U.S. patent application number 11/130126 was filed with the patent office on 2005-09-22 for 7-substituted camptothecin and camptothecin analogs and methods for producing the same.
This patent application is currently assigned to Research Triangle Insitute. Invention is credited to Manikumar, Govindarajan, Wall, Michael A., Wall, Monroe E., Wani, Mansukh C..
Application Number | 20050209263 11/130126 |
Document ID | / |
Family ID | 33540138 |
Filed Date | 2005-09-22 |
United States Patent
Application |
20050209263 |
Kind Code |
A1 |
Wani, Mansukh C. ; et
al. |
September 22, 2005 |
7-Substituted camptothecin and camptothecin analogs and methods for
producing the same
Abstract
Methods of forming camptothecin compounds which are effective
anti-tumor compounds are disclosed. These compounds inhibit the
enzyme topoisomerase I and may alkylate DNA of the associated
topoisomerase I-DNA cleavable complex.
Inventors: |
Wani, Mansukh C.; (Durham,
NC) ; Manikumar, Govindarajan; (Raleigh, NC) ;
Wall, Monroe E.; (Portland, OR) ; Wall, Michael
A.; (Portland, OR) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
Research Triangle Insitute
Research Triangle Park
NC
|
Family ID: |
33540138 |
Appl. No.: |
11/130126 |
Filed: |
May 17, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11130126 |
May 17, 2005 |
|
|
|
10606795 |
Jun 27, 2003 |
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Current U.S.
Class: |
514/279 ;
514/283; 546/38; 546/51 |
Current CPC
Class: |
C07D 491/22 20130101;
A61P 35/00 20180101 |
Class at
Publication: |
514/279 ;
514/283; 546/051; 546/038 |
International
Class: |
A61K 031/4745; C07D
491/14 |
Claims
What is claimed as new and desired to be secured by Letters Patent
of the United States is:
1. A method for the preparation of 7-substituted camptothecin
compounds of formula (I) or (11): 9where X is H, NH.sub.2, H, F,
Cl, Br, O--C.sub.1-6 alkyl, S-C.sub.1-6alkyl, NH--C.sub.1-6alkyl,
N(C.sub.1-6alkyl).sub.2, or C.sub.1-8 alkyl, or X is
-Z--(CH.sub.2).sub.a--N--(C.sub.1-6 alkyl).sub.2 wherein Z is
selected from the group consisting of O, NH and S, and a is an
integer of 2 or 3, or X is --CH.sub.2NR.sup.2R , where (a) R.sup.2
and R.sup.3 are, independently, hydrogen, C.sub.1-6alkyl, C.sub.3-7
cycloalkyl, C.sub.3-7 cycloalkyl-C.sub.1-6alkyl, C.sub.2-6 alkenyl,
C.sub.1-6 alkoxy-C.sub.1-6 COR.sup.4 where R.sup.4 is hydrogen,
C.sub.1-6 alkyl, C.sub.3-7 cycloalkyl, C.sub.3-7
cycloalkyl-C.sub.1-6 alkyl, C.sub.2-6 alkenyl, C.sub.1-6 alkoxy,
C.sub.1-6 alkoxy-C.sub.1-6 alkyl, or (b) R.sup.2 and R.sup.3 taken
together with the nitrogen atom to which they are attached form a
saturated 3-7 membered heterocyclic ring which may contain a O, S
or NR.sup.5 group, where R.sup.5 is hydrogen, C.sub.1-6 alkyl,
alkyl, aryl, aryl substituted with one or more groups selected from
the group consisting of C.sub.1-6 alkyl, amino, C.sub.1-6
alkylamino, C.sub.1-6 alkoxy, C.sub.1-6 alkoxy-C.sub.1-6 alkyl
C.sub.1-6 alkyl C.sub.1-6 alkoxy, aryl, and aryl substituted with
one or more C.sub.1-6 alkyl, or C.sub.1-6 alkoxy-C.sub.1-6 alkyl
groups; R is C.sub.1-30 alkyl, substituted C.sub.1-30 alkyl,
C.sub.1-30 alkenyl, substituted C.sub.1-30 alkenyl, C.sub.1-30
alkynyl, substituted, C.sub.1-30 alkynyl, C.sub.3-30 cycloalkyl,
substituted C.sub.3-30 cycloalkyl, C.sub.6-18 aryl, substituted
C.sub.6-18 aryl, C.sub.6-18 aryalkyl, (C.sub.1-30 alkyl).sub.3
silyl or (C.sub.1-30 alkyl).sub.3 silyl C.sub.1-30 alkyl, Y is
independently H or F, and n is an integer of 1 or 2, and salts
thereof comprising: i) reacting an ortho amino cyano aromatic
compound of formula (II) or (IV) 10with an organometallic reagent
R-M and ii) condensing a resulting product with a 20(S)tricyclic
ketone of formula (VII) 11
2. The method of claim 1, wherein R-M is selected from the group
consisting of cyclohexylmagnesium halide, allyl magnesium halide,
vinyl magnesium halide, ethyl magnesium halide,
4-fluorophenylmagnesium halide, isopropenyl magnesium halide,
isopropyl magnesium halide, methyl magnesium halide, ethynyl
magnesium halide, cyclopentyl magnesium halide, phenyl magnesium
halide, benzyl magnesium halide, propyl magnesium halide,
1-propynyl magnesium halide, p-tolyl magnesium halide, o-tolyl
magnesium halide, 1-trimethylsilymethyl magnesium halide, hexyl
magnesium halide, 2-thiophenyl magnesium halide,
4-dimethylaminophenyl magnesium halide, 4-chloro 1-butenyl
2-magnesium halide, p-methoxylbenzyl magnesium halide,
methoxymethyl magnesiumhalide, and p-chloro phenylmagnesium halide,
n-butyl magnesium halide, s-butyl magnesium halide, t-butyl
magnesium halide and p-trifluoromethylphenylmagnesium halide.
3. The method of claim 2, wherein said ortho amino cyano aromatic
compound is a compound of formula (III), R-M is n-butyl magnesium
halide, and R.sup.7 is n-butyl.
4. The method of claim 2, wherein said ortho amino cyano aromatic
compound is a compound of formula (III), R-M is benzyl magnesium
halide, and R.sup.7 is benzyl.
5. The method of claim 2, wherein said ortho amino cyano aromatic
compound is a compound of formula (III), R-M is p-tolyl magnesium
halide, and R.sup.7 is p-tolyl.
6. The method of claim 2, wherein said ortho amino cyano aromatic
compound is a compound of formula (III), R-M is 4-fluorophenyl
magnesium halide, and R.sup.7 is 4-fluorophenyl.
7. The method of claim 2, wherein said ortho amino cyano aromatic
compound is a compound of formula (III), R-M is p-chlorophenyl
magnesium halide, and R.sup.7 is p-chlorophenyl.
8. The method of claim 2, wherein said ortho amino cyano aromatic
compound is a compound of formula (III), R-M is
p-trifluoromethylphenyl magnesium halide, and R.sup.7 is
p-trifluoromethylphenyl.
9. The method of claim 2, wherein said ortho amino cyano aromatic
compound is a compound of formula (IV), R-M is n-butyl magnesium
halide, and R.sup.7 is n-butyl.
10. The method of claim 2, wherein said ortho amino cyano aromatic
compound is a compound of formula (IV), R-M is s-butyl magnesium
halide, and R.sup.7 is s-butyl.
11. The method of claim 2, wherein said ortho amino cyano aromatic
compound is a compound of formula (IV), R-M is t-butyl magnesium
halide, and R.sup.7 is t-butyl.
