U.S. patent application number 11/800341 was filed with the patent office on 2007-12-13 for constrained cis-diol-borate bioconjugation system.
This patent application is currently assigned to Applera Corporation. Invention is credited to Jaime F. Arenas, Ricky F. Baggio, Rouh-Rong Juo, Alison L. Sparks.
Application Number | 20070287825 11/800341 |
Document ID | / |
Family ID | 35463521 |
Filed Date | 2007-12-13 |
United States Patent
Application |
20070287825 |
Kind Code |
A1 |
Baggio; Ricky F. ; et
al. |
December 13, 2007 |
Constrained cis-diol-borate bioconjugation system
Abstract
The invention pertains to bioconjugation systems comprising
sterically constrained cis-diols and borates.
Inventors: |
Baggio; Ricky F.; (Waltham,
MA) ; Sparks; Alison L.; (North Andover, MA) ;
Juo; Rouh-Rong; (Allston, MA) ; Arenas; Jaime F.;
(Lexington, MA) |
Correspondence
Address: |
HAMILTON, BROOK, SMITH & REYNOLDS, P.C.
530 VIRGINIA ROAD
P.O. BOX 9133
CONCORD
MA
01742-9133
US
|
Assignee: |
Applera Corporation
|
Family ID: |
35463521 |
Appl. No.: |
11/800341 |
Filed: |
May 4, 2007 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11126837 |
May 11, 2005 |
|
|
|
11800341 |
May 4, 2007 |
|
|
|
60570313 |
May 12, 2004 |
|
|
|
60578946 |
Jun 10, 2004 |
|
|
|
Current U.S.
Class: |
530/322 ;
530/300; 530/387.1; 530/395; 536/123.1; 536/22.1; 546/112; 548/400;
548/453; 548/526; 549/406; 549/429; 549/433; 554/1; 568/23;
568/700 |
Current CPC
Class: |
B82Y 30/00 20130101;
G01N 33/54353 20130101; Y10S 530/812 20130101; A61K 47/54 20170801;
C07H 21/04 20130101 |
Class at
Publication: |
530/322 ;
530/300; 530/387.1; 530/395; 536/123.1; 536/022.1; 546/112;
548/400; 548/453; 548/526; 549/406; 549/429; 549/433; 554/001;
568/023; 568/700 |
International
Class: |
C07C 321/12 20060101
C07C321/12; C07C 33/18 20060101 C07C033/18; C07C 53/00 20060101
C07C053/00; C07D 209/02 20060101 C07D209/02; C07D 317/70 20060101
C07D317/70; C07D 487/00 20060101 C07D487/00; C07H 21/00 20060101
C07H021/00; C07K 16/00 20060101 C07K016/00; C07K 2/00 20060101
C07K002/00; C08B 37/00 20060101 C08B037/00 |
Claims
1. A sterically constrained cis-diol compound, represented by:
##STR44## wherein: Ring A is an optionally substituted
bicycloalkyl, heterocyclyl or fused bicycloalkyl-heterocyclyl, or
Ring A is an optionally substituted cycloalkyl; R.sup.1 is an
optionally substituted alkyl, alkoxy, alkyl ether, alkyl sulfide,
cycloalkyl, heterocyclyl, aryl, heteroaryl, cycloalkylalkyl,
heterocyclylalkyl, aralkyl, heteroaralkyl, cycloalkylalkyl ether,
heterocyclylalkyl ether, aralkyl ether, heteroaralkyl ether,
cycloalkylalkyl sulfide, heterocyclylalkyl sulfide, aralkyl sulfide
or heteroaralkyl sulfide linking group; R.sup.2a and R.sup.2a' are
independently --OH or --O--PG, wherein PG is an alcohol protecting
group selected from selected from optionally substituted esters,
ethers, silyl ethers and carbonates, or R.sup.2a and R.sup.2a',
taken together with the portion of Ring A connecting them, are a
protected cis-diol group selected from optionally substituted
cyclic acetals, cyclic ketals, and cyclic ortho esters; X is a
bond, --O--, --S--, --C(O)--, --C(O)O--, --S(O)--, --OSO.sub.2--,
--S(O.sub.2)O--, --SO.sub.2--, --NR.sup.3--, --NR.sup.3C(O)--,
--C(O)NR.sup.3C--, --R.sup.3NNR.sup.3SO.sub.2--,
--SO.sub.2NR.sup.3NR.sup.3--, --NR.sup.3SO.sub.2--,
--SO.sub.2NR.sup.3--, --CR.sup.3.sub.2C(O)NR.sup.3--,
--NR.sup.3C(O)CR.sup.3.sub.2, --CR.sup.3.sub.2C(O)--,
--C(O)CR.sup.3.sub.2--, --R.sup.3NNR.sup.3--, --NR.sup.3NR.sup.3--,
--R.sup.3NNR.sup.3.sub.2.sup.+--, --NR.sup.3.sub.2.sup.+NR.sup.3--,
--CR.sup.3.sub.2Ph-, -PhCR.sup.3.sub.2--, --C(NR.sup.3)NR.sup.3--,
--NR.sup.3C(NR.sup.3)--; each R.sup.3 is independently --H, alkyl,
alkoxy, aryloxy or arylalkoxy; and Y is a bioactive molecule and n
is an integer from 1 to 200; or Y is a solid support or a self
assembled monolayer (SAM)-inducing solid support and n is an
integer from 10 to 10.sup.10; or n is 1 and --Y--X together are
--S--, wherein two cis-diols form a disulfide dimer represented by:
##STR45## wherein each variable is independently as defined above;
or n is 1 and --Y--X together are --OH, --SH, halogen, --OR.sup.5,
--C(O)OR.sup.5, --O(O)CR.sup.5, --NR.sup.5R.sup.6, or
--N-heterocyclyl, wherein R.sup.5 and R.sup.6 are independently
optionally substituted alkyl, cycloalkyl, heterocyclyl, aryl,
heteroaryl, cycloalkylalkyl, heterocyclylalkyl, aralkyl, or
heteroaralkyl, provided that the constrained cis-diol is not a
saccharide.
2. The compound of claim 1, wherein Y is the bioactive
molecule.
3. The compound of claim 2, wherein n is 1.
4. The compound of claim 1, wherein Y is a solid support or a self
assembled monolayer (SAM)-inducing solid support and n is an
integer from 10 to 10.sup.10.
5. The compound of claim 4, wherein the solid support or the
SAM-inducing solid support comprises gold, silver, platinum,
aluminum, or copper.
6. The compound of claim 4, wherein the solid support or the
SAM-inducing solid support is in the form of a bead, a microsphere,
nanoparticle, gel, membrane, surface, film, porous matrix, or
interior surface of a microchannel.
7. The compound of claim 4, wherein the solid support is a
nanoparticle comprising cadmium sulfide, cadmium selenide, cadmium
telluride, silicon, or gallium arsenide.
8. The compound of claim 4, wherein the solid support comprises
optionally substituted polyalkylene, polyvinylene, polystyrene,
polyethylene oxide, nitrocellulose, polyvinyl acetate, polyvinyl
chloride, polyvinyl dichloride, polyfluoroalkylene, polyamide,
polydialkylsiloxane, glass, silica, or quartz.
9. The compound of claim 4, wherein Y comprises a conductive layer
for surface plasmon resonance.
10. The compound of claim 3, wherein R.sup.2a and R.sup.2a' are
--OH, or R.sup.2a and R.sup.2a', taken together with the portion of
Ring A connecting them, are a protected cis-diol group selected
from optionally substituted cyclic acetals, cyclic ketals, and
cyclic ortho esters.
11. The compound of claim 10, wherein Y comprises one or more
nucleic acids, polynucleic acids, amino acids, peptides, proteins,
peptide nucleic acids, hormones, cofactors, fatty acids,
carbohydrates, polysaccharides, glycopeptides, glycoproteins;
peptidoglycans; glycolipids, cyclitols, prenols, terpenoids,
steroids, folates, carotenoids, retinoids, tocopherols, lignans,
quinines, isoprenoids, tetrapyrroles, peptide nucleic acids,
lipids, prostaglandins, immunoglobulins, glycolipids, lipoproteins,
neurotransmitters, biometabolites, pharmaceuticals or environmental
toxins.
12. The compound of claim 10, wherein --Y--X together are --S--,
wherein two cis-diols form a disulfide dimer represented by:
##STR46##
13. The compound of claim 10, wherein --Y--X together are --OH,
--SH, halogen, --OR.sup.5, --C(O)OR.sup.5, --O(O)CR.sup.5,
--NR.sup.5R.sup.6 or --N-heterocyclyl.
14. The compound of claim 13, wherein the cis-diol is represented
by: ##STR47##
15. The compound of claim 14, wherein R.sup.1 is C2-C16 alkyl
ether, C1-C16 alkoxy or C1-C16 alkyl.
16. The compound of claim 15, wherein the compound is represented
by: ##STR48##
17. The compound of claim 16, wherein R' is C6-C12 alkyl.
18. The compound of claim 16, wherein R' is C1-C3 alkyl.
19. The compound of claim 18, wherein --X-- is --S--.
20. The compound of claim 19, wherein the compound is:
##STR49##
21. The compound of claim 18, wherein the compound is:
##STR50##
22. The compound of claim 15, wherein the cis-diol is represented
by: ##STR51##
23. The compound of claim 22, wherein the compound is: ##STR52##
Description
RELATED APPLICATIONS
[0001] This application is a Divisional Application of U.S.
application Ser. No. 11/126,837 filed Mar. 11, 2005, which claims
the benefit of U.S. Provisional Application No. 60/570,313, filed
on May 12, 2004 and claims the benefit of U.S. Provisional
Application No. 60/578,946, filed Jun. 10, 2004. The entire
teachings of the above applications are incorporated herein by
reference.
