned above.
[0052] When the object substance for measurement is a hydrolase,
the compound of the general formula (II) can be designed so that
the compound is hydrolyzed by the enzyme to give a compound wherein
R.sup.11 is hydrogen atom by choosing a compound that can serve as
a specific substrate of the enzyme and functional groups. For
example, when the object substance for measurement is a saccharide
hydrolase, a residue of a saccharide compound that can be a
substrate of the enzyme can be used as R.sup.11. Functional groups
of the saccharide compound, such as hydroxy group and amino group,
may be protected with appropriate protective groups, if needed. Any
of such compounds having a protective group also falls within the
scope of the present invention.
[0053] When R.sup.11 is p-aminophenyl group or p-hydroxyphenyl
group, the compound is decomposed by contact with a reactive oxygen
species to give a compound wherein R.sup.11 is hydrogen atom, and
therefore a reactive oxygen species can be used as the object
substance for measurement. Fluorescent probes for reactive oxygen
species having p-aminophenyl group or p-hydroxyphenyl group are
described in, for example, International Patent Publications
WO2001/064664, WO2004/040296, U.S. Pat. No. 7,378,282, and the
like, and therefore the fluorescent probe of the present invention
can be used in the same manner as those for the fluorescent probes
disclosed in these references.
[0054] Further, when Y is a dialkoxyboranetriyl group, the compound
is decomposed by contact with hydrogen peroxide to give a compound
where Y is hydroxy group, and therefore hydrogen peroxide can be
used as the object substance for measurement in such a case.
Fluorescent probes for hydrogen peroxide having a
dialkoxyboranetriyl group are described in, for example, Nature
Chemical Biology, 3, pp. 263-267, 2007; J. Am. Chem. Soc., 132, pp.
4455-4465, 2010; J. Am. Chem, Soc., 132, pp. 5906-5915, 2010, and
the like, and therefore the fluorescent probe of the present
invention can be used in the same manner as those for the
fluorescent probes disclosed in these references.
[0055] Further, the compound of the general formula (II) where
R.sup.11 in OR.sup.11 as Y represents hydrogen atom reacts with
glucuronic acid transferase and changes into a O-glycoside
compound, and therefore the compound can measure the glucuronic
acid transferase activity. That is, the compound wherein R.sup.11
is hydrogen atom is in a dissociated form (anion form) in the
physiological pH region around neutral before the reaction with
glucuronic acid transferase, but the compound that becomes an
O-glycoside compound after the reaction with glucuronic acid
transferase is in a non-dissociated form (neutral form) showing an
absorption wavelength significantly shifted to the shorter
wavelength side and different fluorescence profile. For example, if
fluorescence intensity of the compound wherein R.sup.11 is hydrogen
atom is measured with an excitation wavelength of 582 nm before and
after the reaction with glucuronic acid transferase, strong
fluorescence is observed around 600 nm before the reaction with
glucuronic acid transferase, but after the reaction, the compound
that became an 0-glycoside compound does not have absorption at 582
nm, and therefore fluorescence is scarcely observed. Further, for
example, if fluorescence intensity of the compound where R.sup.11
is hydrogen atom is measured with an excitation wavelength of 471
nm before and after the reaction with glucuronic acid transferase,
fluorescence intensity around 560 nm increases with advance of the
reaction with glucuronic acid transferase. Specific examples of
fluorescent probe for measurement of the glucuronic acid
transferase activity utilizing a fluorescein derivative are
disclosed in International Patent Publication WO2008/105376, and
accordingly, the compounds of the present invention represented by
the general formula (II) wherein R.sup.11 is hydrogen atom can be
used in the same manner as that of the probe disclosed in the above
reference.
[0056] The compounds represented by the aforementioned general
formulas (I), (II), (III), and (IV) may exist as a salt. Examples
of the salt include base addition salts, acid addition salts, amino
acid salts, and the like. Examples of the base addition salts
include, for example, metal salts such as sodium salt, potassium
salt, calcium salt and magnesium salt, ammonium salts, and organic
amine salts such as triethylamine salt, piperidine salt, and
morpholine salt, and examples of the acid addition salts include,
for example, mineral acid salts such as hydrochloride, sulfate, and
nitrate, and organic acid salts such as methanesulfonate,
para-toluenesulfonate, citrate, and oxalate. As the amino acid
salt, glycine salt, and the like can be exemplified. However, the
salts of the compounds of the present invention are not limited to
these examples.
[0057] The compounds of the present invention represented by the
general formula (I) or (II) may have one or two or more asymmetric
carbons depending to types of substituents, and they may exist as a
stereoisomer such as enantiomer or diastereoisomer. Stereoisomers
in pure form, arbitrary mixtures of stereoisomers, racemates, and
the like all fall within the scope of the present invention.
Further, the compounds of the present invention represented by the
general formula (I) or (II) and salts thereof may exist as a
hydrate or a solvate, and all of these substances are encompassed
by the scope of the present invention. Type of the solvent that
forms the solvate is not particularly limited, and examples
include, for example, such solvents as ethanol, acetone, and
isopropanol.
[0058] The compounds of the present invention represented by the
general formula (I) have a characteristic feature that a
non-dissociated form (neutral form) compound and a dissociated form
(anion form) compound thereof show significantly deviated maximal
absorption wavelengths, of which difference is about twice or more
larger than the difference of the wavelengths of non-dissociated
form (neutral form) and dissociated form (anion form) of a
fluorescein derivative (the oxygen atom at the 10-position of the
xanthene ring is conserved). Therefore, the compounds represented
by the general formula (II) wherein R.sup.11 is hydrogen atom
(corresponding to the compounds represented by the general formula
(I)) have a characteristic feature that the maximal absorption
wavelength thereof significantly changes with pH change, and can be
used as a fluorescent probe for pH detection. Further, the
compounds represented by the general formula (II) wherein R.sup.11
in Y is not hydrogen atom exists substantially as a non-dissociated
form compound, but when R.sup.11 is cleaved by contact with an
object substance for measurement, a dissociated form compound is
generated. Therefore, they have a characteristic feature that
maximal absorption wavelength observed after contact with the
object substance for measurement significantly changes from that
observed before the contact, and can be used as a fluorescent probe
for measuring the object substance for measurement at high
sensitivity. In addition, when Y is a dialkoxyboranetriyl group,
the compounds are decomposed by contact with hydrogen peroxide to
generate a compound wherein Y is hydroxy group (dissociated form),
and therefore the compounds wherein Y is a dialkoxyboranetriyl
group have a characteristic feature that the maximal absorption
wavelength observed after the contact with hydrogen peroxide as the
object substance for measurement significantly changes from that
observed before the contact, and can be similarly used as a
fluorescent probe for measuring hydrogen peroxide at high
sensitivity. As described above, the compounds represented by the
general formula (I) are useful for manufacture of a probe that
utilizes the difference of the maximal absorption wavelengths
between a non-dissociated form compound and a dissociated form
compound, and they do not utilize the intramolecular photoinduced
electron transfer. Therefore, they have a characteristic feature
that it is not necessary to strictly adjust the electron density
(oxidation potential) of the benzene ring, and even if various
substituents exist on the benzene ring, it can function as a
probe.
[0059] For example, the compounds of the general formula (II)
having 4-acetoxymethyloxycarbonylbutoxy group or the like as
R.sup.1 are efficiently incorporated into cells because of high
lipophilicity thereof, and when they are incorporated into cells,
they are converted into a compound of the general formula (II)
having high water-solubility by hydrolysis of the
4-acetoxymethyloxycarbonylbutoxy group by an esterase existing in
the cells, and then stay in the cells for a long period of time.
Therefore, they are extremely suitable for imaging of an object
substance for measurement in the cells. These compounds also do not
utilize the intramolecular photoinduced electron transfer, and
4-acetoxymethyloxycarbonylbutoxy group can be introduced at an
arbitrary position on the benzene ring, and therefore it provides
high degree of freedom for design of fluorescent probes. The
fluorescent probe is preferably designed so that the difference of
fluorescence maximal absorption wavelengths observed before and
after the cleavage of R.sup.11 by an object substance for
measurement is made as large as possible. Further, the fluorescent
probe is more preferably designed so that, in addition to the
aforementioned characteristic features, it is substantially
non-fluorescent before the cleavage of R.sup.11, and becomes
strongly fluorescent after the cleavage of R.sup.11.
[0060] The term "measurement" used in this specification should be
construed in its broadest sense including quantification,
qualification, as well as measurement, examination, detection, and
the like performed for the purposes of diagnosis and the like. The
method for measuring an object substance for measurement utilizing
the fluorescent probe of the present invention wherein R.sup.11 in
Y is not hydrogen atom generally comprises (a) the step of
contacting a compound represented by the aforementioned formula
(II) with an object substance for measurement to cleave R.sup.11,
and (b) the step of measuring fluorescence of the compound
generated in the aforementioned step (a) (corresponding to a
dissociated form compound formed by the cleavage of R.sup.11). The
method for measuring an object substance for measurement utilizing
the fluorescent probe of the present invention wherein Y is a
dialkoxyboranetriyl group generally comprises (a) the step of
contacting the compound represented by the aforementioned formula
(II) with hydrogen peroxide, which is generally the object
substance for measurement, to generate the compound where Y is
hydroxy group, and (b) the step of measuring fluorescence of the
compound generated in the aforementioned step (a). For example, the
fluorescent probe of the present invention or a salt thereof can be
dissolved in an aqueous medium such as physiological saline and
buffer, a mixture of the aqueous medium and a water-miscible
organic solvent such as ethanol, acetone, ethylene glycol, dimethyl
sulfoxide, and dimethylformamide, or the like, this solution can be
added to an appropriate buffer containing cells or tissues, and
fluorescence spectrum can be measured before and after contact with
the object substance for measurement.
[0061] Fluorescence of the compound of which R.sup.11 has been
cleaved by the object substance for measurement can be measured by
a usual method, and a method of measuring a fluorescence spectrum
in vitro, a method of measuring a fluorescence spectrum in vivo by
using a bioimaging technique, and the like can be employed. For
example, when quantification is performed, it is desirable to
create a calibration curve beforehand in a conventional manner.
[0062] The fluorescent probe of the present invention may be mixed
with additives usually used for preparation of reagents when
required, and used as a composition. For example, as additives for
using a reagent in a physiological environment, such additives as
dissolving aids, pH modifiers, buffering agents, and isotonic
agents can be used, and amounts of these can be appropriately
selected by those skilled in the art. Such a composition is
provided as a composition in an appropriate form such as powdery
mixture, lyophilized product, granule, tablet, and solution.