12. A 7-substituted camptothecin compound of formula (I) or (II):
12wherein X is H, NH.sub.2, H, F, Cl, Br, O--C.sub.1-6 alkyl,
S--C.sub.1-6 alkyl, NH--C.sub.1-6 alkyl, N(C.sub.1-6 alkyl).sub.2,
or C.sub.1-8 alkyl, or X is -Z--(CH.sub.2).sub.a--N--(C.sub.1-6
alkyl).sub.2 wherein Z is selected from the group consisting of O,
NH and S, and a is an integer of 2 or 3, or X is
--CH.sub.2NR.sup.2R.sup.3, where (a) R.sup.2 and R.sup.3 are,
independently, hydrogen, C.sub.1-6 alkyl, C.sub.3-7 cycloalkyl,
C.sub.3-7 cycloalkyl-C.sub.1-6 alkyl, C.sub.2-6 alkenyl, C.sub.1-6
alkoxy-C.sub.1-6 COR.sup.4 where R.sup.4 is hydrogen, C.sub.1-6
alkyl, C.sub.3-7 cycloalkyl, C.sub.3-7 cycloalkyl-C.sub.1-6 alkyl,
C.sub.2-6 alkenyl, C.sub.1-6 alkoxy, C.sub.1-6 alkoxy-C.sub.1-6
alkyl, or (b) R.sup.2 and R.sup.3 taken together with the nitrogen
atom to which they are attached form a saturated 3-7 membered
heterocyclic ring which may contain a O, S or NR.sup.5 group, where
R.sup.5 is hydrogen, C.sub.1-6 alkyl, alkyl, aryl, aryl substituted
with one or more groups selected from the group consisting of
C.sub.1-6 alkyl, amino, C.sub.1-6 alkylamino, C.sub.1-6 alkoxy,
C.sub.1-6 alkoxy-C.sub.1-6 alkyl C.sub.1-6 alkyl C.sub.1-6 alkoxy,
aryl, and aryl substituted with one or more C.sub.1-6 alkyl, or
C.sub.1-6 alkoxy-C.sub.1-6 alkyl groups; R is C.sub.1-30 alkyl,
substituted C.sub.1-30 alkyl, C.sub.1-30 alkenyl, substituted
C.sub.1-30 alkenyl, C.sub.1-30 alkynyl, substituted , C.sub.1-30
alkynyl, C.sub.3-30 cycloalkyl, substituted C.sub.3-30 cycloalkyl,
C.sub.6-18 aryl, substituted C.sub.6-18 aryl, C.sub.6-18 aryalkyl,
(C.sub.1-30 alkyl).sub.3 silyl or (C.sub.1-30 alkyl).sub.3 silyl
C.sub.1-30 alkyl, Y is independently H or F, and n is an integer of
1 or 2, and salts thereof.
13. The 7-substituted camptothecin compound of claim 12, wherein R
is selected from the group consisting of cyclohexyl, allyl, vinyl,
4-fluorophenyl, ethynyl, cyclopentyl, phenyl, benzyl, 1-propynyl,
p-tolyl, o-tolyl, 1-trimethylsilymethyl, hexyl, 2-thiophenyl,
4-dimethylaminophenyl, 2-(4-chloro 1-butenyl), p-methoxylbenzyl,
methoxymethyl, p-chloro phenyl, s-butyl, t-butyl, and
p-trifluoromethylphenyl.
14. The 7-substituted camptothecin compound of claim 13, wherein R
is benzyl.
15. The 7-substituted camptothecin compound of claim 13, wherein R
is p-tolyl.
16. The 7-substituted camptothecin compound of claim 13, wherein R
is p-fluorophenyl.
17. The 7-substituted camptothecin compound of claim 13, wherein R
is p-chlorophenyl.
18. The 7-substituted camptothecin compound of claim 13, wherein R
is p-trifluoromethylphenyl.
19. The 7-substituted camptothecin compound of claim 13, wherein R
is s-butyl.
20. The 7-substituted camptothecin compound of claim 13, wherein R
is t-butyl.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to methods of preparing 7-substituted
camptothecin compounds and 7-substituted camptothecin analogs.
Camptothecin (CPT) and CPT analogs have been reported to inhibit
the enzyme topoisomerase I and have in vitro and in vivo anticancer
activity. It has been shown that a large number of substituents can
be placed at C7 of CPT without loss of activity (Redinbo et al.,
Science 279, 1504-1513, 1998).
[0003] 2. Background of the Invention
[0004] Camptothecin (CPT) is a naturally occurring cytotoxic
alkaloid which is known to inhibit the enzyme topoisomerase I and
is a potent anti-tumor agent. Camptothecin compounds have the
general ring structure shown below. 1
[0005] Camptothecin was isolated from the wood and bark of
Camptotheca acuminata by Wall et al. (Wall et al., 1966, J. Am.
Chem. Soc., 88:3888).
[0006] Major synthetic efforts have been directed to derivatizing
the B-ring at C7 to improve cytotoxic and in vivo activity.
[0007] The cytotoxic activity of camptothecin compounds is believed
to arise from the ability of these compounds to inhibit both DNA
and RNA synthesis and to cause reversible fragmentation of DNA in
mammalian cells. Topoisomerase I relaxes both positively and
negatively supercoiled DNA and has been implicated in various DNA
transactions such as replication, transcription and recombination.
The enzyme mechanism is believed to involve a transient breakage of
one of the two DNA strands and the formation of a reversible
covalent topoisomerase I enzyme-DNA complex. Camptothecin
interferes with the DNA breakage-reunion reaction by reversibly
trapping the enzyme-DNA intermediate termed the "cleavable
complex." The cleavable complex assay is a standard test for
determining the potential and in vivo cytotoxic activity of
camptothecin compounds. The high levels of topoisomerase I in
several types of human cancer and the low levels in correspondingly
normal tissue provide the basis for tumor treatment with
biologically active camptothecin analogs.
[0008] U.S. Pat. No. 4,894,456 describes methods of synthesizing
camptothecin compounds which act as inhibitors of topoisomerase I
and are effective in the treatment of leukemia (L-1210). U.S. Pat.
No. 5,225,404 discloses methods of treating colon tumors with
camptothecin compounds.
[0009] Numerous camptothecin compounds and their use as inhibitors
of topoisomerase I are reported by U.S. Pat. No. 5,053,512; U.S.
Pat. No. 4,981,968; U.S. Pat. No. 5,049,668; U.S. Pat. No.
5,106,742; U.S. Pat. No. 5,180,722; U.S. Pat. No. 5,244,903; U.S.
Pat. No. 5,227,380; U.S. Pat. No. 5,122,606; U.S. Pat. No.
5,122,526; and U.S. Pat. No. 5,340,817.
[0010] U.S. Pat. No. 4,943,579 discloses the esterification of the
hydroxyl group at the 20-position of camptothecin to form several
prodrugs. This patent further discloses that the prodrugs are water
soluble and are converted into the parent camptothecin compounds by
hydrolysis.
[0011] Wall et al. U.S. Pat. Nos. 5,646,159 and 5,916,892 disclose
C.sub.20 amino acid esters of CPT compounds.
[0012] Wall et al. U.S. Pat. No. 5,932,588 disclose CPT compounds
bearing a C7 methylene leaving groups at C.sub.7 such as
--CH.sub.2L where L is Cl, Br, I, --OSO.sub.2CH.sub.3,
--OSO.sub.2C.sub.6H.sub.4--CH.sub.3, etc.