INTRODUCTION
[0002] Various methods of bioconjugation are known in the art for
joining bioactive molecules to other bioactive molecules, assay
tags, sensors, solid supports in an assay system, chromatographic
columns, and the like. Two complementary elements can be reacted to
form a conjugate, e.g., an antibody/antigen, a protein/ligand pair
(e.g., streptavidin/biotin), a polynucleotide and its complementary
sequence, and the like. Certain attributes are typically desirable
for such systems, e.g., conjugation or binding specificity,
conjugation reaction rate, conjugation binding strength,
convenience of the conjugation reaction, chemical compatibility,
and the like. Existing bioconjugation systems, however, typically
make trade-offs among these attributes, e.g., one or two attributes
being strong and the others being weak. These tradeoffs can limit
the applicability of existing bioconjugation systems in various
applications of interest. For example, streptavidin/biotin is a
selective bioconjugation system but has disadvantages including the
size of the streptavidin element (preventing formation of
high-density arrays of bioconjugation sites on a solid support or
interfering with the detection of smaller bioactive molecules), the
sensitivity of the streptavidin element to conditions that can
cause denaturation (e.g., pH extremes or conditions used to couple
the streptavidin to a solid support or bioactive molecule), and an
overall ionic charge of avidin and/or biotin can increase adverse
nonspecific binding.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] The patent or application file contains at least one drawing
executed in color. Copies of this patent or patent application
publication with color drawing(s) will be provided by the Office
upon request and payment of the necessary fee.
[0004] The foregoing and other features and advantages will be
apparent from the following description of various embodiments, as
illustrated in the accompanying drawings in which like reference
characters refer to the same parts throughout the different views.
The drawings are not necessarily to scale, emphasis instead being
placed upon illustrating the principles of the teachings. The
skilled artisan will understand that the drawings, described below,
are for illustration purposes only. The drawings are not intended
to limit the scope of the present teachings in any way.
[0005] FIG. 1 is a schematic of covalent conjugation of
surface-bound pinane diol (bound to poly-D-Lys Plates) with
m-dansylaminophenylboronic acid (DAPB).
[0006] FIG. 2 shows the fluorescence signal and signal-to-noise
ratios in control wells (originally containing the DAPB acid
solution) and wells containing pinane diol (bound to poly-D-Lys
Plates) conjugated to DAPB.
[0007] FIG. 3 shows binding curves for 20 .mu.M DAPB binding to
immobilized constrained diol 14 at concentrations of 25 .mu.M.
[0008] FIG. 4 shows the presence or absence of tris
(2-carboxylethyl) phosphine (TCEP) did not appear to have a
significant effect upon end-point binding. At concentrations of 1
and 5 .mu.M, no binding above background levels was observed.
Beginning at concentrations of 100 .mu.M DAPB, a detrimental effect
upon binding at the higher spotted densities of constrained diol 14
was observed.
[0009] FIGS. 5A and 5B show negative controls (bovine serum
albumin, (BSA) and phosphate buffer saline (PBS) with 1 mM TCEP
that show no DAPB binding.
[0010] FIGS. 6A-C show affinity traces observed for 100 .mu.M
pinanediol acetate binding to immobilized 4-mercaptophenylboronic
acid under various buffer conditions.
[0011] In FIG. 6A, the buffer used was 50 mM sodium acetate, 100 mM
sodium chloride, pH 5.5. In FIG. 6B, the buffer used was phosphate
buffered saline with 0.05% Tween-20, pH 7.4. In FIG. 6C, the buffer
used was sodium carbonate-bicarbonate buffer pH 9.4.
DESCRIPTION OF VARIOUS EMBODIMENTS
[0012] The present teachings relate to the use of boronate esters
formed by covalent bond formation and/or complexation between a
boronic acid and a particular type of constrained cis-diol. The
formation of stable boronate esters from boronic acid:cis-diol
pairs can be used to create a surface for capturing biomolecules
and/or subsequently detecting biomolecular interactions. To
accomplish the preferential capture of biomolecules on a surface,
e.g., a microchip or biochip surface, the surface can be
derivatized with a constrained cis-diol and the biomolecule of
interest can be derivatized with a boronic acid. The converse can
also be employed for biomolecular capture, where the surface is
derivatized with boronic acid and the biomolecule is derivatized
with a constrained cis-diol. The boronate ester complex can also be
used preferentially as a bioconjugation method to unite two
functional groups, such as biological or small molecule moieties,
either intermolecularly or intramolecularly for detection of
function analyses. To accomplish the preferential unification of
two functional groups, the first moiety can be derivatized with a
boronic acid, and the second moiety can be derivatized with a
particular constrained cis-diol. The present invention does not
restrict the boronic acid moiety to phenyl boronic acid or related
analogues. Any alkyl or aromatic boronic acid with a linker arm for
attachment to a surface or a biomolecule can be employed. Also
contemplated are constrained cis-diols with a linker arm for
surface attachment or biomolecule modification.
[0013] The present teachings contemplate the ability to conjugate a
biomolecule with high specificity (e.g., with specificity and
affinity that can be as high as that between biotin and
streptavidin) to either a solid support or to another biomolecule.
Also contemplated are various embodiments where surface
modification with covalently linked cis-diols can produce a neutral
environment because both the borate and the constrained cis-diol
can be small, non-reactive organic molecules, and can also be
amenable to incorporation into peptide, nucleic acid and peptide
nucleic acid synthetic syntheses. Such a surface, lacking either
positive or negative charge, can have distinct chemical properties
for example, it can have low non-specific biomolecule binding to
the large majority of unlabeled proteins and other biomolecules,
which can thereby reduce assay noise. Any boronic acid-labeled
biomolecule can bind to such a surface with high specificity, even
in the presence of unlabeled carrier proteins. Compared to commonly
used streptavidin or avidin surfaces, such cis-diol surfaces can
have a much higher binding capacity and density due to the small
size of the capture molecule.
[0014] Also contemplated are various embodiments where a borate
surface is formed, where, for example, depending upon the pKa of
the immobilized boronic acid, such a surface can exist in either a
neutral or negatively charged state. Such borate-modified surfaces
can exhibit an affinity for cis-diol-labeled biomolecules, as well
as certain carbohydrates (based on polyol geometries).
[0015] The present teaching also contemplates various embodiments
wherein any application involving biotin/streptavidin
bioconjugation can be replaced by bioconjugation with
cis-diols/boronic acids, which can 1) reduce noise due to
non-specific binding of biomolecules, 2) increase load capacity on
a surface, and/or 3) create a neutral or negatively charged surface
as needed in assay design.
[0016] In some embodiments, the present invention provides for
conjugation of a biomolecule with high specificity to either a
solid support or to another biomolecule. The conjugation can
involve very strong interaction (equivalent in terms of specificity
and binding affinity to that of streptavidin:biotin), yet because
both the boronic acid and the constrained cis-diol can be small
(e.g., in various embodiments less than about 5000 daltons, less
than about 2500 daltons, or less than about 1000 daltons),
relatively stable organic molecules, they are highly amenable to
incorporation into bioactive molecules (e.g., peptide and nucleic
acid synthetic syntheses). Also, solid support modification with
cis-diols or boronates can produce a charge-neutral surface, which
can lead to lower non-specific binding of other molecules on the
solid support.
[0017] In some embodiments, the present invention provides for
conjugation of a biomolecule with specificity to either a solid
support or to another biomolecule. In these embodiments, n or n' is
greater than 1 and the boronic acid and/or the constrained cis-diol
can independently be, for example, in various embodiments less than
about 30,000 daltons, less than about 20,000 daltons, or less than
about 10,000 daltons.
[0018] Further, because the cis-diol:boronate can be small
molecules (e.g., compared to streptavidin) this system can have a
much higher binding capacity, due to significantly increased
capture agent density in conjugates per cm.sup.2. In other words,
many more small molecules, such as cis-diols or boronic acids, can
fit per cm.sup.2 compared to biomolecules such as streptavidin or
biotin. Increased binding density enables greater detection
sensitivities, especially in increasingly smaller assay loci, such
as array formats. Such a system can therefore lead to higher assay
signals and can also be expected to be stable and exhibit a long
shelf life.
[0019] By forming a boronic acid surface, certain other advantages
can be realized. For example, depending upon the pKa of the
immobilized boronic acid, such a surface can exist in either a
neutral or negatively charged state under physiological conditions,
and changes in pH can adapt the response of the surface to cis-diol
binding, binding of other polyols, and nonspecific binding of other
molecules.
[0020] Also, the constrained cis-diol:boronate system can have
significantly stronger binding affinities than salicylhydroxamic
acid : phenylboronic acid systems (see, for example, U.S. Pat. Nos.
6,630,577, 6,462,179, 6,124,471, 6,075,126, 6,031,117, 6,013,783,
5,877,297, 5,876,938, 5,872,224, 5,869,623, 5,859,210, 5,847,192,
5,837,878, 5,831,046, 5,777,148, and 5,744,627). The constrained
cis-diol:boronate system, where binding affinities are believed to
be driven by steric factors can produce significantly stronger
binding events with minimal analyte dissociation. The stronger
binding affinities of the constrained cis-diol/boronic acid
bioconjugation are amenable to surface and chip assay design where
clean, robust analyte capture is desired.
[0021] These and other features of the present teachings will
become more apparent from the description herein. In various
embodiments, the particulars of the system, the method, and the
compound are further provided below. Each detail provided is
contemplated in some embodiments of each of the system, the method,
and the compound, separately and in combination.
[0022] A bioconjugation system can comprise a sterically
constrained cis-diol and a borate represented respectively by:
##STR1## The variables n and n' are to indicate that a
corresponding number of the groups in parentheses are attached to
the corresponding Y or Y' in parallel, i.e., the groups in
parentheses are not representing an n or n'-fold serial oligomer or
polymer.
[0023] Ring A can be an optionally substituted bicycloalkyl,
heterocyclyl or fused bicycloalkyl-heterocyclyl, or Ring A can be
an optionally substituted cycloalkyl.
[0024] R.sup.1 and R.sup.1' can be independently an optionally
substituted alkyl, alkoxy, alkyl ether, alkyl sulfide, cycloalkyl,
heterocyclyl, aryl, heteroaryl, cycloalkylalkyl, heterocyclylalkyl,
aralkyl, heteroaralkyl, cycloalkylalkyl ether, heterocyclylalkyl
ether, aralkyl ether, heteroaralkyl ether, cycloalkylalkyl sulfide,
heterocyclylalkyl sulfide, aralkyl sulfide or heteroaralkyl sulfide
linking group.