[0063] The compounds prepared by the aforementioned preparation
steps (a) to (e) of the method for preparing the compound of the
present invention represented by the aforementioned the general
formula (I) or a salt thereof comprising the steps (a) to (e) are
novel compounds, and they are useful as synthetic intermediates for
the preparation of the compounds of the present invention
represented by the aforementioned general formula (I) and salts
thereof. In the aforementioned preparation method, it is preferred
that R.sup.2 and R.sup.3 are hydrogen atoms, it is preferred that
R.sup.6 and R.sup.7 are both hydrogen atoms, both chlorine atoms,
or both fluorine atoms, it is preferred that Halo is chlorine atom,
and it is preferred that R.sup.4 and R.sup.5 are C.sub.1-6 alkyl
groups such as methyl group. Further, it is particularly preferred
that R.sup.2, R.sup.3, R.sup.6, and R.sup.7 are hydrogen atoms,
R.sup.4 and R.sup.5 are methyl groups, and R.sup.8 represents
hydroxy group.
[0064] As for the compounds wherein R.sup.6 and R.sup.7 are both
chlorine atoms, or both fluorine atoms, for example,
dihydroxy-X-xanthone synthesized from diamino-X-xanthone wherein
R.sup.6 and R.sup.7 are both hydrogen atoms can be used in the
aforementioned step (d) as a starting compound, a chlorinating
agent such as NaOCl or a fluorinating agent such as Selectfluor
(registered trademark) can be allowed to act on the compound to
prepare a compound wherein R.sup.6 and R.sup.7 are both chlorine
atoms or both fluorine atoms, and this compound can be reacted as a
starting compound with a halogenated benzene derivative to prepare
a compound of the general formula (I) wherein R.sup.6 and R.sup.7
are both chlorine atoms, or both fluorine atoms. As the
chlorinating agent, besides NaOCl, chlorine, tert-butyl
hypochlorite, N-chlorosuccinimide, N-chlorodimethylamine,
chloramine T, and the like can be used. As the fluorinating agent,
N-fluorobenzenesulfonimide, 1-fluoro-2,4,6-trimethylpyridinium
trifluoromethanesulfonate, 1,1'-difluoro-2,2'-bipyridinium
bis(tetrafluoroborate), and the like can be used.
[0065] 2,7-Substituted or 2,7-unsubstituted
4,5-dichloro-3,6-dihydroxyxanthone and 2,7-substituted or
2,7-unsubstituted 4,5-difluoro-3,6-dihydroxyxanthone prepared by
reacting 2,7-substituted or 2,7-unsubstituted 3,6-dihydroxyxanthone
with the aforementioned chlorinating agent or fluorinating agent
are novel compounds, and they are useful as synthetic intermediates
for preparation of 2,7-substituted or 2,7-unsubstituted
4,5-dichloro-3,6-dihydroxyxanthen-9-yl or a salt thereof and
2,7-substituted or 2,7-unsubstituted
4,5-difluoro-3,6-dihydroxyxanthen-9-yl or a salt thereof, to which
a substituted phenyl group binds at the 9-position. By protecting
the hydroxy group at the 3- and 6-positions of 2,7-substituted or
2,7-unsubstituted 4,5-dichloro-3,6-dihydroxyxanthone, or
2,7-substituted or 2,7-unsubstituted
4,5-difluoro-3,6-dihydroxyxanthone with protective groups, reacting
the protected compound with a halogenated benzene derivative, and
then performing deprotection of the hydroxy groups, 2,7-substituted
or 2,7-unsubstituted 4,5-dichloro-3,6-dihydroxyxanthen-9-yl, or
2,7-substituted or 2,7-unsubstituted
4,5-difluoro-3,6-dihydroxyxanthen-9-yl, to which a substituted
phenyl group binds at the 9-position, can be prepared.
[0066] The compounds represented by the general formula (IV) can be
reacted with various halogenated benzene derivatives to prepare the
compounds of the present invention represented by the general
formula (I) introduced with various substituents on the benzene
ring on which R.sup.1 substitutes, and therefore they are
especially useful as synthetic intermediates. Although the
aforementioned preparation steps (a) to (f) are specifically
described in the examples, it should be understood that such
preparation methods further appropriately modified and improved by
those skilled in the art on the basis of their usual knowledge are
also encompassed by the scope of the present invention. Methods
comprising any one of the steps (a) to (e), or two or more
continuous steps among them are also encompassed by the scope of
the present invention.
[0067] In the compounds represented by the general formula (IV),
type of the protective group of the phenolic hydroxy group as
R.sup.18 is not particularly limited, and it can be appropriately
selected from, for example, t-butyldimethylsilyl group, methyl
group, methoxymethyl group, t-butyl group, and the like. About the
protective group of phenolic hydroxy group, for example, T. W.
Greene, Protective Groups in Organic Synthesis, John Wiley &
Sons, Inc. (1981), and the like can be referred to.
EXAMPLES
[0068] Hereafter, the present invention will be more specifically
explained with reference to examples. However, the scope of the
present invention is not limited by the following examples.
Example 1
[0069] The compound of the present invention was synthesized
according to the following scheme.
##STR00013## ##STR00014##
(a) 3-Bromo-N,N-diallylaniline
[0070] K.sub.2CO.sub.3 (22.0 g, 159 mmol) was suspended in
acetonitrile, the suspension was added with 3-bromoaniline (8.71
mL, 80.0 mmol) and allyl bromide (23.7 mL, 280 mmol), and the
mixture was stirred at 80.degree. C. for 14 hours. The reaction
mixture was cooled to room temperature, then filtered through
Celite, and sufficiently washed with ethyl acetate. The solvent was
removed, and then the residue was purified by column chromatography
(silica gel, ethyl acetate/hexane (1/40)) to obtain
3-bromo-N,N-diallylaniline (17.1 g, 67.9 mmol, yield 85%).
[0071] .sup.1H-NMR (300.40 MHz, CDCl.sub.3): .delta. 3.87-3.90 (m,
4H), 5.11-5.15 (m, 2H), 5.17-5.18 (m, 2H), 5.75-5.88 (m, 2H), 6.58
(dd, 1H, J=2.2, 8.1 Hz), 6.77-6.81 (m, 2H), 7.01 (t, 1H, J=8.1
Hz)
[0072] .sup.13C-NMR (75.45 MHz, CDCl.sub.3): .delta. 52.7, 110.8,
115.0, 116.3, 119.0, 123.3, 130.2, 133.2, 150.0
[0073] HRMS (ESI+): Found 252.0429, calculated 252.0388 for [M+H]+
(4.1 mmu)
(b) Bis(2-bromo-4-N,N-diallylaminophenyl)methane
[0074] 3-Bromo-N,N-diallylaniline (17.1 g, 67.9 mmol) was dissolved
in acetic acid (200 mL), the solution was added with a 37%
formaldehyde solution (10.2 g, 340 mmol), and the mixture was
heated at 80.degree. C. for 75 minutes. The reaction mixture was
cooled to room temperature, and then neutralized with saturated
aqueous NaHCO.sub.3 and NaOH. This mixture was extracted with
dichloromethane, and the organic layer was washed with brine. The
organic layer was dried over Na.sub.2SO.sub.4, the solvent was
removed, and then the residue was purified by column chromatography
(silica gel, ethyl acetate/hexane (1/30)) to obtain
bis(2-bromo-4-N,N-diallylaminophenyl)methane (15.2 g, 29.5 mmol,
yield 87%).
[0075] .sup.1H-NMR (300.40 MHz, CDCl.sub.3): .delta. 3.85-3.87 (m,
8H), 3.96 (s, 2H), 5.13-5.19 (m, 8H), 5.76-5.88 (m, 4H), 6.54 (dd,
2H, J=2.9, 8.8 Hz), 6.81 (d, 2H, J=8.1 Hz), 6.90 (d, 2H, J=2.9
Hz)
[0076] .sup.13C-NMR (75.45 MHz, CDCl.sub.3): .delta. 39.7, 52.7,
111.7, 116.0, 116.2, 125.5, 126.9, 130.8, 133.5, 148.1
[0077] HRMS (ESI+): Found 517.0654, calculated 517.0677 for [M+H]+
(-2.3 mmu)
(c) N,N,N',N'-Tetraallyl-diamino-Si-xanthone
[0078] Bis(2-bromo-4-N,N-diallylaminophenyl)methane (8.16 g, 15.8
mmol) and anhydrous tetrahydrofuran (THF, 50 mL) were put into a
dried flask inside of which was substituted with argon. The mixture
was cooled to -78.degree. C., and then added with 1 M
sec-butyllithium (45 mL, 45 mmol), and the mixture was stirred for
20 minutes. The mixture was slowly added with
dichlorodimethylsilane (2.9 mL, 30 mmol) dissolved in anhydrous THF
(10 mL) at the same temperature, and the mixture was returned to
room temperature, and stirred for 1 hour. The reaction was
terminated with 2 N hydrochloric acid, and the reaction mixture was
neutralized with NaHCO.sub.3. This mixture was extracted with
dichloromethane, the organic layer was washed with brine, and dried
over Na.sub.2SO.sub.4, and then the solvent was removed. The
residue was dissolved in acetone (150 mL), the solution was cooled
to 0.degree. C. and added portionwise with KMnO.sub.4 (6.88 g, 43.5
mmol) over 2 hours, and the mixture was further stirred at the same
temperature for 1 hour. The mixture was added with dichloromethane
(200 mL), and the mixture was subjected to suction filtration using
filter paper. The solvent was removed, and the residue was purified
by column chromatography (silica gel, dichloromethane) to obtain
N,N,N',N'-tetraallyl-diamino-Si-xanthone (2.23 g, 520 mmol, yield
33%).
[0079] .sup.1H-NMR (300.40 MHz, CDCl.sub.3): .delta. 0.41 (s, 6H),
4.02 (d, 8H, J=5.1 Hz), 5.17-5.23 (m, 8H), 5.82-5.94 (m, 4H),
6.80-6.83 (m, 4H), 8.34 (d, 2H, J=8.1 Hz)
[0080] .sup.13C-NMR (75.45 MHz, CDCl.sub.3): .delta. -1.1, 52.8,
113.5, 114.8, 116.7, 130.0, 131.7, 133.1, 140.5, 150.2, 185.1
[0081] HRMS (ESI+): Found 429.2347, calculated 429.2362 for [M+H]+
(-1.5 mmu)
(d) Diamino-Si-xanthone
[0082] Pd(PPh.sub.3).sub.4 (35.0 mg, 0.0303 mmol) and
1,3-dimethylbarbituric acid (196 mg, 1.08 mmol) were put into a
dried flask inside of which was substituted with argon. The mixture
was added with N,N,N',N'-tetraallyldiamino-Si-xanthone (99.2 mg,
0.231 mmol) dissolved in dichloromethane (10 mL), and the mixture
was stirred at 64.degree. C. for 16 hours. The solvent was removed,
the residue was suspended in saturated aqueous Na.sub.2CO.sub.3,
and the suspension was extracted with dichloromethane. The organic
layer was dried over Na.sub.2SO.sub.4, the solvent was removed, and
then the residue was purified by column chromatography (silica gel,
ethyl acetate/hexane (4/3)) to obtain diamino-Si-xanthone (48.8 mg,
0.182 mmol, yield 79%).