[0013] Brangi et al., Cancer Research, 59, 5938-5946 Dec. 1, 1999,
report an investigation of Camptothecin resistance in cancer cells
and report the compound difluoro-10,
11-methylenedioxy-20(S)-camptothecin and several C7-substituted
compounds.
[0014] A need continues to exist, however, for a method of
preparing 7-substituted camptothecin compounds. Refs: Du et al.,
Biorg. and Med. Chem. 10, 103-110 (2002); Dallavalle et al., J.
Med. Chem. 44, 3264-3274 (2001).
[0015] The procedure of Sawada et al., Chem. Pharm. Bull. 39,
2574-2580 (1991) for preparing 7-alkyl compounds gives adequate
yields for C.sub.1-3 alkyl compounds; however, the yields for
C.sub.4, C.sub.5, C.sub.6-alkyl rapidly become poor. We have
discovered a novel way of preparing a large variety of alkyl and
aryl C.sub.7-substituted compounds in excellent yields by the
reaction of an orthoaminobenzonitrile or appropriately substituted
orthoaminobenzonitrile with a large variety of organometallic
reagent which will be described in detail in this application.
SUMMARY OF THE INVENTION
[0016] Accordingly, one object of the present invention is to
provide a method of preparing 7-substituted camptothecin compounds
in excellent yield and which cannot be prepared by Sawada et al.
procedure (Sawada et al., Chem. Pharm. Bull. 39, 2574-2580 (1991))
which will be widely applicable to a large number of
7-substituents.
[0017] Another object of the present invention is to provide
7-substituted camptothecin compounds which cannot be made by the
Sawada et al. procedure which include a variety of 7-substituents
like sec-butyl, tert-butyl, cyclopentyl, p-fluorophenyl, p-tolyl,
p-trifluoromethylphenyl- , etc.
[0018] Another object of this invention is to prepare lipophilic
camptothecin compounds with various substituents at the 7
position.
[0019] Another object of the present invention is to provide a
method of treating leukemia or solid tumors in a mammal in need
thereof by administration of 7-substituted camptothecin
compounds.
[0020] Another object of the present invention is to provide a
method of inhibiting the enzyme topoisomerase I and/or alkylating
DNA of associated DNA-topoisomerase I by contacting a
DNA-topoisomerase I complex with a 7-substituted camptothecin
compound.
[0021] These and other objects of the present invention are made
possible by a synthetic method for the preparation of 7-substituted
camptothecin compounds of formula (I) or (II): 2
[0022] where
[0023] X is H; NH.sub.2; F; Cl; Br; alkyl; O--C.sub.1-16 alkyl;
NH--C.sub.1-6 alkyl; N(C.sub.1-6 alkyl).sub.2; or C.sub.1-8
alkyl;
[0024] or X is -Z--(CH.sub.2).sub.a--N--(C.sub.1-6 alkyl).sub.2
wherein Z is selected from the group consisting of O, NH and S, and
a is an integer of 2 or 3;
[0025] or X is --CH.sub.2NR R.sup.3, where (a) R.sup.2 and R.sup.3
are, independently, hydrogen, C.sub.1-6 alkyl, C.sub.3-7
cycloalkyl, C.sub.3-7 cycloalkyl-C.sub.1-6 alkyl, C.sub.2-6
alkenyl, hydroxy-C.sub.1-6 alkyl, C.sub.1-6 alkoxy-C.sub.1-6
COR.sup.4 where R.sup.4 is hydrogen, C.sub.1-6 alkyl,
perhalo-C.sub.1-6 alkyl, C.sub.3-7 cycloalkyl, C.sub.3-7
cycloalkyl-C.sub.1-6 alkyl, C.sub.2-6 alkenyl, hydroxy-C.sub.1-6
alkyl, C.sub.1-6 alkoxy, C.sub.1-6 alkoxy-C.sub.1-6 alkyl, or (b)
R.sup.2 and R.sup.3 taken together with the nitrogen atom to which
they are attached form a saturated 3-7 membered heterocyclic ring
which may contain a O, S or NRs group, where R.sup.5 is hydrogen,
C.sub.1-6 alkyl, alkyl, aryl, aryl substituted with one or more
groups selected from the group consisting of C.sub.1-6 alkyl,
amino, C.sub.1-6 alkylamino, alkyl, C.sub.1-6 alkoxy, C.sub.1-6
alkoxy-C.sub.1-6 alkyl and alkyl, C.sub.1-6 alkoxy, aryl, and aryl
substituted with one or more C.sub.1-6 alkyl, C.sub.1-6 alkyl, or
C-6 alkoxy-C.sub.1-6 alkyl groups;
[0026] R is C.sub.1-30 alkyl, substituted C.sub.1-30 alkyl,
C.sub.1-30 alkenyl, substituted C.sub.1-30 alkenyl, C.sub.1-30
alkynyl, substituted, C.sub.1-30 alkynyl, C.sub.3-30 cycloalkyl,
substituted C.sub.3-30 cycloalkyl, C.sub.6-18 aryl, substituted
C.sub.6-18 aryl, C.sub.6-18 aryalkyl, (C.sub.1-30 alkyl).sub.3
silyl, (C.sub.1-30 alkyl).sub.3 silyl C.sub.1-30 alkyl,
[0027] Y is independently H or F, and
[0028] n is an integer of 1 or 2,
[0029] and salts thereof comprising:
[0030] i) reacting ortho amino cyano aromatic compound of formula
(III) or (IV) 3
[0031] with an organometallic reagent R-M and
[0032] ii) condensing a resulting product with a 20(S)tricyclic
ketone of formula (VII) 4
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] Unless indicated to the contrary, the term "alkyl" as used
herein means a straight-chain or branched chain alkyl group with
1-30, preferably 1-18 carbon atoms, more preferably 1-8 carbon
atoms, including methyl, ethyl, n-propyl, isopropyl, n-butyl,
isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, n-hexyl,
n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, undecyl,
dodecyl, myristyl, heptadecyl and octadecyl groups. Unless
otherwise indicated, the term "alkyl" also includes C.sub.3-30
cycloalkyl groups such as cyclopropyl, cyclopentyl, cyclohexyl,
cycloheptyl and cyclooctyl groups.
[0034] "Substituted" means substituted with one or more
heteroatom(s) and/or halogens and/or alkyl groups of 1 to 4 carbon
atoms and/or alkenyl and/or alkynyl groups of 2 to 4 carbon atoms
and/or cycloalkyl groups of 3 to 7 carbon atoms and/or aryl groups
of 6 to 12 carbon atoms and/or heteroaryl groups, and in which the
alkyl, alkenyl, alkynyl, cycloalkyl, aryl or heteroaryl group may
be further substituted with one or more heteroatoms. Where their
valency permits, heteroatoms may be substituted either within the
carbon chain or by attachment to it by single or double bonds. For
example, , --CH.sub.2--CH.sub.2--O--CH.sub.3,
CH.sub.3--CH.sub.2--CH.sub.2O--,
--CH.sub.2--CH.sub.2--C(.dbd.O)--NH.sub.- 2,
CH.sub.3--CH.sub.2--C(O)--NH-- and CF.sub.3--CC-- all fall within
this definition.
[0035] Unless indicated to the contrary, the term "aryl" as used
herein means a carbocyclic aromatic ring having 6-18 carbon atoms,
preferably 6-10 carbon atoms in the aromatic ring structure. The
aromatic rings may be substituted by one or more alkyl group,
preferably alkyl groups having 1-10 carbon atoms. A particularly
preferred aryl group is phenyl.
[0036] Unless indicated to the contrary, the term "aralkyl" as used
herein means a straight-chain or branched chain alkyl group as
defined above for the term "alkyl" bonded to an aryl group as
defined above for the term "aryl". Preferred aralkyl groups are
benzyl, phenethyl, etc.