[0025] R.sup.2a, R.sup.2a', R.sup.2b and R.sup.2b' can each be
independently --OH (unprotected) or --O--PG (protected), wherein
--PG is an alcohol protecting group selected from optionally
substituted esters, ethers, silyl ethers and carbonates. Also,
R.sup.2a and R.sup.2a' can be taken together with the portion of
Ring A connecting them to be a protected cis-diol group selected
from optionally substituted cyclic acetals, cyclic ketals, and
cyclic ortho esters. e.g., a cis-diol can be protected with an
acetonide group. R.sup.2b and R.sup.2b', taken together with the
boron to which they are bonded, can be a protected borate group
selected from boronates and cyclic boronates. The pairs R.sup.2a,
R.sup.2b, and R.sup.2a', R.sup.2b', can be both --O--, whereby the
cis-diol and borate to which they are bonded form a conjugate
represented by: ##STR2##
[0026] Thus, as used herein, the term "borate" encompasses borates
that are unprotected (e.g., when the corresponding R.sup.2b or
R.sup.2b' is --OH) protected (e.g., when R.sup.2b and R.sup.2b',
taken together with the boron to which they are bonded, can be a
protected borate group selected from boronates and cyclic
boronates), and conjugated (e.g., as in the above structural
formula).
[0027] Also, as used herein, the term "cis-diol" encompasses
cis-diols that are unprotected (e.g., when the corresponding
R.sup.2a or R.sup.2a' is --OH) protected (e.g., when the
corresponding R.sup.2a or R.sup.2a' is --O--PG, or when R.sup.2a
and R.sup.2a' can be taken together with the portion of Ring A
connecting them to be a protected cis-diol group), and conjugated
(e.g., as in the above structural formula).
[0028] Further, the definitions herein are provided such that the
"constrained cis-diol" is not a saccharide. As used herein, the
term "saccharide" means monosaccharides such as fructose, mannitol,
galactose, glucose, mannose, allose, altrose, talose, tagatose,
Psicose, ribose, arabinose, sorbitol, and oligomers and polymers of
any one or any combination of the preceding monosacharrides.
[0029] X and X' can be independently a bond, --O--, --S--,
--C(O)--, --C(O)O--, --S(O)--, --OSO.sub.2--, --S(O.sub.2)O--,
--SO.sub.2--, --NR.sup.3--, --NR.sup.3C(O)--, --C(O)NR.sup.3C--,
--R.sup.3NNR.sup.3SO.sub.2--, --SO.sub.2NR.sup.3NR.sup.3--,
--NR.sup.3SO.sub.2--, --SO.sub.2NR.sup.3--,
--CR.sup.3.sub.2C(O)NR.sup.3--, --NR.sup.3C(O)CR.sup.3.sub.2,
--CR.sup.3.sub.2C(O)--, --C(O)CR.sup.3.sub.2--, --R.sup.3NNR.sup.3
--, --NR.sup.3NR.sup.3--, --R.sup.3NNR.sup.3.sub.2--,
--NR.sup.3.sub.2.sup.+NR.sup.3--, --CR.sup.3.sub.2Ph-,
-PhCR.sup.3.sub.2--, --C(NR.sup.3)NR.sup.3--, or
--NR.sup.3C(NR.sup.3)--.
[0030] Each R.sup.3 can be independently --H, alkyl, alkoxy,
aryloxy or arylalkoxy.
[0031] Y and Y' can be independently a bioactive molecule, a
covalently attached solid support, or a self assembled monolayer
(SAM)-inducing solid support wherein at least one of Y and Y' is
the bioactive molecule. For example, when Y or Y' is a solid
support or a self assembled monolayer (SAM)-inducing solid support,
the corresponding n or n' can be an integer from 10 to 10.sup.10.
For example, when Y is one of the solid supports, n is an integer
from about 10 to about 10.sup.10; when Y' is one of the solid
supports, n' can be an integer from about 10 to about 10.sup.10.
When Y or Y' is a biomolecule, the corresponding n or n' can be an
integer from 1 to about 10.
[0032] A method of preparing a conjugate represented by: ##STR3##
comprises reacting a sterically constrained cis-diol and a borate
represented respectively by: ##STR4## under conditions suitable for
reaction between the constrained cis-diol and the borate, thereby
forming the conjugate. Suitable reaction conditions can be found in
the Examples. Conjugates between sterically constrained cis-diol
and a borate have been observed experimentally at pH 5.5 (50 mM
sodium acetate, 100 mM sodium chloride buffer), FIG. 6A, and at pH
7.4 (phosphate buffered saline with 0.05% Tween-20), FIG. 3 and
FIG. 6B, and at pH 9.4 (200 mM carbonate-bicarbonate buffer), FIG.
6C. In the method, Ring A, R.sup.1, R.sup.1', R.sup.2a, R.sup.2a',
R.sup.2b, R.sup.2b', R.sup.3, X, X', Y, Y', n, and n' are as
provided above for the bioconjugation system.
[0033] A sterically constrained cis-diol compound for
bioconjugation can be represented by: ##STR5## wherein Ring A,
R.sup.1, R.sup.2a, R.sup.2a', R.sup.3, and X are as provided above
for the bioconjugation system.
[0034] Y can be a bioactive molecule and n can be an integer from 1
to about 200, generally 1 to about 100, or typically 1 to about 10.
Y can be a solid support or a self assembled monolayer
(SAM)-inducing solid support and n can be an integer from about 10
to about 10.sup.10. The variable n can be 1 and --Y--X together can
be --S--, wherein two cis-diols form a disulfide dimer represented
by: ##STR6## wherein each variable is independently as defined
above. The variable n can be 1 and --Y--X together can be --OH,
--SH, halogen, --OR.sup.5, --C(O)OR.sup.5, --O(O)CR.sup.5,
--NR.sup.5R.sup.6, or --N-heterocyclyl, wherein R.sup.5 and R.sup.6
are independently optionally substituted alkyl, cycloalkyl,
heterocyclyl, aryl, heteroaryl, cycloalkylalkyl, heterocyclylalkyl,
aralkyl, or heteroaralkyl.
[0035] In various embodiments, for each bioactive molecule, the
corresponding n or n' can be greater than 1, e.g., there can be a
plurality of cis-diols or borates for each bioactive molecule.
[0036] In various embodiments, for each bioactive molecule, the
corresponding n or n' can be 1, e.g., there can be one cis-diol or
one borate for each bioactive molecule.
[0037] When for each bioactive molecule, the corresponding n or n'
is 1, the conjugate can be a stable conjugate, for example, the
conjugate represented by: ##STR7## As used herein, a conjugate that
is stable is one wherein in aqueous 0.10 M phosphate buffer at
25.degree. C. and pH 7.4, the conjugate can have a dissociation
rate of less than about 1.times.10.sup.-4s.sup.-1. In various
embodiments, the stable conjugate can have a dissociation rate of
less than about 1.times.10.sup.-5s.sup.-1. In some embodiments, the
stable conjugate can have a dissociation rate of less than about
1.times.10.sup.-6s.sup.-1. In other embodiments, the stable
conjugate can have a dissociation rate of less than about
1.times.10.sup.-7s.sup.-1. In some embodiments, the conjugate can
have an association rate of greater than about 1
M.sup.-1s.sup.-1.
[0038] In various embodiments, at least one of Y and Y' is the
solid support or the self assembled monolayer (SAM)-inducing solid
support. For example, Y can be the bioactive molecule and Y' can be
the solid support or the self assembled monolayer (SAM)-inducing
solid support. Y' can be the bioactive molecule and Y can be the
solid support or the self assembled monolayer (SAM)-inducing solid
support.
[0039] In various embodiments, Y is the solid support and Y' is the
bioactive molecule. In some embodiments, Y' is the solid support
and Y is the bioactive molecule.
[0040] As used herein, "support", "solid support", or "SAM-inducing
solid support" refers to any solid phase material. Solid support
encompasses terms such as "resin", "synthesis support", "solid
phase", "surface" and/or "membrane". A solid support can be
composed of optionally substituted organic polymers, e.g.,
polyalkylene (e.g., polyethylene, polypropylene), polyvinylene,
polystyrene, polyethylene oxide, nitrocellulose, polyvinyl acetate,
polyvinyl chloride, polyvinyl dichloride, polyfluoroalkylene (e.g.,
polyfluoroethylene), polyamides (e.g., polyacrylamide,
poly(hexamethylene adipamide) and the like), polydialkylsiloxane
(e.g., polydimethylsiloxane), and the like, as well as co-polymers
and grafts thereof. A solid support can also be inorganic, such as
glass (e.g., silicate glass, borate glass, indium tin oxide,
controlled-pore-glass (CPG), and the like), silica, quartz, or
reverse-phase silica and the like. The configuration of a solid
support can be in the form of: one or more beads, spheres (e.g.,
microspheres), or particles (e.g., granules, nanoparticles); a gel,
a membrane, a surface, a film, a porous matrix (e.g., nonwoven
support or supports with channels or pores, e.g., porous glasses,
sol gels, zeolites, and the like), or interior surface of a
microchannel. Surfaces can be planar, substantially planar, or
non-planar. Solid supports can be porous or non-porous, and can
have swelling or non-swelling characteristics. A solid support can
be configured in the form of a well, depression or other container,
vessel, feature or location. A plurality of solid supports can be
configured in an array at various locations, addressable for
robotic delivery of reagents, or by detection methods and/or
instruments.
[0041] In some embodiments, one of Y and Y' is the solid support or
the SAM-inducing solid support and the solid support can have a
conductive layer (e.g., metal, conducting glass (e.g., indium tin
oxide), and the like, typically metal) for surface plasmon
resonance. The solid support or the SAM-inducing solid support can
comprise gold, silver, platinum, aluminum, or copper. In some
embodiments, the solid support is a nanoparticle comprising cadmium
sulfide, cadmium selenide, cadmium telluride, silicon, or gallium
arsenide. In some embodiments, the solid support comprises
optionally substituted polyalkylene (e.g., polyethylene,
polypropylene), polyvinylene, polystyrene, polyethylene oxide,
nitrocellulose, polyvinyl acetate, polyvinyl chloride, polyvinyl
dichloride, polyfluoroalkylene (e.g., polyfluoroethylene),
polyamide (e.g., polyacrylamide, poly(hexamethylene adipamide) and
the like), polydialkylsiloxane (e.g., polydimethylsiloxane), and
the like, as well as co-polymers and grafts thereof; glass (e.g.,
silicate glass, borate glass, indium tin oxide,
controlled-pore-glass (CPG), and the like), silica, or quartz.
[0042] In various embodiments, when one of Y and Y' is the solid
support or the SAM-inducing solid support and the solid support
includes a conductive layer for surface plasmon resonance, the
method further comprises directing light to the conductive layer
and measuring a surface plasmon resonance wavelength in order to
determine an extent of conjugation by measuring a change in the
surface plasmon resonance wavelength before and after formation of
the conjugate. The light is directed to the conductive layer in a
wavelength range between about 400 nanometers (nm) and about 1200
nm at the conductive layer, at an incident angle greater than a
total internal reflectance angle at the solid support, to create a
surface plasmon resonance condition at the solid support surface.