[0083] .sup.1H-NMR (300.40 MHz, CD.sub.3OD): .delta. 0.40 (s, 6H),
6.76 (dd, 2H, J=2.6, 8.4 Hz), 6.88 (d, 2H, J=2.2 Hz), 8.13 (d, 2H,
J=8.8 Hz)
[0084] .sup.13C-NMR (75.45 MHz, CD.sub.3OD): .delta. -1.3, 116.6,
118.4, 131.0, 132.8, 142.6, 153.0, 187.5 HRMS (ESI+Tof): m/z Found
269.1108, calculated 269.1110 for [M+H]+ (-0.2 mmu)
(e) Dihydroxy-Si-xanthone
[0085] Diamino-Si-xanthone (48.8 mg, 0.182 mmol) was dissolved in a
mixed solvent (methanol, 6 N H.sub.2SO.sub.4, 4/5, 45 mL). The
solution was cooled to 0.degree. C., and then slowly added with
NaNO.sub.2 (84.6 mg, 1.22 mmol) dissolved in water (2 mL), and the
mixture was stirred at the same temperature for 1 hour. This
mixture was slowly added to boiling 1 N H.sub.2SO.sub.4 (50 mL),
and the mixture was further refluxed for 10 minutes, and then
cooled on ice. The reaction mixture was extracted with
dichloromethane, and the organic layer was sufficiently washed with
brine. The organic layer was dried over Na.sub.2SO.sub.4, the
solvent was removed, and then the residue was purified by column
chromatography (silica gel, methanol/dichloromethane (1/20)) to
obtain dihydroxy-Si-xanthone (32.9 mg, 0.122 mmol, yield 67%).
[0086] .sup.1H-NMR (300.40 MHz, CD.sub.3OD): .delta. 0.45 (s, 6H),
6.95 (dd, 2H, J=2.2, 8.8 Hz), 7.07 (d, 2H, J=2.2 Hz), 8.26 (d, 2H,
J=8.8 Hz)
[0087] .sup.13C-NMR (75.45 MHz, CD.sub.3OD): .delta. -1.5, 118.4,
120.0, 133.3, 133.8, 143.1, 162.2, 187.6
[0088] HRMS (ESI-Tof): Found 269.0674, calculated 269.0634 for
[M-H]- (4.0 mmu)
(f) 3,6-Di-tert-butyldimethylsilyloxy-Si-xanthone
[0089] Dihydroxy-Si-xanthone (32.9 mg, 0.122 mmol) and imidazole
(85.5 mg, 1.26 mmol) were dissolved in dichloromethane (20 mL), the
solution was slowly added with tert-butyldimethylsilyl chloride
(185 mg, 1.23 mmol) dissolved in dichloromethane (5 mL), and the
mixture was stirred at room temperature for 14 hours. The mixture
was added with water, the mixture was extracted with
dichloromethane, and the organic layer was washed with brine. The
organic layer was dried over Na.sub.2SO.sub.4, the solvent was
removed, and then the residue was purified by column chromatography
(silica gel, ethyl acetate/hexane (1/20)) to obtain
3,6-di-tertbutyldimethylsilyloxy-Si-xanthone (52.8 mg, 0.106 mmol,
yield 84%).
[0090] .sup.1H-NMR (300.40 MHz, CDCl.sub.3): .delta. 0.26 (s, 12H),
0.46 (s, 6H), 1.01 (s, 18H), 6.98 (dd, 2H, J=2.2, 8.8 Hz), 7.04 (d,
2H, J=2.9 Hz), 8.37 (d, 2H, J=8.8 Hz)
[0091] .sup.13C-NMR (75.45 MHz, CDCl.sub.3): .delta. -4.3, -1.6,
18.3, 25.6, 121.8, 123.7, 132.3, 134.5, 141.1, 158.7, 186.0
[0092] HRMS (ESI+): Found 499.2480, calculated 499.2520 for [M+H]+
(-4.0 mmu)
(g) Synthesis of 2-Me TokyoMagenta
[0093] 2-Bromotoluene (200 .mu.L, 1.6 mmol) and anhydrous THF (5
mL) were put into a sufficiently dried flask inside of which was
substituted with argon. The mixture was cooled to -78.degree. C.,
and then added with 1 M sec-butyllithium (1.0 mmol), and the
mixture was stirred for 20 minutes. The mixture was slowly added
with 3,6-ditert-butyldimethylsilyloxy-Si-xanthone (9.4 mg, 0.019
mmol) dissolved in anhydrous THF (5 mL) at the same temperature,
and the mixture was returned to room temperature. The mixture was
stirred at room temperature for 1 hour, and then added with 2 N HCl
(10 mL), and the mixture was stirred for 20 minutes. This mixture
was extracted with dichloromethane, and the organic layer was
washed with brine. The organic layer was dried over
Na.sub.2SO.sub.4, the solvent was removed, and then the residue was
purified by HPLC to obtain 2-Me TokyoMagenta (4.5 mg, 0.013 mmol,
yield 69%).
[0094] .sup.1H-NMR (300.40 MHz, D.sub.2O): .delta. 0.46 (s 6H),
2.01 (s, 3H), 6.33 (dd, 2H, J=2.9, 9.5 Hz), 7.01-7.09 (m, 5H),
7.27-7.46 (m, 310
[0095] HRMS (ESI-): Found, 343.1120 calculated 343.1154 for [M-H]-
(-3.41 mmu)
(h) Synthesis of 2-Me TokyoMagenta .beta.gal
##STR00015##
[0097] 2-Me TokyoMagenta (4.6 mg, 0.013 mmol),
2,3,4,6-tetra-0-acetyl-.alpha.-galactopyranosyl bromide (80.8 mg,
0.197 mmol) and Cs.sub.2CO.sub.3 (29.6 mg, 0.0909 mmol) were added
to acetonitrile (3 mL), and the mixture was stirred overnight at
room temperature under an argon-substituted atmosphere. The mixture
was filtered, and the solvent of the filtrate was removed. The
residue was dissolved in methanol (3 mL), the solution was cooled
to 0.degree. C., and slowly added with 15 .mu.L of a 28% solution
of sodium methoxide in methanol, and then this mixture was stirred
for 1 hour. The reaction was terminated with 0.2 N aqueous HCl, and
the reaction mixture was extracted with dichloromethane. The
organic layer was washed with brine, and dried over
Na.sub.2SO.sub.4, and the solvent was removed. The residue was
purified by HPLC to obtain 2-Me TokyoMagenta .beta.gal (2.4 mg,
0.0047 mmol, yield 36%).
[0098] .sup.1H-NMR (300.40 MHz, CD.sub.3OD): .delta. 0.51 (d, 3H,
J=1.8 Hz), 0.52 (d, 3H j=1.8 Hz), 2.04 (s, 3H), 3.59 (dd, 1H,
J=3.7, 9.5 Hz), 3.69-3.89 (m, 5H), 4.98 (dd, 1H, J=3.3, 7.7 Hz),
6.23 (dd, 1H, J=2.2, 10.3 Hz), 6.87-6.91 (m, 2H), 6.98-7.13 (m,
3H), 7.33-7.46 (m, 3H), 7.50 (d, 1H, J=2.2 Hz)
[0099] HRMS (ESI+): m/z Found 507.1826 calculated 507.1839 for
[M+H]+ (-1.3 mmu)
Example 2
[0100] Absorption and fluorescence profiles of 2-Me TokyoMagenta
obtained in the step (g) mentioned above were measured at various
pH values. The results are shown in FIG. 1. It was confirmed that,
with the shift of pH from the acidic side to the alkaline side, the
maximal absorption wavelength shifted to the longer wavelength side
from around 471 nm to around 582 nm (FIG. 1, upper graph), and that
fluorescence emission with excitation light of 550 nm significantly
increased (FIG. 1, lower graph). It is considered that 2-Me
TokyoMagenta exists in an equilibrated state of the non-dissociated
form (neutral form) and the dissociated form (anion form) mentioned
below depending on pH. It was found that the fluorescence profiles
of the compounds were significantly different from each other, for
example, the absorption spectrum of the dissociated form shifts to
the longer wavelength side compared with the non-dissociated form,
absorption coefficients and fluorescence quantum yields of them are
different, and the like.
TABLE-US-00001 ##STR00016## [Formula 15] ##STR00017## .epsilon.
.PHI..sub.fl Anion form 110000 0.42 Neutral form 29000 0.10
[0101] The results of comparison of the absorption wavelengths of
2-Me TokyoMagenta and 2-Me TokyoGreen
(9-(2'-methylphenyl)-xanthen-3-one) having oxygen atom at the
10-position of the xanthene ring are shown in FIG. 2 and Table 1.
The measurement was performed at pH 3 and 9 in a sodium phosphate
buffer. As a result, it was demonstrated that 2-Me TokyoMagenta
showed a larger absorption wavelength change with change of pH
compared with 2-Me TokyoGreen (in Table 1, Neutral form corresponds
to pH 3, and Anion form corresponds to pH 9).
TABLE-US-00002 TABLE 1 .lamda.max 2-Me TokyoGreen 2-Me TokyoMagenta
Anion form 492 582 Neutral form 439 471
Example 3
[0102] The characteristics of 2-Me TokyoMagenta .beta.gal, which
was designed as a fluorescent probe for .beta.-galactosidase
measurement, as an enzyme substrate and a fluorescent probe were
evaluated. There are shown absorption spectra (FIG. 3, upper left
graph) and fluorescence spectra (FIG. 3, upper right graph
(excitation wavelength, 582 nm) and FIG. 3, lower left graph
(excitation wavelength, 448 nm)) of 2-Me TokyoMagenta .beta.gal
measured before and after a treatment with .beta.-galactosidase (6
units) in a 0.1 M sodium phosphate buffer (pH 7.0) containing 0.1%
dimethyl sulfoxide. The Amax values measured before and after the
reaction were 448 nm (before the reaction), and 582 nm (after the
reaction), respectively.