[0037] The present method may be practiced by condensation of an
ortho amino cyano phenyl compound of formula III or IV 5
[0038] where Y is independently H or F and n is an integer of 1 or
2;
[0039] X is H, NH.sub.2, F, Cl, Br, O--C.sub.1-6 alkyl,
S--C.sub.1-6 alkyl, NH--C.sub.1-6 alkyl, N(C.sub.1-6 alkyl).sub.2,
or C.sub.1-8 alkyl,
[0040] or X is -Z--(CH.sub.2).sub.a--N--(C.sub.1-6 alkyl).sub.2
wherein Z is selected from the group consisting of O, NH and S, and
a is an integer of 2 or 3,
[0041] or X is --CH.sub.2NR.sup.2R.sup.3, where (a) R.sup.2 and
R.sup.3 are, independently, hydrogen, C.sub.1-6 alkyl, C.sub.3-7
cycloalkyl, C.sub.3-7 cycloalkyl-C.sub.1-6 alkyl, C.sub.2-6
alkenyl, C.sub.1-6 alkoxy-C.sub.1-6 COR.sup.4 where R.sup.4is
hydrogen, C.sub.1-6 alkyl, C.sub.3-7 cycloalkyl, C.sub.3-7
cycloalkyl-C.sub.1-6 alkyl, C.sub.2-6 alkenyl, C.sub.1-6 alkoxy,
C.sub.1-6 alkoxy-C.sub.1-6 alkyl, or (b) R.sup.2 and R.sup.3 taken
together with the nitrogen atom to which they are attached form a
saturated 3-7 membered heterocyclic ring which may contain a O, S
or NR.sup.5 group, where R.sup.5 is hydrogen, C.sub.1-6 alkyl,
aryl, aryl substituted with one or more groups selected from the
group consisting of C.sub.1-6 alkyl, amino, C.sub.1-6 alkylamino,
perhalo-C.sub.1-6 alkyl, C.sub.1-6 alkoxy, C.sub.1-6
alkoxy-C.sub.1-6 alkyl and is hydrogen, C.sub.1-6 alkyl C.sub.1-6
alkoxy, aryl, and aryl substituted with one or more C.sub.1-6
alkyl, or C.sub.1-6 alkoxy-C.sub.1-6 alkyl groups;
[0042] with an organometallic compound R-M.
[0043] Compounds of formula I and II may be prepared by
conventional methods known to those of ordinary skill in the art,
without undue experimentation. For example, compounds of formula
(I) and (II) may be prepared by oxidation of a monoprotected
diamine, followed by removal of the amine protecting group.
[0044] Non limiting examples of suitable organometallic compounds
are cyclohexylmagnesium halide, allyl magnesium halide, vinyl
magnesium halide, ethyl magnesium halide, 4-fluorophenyl magnesium
halide, isopropenyl magnesium halide, isopropyl magnesium halide,
methyl magnesium halide, ethynyl magnesium halide, cyclopentyl
magnesium halide, phenyl magnesium halide, benzyl magnesium halide,
propyl magnesium halide, 1-propynyl magnesium halide, p-tolyl
magnesium halide, o-tolyl magnesium halide, 1-trimethylsilymethyl
magnesium halide, hexyl magnesium halide, 2-thiophenyl magnesium
halide, 4-dimethylaminophenyl magnesium halide, 4-chloro 1-butenyl
2-magnesium halide, p-methoxylbenzyl magnesium halide,
methoxymethyl magnesiumhalide, p-trifluoromethylphenyl magnesium
halide, and p-chloro phenylmagnesium halide. These organometallic
reagents may be prepared by conventional methods known to those of
ordinary skill in the art without undue experimentation.
[0045] The reaction of the organometallic reagent compound with the
compound of formula I or formula II, may be accelerated by the
addition of a catalyst. Suitable catalysts include, but are not
limited to, CuBr, CuCl, or CuI.
[0046] The reaction of the organometallic reagent compound with the
compound of formula I or formula II, may be conducted in an organic
solvent. The most common solvents used are ethers, preferably
tetrahydrofuran, diethyl ether or the like.
[0047] The reaction may be conducted at from 0-70.degree. C.,
preferably in refluxing tetrahydrofuran.
[0048] The product of condensation of organometallic reagent
compound with the compound of formula III or formula IV, is an
o-amino ketone of structure V or VI 6
[0049] The product o-amino ketone may be isolated and purified or
reacted directly with the tricyclic ketone (VII) as described
below. Condensation with a tricyclic ketone of formula VII yields
the 7-substituted camptothecin. 7
[0050] Tricyclic ketone of formula VII may be prepared by
conventional methods known to those of ordinary skill in the art,
such as that described by Wall et al. U.S. Pat. No. 5,122,526, the
relevant portions of which are hereby incorporated by
reference.
[0051] The condensation with tricyclic ketone (VII) is typically
conducted under acid catalyzed conditions. The dehydration is
preferably performed to help drive the condensation reaction.
[0052] Condensation of tricylic ketone (VII) with the aminoketone V
or VI may be in a suitable organic solvent such as toluene,
benzene, xylene or the like.
[0053] The Friedlander reaction of the orthoaminoketone and the
tricycloketone may be conducted preferably in refluxing
toluene.
[0054] Camptothecin compounds have an asymmetric carbon atom at the
20-position making two enantiomeric forms, i.e., the (R) and the
(S) configurations, possible. This invention includes both
enantiomeric forms and any combinations or mixtures of these forms.
The invention also includes other forms of the camptothecin
compounds including solvates, hydrates, polymorphs, salts, etc.
Particularly preferred compounds are camptothecin derivatives
having the (S) configuration at the 20-position.
[0055] Throughout the present application many CPT compounds have
been defined with a substituent X as shown in structure I or II
where X is defined and many substituents are shown. With the
exception of the simple substituents where R is C.sub.1-5 alkyl
(which can be prepared by the method of Sawada et al. (Chem. Pharm.
Bull. 39, 2574-2580 (1999))), the other compounds recited herein
can not be made by conventional methods, but require, to the best
of the inventors' knowledge, the use of the method of the present
invention. Using the method of Sawada et al, the yield of alkyl
became progressively lower essentially terminating where R is
C.sub.5 alkyl. All other R substituents shown herein can be made
only by the present method involving Grignard reactions, especially
analogs like 7-t-butyl-10,11-methylenedioxy-CPT,
7-trimethylsilymethyl-10,11-meth- ylenedioxy-CPT,
7-naphthylmethyl-10,11-methylenedioxy-CPT,
7-p-fluorophenyl-10,11-methylenedioxy-CPT,
7-p-trifluoromethyl-10,11-meth- ylenedioxy-CPT, and
7-p-tolyl-10,11-methylenedioxy-CPT. A number of compounds made by
this method have shown unusual properties. For example, Table 1
gives the methylene chloride solubility of a number of compounds
which are made by the methods described by this patent. For
example,7-butyl-10-aminocamptothecin made by this procedure is
remarkably lipophilic. 10-Aminocamptothecin has a solubility of
.sub.--0.2 mg/ml. However, 7-n-butyl-10-aminocamptothecin has a
solubility of 140 mg/mL in methylenechloride, unexpectedly making
this compound the most lipophilic camptothecin known. It has been
found by several groups that lipophilic substituents at the 7
position have excellent activity in the inhibition of topoisomerase
I and in in vitro and in vivo cancer therapy.