Typically, the light is in a wavelength range between about 820 nm
and 920 nm.
[0043] As used herein "array" refers to a predetermined spatial
arrangement of reaction sites, e.g., bioconjugation sites present
on a solid support or in an arrangement of vessels. Certain array
formats can be referred to as a "chip" or "biochip" (M. Schena, Ed.
Microarray Biochip Technology, BioTechnique Books, Eaton
Publishing, Natick, Mass. (2000). An array can comprise a
low-density number of addressable locations, e.g., 2 to about 12,
medium-density, e.g., about a hundred or more locations, or a
high-density number, e.g., a thousand or more. An array or chip can
be a geometrically-regular shape that allows for fabrication,
handling, placement, stacking, reagent introduction, detection, and
storage. An array or chip can be irregularly shaped. An array or
chip can be configured in a row and column format, with regular
spacing between each location. An array or chip can be configured
in a row and column format, with irregular spacing. Alternatively,
the locations may be bundled, mixed, or homogeneously blended for
equalized treatment or sampling. An array may comprise a plurality
of addressable locations configured so that each location is
spatially addressable for high-throughput handling, robotic
delivery, masking, or sampling of reagents, or by detection means
including scanning by laser illumination and confocal or deflective
light gathering.
[0044] In various embodiments, an array can be constructed by
preparing the conjugate at a plurality of spatially distinct
reaction sites on the solid support. The sites can be located in a
regular array (e.g., at the vertices of a square grid) or an
irregular, e.g., random array. Typically, the reaction sites are
located in a regular array, such as may be provided by a printing
mechanism, an automated pin-spotting mechanism, and the like.
Generally, each spatially distinct reaction site in the array can
be an average diameter of between about 5 .mu.m and about 1000
.mu.m. In typical arrays, the spatially distinct reaction sites in
the array can be in a surface density of between about 12 sites per
cm.sup.2 and about 50,000 sites per cm.sup.2.
[0045] Some embodiments comprise preparing the conjugate at two or
more reaction sites in the array to be compositionally distinct,
e.g., the conjugate at each of the two or more sites is different
in one or more aspects such as concentration, chemical structure,
associated bioactive molecule, and the like. Two compositionally
distinct sites can also mean the same or different sites measured
at different times. The method can comprise contacting a first site
with the cis-diol or the borate having the bioactive molecule, in
an composition distinct from that employed at a second site. The
method can comprise contacting a first site with a first cis-diol
or borate containing a first bioactive molecule and contacting a
second site with a second cis-diol or borate containing a second
bioactive molecule. Some embodiments can comprise determining the
extent of conjugation at the first and the second site, e.g., by
determining an extent of conjugation by measuring a change in the
surface plasmon resonance wavelength between the two
compositionally distinct sites.
[0046] In some embodiments, when the solid support can be
configured as a plurality of particles, beads, microspheres,
nanoparticles, granules, and the like, the distinct reaction sites
on the solid support can be one or more reaction sites, typically
one, on each individual solid support. In some such embodiments, a
plurality of compositionally distinct reaction sites can be
prepared by repeatedly conjugating one of a library of distinct
bioactive molecules with a portion of reaction sites (e.g.,
particles) to create separate portions of compositionally distinct
reaction sites, and then combining them to result in a plurality of
compositionally distinct reaction sites, e.g., resulting in a
library of bioactive molecules conjugated to distinct
particles.
[0047] The bioactive molecule can be any biologically relevant
molecule of interest, for example, the bioactive molecule can
comprise one or more nucleic acids, polynucleic acids, amino acids,
peptides, proteins, peptide nucleic acids, hormones, cofactors,
fatty acids, carbohydrates, polysaccharides, glycopeptides,
glycoproteins; peptidoglycans; glycolipids, cyclitols, prenols,
terpenoids, steroids, folates, carotenoids, retinoids, tocopherols,
lignans, quinines, isoprenoids, tetrapyrroles, lipids,
prostaglandins, immunoglobulins, glycolipids, lipoproteins,
neurotransmitters, biometabolites, pharmaceuticals environmental
toxins, small organic molecules (e.g., pharmaceuticals) and the
like. Molecules in the preceding list can be obtained from
commercial sources, generated by chemical synthesis by
combinatorial synthesis methods known to the art, extracted from
natural sources, and the like. In some embodiments, the bioactive
molecule includes a library of bioactive molecules, e.g., a
plurality of biologically or chemically distinct bioactive
molecules of one or more classes of molecules from the preceding
list, typically one class. Typically, a library of bioactive
molecules can be a plurality of molecules generated by chemical
synthesis or combinatorial chemistry, each generally having a
molecular weight from about 100 daltons to about 5000 daltons.
[0048] Screening of libraries of small molecules for binding or
other interaction with target biomolecules of interest has
typically been done in solution, with compounds attached to beads,
and recently, with libraries attached to microarrays (see, for
example, MacBeath, G. (2001) Genome Biology 2(6): comment
2005.1-2005.6; Lam, K S., and Renil, M (2002). Curr. Op. Chem.
Biol. 6:353-358; and Khandurina J,. and Guttman, A. (2002) Curr.
Op. Chem. Biol. 6:359-366). In microarrays, the small molecules of
the library can have a common functional group, which can be
reacted with a suitable functional group on the surface to form a
stable bond. Functional groups described for immobilization of
small molecule libraries include thiols (MacBeath, et al. (1999)
JACS 121:7967-7968), alcohol (Hergenrother, et al. (2000) JACS
122:7849-7850), amino-oxy group (Falsey, et al. (2001) Bioconjug
Chem 12:346-353) and phenols (Bames-Seeman, et al. (2003) Angew
Chem Int Ed 42:2376-2379. The entire teachings of each reference in
this paragraph are incorporated herein by reference.
[0049] In various embodiments, the bioconjugation system can
include a library of bioactive compounds, i.e., a plurality of
reaction sites on the solid support can be prepared to have
chemically or biologically distinct bioactive molecules conjugated
at each site. The library can be a collection of any bioactive
molecules as described herein, but can typically be a collection of
small molecules synthesized by combinatorial methods. In such
libraries, each bioactive molecule can have any size, though
typically each molecule is in a size range between about 100 and
about 5000 daltons. The plurality of spatially distinct reaction
sites on the support can each be a distinct support (e.g., when the
solid support is configured as a plurality of particles, beads,
granules, and the like) or a spatially distinct reaction site on a
single solid support, e.g., an array as described herein.
Typically, the bioactive molecule library can be prepared as an
array on a single solid support.
[0050] Such bioconjugation libraries can be used for any purpose
known to the art for compound libraries. For example, a small
compound library array can be tested for interaction, e.g.,
chemical reaction, specific binding, or nonspecific binding, and
the like, of its bioactive molecules to a target of interest, such
as a therapeutic target protein, peptide, or nucleic acid using any
of many methods known to the art such as surface plasmon resonance,
fluorescence, luminescence, staining, enzyme-linked immunoabsorbent
assay, radioactivity based methods, and the like. Thus, in some
embodiments, the bioconjugation system comprising a bioactive
molecule library array as described herein is combined with a
target bioactive molecule of interest and the combination is
assayed for specific binding between the target and each bioactive
molecule in the library.
[0051] In various embodiments, the library of bioactive molecules
can be prepared by chemical synthesis or combinatorial synthesis,
for example, bioactive molecules prepared by such methods can, for
example, be coupled to the cis-diols or borates herein by synthetic
methods described in the Examples. In some embodiments, precursors
or intermediates to library molecules can be prepared by chemical
synthesis or combinatorial synthesis and be coupled to the
cis-diols or borates herein by synthetic methods described in the
Examples, and the cis-diol:borate bioconjugates formed;
subsequently, the coupled precursors or intermediates can be
further modified by chemical synthesis or combinatorial synthesis
methods known to the art to further diversify molecules of the
library.
[0052] Thus, in various embodiments, the bioconjugation system
further comprises a plurality of each of the sterically constrained
cis-diols and the borates; wherein at least one of Y or Y' is,
independently for each corresponding cis-diol or borate, a distinct
bioactive molecule selected from a plurality of distinct bioactive
molecules (e.g., a bioactive molecule library), and each
corresponding n or n' is an integer from 1 to 3, whereby the
bioconjugation system comprises a library of distinct bioactive
molecules. Thus, in some embodiments, at least one of Y or Y'
represents the library of bioactive molecules. Typically, the other
of Y or Y' is the solid support comprising a plurality of spatially
distinct reaction sites, wherein a plurality of the reaction sites
can be prepared to be compositionally distinct by conjugation with
distinct bioactive molecules from the library. Generally, the solid
support is in the form of covalently attached particles, a single
covalently attached solid support, or the self-assembled monolayer
(SAM) inducing support, or more typically, the solid support is a
single covalently attached solid support, e.g., an array as
described herein. Thus, in some embodiments, the bioconjugation
system is a bioactive molecule library array, wherein Y represents,
independently for each cis-diol, a distinct bioactive molecule from
the bioactive molecule library (e.g., Y collectively represents the
bioactive molecule library) and Y' represents, independently for
each borate, a spatially distinct reaction site in an array (e.g.,
Y' collectively represents a spatially distinct array of cis-diols
on a solid support). In other embodiments of the bioactive molecule
library array, Y' represents, independently for each borate, a
distinct bioactive molecule from the bioactive molecule library
(e.g., Y' collectively represents the bioactive molecule library),
and Y represents, independently for each cis-diol, a spatially
distinct reaction site in an array (e.g., Y collectively represents
a spatially distinct array of cis-diols on a solid support). In the
embodiments described in this paragraph, the variables n and n' can
independently be an integer of between 1 to 3, or more typically, n
and n' can each be 1. Typically, each bioactive molecule in the
library is from about 100 daltons to about 5000 daltons, and the
library is typically constructed by chemical synthesis or
combinatorial synthesis methods.
[0053] In some embodiments, the structures and variables of the
cis-diol, borate, and conjugate are as provided above, with the
following modifications.
[0054] In some embodiments, R.sup.1' can be an optionally
substituted aryl, aralkyl, C1-C16 alkyl, or C1-C16 alkoxy group. In
some embodiments, R' can be C2-C16 alkyl ether, C1-C16 alkoxy or
C1-C16 alkyl.