[0103] Advance of the hydrolysis reaction of 2-Me TokyoMagenta
.beta.gal by .beta.-galactosidase was monitored by periodically
measuring fluorescence intensity. As a control, 2-Me-4-OMe
TokyoGreen .beta.gal
(9-(4'-methoxy-2'-methylphenyl)-6-(.beta.-D-galactopyranosyloxy)-xanthen--
3-one), which had been already widely used as a fluorescent probe
for .beta.-galactosidase measurement, was used. The reaction was
performed at 37.degree. C. in a 0.1 M sodium phosphate buffer (pH
7.4) containing 1 .mu.M 2-Me TokyoMagenta .beta.gal or 2-Me-4-OMe
TokyoGreen .beta.gal and 0.1% dimethyl sulfoxide. One unit (1.3
.mu.g) of .beta.-galactosidase was added 40 seconds afterward. The
results are shown in FIG. 4. As shown in the following scheme,
fluorescence was generated by cancellation of PET in the case of
2-Me-4-OMe TokyoGreen .beta.gal, and increase of fluorescence
intensity due to red shift was observed in the case of 2-Me
TokyoMagenta .beta.gal.
##STR00018##
Example 4
[0104] 2-Me TokyoMagenta .beta.gal was introduced into cells, and
it was confirmed that it functioned as a fluorescent probe for
.beta.-galactosidase measurement. The HEK293 cells (lacZ(+) or
lacZ(-)) were incubated with 10 .mu.M 2-Me TokyoMagenta .beta.gal
at 37.degree. C. for 30 minutes in the Dulbecco's modified Eagle
medium (DMEM) containing 0.1% dimethyl sulfoxide, and fluorescence
spectrum was measured with an excitation wavelength of 580 nm and
detection wavelength of 600 to 620 nm. The results are shown in
FIG. 5. In the lacZ(+) cells, fluorescence emitted by the
fluorescent probe hydrolyzed by .beta.-galactosidase was confirmed,
whereas fluorescence was not observed in the lacZ(-) cells. On the
basis of this result, it is clear that 2-Me TokyoMagenta .beta.gal
introduced into cells functions as a fluorescent probe for
.beta.-galactosidase measurement.
Example 5
[0105] By using 3,6-di-tert-butyldimethylsilyloxy-Si-xanthone
obtained in Example 1, the step (f), Compounds (A) to (E) of the
present invention were synthesized by the following procedures.
[0106] A bromobenzene derivative (1.0 mmol) and anhydrous
tetrahydrofuran (THF, 5 mL) were put into a sufficiently dried
flask inside of which was substituted with argon. The mixture was
cooled to -78.degree. C., and then added with 1 M sec-butyllithium
(0.5 mmol), and the mixture was stirred for 20 minutes. The mixture
was slowly added with 3,6-di-tert-butyldimethylsilyloxy-Si-xanthone
(0.015 to 0.019 mmol) dissolved in anhydrous THF (5 mL) at the same
temperature, and the mixture was returned to room temperature. The
mixture was stirred at room temperature for 1 hour, and then added
with 2 N HCl (5 mL), and the mixture was stirred for 20 minutes.
The reaction mixture was extracted with dichloromethane, and the
organic layer was washed with brine, and dried over anhydrous
sodium sulfate. The solvent was removed, and then the residue was
purified by HPLC to obtain the objective substance.
(a) 2,4-Dimethyl TokyoMagenta (Compound (A))
##STR00019##
[0108] Yield: 93%
[0109] .sup.1H-NMR (300 MHz, D.sub.2O): .delta. 0.37 (s, 6H), 1.83
(s, 3H), 2.25 (s, 3H), 6.21 (dd, 2H, J=1.5, 9.5 Hz), 6.75 (d, 1H,
J=8.1 Hz), 6.89-6.94 (m, 5H), 7.07 (s, 1H)
(b) 2,5-Dimethyl TokyoMagenta (Compound (B))
##STR00020##
[0111] Yield: 96%
[0112] .sup.1H-NMR (300 MHz, D.sub.2O): .delta. 0.38, (s, 3H),
0.40, (s, 3H), 1.82 (s, 3H), 2.10 (s, 3H), 6.19 (dd, 2H, J=2.2, 9.5
Hz), 6.73 (s, 1H), 6.89-7.11 (m, 6H)
(c) 2-Methoxy TokyoMagenta (Compound (C))
##STR00021##
[0114] Yield: 88%
[0115] .sup.1H-NMR (300 MHz, D.sub.2O): .delta. 0.40, (s, 3H),
0.44, (s, 3H), 3.65 (s, 3H), 6.29 (dd, 2H, J=2, 9, 9.5 Hz),
6.96-7.18 (m, 7H), 7.50 (dd, 1H, J=7.0, 7.0 Hz)
(d) 2-Methoxy-5-methyl TokyoMagenta (Compound (D))
##STR00022##
[0117] Yield: 99%
[0118] .sup.1H-NMR (300 MHz, D.sub.2O): .delta. 0.40, (s, 3H),
0.42, (s, 3H), 2.11 (s, 3H), 3.58 (s, 3H), 6.23 (dd, 2H, J=2.2, 9.5
Hz), 6.75 (s, 1H), 6.95-7.03 (m, 5H), 7.21 (d, 1H, J=8.1 Hz)
(e) 2,5-Dimethoxy TokyoMagenta (Compound (E))
##STR00023##
[0120] Yield: 90%
[0121] .sup.1H-NMR (300 MHz, D.sub.2O): .delta. 0.39, (s, 3H),
0.41, (s, 3H), 3.53 (s, 3H), 3.58 (s, 3H), 6.22 (dd, 2H, J=2.2, 9.5
Hz), 6.54 (d, 1H, J=2.9 Hz), 6.89-7.02 (m, 6H)
Example 6
[0122] Absorption and fluorescence profiles of 2-Me TokyoMagenta
obtained in the step (g) mentioned above were measured at various
pH values (excitation wavelength, 471 nm). The results are shown in
FIG. 6. It was confirmed that, with the shift of pH from the acidic
side to the alkaline side, fluorescence intensity decreased around
590 nm, and fluorescence intensity increased around 560 nm. It is
considered that 2-Me TokyoMagenta exists in an equilibrated state
of the non-dissociated form (neutral form) and the dissociated form
(anion form) mentioned below depending on pH, and it was found that
the fluorescence spectra of the dissociated form and the
non-dissociated form observed with the excitation wavelength of 471
nm were significantly different from each other.
Example 7
[0123] A germanium-containing compound was synthesized by the
following procedures.
##STR00024##
(a) N,N,N',N'-3,6-Tetraallyldiamino-Ge-xanthone
[0124] Bis(2-bromo-4-N,N-diallylaminophenyl)methane (6.16 g, 11.9
mmol) and anhydrous THF (40 mL) were put into a dried flask inside
of which was substituted with argon. The mixture was cooled to
-78.degree. C., and then added with 1 M sec-butyllithium (BuLi, 34
mL, 34 mmol), and the mixture was stirred for 20 minutes. The
mixture was slowly added with GeMe.sub.2Cl.sub.2 (2.62 mL, 22.7
mmol) dissolved in anhydrous THF (15 mL) at the same temperature,
and the mixture was returned to room temperature, and stirred for 1
hour. The reaction was terminated with 2 N HCl, and the reaction
mixture was neutralized with NaHCO.sub.3. This mixture was
extracted with dichloromethane, the organic layer was washed with
brine, and dried over Na.sub.2SO.sub.4, and then the solvent was
removed. The residue was dissolved in acetone (120 mL), and the
solution was cooled to 0.degree. C. The solution was added
portionwise with KMnO.sub.4 (5.20 g, 32.9 mmol) over 2 hours, and
the mixture was further stirred at the same temperature for 1 hour.
The mixture was added with dichloromethane (200 mL), and the
mixture was subjected to suction filtration using filter paper.
Then, the solvent was removed, and the residue was purified by
column chromatography (silica gel, dichloromethane) to obtain the
objective substance (1.29 g, 2.72 mmol, yield 23%).
[0125] .sup.1H NMR (300 MHz, CDCl.sub.3): .delta. 0.54 (s, 6H),
4.00-4.02 (m, 8H) 5.17-5.23 (m, 8H), 5.81-5.94 (m, 4H), 6.72 (d,
2H, J=2.9 Hz), 6.78 (dd, 2H, J=2.6, 9.2 Hz), 8.36 (d, 2H, J=8.8
Hz)
[0126] .sup.13C NMR (75 MHz, CDCl.sub.3): .delta. -1.8, 52.3,
112.6, 114.4, 116.2, 129.6, 131.7, 132.7, 142.8, 149.8, 184.5
[0127] LRMS (ESI+): m/z Found 475, calculated 475 for [M+H]+
(b) 3,6-Dihydroxy-Ge-xanthone
[0128] Pd(PPh.sub.3).sub.4 (330 mg, 0.285 mmol) and
1,3-dimethylbarbituric acid (1.41 g, 9.04 mmol) were put into a
dried flask inside of which was substituted with argon. The mixture
was added with N,N,N',N'-tetraallyldiamino-Ge-xanthone (1.00 g,
2.11 mmol) dissolved in dichloromethane (50 mL), and the mixture
was stirred at 35.degree. C. for 16 hours. The solvent was removed,
the residue was suspended in saturated aqueous Na.sub.2CO.sub.3,
and the suspension was extracted with dichloromethane. The organic
layer was dried over Na.sub.2SO.sub.4, the solvent was removed, and
then the residue was purified by column chromatography (silica gel,
ethyl acetate/hexane (4/3)) to obtain a 3,6-diamino-Ge-xanthone
mixture (760 mg, quantum yield).
[0129] .sup.1H NMR (300 MHz, CD.sub.3OD): .delta. 0.55 (s, 6H),
6.73-6.76 (m, 4H), 8.33 (d, 2H, J=9.5 Hz)
[0130] .sup.13C NMR (75 MHz, CD.sub.3OD): 8.1.9, 116.1, 118.3,
130.9, 133.2, 145.2, 152.9, 187.3
[0131] LRMS (ESI+): m/z Found 315, calculated 315 for [M+H]+
(c) 3,6-Dihydroxy-Ge-xanthone
[0132] The 3,6-diamino-Ge-xanthone mixture (760 mg) was dissolved
in methanol/6 N H.sub.2SO.sub.4 (3/4, 45 mL). The solution was
cooled to 0.degree. C., and then slowly added with NaNO.sub.2 (838
mg, 12.1 mmol) dissolved in 1120 (5 mL), and the mixture was
stirred at the same temperature for 1 hour. The mixture was slowly
added to boiling 1 N H.sub.2SO.sub.4 (70 mL), and the mixture was
further refluxed for 10 minutes, and then cooled on ice. The
reaction mixture was extracted with dichloromethane, and the
organic layer was sufficiently washed with brine. The organic layer
was dried over Na.sub.2SO.sub.4, the solvent was removed, and then
the residue was purified by column chromatography (silica gel,
ethyl acetate/hexane (1/1)) to obtain 3,6-dihydroxy-Ge-xanthone
(478 mg, 1.52 mmol, yield 56% in 2 steps).