1TABLE 1 Sobulity in CH.sub.2Cl.sub.2 Compound Solubility (mg/ml)
9-Methyl-CPT 0.1 mg/ml 10-Amino-CPT 0.2 mg/ml 10,11-ED-CPT 0.2
mg/ml Camptothecin 0.6 mg/ml 9-Amino-10,11-MD-CPT <0.02 mg/ml
9-Amino-CPT <0.03 mg/ml 10-OH-CPT <0.04 mg/ml
7-Butyl-10-OH-CPT <0.05 mg/ml 10,11-MD-CPT <0.008 mg/ml
7-Butyl-9-methyl-CPT 0.18 mg/ml 9-Nitro-10,11-MD-CPT 0.25 mg/ml
7-Benzyl-10,11-CPT 1.8 mg/ml 7-Benzyl-10,11-MD-CPT 1.8 mg/ml
7-Butyl-10-methoxy-CPT 2 mg/ml 7-p-Fluorophenyl-10,11-MD-CPT 2.55
mg/ml 10-Methoxy-CPT 3 mg/ml 7-p-Tolyl-10,11-MD-CPT 4.6 mg/ml
7-p-Chlorophenyl-10,11-MD-- CPT 6.3 mg/ml 7-Butyl-10,11-ED-CPT 7
mg/ml 7-Butyl-10,11-MD-CPT 8.5 mg/ml 7-Butyl-CPT 20 mg/ml
7-(sec)Butyl-CPT 33 mg/ml 7-Butyl-10-Amino-CPT 145 mg/ml
[0056] References for the increase in cytotoxic potency: Dallavale
et al. Novel Cytotoxic 7-Aminomethyl and 7-Aminomethyl Derivatives
of Camptothecin, Biorg. & Med. Chem. Lett. 11, 291-294 (2001),
Bom et al. Novel A, B, E-Ring Modified Camptothecins Displaying
High Lipophilicity and Markedly Improved Blood Stability, J. Med.
Chem. 42, 30i8-3022 (1999), Bom et al., Novel Silotecan
7-Tertbutyldimethylsilyl-10-hydroxyca- mptothecin Displays High
Lipophilicity, Improved Human Blood Stability, and Potent
Anticancer Activity, J. Med. Chem. 43, 3970-3980 (2000).
[0057] We have utilized a standard method for ascertaining the
lipophilicity of a number of camptothecin analogs. This involves
the solubility in methylene chloride. This solvent is an excellent
solvent for fat-soluble compounds. As can be noted with only one
exception, compounds with the 7-butyl substituent are considerably
more soluble than those without this constituent. Thus camptothecin
is soluble only to the extent of 0.6 mg/ml whereas
7-butyl-camptothecin has a solubility of 20 mg/ml.
10-Amino-camptothecin is soluble only to the extent of 0.2 mg/ml.
Very unexpectedly, 7-butyl-10-amino-camptothecin is very soluble at
145 mg/ml. It is also conceivable that camptothecin analogs with
7-pentyl or 7-hexyl substituents or 7-cyclopentyl or 7-cyclohexyl
substituents will have increased solubility.
[0058] Another compound with special properties is
7-p-fluorophenyl-10,11-- methylenedioxycamptothecin with an
IC.sub.50 of 0.692. In contrast, 10,11-methylenedioxy-CPT has an
IC.sub.50 of 1.24. The
7-p-fluorophenyl-10,11-methylenedioxycamptothecin is the most
cytotoxic compound that has ever been made.
[0059] Within the scope of the present invention, the lactone ring
of the camptothecin compounds shown above may be opened by alkali
metal or alkaline earth metal bases (MOH) for example, sodium
hydroxide or calcium hydroxide to form alkali metal or alkaline
earth metal salts of the open ring salt form of the camptothecin
compounds, illustrated for example only for the alkylenedioxy
compound. 8
[0060] Open ring compounds generally have better solubility in
water. The group M may also be any pharmaceutically acceptable
cation, obtained either directly by ring opening or by cation
exchange of a ring open salt. Suitable groups M include Li.sup.+,
Na.sup.+, K.sup.+ and Mg.sup.+2.
[0061] The C.sub.20 OH CPT compounds of the present invention may
be prepared by conventional methods known to those of ordinary
skill in the art, such as that described by Wall et al. U.S. Pat.
No. 5,122,526, the relevant portions of which are hereby
incorporated by reference.
[0062] Esterification with an amino acid at C.sub.20 is possible by
conventional methods known to those of ordinary skill in the art.
Suitable esters formed at C.sub.20 are those described in U.S. Pat.
No. 6,268,375, the relevant portions of which are hereby
incorporated by reference. Substitution at C.sub.9 with groups such
a nitro and amino is also possible in a manner analogous to that
described in the literature.
[0063] The compounds of the invention having the group --CH.sub.2-L
at C.sub.9 are prepared from known 20(S)--CPT compounds bearing a
halogen, for example, a bromine atom, at the C.sub.9 position. The
halogen atom can be readily converted into the corresponding cyano
analog by reaction with CuCN, followed by hydrolysis to form the
corresponding carboxy analog. The carboxy analog is reduced to the
corresponding hydroxy methyl analog which can be reacted with
Ph.sub.3P-CCl.sub.4 to provide the corresponding chloromethyl
analog. The chloromethyl analog can be readily converted to the
bromomethyl and iodomethyl analogs using LiBr or LiI. The remaining
compounds of the invention are prepared from these compounds by
reaction with the corresponding acid chloride, sulfonyl chloride,
etc. These reactions are well known to one having ordinary skill in
this art.
[0064] Compounds in which L is Br or I are readily prepared from
the compound in which L is Cl by simple halide exchange employing
LiBr or LiI in dimethylformamide (DMF) solution (Larock, R. C.,
Comprehensive Organic Transformations, VCH Publishers, Inc., p.
337, N.Y. 1989).
[0065] C.sub.20 esters may be prepared by esterifying the
20-position hydroxyl group of a camptothecin compound to form an
ester containing a water-soluble moiety. Generally, the
camptothecin compound is initially suspended in methylene chloride
or other inert solvent, stirred and cooled. To the cooled mixture
is added one equivalent of an acid having the formula
HOOC--CH.sub.2--CH.sub.2--NR.sup.8R.sup.9, where R.sup.8 and
R.sup.9 are independently, hydrogen, C.sub.1-8 alkyl,
C(O)--(CH.sub.2).sub.m--NR.sup.10R.sup.11, where m is an integer
from 1 to 6, or --C(O)CHR.sup.12NR.sup.13R.sup.14, where R.sup.12
is the side chain of one of the naturally occurring .alpha.-amino
acids and R.sup.10, R.sup.11, R.sup.13 and R.sup.14 are each
independently hydrogen or C.sub.1-8 alkyl. Suitable side chains
R.sup.12 are the side chains of the amino acids glycine,
.alpha.-alanine, .beta.-alanine, valine, leucine, isoleucine,
phenylalanine, tyrosine, tryptophan, leucine, arginine, histidine,
aspartate, glutamate, asparagine, glutamine, cysteine and
methionine. A particularly useful ester can be prepared from the
peptide .beta.-alanine-lysine which forms a very water-soluble
dihydrochloride Salt. One equivalent of dicyclohexylcarbodiimide
(DCC) and a catalytic amount of an amine base, preferably a
secondary or tertiary amine, are also added to the mixture, which
is then stirred to complete the reaction. Any precipitate which
forms is removed by filtration and the product is isolated after
removal of the solvent.