[0055] In various embodiments, the cis-diol can be represented by:
##STR8##
[0056] In some embodiments, the cis-diol can be represented by:
##STR9## Here, R.sup.1 can be as described above, or can be C2-C16
alkyl ether, C1-C16 alkoxy or C1-C16 alkyl; and X can be --NH--,
--C(O)NH--, --NHC(O)-- or --S--. Or, X can be --S-- and R.sup.1 can
be --(CH.sub.2).sub.2O(CH.sub.2).sub.8-- or --(CH.sub.2).sub.11--.
In some embodiments, --X--R.sup.1-- can be --(CH.sub.2)S--. In
various embodiments, R.sup.2a and R.sup.2a' can independently be
--OH or --O--PG, or R.sup.2a and R.sup.2a' can be taken together
with the portion of the ring connecting them to be a protected
cis-diol group as noted above, e.g., a cis-diol protected as an
acetonide group. In some embodiments, R.sup.2a and R.sup.2a' can be
--OH.
[0057] These cis-diols can form a conjugate with borates as
represented by: ##STR10## Here, R.sup.1 can be as defined above, or
can be C6-C12 alkyl, or can be C1-C3 alkyl. In some embodiments,
R.sup.1 can be --(CH.sub.2)--, e.g., the conjugate is represented
by: ##STR11##
[0058] In some embodiments, these cis-diols can form a conjugate
with borates as represented by: ##STR12## Here, R.sup.1 can be as
defined above, or can be C6-C12 alkyl, or can be C1-C3 alkyl.
"Amide" can be --NHC(O)-- or --C(O)NH--. In some embodiments,
R.sup.1 can be --(CH.sub.2)--, e.g., the conjugate is represented
by: ##STR13##
[0059] In some embodiments, the cis-diol can be represented by:
##STR14##
[0060] Here, R.sup.1 can be as defined above. In some embodiments,
R.sup.1 can be C1-C4 alkoxy or C1-C4 alkyl and X can be --C(O)O--
or amide. In various embodiments, R.sup.2a and R.sup.2a' can
independently be --OH or --O--PG, or R.sup.2a and R.sup.2a' can be
taken together with the portion of the ring connecting them to be a
protected cis-diol group as noted above, e.g., a cis-diol protected
as an acetonide group. In some embodiments, R.sup.2a and R.sup.2a'
can be --OH.
[0061] In various embodiments, cis-diols can form a conjugate with
the borate as represented by: ##STR15## "Amide" can be --NHC(O)--
or --C(O)NH--.
[0062] In some embodiments of the compound, --Y--X together can be
--S--, wherein two cis-diols form a disulfide dimer represented by:
##STR16##
[0063] In some embodiments, --Y--X together can be --OH, --SH,
halogen, --OR.sup.5, --C(O)OR.sup.5, --O(O)CR.sup.5,
--NR.sup.5R.sup.6 or --N-heterocyclyl. In some embodiments, X can
be --S--.
[0064] In various embodiments, the cis-diol, unprotected, can be
one of: ##STR17##
[0065] In some embodiments, the cis-diol, protected by an acetonide
group, can be one of: ##STR18##
[0066] In some embodiments, the cis-diol, unprotected or protected
by an acetonide group, can be one of: ##STR19##
[0067] In some embodiments, the cis-diol, unprotected or protected
by an acetonide group, can be one of: ##STR20##
[0068] In some embodiments, the cis-diol, unprotected or protected
by an acetonide group, can be one of: ##STR21##
[0069] In some embodiments, the cis-diol, protected by an acetonide
group, can be: ##STR22##
[0070] As used herein, a "constrained" cis-diol is a cyclic
structure wherein steric or cyclic constraints cause the diol --OH
groups to be held in a relatively fixed aspect to each other,
whereby the conjugation reaction with a borate produces a conjugate
with the specificity and/or affinity taught in various embodiments.
For example, in the constrained cis-diol represented by Ring A in
some embodiments, the diol --OH groups, (represented by R.sup.2a
and R.sup.2a') are held in various aspects relative to each other
by virtue of being bound to an optionally substituted bicycloalkyl,
heterocyclyl or fused bicycloalkyl-heterocyclyl.
[0071] As used herein, --PG is an alcohol protecting group for
example, optionally substituted esters, ethers, silyl ethers and
carbonates. Suitable alcohol protecting groups are well known in
the art; see, for example, Greene T W and Wuts P G M, Protective
Groups in Organic Synthesis, 3R.sup.d ed., Wiley, NY (1999), the
entire teachings of which are incorporated herein by reference.
[0072] As used herein, cyclic acetals, cyclic ketals, and cyclic
ortho esters can be formed with the cis-diol as diol protecting
groups, e.g., the acetonides in structures 4-8 in the synthetic
examples. Suitable diol protecting groups are well known in the
art; see, for example, Greene T W and Wuts P G M, Protective Groups
in Organic Synthesis, 3R.sup.d ed., Wiley, N.Y. (1999), the
teachings of which, that pertain to hydroxyl group protection, are
incorporated herein by reference.
[0073] As used herein, the term "borate" can mean any typical state
of a borate derivative, e.g., the boric acid --B(OH).sub.2, salts,
hydrates, and/or solvates thereof, and/or boronate esters, e.g.,
alkyl esters, aromatic esters, e.g., catechol esters, and the like.
Typical boric acid protecting groups, e.g., borate/boronate esters,
are well-known in the art; see, for example, Ferrier R J, Adv.
Carbohydr. Chem. Biochem. 1978, 35:31; Brooks C J W et al., Adv.
Mass Spectrom. 1978, 7B:1578; Knapp D R, Handbook of Analytical
Derivatisation Reactions, Wiley, N.Y. (1979); Greene T W and Wuts P
G M, Protective Groups in Organic Synthesis, 3R.sup.d ed., Wiley,
N.Y. (1999), the teachings of which, that pertain to hydroxyl group
protection, are incorporated herein by reference.
[0074] The teachings herein do not restrict the borate to phenyl
boronic acid or related analogues. Any alkyl or aromatic borate
with a linker arm for attachment to a surface or a biomolecule can
be employed. For example, commercially available boronic acids for
use in this manner include, e.g.: ##STR23## Aldrich #51,268-0
(Sigma Aldrich, St. Louis, Mo.) and ##STR24## Lancaster Synthesis
#17485 (Lancaster Synthesis, Windham, N.H.).
[0075] As used herein, the term "linking group", (e.g., the linking
groups represented by R.sup.1, R.sup.1', X, X', and the like) means
any chemical group that connects two or more other chemical
groups.
[0076] The term "alkyl" (e.g., the alkyl groups represented by
R.sup.1, R.sup.1', R.sup.3, and the like), used alone or as part of
a larger moiety (e.g., aralkyl, alkoxy, alkylamino,
alkylaminocarbonyl, haloalkyl), is a straight or branched
non-aromatic hydrocarbon which is completely saturated. Typically,
a straight or branched alkyl group has from 1 to about 20 carbon
atoms, generally from 1 to about 16 if not otherwise specified,
Examples of suitable straight or branched alkyl group include
methyl, ethyl, n-propyl, 2-propyl, n-butyl, sec-butyl, tert-butyl,
pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl,
terdecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl,
nonadecyl, icosyl, and the like. The term "alkenyl" means alkyl
groups with one or more units of unsaturation resulting in one or
more double bonds, e.g., butenyl, pentadienyl, hexadecenyl, and the
like. The term "alkynyl" means alkyl groups with one or more units
of unsaturation resulting in one or more triple bonds, e.g.,
butynyl, hexadecynyl, and the like.
[0077] The term "cycloalkyl group" (e.g., the cycloalkyl groups
represented by Ring A) can be a cyclic alkyl group having from 3 to
about 10 carbon atoms, generally from 5 to 6. Examples of suitable
cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl,
cyclohexyl, cycloheptyl and cyclooctyl. The term cycloalkenyl
includes cycloalkyl groups having one or more units of unsaturation
resulting in a double bond, e.g., cyclopentenyl, cyclohexenyl, and
the like.
[0078] The term "aryl" group, (e.g., the aryl groups represented by
R.sup.1 and R.sup.1', and the like) refers to carbocyclic aromatic
groups such as phenyl, naphthyl, tetrahydronaphthyl, anthracyl, and
the like.
[0079] The term "heteroaryl" group (e.g., the heteroaryl groups
represented by R.sup.1 and R.sup.1', and the like) refers to
heteroaromatic groups, for example imidazolyl, isoimidazolyl,
thienyl, furanyl, pyridyl, pyrimidyl, pyranyl, pyrazolyl, pyrrolyl,
pyrazinyl, thiazolyl, isothiazolyl, oxazolyl, isooxazolyl,
1,2,3-triazolyl, 1,2,4-triazolyl, tetrazolyl, benzo[1,3]dioxolyl,
2,3-dihydro-benzo[1,4]dioxine, benzopyrimidyl, benzopyrazyl,
benzofuranyl, indolyl, benzothienyl, benzoxazolyl,
benzoisooxazolyl, benzothiazolyl, benzoisothiazolyl, quinolinyl,
isoquinolinyl, benzimidazolyl, tetrahydroquinolinyl, and
tetrahydroisoquinolinyl. Generally, aryl and heteroaryl groups
comprise phenyl and pyridyl. The term "Ph" indicates a phenyl or a
phenylene group, e.g., phenylene in --CR.sup.3.sub.2Ph- in X and
X'.
[0080] The term "nonaromatic heterocycle" and "heterocyclyl" (e.g.,
the heterocyclyl groups represented by R.sup.1 and R.sup.1', and
the like) refers to non-aromatic ring systems typically having
three to eight members, generally five to six, in which one or more
ring carbons, generally one to four, are each replaced by a
heteroatom such as N, O, or S. Examples of non-aromatic
heterocyclic rings include 3-tetrahydrofuranyl,
2-tetrahydropyranyl, 3-tetrahydropyranyl, 4-tetrahydropyranyl,
[1,3]-dioxalanyl, [1,3]-dithiolanyl, [1,3]-dioxanyl,
2-tetrahydrothienyl, 3-tetrahydrothienyl, N-morpholinyl,
2-morpholinyl, 3-morpholinyl, 4-morpholinyl, N-thiomorpholinyl,
2-thiomorpholinyl, 3-thiomorpholinyl, 4-thiomorpholinyl,
1-pyrrolidyl, 2-pyrrolidyl, 3-pyrorolidyl, 1-piperazyl,
2-piperazyl, 1-piperidyl, 2-piperidyl, 3-piperidyl, 4-piperidyl,
4-thiazolidyl, diazolonyl, N-substituted diazolonyl, 1-pthalimidyl,
azetidyl, aziridyl, oxaziridyl, oxazolidyl, isooxazolidyl,
thiazolidyl, isothiazolidyl, oxazinanyl, thiazinanyl, azepanyl,
oxazepanyl, and thiazepanyl. Typically, the nonaromatic heterocycle
groups represented by R.sup.1 and R.sup.1' can be optionally
substituted pyrrolidyl, piperidyl, piperazyl, morpholinyl, and
thiomorpholinyl., or generally, unsubstituted piperidyl or
morpholinyl.