[0133] .sup.1H NMR (300 MHz, CD.sub.3OD): .delta. 0.58 (s, 6H),
6.90 (dd, 2H, J=2.2, 8.8 Hz), 7.0 (d, 2H, J=2.2 Hz), 8.25 (d, 2H,
J=8.8 Hz)
[0134] .sup.13C NMR (75 MHz, CD.sub.3OD): .delta. -2.0, 117.7,
120.0, 133.7, 133.8, 145.6, 162.0, 187.7
[0135] LRMS (ESI+): Found 317, calculated 317 for [M+H]+
(d) 3,6-DiTBDMSO-Ge-xanthone
[0136] Dihydroxy-Ge-xanthone (478 mg, 1.52 mmol) and imidazolo
(1.77 g, 26.0 mmol) were dissolved in dichloromethane (150 mL), the
solution was slowly added with TBDMSCl (3.70 g, 24.5 mmol)
dissolved in dichloromethane (50 mL), and the mixture was stirred
at room temperature for 14 hours. The mixture was added with 1120,
the mixture was extracted with dichloromethane, and the organic
layer was washed with brine. The organic layer was dried over
Na.sub.2SO.sub.4, the solvent was removed, and then the residue was
purified by column chromatography (silica gel, ethyl acetate/hexane
(1/30)) to obtain 3,6-diTBDMSO-Ge-xanthone (702 mg, 1.29 mmol,
yield 85%).
[0137] .sup.1H NMR (300 MHz, CDCl.sub.3): .delta. 0.25 (s, 12H),
0.59 (s, 6H), 1.01 (s, 18H), 6.92-6.98 (d, 4H, m), 8.36 (d, 2H,
J=8.1 Hz)
[0138] .sup.13C NMR (75 MHz, CDCl.sub.3): .delta. 4.4, 1.6, 18.2,
25.8, 121.1, 123.7, 132.5, 134.6, 143.6, 158.6, 185.9
[0139] LRMS (ESI+): m/z Found 145, calculated 145 for [M+H]+
(e) Synthesis of Compound Represented by the General Formula (I)
(General Procedure)
[0140] A bromobenzene derivative (1.0 mmol) and anhydrous THF (5
mL) were put into a sufficiently dried flask inside of which was
substituted with argon. The mixture was cooled to -78.degree. C.,
and then added with 1 M sec-BuLi (0.5 mmol), and the mixture was
stirred for 20 minutes. The mixture was slowly added with
3,6-diOTBDMS-X-xanthone (0.015 to 0.020 mmol) dissolved in
anhydrous THF (5 mL) at the same temperature, and the mixture was
returned to room temperature. The mixture was stirred at room
temperature for 1 hour, and then added with 2 N HCl (10 mL), and
the mixture was stirred for 20 minutes. The mixture was extracted
with dichloromethane, and the organic layer was washed with brine.
The organic layer was dried over Na.sub.2SO.sub.4, the solvent was
removed, and then the residue was purified by HPLC to obtain a
compound represented by the general formula (I).
(e) 2-Me Ge-TM
[0141] According to the method of (e) mentioned above, the
objective substance was obtained (yield 99%)
[0142] .sup.1H-NMR (300 MHz, D.sub.2O): .delta. 0.42 (s, 6H), 1.80
(s, 3H), 6.11 (dd, 2H, J=2.2, 9.5 Hz), 6.79-6.86 (m, 5H), 7.06-7.26
(m, 4H)
[0143] HRMS (ESI+): m/z Found 391.0755, calculated 391.0753 for
[M+H]+ (0.2 mmu)
Example 8
##STR00025##
[0144] (a) N,N,N',N'-3,6-Tetraallyldiamino-diethyl-Si-xanthone
[0145] Bis(2-bromo-4-N,N-diallylaminophenyl)methane (1.65 g, 3.20
mmol) and anhydrous THF (20 mL) were put into a dried flask inside
of which was substituted with argon. The mixture was cooled to
-78.degree. C., and then added with 1 M sec-BuLi (10 mL, 10 mmol),
and the mixture was stirred for 20 minutes. The mixture was slowly
added with SiEt.sub.2Cl.sub.2 (1.04 mL, 7.02 mmol, Et represents
ethyl group) dissolved in anhydrous THF (5 mL) at the same
temperature, and the mixture was returned to room temperature, and
stirred for 1 hour. The reaction was terminated with 2 N HCl, and
the reaction mixture was neutralized with NaHCO.sub.3. This mixture
was extracted with dichloromethane, the organic layer was washed
with brine, and dried over Na.sub.2SO.sub.4, and then the solvent
was removed. The residue was dissolved in acetone (50 mL), and the
solution was cooled to 0.degree. C. This solution was added
portionwise with KMnO.sub.4 (1.49 g, 9.43 mmol) over 2 hours, and
the mixture was further stirred at the same temperature for 1 hour.
This mixture was added with dichloromethane (50 mL), and the
mixture was filtered through Celite. Then, the solvent was removed,
and the residue was purified by column chromatography (silica gel,
hexane/ethyl acetate (10/1)) to obtain
N,N,N',N'-3,6-tetraallyldiamino-diethyl-Si-xanthone (419 g, 0.917
mmol, yield 29%).
[0146] .sup.1H NMR (300 MHz, CDCl.sub.3): .delta. 0.91 (s, 10H),
4.01-4.02 (m, 8H) 5.17-5.22 (m, 8H), 5.82-5.94 (m, 4H), 6.79-6.84
(m, 4H), 8.35 (d, 2H, J=8.8 Hz)
[0147] .sup.13C NMR (75 MHz, CDCl.sub.8): .delta. 5.56, 7.48, 52.7,
113.3, 115.0, 116.5, 130.9, 131.6, 133.1, 138.3, 149.9, 185.3
[0148] HRMS (ESI+): m/z Found 457.2661, calculated 457.2675 for
[M+H]+ (-1.5 mmu)
(b) 3,6-Diaminodiethyl-Si-xanthone
[0149] Pd(PPh.sub.3).sub.4 (204 mg, 0.176 mmol) and
1,3-dimethylbarbituric acid (1.04 g, 6.67 mmol) were put into a
dried flask inside of which was substituted with argon. The mixture
was added with N,N,N',N'-tetraallyldiamino-diethyl-Si-xanthone (419
mg, 0.917 mmol) dissolved in dichloromethane (30 mL), and the
mixture was stirred at 35.degree. C. for 16 hours. The solvent was
removed, the residue was suspended in saturated aqueous
Na.sub.2CO.sub.3, and the suspension was extracted with
dichloromethane. The organic layer was dried over Na.sub.2SO.sub.4,
the solvent was removed, and then the residue was purified by
column chromatography (silica gel, ethyl acetate/hexane (4/5)) to
obtain 3,6-diamino-diethyl-Si-xanthone (236 mg, 0.796 mmol, yield
87%).
[0150] .sup.1H NMR (300 MHz, CDCl.sub.3): .delta. 0.83-0.95 (m,
10H), 4.10 (s, 4H), 6.76-6.81 (m, 4H), 8.33 (d, 2H, J=7.8 Hz)
[0151] .sup.13C NMR (75 MHz, CDCl.sub.3): .delta. 5.37, 7.38,
116.2, 117.5, 132.0, 132.9, 138.8, 148.9, 185.5
[0152] HRMS (ESI+): m/z Found 297.1462, calculated 297.1423 for
[M+H]+ (3.9 mmu)
(c) 3,6-Dihydroxy-diethyl-Si-xanthone
[0153] The 3,6-Diamino-diethyl-Si-xanthone mixture (236 mg, 0.796
mmol) was dissolved in methanol/6 N H.sub.2SO.sub.4 (3/4, 35 mL).
The solution was cooled to 0.degree. C., and then slowly added with
NaNO.sub.2 (315 mg, 4.56 mmol) dissolved in 1120 (3 mL), and the
mixture was stirred at the same temperature for 1 hour. The mixture
was slowly added to boiling 1 N H.sub.2SO.sub.4 (50 mL), and the
mixture was further refluxed for 10 minutes, and then cooled on
ice. The reaction mixture was extracted with dichloromethane, and
the organic layer was sufficiently washed with brine. The organic
layer was dried over Na.sub.2SO.sub.4, the solvent was removed, and
then the residue was purified by column chromatography (silica gel,
ethyl acetate/hexane (1/1)) to obtain
3,6-dihydroxy-diethyl-Si-xanthone (74.3 mg, 0.249 mmol, yield
31%).
[0154] .sup.1H NMR (300 MHz, CD.sub.3OD): .delta. 0.83-1.04 (m,
10H), 6.99 (dd, 2H, J=2.2, 8.8 Hz), 7.09 (d, 2H, J=2.9 Hz), 8.31
(d, 2H, J=8.8 Hz)
[0155] .sup.13C NMR (75 MHz, CD.sub.3OD): .delta. 6.07, 7.56,
118.4, 120.0, 133.4, 135.0, 140.9, 162.0, 187.9
[0156] HRMS (ESI+): m/z Found 321.0964, calculated 321.0923 for
[M+Na]+ (4.1 mmu)
(d) 3,6-DiTBDMSO-diethyl-Si-xanthone
[0157] Dihydroxy-diethyl-Si-xanthone (74.3 mg, 0.249 mmol), and
imidazole (326 mg, 4.79 mmol) were dissolved in dichloromethane (20
mL), the solution was slowly added with TBDMSCl (715 mg, 4.74 mmol)
dissolved in dichloromethane (5 mL), and the mixture was stirred at
room temperature for 14 hours. The mixture was added with H.sub.2O,
the mixture was extracted with dichloromethane, and the organic
layer was washed with brine. The organic layer was dried over
Na.sub.2SO.sub.4, the solvent was removed, and then the residue was
purified by column chromatography (silica gel, ethyl acetate/hexane
(1/30)) to obtain 3,6-diTBDMSO-diethyl-Si-xanthone (93.2 mg, 0.177
mmol, yield 71%).
[0158] .sup.1H NMR (300 MHz, CDCl.sub.3): .delta. 0.26 (s, 12H),
0.85-1.02 (m, 28H), 6.98-7.05 (m, 4H), 8.39 (d, 2H, J=8. Hz)
[0159] .sup.13C NMR (75 MHz, CDCl.sub.3): .delta. -4.14, 5.46,
7.45, 18.5, 25.8, 122.1, 123.9, 132.5, 135.8, 139.2, 158.7,
186.3
[0160] HRMS (ESI+): m/z Found 527.2869, calculated 527.2833 for
[M+H]/ (3.6 mmu)
(e) 2-Me DiEtTM
[0161] According to the method of Example 8, the step (e), the
objective substance was obtained (yield 94%).