[0066] The free amine(s) may be converted to an acid addition salt
by the addition of a pharmaceutically acceptable acid. Suitable
acids include both inorganic and organic acids. Suitable addition
salts include, but are not limited to hydrochloride, sulfate,
phosphate, diphosphate, hydrobromide, nitrate, acetate, malate,
maleate, fumarate, tartrate, succinate, citrate, lactate,
methanesulfonate, p-toluenesulfonate, palmoate, salicylate and
stearate salts. The salts may be purified by crystallization from a
suitable solvent.
[0067] The camptothecin compounds are administered in a dose which
is effective to inhibit the growth of tumors. As used herein, an
effective amount of the camptothecin compounds is intended to mean
an amount of the compound that will inhibit the growth of tumors,
that is, reduce the site of growing tumors relative to a control in
which the tumor is not treated with the camptothecin compound.
These effective amounts are generally from about 1-60 mg/kg of body
weight per week, preferably about 2-20 mg/kg per week.
[0068] The compounds of the present invention may be administered
as a pharmaceutical composition containing the camptothecin
compound and a pharmaceutically acceptable carrier or diluent. The
active materials can also be mixed with other active materials
which do not impair the desired action and/or supplement the
desired action. The active materials according to the present
invention can be administered by any route, for example, orally,
parenterally, intravenously, intradermally, subcutaneously, or
topically, in liquid or solid form.
[0069] For the purposes of parenteral therapeutic administration,
the active ingredient may be incorporated into a solution or
suspension. The solutions or suspensions may also include the
following components: a sterile diluent such as water for
injection, saline solution, fixed oils, polyethylene glycols,
glycerine, propylene glycol or other synthetic solvents;
antibacterial agents such as benzyl alcohol or methyl parabens;
antioxidants such as ascorbic acid or sodium bisulfite; chelating
agents such as ethylenediaminetetraacetic acid; buffers such as
acetates, citrates or phosphates and agents for the adjustment of
tonicity such as sodium chloride or dextrose. The parenteral
preparation can be enclosed in ampoules, disposable syringes or
multiple dose vials made of glass or plastic.
[0070] Another mode of administration of the compounds of this
invention is oral. Oral compositions will generally include an
inert diluent or an edible carrier. For the purpose of oral
therapeutic administration, the aforesaid compounds may be
incorporated with excipients and used in the form of tablets,
gelatine capsules, troches, capsules, elixirs, suspensions, syrups,
wafers, chewing gums and the like. Compositions may be prepared
according to any method known to the art for the manufacture of
pharmaceutical compositions and such compositions may contain one
or more agents selected from the group consisting of sweetening
agents, flavoring agents, coloring agents and preserving agents.
Tablets containing the active ingredient in admixture with nontoxic
pharmaceutically acceptable excipients which are suitable for
manufacture of tablets are acceptable. These excipients may be, for
example, inert diluents, such as calcium carbonate, sodium
carbonate, lactose, calcium phosphate or sodium phosphate
granulating and disintegrating agents, such as maize starch, or
alginic acid; binding agents, such as starch, gelatin or acacia;
and lubricating agents, such as magnesium stearate, stearic acid or
talc. Tablets may be uncoated or may be coated by known techniques
to delay disintegration and adsorption in the gastrointestinal
tract and thereby provide a sustained action over a longer period.
For example, a time delay material such as glyceryl monostearate or
glyceryl distearate alone or with a wax may be employed.
Formulations for oral use may also be presented as hard gelatin
capsules wherein the active ingredient is mixed with an inert solid
diluent, for example calcium carbonate, calcium phosphate or
kaolin, or as soft gelatin capsules wherein the active ingredient
is mixed with water or an oil medium, such as peanut oil, liquid
paraffin or olive oil.
[0071] The tablets, pills, capsules, troches and the like may
contain the following ingredients: a binder such as
microcrystalline cellulose, gum tragacanth or gelatin; an excipient
such as starch or lactose, a disintegrating agent such as alginic
acid, Primogel, corn starch and the like; a lubricant such as
magnesium stearate or Sterotes; a glidant such as colloidal silicon
dioxide; and a sweetening agent such as sucrose or saccharin or
flavoring agent such as peppermint, methyl salicylate, or orange
flavoring may be added. When the dosage unit form is a capsule, it
may contain, in addition to material of the above type, a liquid
carrier such as a fatty oil. Other dosage unit forms may contain
other various materials which modify the physical form of the
dosage unit, for example, as coatings. Thus tablets or pills may be
coated with sugar, shellac, or other enteric coating agents. A
syrup may contain, in addition to the active compounds, sucrose as
a sweetening agent and certain preservatives, dyes and colorings
and flavors. Materials used in preparing these various compositions
should be pharmaceutically or veterinarially pure and non-toxic in
the amounts used.
[0072] Aqueous suspensions of the invention contain the active
materials in admixture with excipients suitable for the manufacture
of aqueous suspensions. Such excipients include a suspending agent,
such as sodium carboxymethylcellulose, methylcellulose,
hydroxypropylethyl cellulose, sodium alginate,
polyvinylpyrrolidone, gum tragacanth and gum acacia, and dispersing
or wetting agents such as a naturally occurring phosphatide (e.g.,
lecithin), a condensation product of an alkylene oxide with a fatty
acid (e.g., polyoxyethylene stearate), a condensation product of
ethylene oxide with a long chain aliphatic alcohol (e.g.,
heptadecaethylene oxycetanol), a condensation product of ethylene
oxide with a partial ester derived from a fatty acid and a hexitol
(e.g., polyoxyethylene sorbitol mono-oleate), or a condensation
product of ethylene oxide with a partial ester derived from fatty
acid and a hexitol anhydride (e.g., polyoxyethylene sorbitan
mono-oleate). The aqueous suspension may also contain one or more
preservatives such as ethyl or n-propyl p-hydroxybenzoate, one or
more coloring agents, one or more flavoring agents and one or more
sweetening agents, such as sucrose, aspartame, saccharin, or
sucralose.
[0073] Oil suspensions may be formulated by suspending the active
ingredient in a vegetable oil, such as arachis oil, olive oil,
sesame oil or coconut oil, or in a mineral oil such as liquid
paraffin. The oil suspensions may contain a thickening agent, such
as beeswax, hard paraffin or cetyl alcohol. Sweetening agents may
be added to provide a palatable oral preparation. These
compositions may be preserved by the addition of an antioxidant
such as ascorbic acid.
[0074] Dispersible powders and granules of the invention suitable
for preparation of an aqueous suspension by the addition of water
may be formulated from the active ingredients in admixture with a
dispersing, suspending and/or wetting agent, and one or more
preservatives. Suitable dispersing or wetting agents and suspending
agents are exemplified by those disclosed above. Additional
excipients, for example sweetening, flavoring and coloring agents,
may also be present.
[0075] The pharmaceutical composition of the invention may also be
in the form of oil-in-water emulsions. The oily phase may be a
vegetable oil, such as olive oil or arachis oil, a mineral oil,
such as liquid paraffin, or a mixture of these. Suitable emulsifyng
agents include naturally occurring gums, such as gum acacia and gum
tragacanth, naturally occurring phosphatides, such as soybean
lecithin, esters or partial esters derived from fatty acids and
hexitol anhydrides, such as sorbitan mono-oleate, and condensation
products of these partial esters with ethylene oxide, such as
polyoxyethylene sorbitan mono-oleate. The emulsion may also contain
sweetening and flavoring agents.
[0076] Syrups and elixirs may be formulated with sweetening agents,
such as glycerol, sorbitol or sucrose. Such formulations may also
contain a demulcent, a preservative, a flavoring or a coloring
agent.