[0081] An "______oxy" group (e.g., alkoxy, cycloalkoxy, aryloxy,
aralkyloxy, and the like) refers to the indicated group when
connected through an intervening oxygen atom, e.g., alkoxy groups
include methoxy, ethoxy, n-propoxy, 2-propoxy, n-butoxy,
sec-butoxy, tert-butoxy, pentoxy, hexoxy, heptoxy, octoxy, nonoxy,
decoxy, undecoxy, dodecoxy, terdecoxy, tetradecoxy, pentadecoxy,
hexadecoxy, heptadecoxy, octadecoxy, nonadecoxy, icosoxy, and the
like. Examples of cycloalkoxy groups include cyclopropoxy,
cyclobutoxy, cyclopentoxy, cyclohexoxy, cycloheptoxy and
cyclooctoxy. Examples of aryloxy and aralkyloxy groups include
phenoxy and benzyloxy.
[0082] A "______sulfide group (e.g., alkyl sulfide, cycloalkyl
sulfide, aryl sulfide, aralkyl sulfide, cycloalkylalkyl sulfide,
heterocyclylalkyl sulfide, heteroaralkyl sulfide and the like)
refers to the indicated group when connected through an intervening
sulfur atom, e.g., analogous to "______oxy" groups described
herein.
[0083] An "alkyl ether" (e.g., in alkyl ether, cycloalkylalkyl
ether, heterocyclylalkyl ether, aralkyl ether, heteroaralkyl ether,
and the like) indicates an alkyl group that is interrupted by one
or more, typically one, oxygen atoms, e.g., groups of the formula
--(CH.sub.3).sub.iO(CH).sub.k--, wherein i and k are positive
integers greater than zero and i+k is between 2 to 20, generally
between 2 to 16. An "alkylthioether" is an analogous group wherein
the oxygen is replaced by sulfur.
[0084] An "______alkyl" group (e.g., cycloalkylalkyl,
heterocyclylalkyl, aralkyl, heteroaralkyl, and the like) indicates
the named group is connected through an intervening alkyl group,
e.g., benzyl, --CH.sub.2H.sub.2-pyridine, and the like.
[0085] The terms "optionally substituted" means that the named
group can be unsubstituted or can be substituted with one or more
groups, provided the groups do not substantially interfere with the
conjugation methods.
[0086] "Optionally halogenated", as used herein, includes the
respective group substituted with one or more of --F, --Cl, --Br,
or --I.
[0087] The terms "alkanoyl", "aroyl", and the like, as used herein,
indicates the respective group connected through an intervening
carbonyl, for example, --(CO)CH.sub.2CH.sub.3, benzoyl, and the
like. The terms "alkanoyloxy", "aroyloxy", and the like, as used
herein, indicates the respective group connected through an
intervening carboxylate, for example, --O(CO)CH.sub.2CH.sub.3,
--O(CO)C.sub.6H.sub.5, and the like.
[0088] The disclosed compounds can contain one or more chiral
centers. For example, in Ring A, the carbons bonded to R.sup.2a and
R.sup.2a' are each a chiral center. The presence of chiral centers
in a molecule gives rise to stereoisomers. For example, a pair of
optical isomers, referred to as "enantiomers", exist for every
chiral center in a molecule. A pair of diastereomers exists for
every chiral center in a compound having two or more chiral
centers. Where the structural formulas do not explicitly depict the
stereochemistry of each chiral center it is to be understood that
these formulas encompass enantiomers free from the corresponding
optical isomer, racemic mixtures, mixtures enriched in one
enantiomer relative to its corresponding optical isomer, a
diastereomer free of other diastereomers, a pair of diastereomers
free from other diasteromeric pairs, mixtures of diasteromers,
mixtures of diasteromeric pairs, mixtures of diasteromers in which
one diastereomer is enriched relative to the other diastereomer(s)
and mixtures of diasteromeric pairs in which one diastereomeric
pair is enriched relative to the other diastereomeric pair(s).
[0089] The term "derivative" refers to compounds that have a common
core structure, and are substituted with various groups as
described herein.
[0090] A line across a bond in a ring, for example, the line from
R.sup.1 across Ring A, indicates that the represented bond can be
connected to any substitutable atom in the ring.
[0091] A "substitutable atom" is any atom such as nitrogen or
carbon that can be substituted by replacing a hydrogen atom bound
to the atom with a substituent. A "substitutable ring atom" in a
ring is any ring atom, e.g., a carbon or nitrogen, which can be
substituted.
[0092] Suitable substituents are those that do not substantially
interfere with the conjugation activity of the disclosed compound.
A compound or group can have one or more substituents, which can be
identical or different. Examples of suitable substituents for a
substitutable carbon atom in an alkyl, cycloalkyl, cycloalkenyl,
non-aromatic heterocycle, aryl, or heteroaryl group include --OH,
halogen (--Br, --Cl, --I and --F), --R, --OR, --CH.sub.2R,
--CH.sub.2CH.sub.2R, --OCH.sub.2R, --CH.sub.2OR,
--CH.sub.2CH.sub.2OR, --CH.sub.2OC(O)R, --O--COR, --COR, --SR,
--SCH.sub.2R, --CH.sub.2SR, --SOR, --SO.sub.2R, --CN, --NO.sub.2,
--COOH, --SO.sub.3H, --NH.sub.2, --NHR, --N(R).sub.2, --COOR,
--CH.sub.2COOR, --CH.sub.2CH.sub.2COOR, --CHO, --CONH.sub.2,
--CONHR, --CON(R).sub.2, --NHCOR, --NRCOR, --NHCONH.sub.2,
--NHCONRH, --NHCON(R).sub.2, --NRCONH.sub.2, --NRCONRH,
--NRCON(R).sub.2, --C(.dbd.NH)--NH.sub.2, --C(.dbd.NH)--NHR,
--C(.dbd.NH)--N(R).sub.2, --C(.dbd.NR)--NH.sub.2,
--C(.dbd.NR)--NHR, --C(.dbd.NR)--N(R).sub.2,
--NH--C(.dbd.NH)--NH.sub.2, --NH--C(.dbd.NH)--NHR,
--NH--C(.dbd.NH)--N(R).sub.2, --NH--C(.dbd.NR)--NH.sub.2,
--NH--C(.dbd.NR)--NHR, --NH--C(.dbd.NR)--N(R).sub.2,
--NRH--C(.dbd.NH)--NH.sub.2, --NR--C(.dbd.NH)--NHR,
--NR--C(.dbd.NH)--N(R).sub.2, --NR--C(.dbd.NR)--NH.sub.2,
--NR--C(.dbd.NR)--NHR, --NR--C(.dbd.NR)--N(R).sub.2,
--SO.sub.2NH.sub.2, --SO.sub.2NHR, --SO.sub.2NR.sub.2, --SH,
--SO.sub.kR (k is 0, 1 or 2) and --NH--C(.dbd.NH)--NH.sub.2. Each R
is independently an alkyl, cycloalkyl, benzyl, aromatic,
heteroaromatic, or phenylamine group that is optionally
substituted. Generally, R is unsubstituted. In addition,
--N(R).sub.2, taken together, can also form a substituted or
unsubstituted heterocyclic group, (e.g., as for NR.sup.c.sub.2, and
NR.sup.j.sub.2) such as pyrrolidinyl, piperidinyl, morpholinyl and
thiomorpholinyl. Examples of substituents on group represented by R
include amino, alkylamino, dialkylamino, aminocarbonyl, halogen,
alkyl, alkylaminocarbonyl, dialkylaminocarbonyloxy, alkoxy, nitro,
cyano, carboxy, alkoxycarbonyl, alkylcarbonyl, hydroxy, haloalkoxy,
or haloalkyl.
[0093] Suitable substituents on the nitrogen of a heterocyclic
group or heteroaromatic group include --R', --N(R').sub.2,
--C(O)R', --CO.sub.2R', --C(O)C(O)R', --C(O)CH.sub.2C(O)R',
--SO.sub.2R', --SO.sub.2N(R').sub.2, --C(.dbd.S)N(R').sub.2,
--C(.dbd.NH)--N(R').sub.2, and --NR'SO.sub.2R'. R' is hydrogen, an
alkyl, alkoxy, cycloalkyl, cycloalkoxy, phenyl, phenoxy, benzyl,
benzyloxy, heteroaromatic, or heterocyclic group that is optionally
substituted. Examples of substituents on the groups represented by
R' include amino, alkylamino, dialkylamino, aminocarbonyl, halogen,
alkyl, alkylaminocarbonyl, dialkylaminocarbonyloxy, alkoxy, nitro,
cyano, carboxy, alkoxycarbonyl, alkylcarbonyl, hydroxy, haloalkoxy,
or haloalkyl. Generally, R' is unsubstituted.
[0094] Exemplification
[0095] Aspects of the present teachings may be further understood
in light of the following examples, which should not be construed
as limiting the scope of the present teachings in any way.
SYNTHETIC EXAMPLES
[0096] The compounds defined above can be made by the procedures
provided in the following synthetic examples. All reagents can be
obtained from Sigma-Aldrich, St. Louis, Mo., unless otherwise
noted.