[0162] .sup.1H NMR (300 MHz, D.sub.2O, CD.sub.3OD): .delta.
0.78-1.00 (m, 10H), 1.94 (s, 3H), 8.26 (dd, 2H, J=2.6, 9.2 Hz)
6.88-6.98 (m, 5H), 7.24-7.39 (m, 3H)
[0163] HRMS (ESI+): m/z Found 373.1621, calculated 373.1624 for
[M+H]+ (-0.3 mmu)
[0164] The optical characteristics of 2-Me TM, 2-Me Ge-TM, and 2-Me
DiEtTM obtained in Example 1, 7, and 8, respectively, are shown in
Table 2 mentioned below. In the table, the items attached with the
letter a were measured in a phosphate buffer (pH 9), and the item
attached with the letter b was measured in a 0.1 M phosphate buffer
containing 1% DMSO.
TABLE-US-00003 TABLE 2 .lamda..sub.abs.sup.a (nm)
.lamda..sub.fl.sup.a (nm) .PHI..sub.fl.sup.a pK.sub.a.sup.b 2-Me TM
582 598 0.42 6.8 2-Me Ge-TM 572 590 0.47 6.7 2-Me DiEtTM 582 601
0.48 6.9
Example 9
Synthesis of 2-COOH TM
##STR00026##
[0166] tert-Butyl 2-bromobenzoate (800 mg, 3.11 mmol) and anhydrous
THF (5 mL) were put into a dried flask inside of which was
substituted with argon. The mixture was cooled to -78.degree. C.,
and then added with 1 M sec-BuLi (2.0 mmol), and the mixture was
stirred for 20 minutes. The mixture was slowly added with
3,6-diOTBDMS-Si-xanthone (40.0 mg, 0.0802 mmol) dissolved in
anhydrous THF (5 mL) at the same temperature, and the mixture was
returned to room temperature. The mixture was stirred at room
temperature for 30 minutes, and then added with 2 N HCl (10 mL),
and the mixture was stirred for 20 minutes. The mixture was
extracted with dichloromethane, and the organic layer was washed
with brine, and dried over Na.sub.2SO.sub.4. The solvent was
removed, then the residue was added with trifluoroacetic acid (TFA,
3 mL), and the mixture was stirred at room temperature for 1 hour.
The solvent was removed, and then the residue was purified by HPLC
to obtain 2-COOH TM (13.6 mg, 0.0358 mmol, yield 45%).
[0167] .sup.1H-NMR (300 MHz, CD.sub.3COCD.sub.3): .delta. 0.56 (s,
3H), 0.64 (s, 3H), 6.76 (dd, 2H J=2.9, 8.8 Hz), 6.83 (d, 2H, J=8.8
Hz), 7.23 (d, 2H J=2.9 Hz), 7.38 (d, 1H, J=7.3 Hz), 7.67 (td, 1H,
J=1.5, 7.3 Hz), 7.80 (td, 1H, J=1.5, 7.3 Hz), 7.94 (dd, 1H, J=1.5,
7.3 Hz)
[0168] .sup.13C-NMR (100 MHz, CD.sub.3COCD.sub.3): .delta. 1.4,
0.2, 91.1, 117.6, 121.1, 125.5, 126.3, 127.0, 129.3, 130.1, 135.1,
136.7, 138.2, 155.3, 157.7, 170.4
[0169] HRMS (ESI+): m/z Found 375.1018, calculated 375.1053 for
[M+H]+ (-3.5 mmu)
Example 10
##STR00027## ##STR00028##
[0170] (a) 4,5-Dichloro-3,6-dihydroxy-Si-xanthone
[0171] 3,6-Dihydroxy-Si-xanthone (81.1 mg, 0.300 mmol) was
dissolved in methanol (5 mL), the solution was slowly added with
0.1 N NaOH (4 mL) in which NaOCl was dissolved at 100 mM, and the
mixture was stirred at room temperature for 1 hour. The reaction
mixture was adjusted to pH 2 by addition of 2 N HCl, and then
extracted with ethyl acetate, and the organic layer was washed with
brine. The organic layer was dried over Na.sub.2SO.sub.4, the
solvent was removed, and then the residue was purified by column
chromatography (silica gel, ethyl acetate/hexane (1/1)) to obtain
4,5-dichloro-3,6-dihydroxy-Si-xanthone (83.8 mg, 0.247 mmol, yield
82%).
[0172] .sup.1H-NMR (400 MHz, CD.sub.3OD): .delta. 0.80 (s, 1H),
7.11 (d, 2H, J=8.8 Hz), 8.27 (d, 2H, J=8.8 Hz)
[0173] .sup.13C-NMR (100 MHz, CD.sub.3OD): .delta. 1.6, 119.0,
127.0, 132.0, 133.8, 141.4, 158.4, 186.0
[0174] HRMS (ESI+): m/z Found 339.0053, calculated 339.0011 for
[M+H]+ (4.2 mmu)
(b) 4,5-Dichloro-3,6-diOTBDMS-Si-xanthone
[0175] 4,5-Dichloro-3,6-dihydroxy-Si-xanthone (69.0 mg, 0.203
mmol), and imidazole (54.5 mg, 0.801 mmol) were dissolved in
dichloromethane (10 mL), the mixture was slowly added with TBDMSCl
(121 mg, 0.803 mmol), and the mixture was stirred overnight at room
temperature. The solvent was removed, and then the residue was
purified by column chromatography (silica gel, dichloromethane) to
obtain 4,5-dichloro-3,6-diOTBDMS-Si-xanthone (109 mg, 0.193 mmol,
yield 95%).
[0176] .sup.1H-NMR (400 MHz, CDCl.sub.3): .delta. 0.30 (s, 12H),
0.81 (s, 6H), 1.06 (s, 18H), 7.06 (d, 2H, J=8.8 Hz), 8.35 (d, 2H,
J=8.8 Hz)
[0177] .sup.13C-NMR (100 MHz, CDCl.sub.3): .delta. 4.3, 2.0, 18.4,
25.6, 121.5, 130.6, 131.0, 134.2, 140.5, 155.1, 184.9
[0178] HRMS (ESI+): m/z Found 567.1731, calculated 567.1740 for
[M+H]+ (-0.9 mmu)
(c) 2-Me DCTM
[0179] 2-Bromotoluene (17.1 mg, 0.100 mmol) and anhydrous THF (2
mL) were put into a dried flask inside of which was substituted
with argon. The mixture was cooled to -78.degree. C., and then
added with 1 M sec-BuLi (0.10 mmol), and the mixture was stirred
for 20 minutes. The mixture was slowly added with
4,5-dichloro-3,6-diOTBDMS-Si-xanthone (11.3 mg, 0.0200 mmol)
dissolved in anhydrous THF (2 mL) at the same temperature, and the
mixture was returned to room temperature. The mixture was stirred
at room temperature for 1 hour, and then added with 2 N HCl (2 mL),
and the mixture was stirred for 20 minutes. The mixture was
extracted with dichloromethane, and the organic layer was washed
with brine. The organic layer was dried over Na.sub.2SO.sub.4, the
solvent was removed, and then the residue was purified by HPLC to
obtain 2-Me DCTM (8.2 mg, 0.020 mmol, yield 99%).
[0180] .sup.1H-NMR (300 MHz, CD.sub.2OD): .delta. 0.87 (s, 3H),
0.87 (s, 3H), 2.04 (s, 3H), 6.57 (d, 2H, J=9.5 Hz), 6.90 (d, 2H,
J=9.5 Hz), 7.10 (d, 2H, J=6.6 Hz), 7.32-7.47 (m, 3H)
[0181] HRMS (ESI+): m/z Found 413.0526, calculated 413.0531 for
[M+H]+ (-0.5 mmu)
(d) 2-COOH DCTM
[0182] tert-Butyl 2-bromobenzoate (129 mg, 0.502 mmol) and
anhydrous THF (5 mL) were put into a dried flask inside of which
was substituted with argon. The mixture was cooled to -78.degree.
C., and then added with 1 M sec-BuLi (0.30 mmol), and the mixture
was stirred for 20 minutes. The mixture was slowly added with
4,5-dichloro-3,6-diOTBDMS-Si-xanthone (11.3 mg, 0.0200 mmol)
dissolved in anhydrous THF (5 mL) at the same temperature, and the
mixture was returned to room temperature. The mixture was stirred
at room temperature for 1 hour, and then added with 2 N HCl (10
mL), and the mixture was stirred for 20 minutes. The mixture was
extracted with dichloromethane, and the organic layer was washed
with brine, and dried over Na.sub.2SO.sub.4. The solvent was
removed, then the residue was added with TFA (5 mL), and the
mixture was stirred at room temperature for 2 hours. The solvent
was removed, and then the residue was purified by HPLC to obtain
2-COOH DCTM (5.7 mg, 0.013 mmol, yield 64%).
[0183] .sup.1H-NMR (400 MHz, CD.sub.3OD): .delta. 0.83 (s, 3H),
0.98 (s, 3H), 6.85 (d, 2H J=8.8 Hz), 6.89 (d, 2H, J=8.8 Hz), 6.98
(d, 1H J=7.8 Hz), 7.51 (td, 1H, J=1.0, 7.6 Hz), 7.60 (td, 1H,
J=1.0, 7.6 Hz), 7.90 (d, 1H, J=7.8 Hz)
[0184] .sup.13C-NMR (100 MHz, CD.sub.2COCD.sub.3): .delta. -0.2,
0.5, 90.0, 119.8, 123.6, 124.3, 126.4, 127.1, 127.8, 129.9, 135.1,
136.2, 136.7, 153.6, 158.3, 171.2
[0185] HRMS (ESI+): m/z Found 443.0241, calculated 443.0273 for
[M+H].sup.+ (-3.2 mmu)
(e) 4,5-Difluoro-3,6-dihydroxy-Si-xanthone
[0186] 3,6-Dihydroxy-Si-xanthone (13.5 mg, 0.050 mmol) was
dissolved in acetonitrile (3 mL), the solution was added with
Selectfluor (registered trade mark, 35.4 mg, 0.1 mmol), and the
mixture was refluxed overnight by heating at 80.degree. C., and
then purified by HPLC to obtain
4,5-difluoro-3,6-dihydroxy-Si-xanthone (4.1 mg, 0.013 mmol, yield
27%).
[0187] .sup.1H-NMR (400 MHz, CD.sub.3OD): .delta. 0.62-0.63 (m,
OH), 7.12 (m, 2H), 8.13 (d, 2H, J=8.8 Hz)
[0188] HRMS (ESI+): m/z, Found 329.0393, calculated 329.0422 for
[M+Na]+ (-2.9 mmu)
(f) 4,5-Difluoro-3,6-diOTBDMS-Si-xanthone
[0189] 4,5-Difluoro-3,6-dihydroxy-Si-xanthone (3.1 mg, 0.010 mmol)
and imidazole (6.8 mg, 0.10 mmol) were dissolved in dichloromethane
(2 mL), the solution was slowly added with TBDMSCl (15.1 mg, 0.10
mmol), and the mixture was stirred overnight at room temperature.