[0077] The pharmaceutical compositions of the invention may be in
the form of a sterile injectable preparation, such as a sterile
injectable aqueous or oleaginous suspension. This suspension may be
formulated according to the known art using those suitable
dispersing or wetting agents and suspending agents which have been
mentioned above. The sterile injectable preparation may also be a
sterile injectable solution or suspension in a nontoxic
parenterally acceptable diluent or solvent, such as a solution of
1,3-butanediol. Among the acceptable vehicles and solvents that may
be employed are water and Ringer's solution, an isotonic sodium
chloride. In addition, sterile fixed oils may conventionally be
employed as a solvent or suspending medium. For this purpose any
bland fixed oil may be employed including synthetic mono- or
diglycerides. In addition, fatty acids such as oleic acid may
likewise be used in the preparation of injectables. Sterilization
may be performed by conventional methods known to those of ordinary
skill in the art such as by aseptic filtration, irradiation or
terminal sterilization (e.g. autoclaving).
[0078] Aqueous formulations (i.e., oil-in-water emulsions, syrups,
elixirs and injectable preparations) may be formulated to achieve
the pH of optimum stability. The determination of the optimum pH
may be performed by conventional methods known to those of ordinary
skill in the art. Suitable buffers may also be used to maintain the
pH of the formulation.
[0079] The compounds of this invention may also be administered in
the form of suppositories for rectal administration of the drug.
These compositions can be prepared by mixing the drug with a
suitable nonirritating excipient which is solid at ordinary
temperatures but liquid at the rectal temperatures and will
therefore melt in the rectum to release the drug. Non-limiting
examples of such materials are cocoa butter and polyethylene
glycols.
[0080] They may also be administered by intranasal, intraocular,
intravaginal, and intrarectal routes including suppositories,
insufflation, powders and aerosol formulations.
[0081] The compounds of the present invention may also be
administered in the form of liposome or microvesicle preparations.
Liposomes are microvesicles which encapsulate a liquid within lipid
or polymeric membranes. Liposomes and methods of preparing
liposomes are known and are described, for example, in U.S. Pat.
No. 4,452,747, U.S. Pat. No. 4,448,765, U.S. Pat. No. 4,837,028,
U.S. Pat. No. 4,721,612, U.S. Pat. No. 4,594,241, U.S. Pat. No.
4,302,459 and U.S. Pat. No. 4,186,183. The disclosures of these
U.S. patents are incorporated herein by reference. Suitable
liposome preparations for use in the present invention are also
described in WO-9318749-A1, J-02056431-A and EP-276783-A.
[0082] The camptothecin compounds may be used individually to
inhibit the growth of tumors. Alternatively, combinations of two or
more camptothecin compounds may be used or combinations of one or
more camptothecin compounds with one or more known anti-tumor
compounds. When a camptothecin compound is combined with a
conventional anti-tumor compound, the camptothecin compound will
generally be present in an amount ranging from about 1-99 wt. %,
preferably, 5-95 wt. % of the combined amount of camptothecin and
conventional anti-tumor compound. The pharmaceutical compositions
noted above may contain these combinations of compounds together
with an acceptable carrier or diluent.
[0083] The ester compounds of the invention may be administered to
treat leukemia and solid tumors in mammals, including humans. The
esters of the present invention are prodrugs which are hydrolyzed
to camptothecin compounds demonstrating inhibitory activity on
topoisomerase I. The camptothecin compounds formed by hydrolysis of
the esters of the invention are also effective in treating leukemia
and solid tumors in mammals. Numerous camptothecin compounds have
been shown to be effective against leukemia using the standard
L1210 leukemia assay (Wall et al. (1993), Journal of Medicinal
Chemistry, 36:2689-2700). High activity of camptothecin and
camptothecin analogs has also been shown in the P388 leukemia assay
(Wall (1983), Medical and Pediatric Oncology, 11:480A-489A). The
latter reference also provides a correlation between anti-leukemia
activity as determined by the L1210 and the P388 leukemia assays
with efficacy of camptothecin compounds against solid tumors.
Compounds reported as active in the leukemia assays also have
demonstrated activity in a number of solid tumors including a colon
xenograft, a lung xenograft, a Walker sarcoma and a breast
xenograft (Wall (1983), Table IV, page 484 A). Recent studies have
confirmed the correlation between topoisomerase I inhibitory
activity and anti-leukemia/anti-tumor activity of camptothecin
compounds (Giovanella et al. (1989), Science, 246: 1046-1048). The
compounds of the present invention are particularly effective in
the treatment of colon, lung, breast and ovary solid tumors, brain
glioma and leukemia. These compounds may also be used to treat
malaria.
[0084] Different aminoketones used were made by following the
general procedure of reacting the nitrile with an appropriate
Grignard reagent and hydrolyzing the product.
EXAMPLE 1
2-Amino-4,5-methylenedioxy-phenylbenzylmethanone
[0085] To a stirred solution of 1.5 g (10.0 mmol) of
2-amino-4,5-methylenedioxy-benzonitrile in THF (40 mL) was added
CuBr (50 mg, 0.34 mmol) and benzylmagnesium chloride (40 mL, 1.0 M
solution in Et.sub.2O). The reaction mixture was refluxed for 12 h.
After cooling to 25.degree. C., H.sub.2O (5 mL) was added followed
by 15% H.sub.2SO.sub.4 (15 mL). After stirring for 14 h, ether (50
mL) was added. Organic layer was separated. Aqueous layer was
extracted with ether (2.times.50 mL). The combined organic layer
was dried and evaporated. Following chromatography (silica gel,
CHCl.sub.3), 1.2 g (52%) of the title compound was obtained. IR
(CHCl.sub.3) 1675 cm.sup.-1 MS m/z 255 (M.sup.+).
EXAMPLE 2
7-Benzyl-10, 11-MD-20(S)-Camptothecin
[0086] A mixture of S-tricyclic ketone (1.0 g, 4.2 mmol),
2-amino-4,5-methylenedioxy-phenylbenzylmethanone (1.1 g, 4.3 mmol)
acetic acid (1 mL), p-TsOH (50 mg) in toluene (100 mL) was refluxed
for 15 h. After removing the solvent, the crude product was
purified by column chromatography (silica gel, CHCl.sub.3) to yield
the product as a cream powder (1.33 g, 66%).sup.1H-NMR
(DMSO-d.sub.6) .delta. 0.89 (t, 3H), 1.91 (m, 2H), 4.62 (s, 2H),
5.22 (s, 2H), 5.41 (s, 2H), 6.10 (s, 2H), 6.50 (s, 1H), 6.90-7.10
(m, 5H), 7.21 (s, 1H), 8.07 (s, 1H), 8.22 (s, 1H); MS: m/z 483
(M+1).sup.+.
EXAMPLE 3
7- Trimethylsilylmethyl-10,11 -MD-20(S)-Camptothecin
[0087] The title compound was prepared following analogous
procedures as described in Examples 1 and 2 and involving the use
of trimethylsilyl magnesium chloride as the Grignard reagent.
.sup.1H-NMR (DMSO-d.sub.6+CDCl.sub.3) .delta. 0.87 (t, 3H), 1.83
(m, 2H), 2.28 (s, 2H), 5.11 (s, 2H), 5.37 (s, 2H), 6.25 (s, 2H),
6.47 (s, 1H), 7.20 (s, 1H), 7.43 (s, 1H), 7.48 (s, 1H). MS m/z 478
(M.sup.+).