[0097] Synthesis of Pinane Acetonide With Carboxylic Acid
Linker
[0098] Scheme 1 shows preparation of pinanediol derivative 6,
masked as an acetonide, with an acetic acid linker attachment for a
solid support or biomolecule. Oxidation of nopol acetate with
osmium tetroxide yielded the cis-diol. After acetonization of the
diol and deacylation, the side chain alcohol was oxidized to a
carboxylic acid. ##STR25## Pinene Acetate 2: To a mixture of
(1R)-(-)-nopol (10 g, 59 millimole (mmol)), triethylamine (12.3 ml,
88 mmol, 1.5 equiv) and dimethylaminopyridine (DMAP. 16.5 mg) in
100 ml of CH.sub.2Cl.sub.2, acetic anhydride (6.7 ml, 71 mmol, 1.2
equiv) was added dropwise via syringe. The resulting mixture was
stirred at room temperature under an argon atmosphere. Thin layer
chromatography (TLC) after two hours showed the reaction was nearly
complete, but was allowed to stir overnight. In the morning, the
reaction mixture was washed with 50% NaHCO.sub.3 solution and
brine, dried over anhydrous Na.sub.2SO.sub.4 and concentrated. The
crude product was purified over a silica gel plug, eluting with
2.about.5% ethyl acetate (EtOAc) in hexanes, to afford the pinene
acetate 2 as a colorless oil (12.4 g,>100%). IR (CHCl.sub.3):
3030, 2990, 2920, 2838, 1730, 1470, 1435, 1385, 1368, 1250, 1128,
1032, and 886 cm.sup.-1. .sup.1H NMR (400 MHz, CDCl.sub.3): .delta.
5.30 (br s, 1H), 4.02-4.13 (m, 2H), 2.34-2.40 (m, 1H), 2.16-2.32
(m, 4H), 2.02-2.12 (m, 2H), 2.04 (s, 3H), 1.28 (s, 3H), 1.15 (d,
J=8.9 Hz, 1H), 0.83 (s, 3H). ##STR26## Pinanediol Acetate 3: A 250
ml round-bottomed flask was purged with argon gas three times, and
then heated under argon atmosphere. After cooling back to room
temperature, the flask was charged with a mixture of
4-methylmorpholine-N-oxide (NMO, 1.2 g, 10.5 mmol, 1.05 equiv),
t-butanol (21.25 ml), water (3.75 ml) and hexamethylenetetraamine
(HMTA, 3.9 g, 27.6 mmol, 2.8 equiv). Pinene acetate 2 (2.1 g, 10
mmol) was added to the mixture, followed by osmium tetroxide stock
solution (40 mg/ml H.sub.2O, 0.875 ml., 0.14 mmol, 0.014 equiv).
The resulting light tan mixture was heated to 71.degree. C. in 23
minutes and maintained at 68.about.75.degree. C. for 20 hours. The
reaction mixture was cooled back to room temperature and stirred
with 30 ml of 10% NaHSO.sub.3 solution for 30 minutes; no color
changed was noticed.
[0099] The mixture was extracted with 50% EtOAc/hexanes two times.
The combined organic extract was washed with 10% NaHSO.sub.3
solution and water, dried over anhydrous Na.sub.2SO.sub.4 and
concentrated to afford the crude product as a tan oil (2.85 g). The
pinanediol acetate 3 was purified by silica gel chromatography,
eluting with 5.about.50% EtOAc/hex, to yield a nearly colorless oil
(2.03 g, 84%) containing a small amount of a less polar
pinane-keto-alcohol acetate byproduct. IR (CHCl.sub.3): 3450, 3000,
2927, 2870, 1730, 1475, 1455, 1388, 1370, 1230, 1128, 1042, and 605
cm.sup.-1. .sup.1HNMR (400 MHz, CDCl.sub.3): .delta. 4.26-4.38 (m,
2H), 4.03-4.09 (m, 1H), 3.15 (s, 1H, OH), 2.89 (d, J=6.2 Hz, 1H,
OH), 2.46-2.54 (m, 1H), 2.18-2.26 (m, 1H), 2.10 (t, J=5.8 Hz, 1H),
2.06 (s, 3H), 1.92-2.05 (m, 2H), 1.79-1.87 (m, 1H), 1.63-1.70 (m,
1H), 1.38 (d, J=10.4 Hz, 1H), 1.27 (s, 3H), 0.94 (s, 3H). ##STR27##
Pinane Acetonide Acetate 4: To a solution of pinanediol acetate 3
(9.3 g, 38.5 mmol) in 110 ml of acetone, 2,2-dimethoxypropane (9.5
ml, 77 mmol, 2 equiv) was added dropwise via syringe at room
temperature under argon atmosphere. To the mixture was then added
catalytic p-toluene sulfonic acid (TsOH, 17.5 mg) and the reaction
was stirred for 2 hours. Ten drops of triethylamine were added via
pipette and the solution was concentrated by rotary evaporation to
produce a yellow residue. The crude product was purified by a
silica gel plug, eluting with 3.about.6% EtOAc/hex, to give the
slightly impure pinane acetonide acetate 4 as a colorless oil (9.1
g, 83%). IR (CHCl.sub.3): 2995, 2945, 2877, 1732, 1460, 1384, 1373,
1238, 1125, 1044, 1029 and 886 cm.sup.-1. .sup.1H NMR (400 MHz,
CDCl.sub.3): .delta. 4.19-4.31 (m, 2H), 4.13 (d, J=7.2 Hz, 1H),
2.01-2.25 (m, 5H), 2.04 (s, 3H), 1.87-2.0 (m, 2H), 1.63 (d, J=9.8
Hz, 1H), 1.48 (s, 3H), 1.39 (s, 3H), 1.29 (s, 3H), 0.88 (s, 3H).
##STR28## Pinane Acetonide Alcohol 5: To a solution of pinane
acetonide acetate 4 (9.0 g, 38.5 mmol) in 75 ml of anhydrous
methanol (MeOH), a solution of 4.37 M sodium methoxide (MeONa) in
MeOH (0.36 ml, 0.05 equiv) was added dropwise via syringe. The
reaction vessel was sealed with a septum and stirred at room
temperature for 25 hours until the reaction was nearly complete.
Upon removal of volatiles on a rotary evaporator, a milky colored
gum was obtained. The crude product was purified by silica gel
plug, eluting with 10.about.30% EtOAc/hex, to produce the slightly
impure pinane acetonide alcohol 5 as a light yellow gum (7.5 g,
97%), containing impurities above and below the product spot by
TLC. IR (CHCl.sub.3): 3500, 2992, 2942, 2878, 1455, 1385, 1375,
1243, 1123, 1050, 1028, 1002, 978, 926 and 885 cm.sup.-1. .sup.1H
NMR (400 MHz, CDCl.sub.3): .delta. 4.15 (d, J=6.9 Hz, 1H),
3.85-3.95 (m, 1H), 3.65-3.75 (m, 1H), 2.89 (dd, J=8.2, 2.3 Hz, 1H),
2.28-2.31 (m, 1H), 1.89-2.21 (m, 6H), 1.67 (d, J=10.4 Hz, 1H), 1.49
(s, 3H), 1.44 (s, 3H), 1.29 (s, 3H), 0.83 (s, 3H). ##STR29## Pinane
Acetonide Carboxylic Acid 6: To a solution of pinane acetonide
alcohol 5 (2 g, 8.3 mmol) in 57 ml of anhydrous
N,N'-dimethylformamide (DMF), powdered pyridinium dichromate(PDC)
(15.7 g, 41.6 mmol, 5 equiv) was added in small portions under an
argon atmosphere. TLC monitoring of the reaction showed all of the
starting material was consumed after 19 hours of stirring at room
temperature, but a small amount of intermediate aldehyde was still
present. Water (100 ml) was added, and the dark brown mixture was
extracted five times with EtOAc (100 ml). The combined organic
extract was washed with H.sub.2O, and dried over anhydrous
Na.sub.2SO.sub.4. Most of the brown color in organic solution was
removed by filtration on a cake of silica gel, to afford 4.0 g of a
light brown oil after concentration of the filtrate. Residual
pyridine and dimethyl formamide (DMF) were pumped off under vacuum
with gentle heating, until the crude product weight stabilized at
2.7 g. The product was purified by silica gel chromatography,
eluting with 10.about.20% acetone/CH.sub.2Cl.sub.2, to yield the
1.sup.st crop of pinane acetonide carboxylic acid 6, as a light
yellow solid (1.4 g, 67%). Re-chromatography of impure fractions
provided additional acid 6 (0.3 g, 16%). IR (CHCl.sub.3): 3550,
3010-3400 (broad), 2990, 2942, 2878, 1770, 1715, 1455, 1387, 1378,
1235, 1186, 1149, 1039, 1000, 975, 920, 870 and 818 cm.sup.-1.
.sup.1H NMR (400 MHz, CDCl.sub.3): .delta. 4.21 (d, J=7.0 Hz, 1H),
2.93 (d, J=15 Hz, 1H), 2.82 (d, J=14.1 Hz, 1H), 2.35-2.43 (m, 1H),
2.13-2.27 (m, 2H), 1.91-2.05 (m, 2H), 1.65 (d, J=10.7 Hz, 1H), 1.55
(s, 3H), 1.48 (s, 3H), 1.32 (s, 3H), 0.90 (s, 3H). The carboxylic
acid proton was not observed. Coupling of Pinane Acetonide Via
Activated Ester
[0100] One-step and two-step coupling methods were developed to
couple an activated ester of the pinane acetonide carboxylic acid
with amines. O--(N-succinimidyl)-N,N,N',N'-tetramethyluronium
tetrafluoroborate (TSTU) activation in aqueous acetonitrile
afforded the N-hydroxysuccinimido (NHS) ester, which could be
isolated or reacted in situ with amines. The coupling proceeded
quickly in moderate yields, which were not optimized (66%), and
appeared to tolerate a variety of solvent mixes (DMF, DMF/H.sub.2O
4:1, DMF/dioxane/H.sub.2O 2:2:1, CH.sub.3CN, CH.sub.3CN/H.sub.2O
4:1). Model coupling methods were demonstrated with n-butylamine in
synthetic protocols detailed below. ##STR30## Pinane Acetonide NHS
Ester 7: To a mixture of the slightly impure acid 6 (341.4 mg, 1.34
mmol) and TSTU (606 mg, 2 mmol, 1,5 equiv) in 10 ml of 20%
water/CH.sub.3CN, diisopropylethylamine (DIPEA, 0.7 ml, 4 mmol, 3
equiv) was added dropwise via syringe. After 30 minutes of stirring
at room temperature, TLC of the light yellow mixture showed the
reaction was complete. After evaporation of CH.sub.3CN at reduced
pressure, the residue was partitioned between EtOAc and water. The
aqueous phase was extracted three times with EtOAc, and the
combined organic extracts were then washed with brine, dried over
anhydrous Na.sub.2SO.sub.4 and evaporated. The crude material was
purified by silica gel chromatography, eluting with 50 ml of 3%
acetone in CH.sub.2Cl.sub.2, to give the NHS ester 7 as an
off-white powder (309.7 mg, 66%). IR (CHCl.sub.3): no acid
absorption at 3500 cm.sup.-1; the C.dbd.O absorptions at 1822 (m),
1793 (m) and 1745 (s) cm.sup.-1. .sup.1H NMR (400 MHz, CDCl.sub.3):
.delta. 4.22 (d, J=7.2 Hz, 1H), 3.10 (d, J=14.4 Hz, 1H), 3.05 (d,
J=14.4 Hz, 1H), 2.83 (br s, 4H), 2.58 (m, 1H), 2.14-2.25 (m, 2H),
2.0 (dd, J=14.4, 3.9 Hz, 1H), 1.91-1.96 (m, 1H), 1.64 (d, J=10.6
Hz, 1H), 1.52 (s, 3H), 1.48 (s, 3H), 1.31 (s, 3H), 0.91 (s,
3H).