The solvent was removed, and then the residue was purified by
column chromatography (silica gel, dichloromethane) to obtain
4,5-difluoro-3,6-diOTBDMS-Si-xanthone (4.7 mg, 0.088 mmol, yield
88%).
[0190] .sup.1H-NMR (400 MHz, CDCl.sub.3): .delta. 0.25 (s, 12H),
0.64 (s, 6H), 1.02 (s, 18H), 7.09 (t, 2H, J=8.8 Hz), 8.20 (d, 2H,
J=8.8 Hz)
[0191] HRMS (ESI+): m/z Found 535.2380, calculated 535.2332 for
[M+H]+ (4.8 mmu)
(g) 2-Me DFTM
[0192] 2-Bromotoluene (85.5 mg, 0.500 mmol) and anhydrous THF (3
mL) were put into a dried flask inside of which was substituted
with argon. The mixture was cooled to -78.degree. C., and then
added with 1 M sec-BuLi (0.050 mmol), and the mixture was stirred
for 20 minutes. The mixture was slowly added with
4,5-difluoro-3,6-diOTBDMS-Si-xanthone (5.4 mg, 0.010 mmol)
dissolved in anhydrous THF (3 mL) at the same temperature, and the
mixture was returned to room temperature. The mixture was stirred
at room temperature for 1 hour, and then added with 2 N HCl (2 mL),
and the mixture was stirred for 20 minutes. The mixture was
extracted with dichloromethane, and the organic layer was washed
with brine. The organic layer was dried over Na.sub.2SO.sub.4, the
solvent was removed, and then the residue was purified by HPLC to
obtain 2-Me DFTM (3.8 mg, 0.010 mmol, quant.).
[0193] .sup.1H-NMR (300 MHz, D.sub.2O): .delta. 0.60-0.64 (m, 6H),
1.94 (s, 3H), 6.42 (t, 2H, J=9.5 Hz), 6.90 (d, 2H, J=9.5 Hz), 6.95
(d, 1H, J=7.3 Hz), 7.22 (t, 2H, J=7.3 Hz), 7.32 (t, 1H, J=7.3 Hz),
7.44 (d, 1H, J=7.3 Hz)
[0194] HRMS (ESI+): m/z Found 381.11145, calculated 381.1122 for
[M+H]+ (2.3 mmu)
(h) 2-COOH DFTM
[0195] tert-Butyl 2-bromobenzoate (51 mg, 0.20 mmol) and anhydrous
THF (3 mL) were put into a dried flask inside of which was
substituted with argon. The mixture was cooled to -78.degree. C.,
and then added with 1 M sec-BuLi (0.30 mmol), and the mixture was
stirred for 20 minutes. The mixture was slowly added with
4,5-difluoro-3,6-diOTBDMS-Si-xanthone (5.4 mg, 0.010 mmol)
dissolved in anhydrous THF (3 mL) at the same temperature, and the
mixture was returned to room temperature. The mixture was stirred
at room temperature for 1 hour, and then added with 2 N HCl (10
mL), and the mixture was stirred for 20 minutes. The mixture was
extracted with dichloromethane, and the organic layer was washed
with brine, and dried over Na.sub.2SO.sub.4. The solvent was
removed, then the residue was added with TFA (3 mL), and the
mixture was stirred at room temperature for 2 hours. The solvent
was removed, and then the residue was purified by HPLC to obtain
2-COOH DFTM (2.2 mg, 0.054 mmol, yield 54%).
[0196] .sup.1H-NMR (300 MHz, CD.sub.3OD): .delta. 0.68 (s, 3H),
0.79 (s, 3H), 6.66 (d, 2H J=8.8 Hz), 6.87 (t, 2H, J=9.2 Hz), 7.13
(d, 1H J=7.3 Hz), 7.57-7.68 (m, 2H), 7.92 (d, 1, J=8.1 Hz)
[0197] HRMS (ESI+): m/z Found 411.0902, calculated 411.0864 for
[M+H]+ (3.8 mmu)
Example 11
##STR00029##
[0198] (a) 4,5-Dichloro-3,6-dihydroxyxanthone
[0199] 3,6-Dihydroxyxanthone (45.6 mg, 0.200 mmol) was dissolved in
methanol (5 mL), the solution was slowly added with 0.1 N NaOH (45
mL) in which NaOCl was dissolved at 10 mM, and the mixture was
stirred overnight at room temperature. The reaction mixture was
adjusted to pH 2 by addition of 2 N HCl, and then extracted with
ethyl acetate, and the organic layer was washed with brine. The
organic layer was dried over Na.sub.2SO.sub.4, the solvent was
removed, and then the residue was purified by column chromatography
(silica gel, ethyl acetate/hexane (2/1)) to obtain
4,5-dichloro-3,6-dihydroxyxanthone (57.3 mg, 0.193 mmol, yield
96%).
[0200] .sup.1H-NMR (400 MHz, CD.sub.3OD): .delta. 7.02 (d, 2H,
J=8.8 Hz), 8.01 (d, 2H, J=8.8 Hz)
[0201] .sup.13C-NMR (100 MHz, CD.sub.3OD): .delta. 109.2, 114.7,
116.0, 126.4, 154.9, 161.2, 176.7
[0202] HEMS (ESI+): m/z Found 318.9527, calculated 318.9541 for
[M+Na]+ (-1.4 mmu)
(b) 4,5-Dichloro-3,6-diOTBDMS-xanthone
[0203] 4,5-Dichloro-3,6-dihydroxyxanthone (44.6 mg, 0.150 mmol) and
imidazole (40.8 mg, 0.600 mmol) were dissolved in dichloromethane
(10 mL), the solution was slowly added with TBDMSCl (90.4 mg, 0.600
mmol), and the mixture was stirred overnight at room temperature.
The solvent was removed, and then the residue was purified by
column chromatography (silica gel, dichloromethane) to obtain
4,5-dichloro-3,6-diOTBDMS-xanthone (68.2 mg, 0.130 mmol, yield
87%).
[0204] .sup.1H-NMR (400 MHz, CDCl.sub.3): .delta. 0.31 (s, 12H),
1.07 (s, 18H), 6.95 (d, 2H, J=8.8 Hz), 8.12 (d, 2H, J=8.8 Hz)
[0205] .sup.13C-NMR (100 MHz, CDCl.sub.3): .delta. 4.2, 18.4, 25.6,
113.8, 116.7, 117.1, 125.2, 153.5, 157.6, 175.2
[0206] HRMS (ESI+): m/z Found 525.1495, calculated 525.1451 for
[M+H]+ (4.4 mmu)
[0207] The optical characteristics of 2-COOH TM, 2-Me DCTM, 2-COOH
DCTM, 2-Me DFTM, and 2-COOH DFTM obtained in Examples 9 and 10 are
shown in Table 3 mentioned below. The measurement was performed in
a 0.1 M phosphate buffer (pH 9) containing 1% DMSO. pKa was
obtained from the absorbance measured in a phosphate buffer (pH 9)
by single-phase or two-phase curve fitting. The quantum yield was
obtained by using the quantum yield of 2-Me TokyoMagenta (0.42) in
a 0.1 M phosphate buffer (pH 9) as the standard.
TABLE-US-00004 TABLE 3 .lamda..sub.max,abs (nm) Compound pH 3 pH 9
.lamda..sub.max,fl (nm) pKa .PHI..sub.fl 2-Me TM 472 582 598 6.8
0.42 2-Me DCTM 477 595 607 5.2 0.48 2-Me DFTM 485 583 598 5.3 0.57
2-COOH TM 582 598 8.3, 7.6 0.38 2-COOH DCTM 591 607 7.1, 7.0 0.48
2-COOH DFTM 581 596 7.1, 6.9 0.54
Example 12
##STR00030##
[0209] 2-Me TM (10.6 mg, 0.0308 mmol) and diisopropylethylamine
(DIEA, 17.4 .mu.L, 0.0999 mmol) were dissolved in acetonitrile (5
mL), the solution was slowly added with acetic acid bromomethyl
ester (9.8 .mu.L, 0.10 mmol), and the mixture was stirred overnight
at room temperature. The mixture was neutralized by addition of
acetic acid, and then purified by HPLC to obtain 2-Me TMAM (8.9 mg,
0.021 mmol, yield 69%).
[0210] .sup.1H-NMR (300 MHz, CDCl.sub.3): .delta. 0.49 (s, 3H),
0.51 (s, 3H), 2.06 (s, 3H), 2.11 (s, 3H), 5.79 (s, 2H), 6.31 (dd,
1H, J=9.5, 2.2 Hz), 6.89-6.99 (m, 3H), 7.00 (dd, 1H, J=9.5, 2.2
Hz), 7.09 (d, 1H, J=8.1 Hz), 7.30-7.40 (m, 4H)
[0211] HRMS (ESI+): m/z Found 417.1536, calculated 417.1522 for
[M+H]+ (1.4 mmu)
Example 13
##STR00031##
[0212] (a) 2-Me-4-COOH TM
[0213] tert-Butyl 4-bromo-3-methylbenzoate (1.08 g, 3.98 mmol) and
anhydrous THF (20 mL) were put into a dried flask inside of which
was substituted with argon. The mixture was cooled to -78.degree.
C., and then added with 1 M sec-BuLi (4.0 mmol), and the mixture
was stirred for 20 minutes. The mixture was slowly added with
3,6-diOTBDMS-Si-xanthone (200 mg, 0.403 mmol) dissolved in
anhydrous THF (10 mL) at the same temperature, and the mixture was
returned to room temperature. The mixture was stirred at room
temperature for 1 hour, and then added with 2 N HCl (20 mL), and
the mixture was stirred for 20 minutes. The mixture was extracted
with dichloromethane, and the organic layer was washed with brine,
and dried over Na.sub.2SO.sub.4. The solvent was removed, then the
residue was added with TFA (20 mL), and the mixture was stirred at
room temperature for 2 hours. The solvent was removed, and then the
residue was purified by column chromatography (silica gel,
methanol/dichloromethane (1/24)) to obtain 2-Me-4-COOH TM (148 mg,
0.381 mmol, yield 96%).