EXAMPLE 4
7-t-Butyl-10, 11-MD-20(S)-Camptothecin
[0088] The title compound was prepared following analogous
procedures as described in Examples 1 and 2 and involving the use
of t-butylmagnesium chloride as the Grignard reagent. .sup.1H-NMR
(DMSO-d.sub.6): .delta. 0.88 (t, 3H), 1.77 (s, 9H), 1.91 (m, 2H),
5.40 (s, 2H), 5.55 (s, 2H), 6.25 (s, 2H), 6.50 (s, 1H), 7.22 (s,
1H), 7.44 (s, 1H), 7.56 (s, 1H). MS m/z 448 (M.sup.+).
EXAMPLE 5
7- Benzyl-20(S)-Camptothecin
[0089] The title compound was prepared following analogous
procedures as described in Examples 1 and 2 and involving the use
of benzylmagnesium chloride and orthoamino benzonitrile.
.sup.1H-NMR (DMSO-d.sub.6) .delta. 0.89 (t, 3H), 1.92 (m, 2H), 4.62
(s, 2H), 5.20 (s, 2H), 5.38 (s, 2H), 6.58 (s, 1H), 7.1-7.3 (m, 5H),
7.35 (s, 1H), 7.68 (t, 1H), 7.84 (t, 1H), 8.18 (d, 1H), 8.29 (d,
2H). MS m/z 439 (M+1).sup.+.
EXAMPLE 6
7-Benzyl-10,11 -DFMD-20(S)-Camptothecin
[0090] The title compound was prepared following analogous
procedures as described in Examples 1 and 2 and involving the use
of 2-amino-3,4-difluoromethylenedioxybenzonitrile and
benzylmagnesium chloride. .sup.1H-NMR (DMSO-d.sub.6): .delta. 0.85
(t, 3H), 1.82 (m, 2H), 4.60 (s, 2H), 5.29 (s, 2H), 5.39 (s, 2H),
6.51 (s, 1H), 6.88-7.12 (m, 5H), 8.08 (s, 1H), 8.26 (s, 1H). MS m/z
518 (M.sup.+).
EXAMPLE 7
7 -Benzyl-10-hydroxy-20(S)-Camptothecin
[0091] The title compound was prepared following analogous
procedures as described in Examples 1 and 2 and involving the use
of appropriately protected orthoaminobenzonitrile and
benzylmagnesium chloride. .sup.1H-NMR (DMSO-d.sub.6): .delta. 0.89
(t, 3H), 1.86 (m, 2H), 4.57 (s, 2H), 5.25 (s, 2H), 5.41 (s, 2H),
6.5 (s, 1H), 7.05-7.19 (m, 5H), 7.23 (s, 1H), 7.30 (s, 1H), 7.36
(d, 1H), 7.92 (d, 1H), 10.29 (s, 1H). MS m/z 454 (M.sup.+).
EXAMPLE 8
7-p-Fluorophenyl-10,11-MD-20(S)-Camptothecin
[0092] The title compound was prepared following analogous
procedures as described in Example 1 and 2 and involving the use of
p-fluorophenyl magnesium bromide. .sup.1H-NMR (DMSO-d.sub.6):
.delta. 0.91 (t, 3H), 1.86 (m, 2H), 5.00 (2H), 5.43 (s, 2H), 6.30
(s, 2H), 6.55 (s, 1H), 6.99 (s, 1H), 7.29 (s, 1H), 7.52-7.75 (m,
5H. MS: m/z 486 (M.sup.+).
EXAMPLE 9
7-p-Chlorophenyl-10,11-MD-20(S)-Camptothecin
[0093] The title compound was prepared following analogous
procedures as described in Examples 1 and 2 and involving the use
of p-chlorophenyl magnesium bromide. .sup.1H-NMR (DMSO-d.sub.6):
.delta. 0.93 (t, 3H), 1.89 (m, 2H), 5.08 (s, 2H), 5.46 (s, 2H),
6.33 (s, 2H), 6.55 (s, 1H), 7.05 (s, 1H), 7.34 (s, 1H), 7.67 (s,
1H), 7.71 (d, 2H), 7.79 (d, 2H). MS: m/z 502 (M.sup.+).
EXAMPLE 10
7-p-Tolyl-10,11-MD-20(S)-Camptothecin
[0094] The title compound was prepared following analogous
procedures as described in Examples 1 and 2 and involving the use
of p-tolyl magnesium bromide. .sup.1H-NMR (DMSO-d.sub.6): .delta.
0.85 (t, 3H), 1.82 (m, 2H), 2.45 (s, 3H), 4.94 (s, 2H), 5.39 (s,
2H), 6.24 (s, 2H), 6.49 (s, 1H), 6.97 (s, 1H), 7.24 (s, 1H), 7.44
(m, 4H), 7.83 (s, 1H). MS: m/z 482 (M.sup.+).
EXAMPLE 11
7-Cyclohexyl-10,11-MD-20(S)-Camptothecin
[0095] The title compound was prepared following analogous
procedures as described in Examples 1 and 2 and involving the use
of cyclohexyl magnesium bromide. .sup.1H-NMR
(DMSO-d.sub.6+CDCl.sub.3) .delta. 0.86 (t, 3H), 1.2-1.95 (m, 12H),
2.42 (m, 1H), 5.20 (s, 2H), 5.36 (s, 2H), 6.25 (s, 2H), 6.48 (s,
1H), 7.15 (s, 1H), 7.42 (s, 1H), 7.66 (s, 1H). MS: nm/z 474
(M.sup.+).
EXAMPLE 12
7-n-Hexyl-10,11-MD-20(S)-Camptothecin
[0096] The title compound was prepared following analogous
procedures as described in Examples 1 and 2 and involving the use
of n-hexyl magnesium bromide. .sup.1H-NMR
(DMSO-d.sub.6+CDCl.sub.3): .delta. 0.84-1.89 (m, 15H), 2.63 (m,
2H), 5.19 (s, 2H), 5.34 (s, 2H), 6.26 (s, 2H), 6.49 (s, 1H), 7.16
(s, 1H), 7.39 (s, 1H), 7.68 (s, 1H). MS: m/z 476 (M.sup.+).
EXAMPLE 13
7-p-Trifluoromethylphenyl-10,11-MD-20(S)-Camptothecin
[0097] The title compound was prepared following analogous
procedures as described in Examples 1 and 2 and involving the use
of p-trifluoromethylphenyl magnesium bromide. .sup.1H-NMR
(DMSO-d.sub.6+CDCl.sub.3): .delta. 0.89 (t, 3H) 1.87 (m, 2H), 5.08
(s, 2H), 5.41 (s, 2H), 6.29 (s, 2H), 6.57 (s, 1H), 7.01 (s, 1H),
7.30 (s, 1H), 7.48-8.06 (m, 5H). MS: m/z 536 (M.sup.+).
EXAMPLE 14
7-n-Butyl-10-Amino-20(S)-Camptothecin
[0098] The title compound was prepared following analogous
procedures as described in Examples 1 and 2 and involving the use
of 2,5-diaminobenzonitrile and n-butyl magnesium bromide.
.sup.1H-NMR (DMSO-d.sub.6): .delta. 0.86 (t, 3H), 0.95 (t, 3H),
1.42-1.86 (m, 6H), 2.97 (m, 2H), 5.19 (s, 2H), 5.39 (s, 2H), 5.94
(s, 2H), 6.44 (s, 1H), 7.04 (s, 1H), 7.15 (s, 1H), 7.22 (d, 1H),
7.82 (d, 1H). MS: m/z 419 (M.sup.+).
[0099] Obviously, numerous modifications and variations of the
present invention are possible in light of the above teachings. It
is therefore to be understood that within the scope of the appended
claims, the invention may be practiced otherwise than as
specifically described herein.
* * * * *