[0214] .sup.1H-NMR (400 MHz, CD.sub.3COCD.sub.3): .delta. 0.51 (s,
3H), 0.53 (s, 3H), 2.14 (s, 3H), 6.50 (dd, 2H, J=2.4, 9.8 Hz), 6.84
(d, 2H, J=9.8 Hz), 7.11 (d, 2H, J=2.4 Hz), 7.31 (d, 1H, J=7.8 Hz),
8.03 (dd, 1H, J=1.0, 7.8 Hz), 8.05 (s, 1H)
[0215] .sup.13C-NMR (100 MHz, CD.sub.3COCD.sub.3): .delta. -1.5,
-1.3, 19.5, 123.0, 128.0, 130.1, 130.5, 131.4, 132.1, 137.5, 139.2,
145.0, 145.1, 145.3, 156.4, 167.4, 172.2
[0216] HRMS (ESI+): m/z Found 389.1209, calculated 389.1209 for
[M+H]+ (0.0 mmu)
(b) 2-Me TMCOOAM
[0217] 2-Me-4-COOH TM (1.9 mg, 0.0049 mmol) and DIEA (20 mg, 0.15
mmol) were dissolved in acetonitrile (1 mL), the solution was
slowly added with acetic acid bromomethyl ester (25 mg, 0.16 mmol),
and the mixture was stirred overnight at room temperature. The
mixture was neutralized by addition of acetic acid, and then
purified by HPLC to obtain 2-Me TMCOOAM (1.3 mg, 0.0024 mmol, yield
50%).
[0218] .sup.1H-NMR (300 MHz, CD.sub.3CN): .delta. 0.49-0.52 (m,
6H), 2.04 (s, 3H), 2.11 (s, 3H), 5.78 (s, 2H), 5.97 (s, 2H), 6.12
(dd, 1H, J=10.3, 2.2 Hz), 6.77 (d, 1H, J=8.8 Hz), 6.82 (d, 1H,
J=2.2 Hz), 6.85 (d, 1H, J=10.3 Hz), 6.92 (dd, 1H, J=8.8, 2.9 Hz),
7.28 (d, 1H, J=8.1 Hz), 7.41 (d, 1H, J=2.9 Hz), 7.99 (d, 1H, J=8.1
Hz), 8.05 (s, 1H)
[0219] HRMS (ESI+): m/z Found 533.1596, calculated 533.1632 for
[M+H]+ (-3.6 mmu)
Example 14
[0220] A compound in which a hydrophilic functional group was
introduced into the benzene ring was synthesized as follows.
(a) 2-Me TMIDA
##STR00032##
[0222] 2-Me-4-COOH TM (77.6 mg, 0.200 mmol), HATU (114 mg, 0.300
mmol), HOBt.H.sub.2O (45.9 mg, 0.300 mmol), di-tert-butyl
iminodiacetate (490 mg, 2.00 mmol) and DIEA (258 mg, 2.00 mmol)
were dissolved in DMF (20 mL), and the solution was stirred at room
temperature for 3 hours. The solution was added with ethyl acetate
(50 mL), and the organic layer was washed with 2 N HCl, and then
with brine. The organic layer was dried over Na.sub.2SO.sub.4, the
solvent was removed, and then the residue was purified by column
chromatography (silica gel, methanol/dichloromethane (1/24)). The
resultant was added with trifluoroacetic acid (10 mL), and the
mixture was stirred at room temperature for 1 hour. The solvent was
removed, and then the residue was purified by HPLC to obtain 2-Me
TMIDA (58.8 mg, 0.117 mmol, yield 59%).
[0223] .sup.1H-NMR (300 MHz, CD.sub.3COCD.sub.3): .delta. 0.50 (s,
3H), 0.51 (s, 3H), 2.09 (s, 3H), 4.32 (s, 2H), 4.37 (s, 2H), 6.48
(dd, 2H, J=9.5, 2.2 Hz), 6.90 (d, 2H, J=9.5 Hz), 7.09 (d, 2H, J=2.2
Hz), 7.24 (d, 1H, J=7.3 Hz), 7.42 (dd, 1H, J=7.3, 1.5 Hz), 7.45 (d,
1H, J=1.5 Hz)
[0224] .sup.13C-NMR (75 MHz, CD.sub.3COCD.sub.3): .delta. 1.6, 1.3,
19.5, 48.5, 52.4, 123.0, 125.1, 129.5, 130.0, 130.3, 130.7, 136.4,
137.5, 139.4, 142.2, 145.2, 156.7, 170.7, 171.3, 172.1
[0225] HRMS (ESI+): m/z Found 504.1471, calculated 504.1479 for
[M+H]+ (-0.8 mmu)
(b) 2-Me TMIDAAM
##STR00033##
[0227] 2-Me TMIDA (5.0 mg, 0.0099 mmol) and DIEA (3.5 .mu.L, 0.020
mmol) were dissolved in acetonitrile (1 mL), the solution was
slowly added with bromomethyl acetate (3.0 .mu.L, 0.31 mmol), and
the mixture was stirred overnight at room temperature. The mixture
was slowly added with DIEA (3.5 .mu.L, 0.020 mmol) and bromomethyl
acetate (3.0 .mu.L, 0.31 mmol), and the mixture was further stirred
overnight at room temperature. The mixture was neutralized by
addition of acetic acid, and then purified by HPLC to obtain 2-Me
TMIDAAM (1.1 mg, 0.0015 mmol, yield 15%).
[0228] .sup.1H-NMR (300 MHz, CD.sub.3CN): .delta. 0.49-0.52 (m,
6H), 2.01 (s, 3H), 2.04 (s, 3H), 2.05 (s, 3H), 2.09 (s, 3H),
4.28-4.31 (m, 4H), 5.73 (s, 2H), 5.77 (s, 2H), 5.79 (s, 2H), 6.14
(d, 1H, J=10.3, 2.2 Hz), 6.81-6.98 (m, 4H), 7.19 (d, 1H, J=8.1 Hz),
7.33 (d, 1H, J=8.1 Hz), 7.38-7.43 (m, 2H)
[0229] HRMS (ESI+): m/z Found 720.2120, calculated 720.2112 for
[M+H]+ (0.8 mmu).
(c) 2-Me TMIDAIDA
##STR00034##
[0231] 2-Me TMIDA (25.2 mg, 0.0500 mmol), HATU (190 mg, 0.500
mmol), HOBt.H.sub.2O (77 mg, 0.50 mmol), di-tert-butyl
iminodiacetate (245 mg, 1.00 mmol) and DIEA (129 mg, 1.00 mmol)
were dissolved in DMF (5 and the solution was stirred at room
temperature for 8 hours. The solution was added with
dichloromethane (50 mL), and the organic layer was washed with 2 N
HCl, and then with brine. The organic layer was dried over
Na.sub.2SO.sub.4, the solvent was removed, and then the residue was
purified by column chromatography (silica gel,
methanol/dichloromethane (1/24)). The resultant was added with
trifluoroacetic acid (10 mL), and the mixture was stirred at room
temperature for 2 hours. The solvent was removed, and then the
residue was purified by HPLC to obtain 2-Me TMIDAIDA (5.2 mg,
0.0070 mmol, yield 14%).
[0232] .sup.1H-NMR (300 MHz, CD.sub.3OD+NaOD): .delta. 0.45 (s,
3H), 0.46 (s, 3H), 2.10 (s, 3H), 3.80-4.00 (m, 8H), 4.49-4.55 (m,
4H), 6.29 (dd, 2H J=9.5, 2.9 Hz), 6.86 (d, 2H, J=9.5 Hz), 6.89 (d,
1H J=2.9 Hz), 7.19 (d, 1H, J=8.1 Hz), 7.54 (d, 1H, J=8.1 Hz), 7.58
(s, 1H)
[0233] HRMS (ESI+): m/z Found 734.1985, calculated 734.2017 for
[M+H]+ (-3.2 mmu)
(d) 2-Me TMIDAIDAAM
##STR00035##
[0235] 2-Me TMIDAIDA (2.7 mg, 0.0037 mmol) and DIEA (3.6 .mu.L,
0.021 mmol) were dissolved in acetonitrile (3 mL), the solution was
slowly added with bromomethyl acetate (2.0 .mu.L, 0.020 mmol), and
the mixture was stirred overnight at room temperature. The mixture
was further added with DIEA (1.8 .mu.L, 0.010 mmol) and bromomethyl
acetate (1.0 .mu.L, 0.010 mmol), and the mixture was stirred
overnight at room temperature. The mixture was neutralized by
addition of acetic acid, and then the tetra-AM ester compound as a
reaction intermediate was purified by HPLC. The obtained
intermediate (2.1 mg) and DIEA (3.6 .mu.L, 0.020 mmol) were
dissolved in acetonitrile (2 mL), the solution was slowly added
with bromomethyl acetate (1.0 .mu.L, 0.010 mmol), and the mixture
was stirred at room temperature for two days. The mixture was
neutralized by addition of acetic acid, and then purified by HPLC
to obtain 2-Me TMIDAIDAAM (0.8 mg, 0.0007 mmol, yield 20%).
[0236] .sup.1H-NMR (400 MHz, CD.sub.2Cl.sub.2): .delta. 0.38-0.43
(m, 6H), 1.96-2.04 (m, 18H), 3.98 (s, 2H), 4.12 (s, 2H), 4.17 (s,
2H), 4.26 (s, 2H), 4.29 (s, 2H), 4.34 (s, 2H), 5.59 (s, 2H), 5.64
(s, 5.67 (s, 2H), 5.69 (s, 2H), 5.73 (s, 2H), 6.09 (d, 1H, J=9.8
Hz), 6.72 (d, 1H, J=2.0 Hz) 6.82-6.90 (m, 3H), 7.09 (dd, 1H, J=7.8,
2.0 Hz), 7.22 (d, 1H, J=2.4 Hz), 7.30 (d, 1H, J=7.3 Hz), 7.36 (s,
1H)
[0237] HRMS (ESI+): m/z Found 1094.3043, calculated 1094.3074 for
[M+H]+ (-3.1 mmu)
Example 15
[0238] Intracellular retentivity of the compounds introduced with a
functional group having the hydrophilic IDA structure into the
benzene ring was examined. It was demonstrated that the
intracellular retentivity was improved by the introduction of the
IDA structure, and thus imaging for a long period of time could be
enabled (FIG. 13).
INDUSTRIAL APPLICABILITY
[0239] The compounds represented by the general formula (I) and
salts thereof provided by the present invention show significantly
deviated maximal absorption wavelengths of the non-dissociated form
(neutral form) and dissociated form (anion form) compounds thereof,
and provide difference of the wavelengths about twice or more
larger than the difference observed for fluorescein derivatives,
and therefore they are useful as mother nucleus compounds for
preparing a fluorescent probe enabling highly sensitive measurement
of pH, reactive oxygen species, various enzymes, and the like
without depending on the intramolecular photoinduced electron
transfer and control of spiro ring cyclization.
* * * * *