[0101] The same NHS ester 7 could be prepared in the same fashion
in other solvent systems: DMF (22.7 mg, 77%), DMF/p-dioxane/water
(2:2:1, 66%), 20% water in DMF (66%), CH.sub.3CN (good yield by
TLC) and 20% water in ethanol (poor yield by TLC). ##STR31## Pinane
Acetonide Butylamide 8: To a solution of the NHS ester 7 (45 mg,
0.13 mmol) in 2 ml of 20% water in CH.sub.3CN, n-butylamine (20
.mu.l, 0.19 mmol, 1.5 equiv) and diisopropylethylamine (67 .mu.l,
0.38 mmol, 3 equiv) were added sequentially at room temperature.
The mixture was stirred overnight (20 hours). Volatile components
were removed by rotary evaporation; the residue was partitioned
between CH.sub.2Cl.sub.2 and brine. The aqueous phase was extracted
three times with CH.sub.2Cl.sub.2. The combined organic extracts
were washed with water, dried over anhydrous Na.sub.2SO.sub.4 and
concentrated to give the amide 8 as a light brown gum (28.4 mg,
72%). The amide 8 can be prepared directly in a one-pot reaction
between the acid 6 and butylamine in the presence of TSTU without
isolation of the NHS ester 7, as shown by the next reaction.
##STR32## One-Pot Synthesis of Pinane Acetonide Butylamide 8: To a
mixture of the acid 6 (90.7 mg, 0.36 mmol) and TSTU (161 mg, 0.53
mmol, 1.5 equiv) in 2 ml of 20% water/CH.sub.3CN,
diisopropylethylamine (0.19 ml, 1.07 mmol, 3 equiv) was added
dropwise. The resulting mixture was stirred at room temperature for
40 minutes and then treated with n-butylamine (44 .mu.l, 0.45 mmol,
1.25 equiv) dropwise. TLC analysis showed that the reaction was
complete in 40 minutes. Volatile components were removed by rotary
evaporation; the residue was partitioned between EtOAc and brine.
The aqueous phase was extracted three times with EtOAc. The
combined organic extract was washed with water, dried over
anhydrous Na.sub.2SO.sub.4 and concentrated. The crude material was
purified by silica gel chromatography, eluting with 3.about.5%
acetone in CH.sub.2Cl.sub.2 to give the amide 8 as a colorless gum
(73 mg, 66%). IR (CHCl.sub.3): 3400, 2990, 2937, 2838, 1660, 1535,
1387, 1377, 1210-1235, 1156, 1118, 1035 and 917 cm.sup.-1. .sup.1H
NMR (400 MHz, CDCl.sub.3): .delta. 6.69 (br s, 1H, N--H), 4.13 (d,
J=7.1 Hz, 1H), 3.16-3.31 (m, 2H), 2.73 (s, 2H), 2.11-2.23 (m, 3H),
1.90-2.0 (m, 2H), 1.62 (d, J=9.7 Hz, 1H), 1.52 (s, 3H), 1.46-1.51
(m, 2H), 1.44 (s, 3H), 1.29-1.40 (m, 2H), 1.27 (s, 3H), 0.93 (t,
J=7.3 Hz, 3H), 0.92 (s, 3H). Acetonide Deprotection: Synthetic
Protocol: ##STR33## Pinanediol Butylamide 9: Pinane acetonide
butylamide 8 (107 mg, 0.35 mmol) was stirred with a 1:1 mixture of
trifluoroacetic acid (TFA)/water (3 ml) at room temperature. The
reaction was monitored by TLC and showed about 75% conversion to
the cis-diol after 2 hours, then the reaction stalled and the
intensity of a new spot between starting material and product
started to build up. The unknown byproduct may be formed from
fragmentation of the pinane ring in product 9 under the acidic
condition. The optimal reaction time was about 3.5 hours. The
reaction mixture was neutralized with saturated NaHCO.sub.3
solution, and then was extracted 3 times with 50% EtOAc/hex. The
combined organic extract was washed with H.sub.2O, dried over
anhydrous Na.sub.2SO.sub.4 and concentrated. Residual unreacted
starting material 8 and byproduct from the pinanediol butylamide 9
was not removed by silica chromatography. IR (CHCl.sub.3): 3455,
3390, 3000, 2960, 2930, 2875, 1647, 1530, 1463, 1385, 1140, 1117,
1054, 1033 and 1018 cm.sup.-1. Synthesis of Pinanediol C2
Thiol/Disulfide
[0102] Scheme 3 shows methods using nopol as the starting material
to make a pinanediol analogue with a 2C thiol chain. This compound
can be a candidate for surface modification via SAMs on gold. The
2C thiol derivative can serve as a model for developing general
methods to synthesize pinanediols with longer (C11+) aliphatic
thiol side chains. Conversion of nopol to an alkyl halide (Cl or
Br), followed by oxidation to the cis-diol and displacement of the
halide by (TMSi)S.sup.-(((CH.sub.3).sub.3Si)S.sup.-) at room
temperature gave the pinanediol 2C thiol/disulfide mixture in 3
steps under mild conditions. ##STR34## Pinene Bromide 11: To a
solution of triphenylphosphine (6.1 g, 23.4 mmol, 2 equiv) in 45 ml
of CH.sub.2Cl.sub.2 at 0.degree. C., orange powdered
N-bromosuccinimide (NBS, 4.2 g, 23.4 mmol, 2 equiv) was added in
small portions under an argon atmosphere. The resulting deep red
mixture was stirred at room temperature for 30 minutes and then 1
ml pyridine was added. The color darkened to reddish-brown, and
nopol (2 ml, 117 mmol) was added to the mixture dropwise via
syringe over 10 minutes. TLC showed the reaction was complete in 3
hours. The mixture was diluted with 40 ml of hexanes and filtered
through a coarse silica gel plug. 100 ml of 5% EtOAc/hex was used
to flush the column; the combined filtrate was concentrated to
generate 6.12 g of wet solid. Suspension of the solid in 100 ml
hexane precipitated white crystalline succinimide, which was
removed by filtration. The filtrate was concentrated to yield 2.95
g of a slightly yellow oil. The crude product was further purified
by silica gel plug, eluting with hexanes, to give the pinene
bromide 11 as a colorless oil (2.6 g, 97%). IR (CHCl.sub.3): 2993,
2923, 2840, 1470, 1448, 1437, 1386, 1370, 1268, 1083, 956 and 636
cm.sup.-1. .sup.1H NMR (400 MHz, CDCl.sub.3): .delta. 5.33 (s with
fine splittings, 1H), 3.31-3.42 (m, 2H), 2.48-2.56 (m, 2H),
2.33-2.41 (m, 1H), 2.14-2.32 (m, 2H), 2.05-2.12 (m, 1H), 1.98-2.04
(m, 1H), 1.28 (s, 3H), 1.17 (d, J=8.6 Hz, 1H), 0.84 (s, 3H).
##STR35## Pinene Chloride 10: Pinene chloride 10 was prepared as a
colorless oil in the same manner as described for pinene bromide 11
except that N-chlorosuccinimide (NCS) was substituted for
N-bromosuccinimide. (4.2 g, 95%). IR (CHCl.sub.3): 2993, 2924,
2838, 1450, 1387, 1370, 1297, 1267, 1120, 1100, 1085, 958 and 888
cm.sup.-1. .sup.1H NMR (400 MHz, CDCl.sub.3): .delta.5.34 (s with
fine splittings, 1H), 3.46-3.57 (m, 2H), 2.34-2.47 (m, 3H),
2.16-2.34 (m, 2H), 2.06-2.14 (m, 1H), 2.03 (dt J=1.5, 5.6 Hz, 1H),
1.29 (s, 3H), 1.17 (d, J=8.7 Hz, 1H), 0.85 (s, 3H). ##STR36##
Pinanediol Chloride 12: To a mixture of 4-methylmorpholine-N-oxide
(NMO, 2.6 g, 22 mmol, 1.05 equiv), t-butanol (45 ml), water (8 ml)
and hexamethylenetetraamine (HMTA, 4.1 g, 29 mmol, 1.4 equiv),
pinene chloride 10 (3.9 g, 21 mmol) and osmium tetroxide stock
solution (40 mg/ml H.sub.2O, 1.7 ml. 0.26 mmol, 0.0125 equiv) were
added at room temperature under an argon atmosphere. The resulting
light tan mixture was heated to <55.degree. C. for 6 hours.
After cooling to room temperature, the mixture was quenched with 40
ml of 10% NaHSO.sub.3 solution and stirred for 30 minutes. The
aqueous solution was extracted three times with 30% EtOAc/hex. The
combined organic extracts were washed with brine and water, dried
over anhydrous Na.sub.2SO.sub.4 and concentrated to afford the
crude product as a dark tan oil. The crude product was purified by
silica gel chromatography, eluting first with hexanes to recover
the unreacted starting material 10 as a colorless oil (2.1 g, 54%).
The column was further eluted with 10.about.25% EtOAc/hex, and the
clean fractions were pooled and concentrated to give a tan solid.
The product was crystallized in hexanes to give the 1.sup.st crop
of pinanediol chloride 12 as white crystalline plates (1.3 g, 29%).
The mother liquor and the impure fractions were pooled and
repurified to give the 2.sup.nd crop of diol 12 (0.43 g, 9.4%). IR
(CHCl.sub.3): 3617, 3515, 3004, 2930, 2876, 1455, 1374, 1110, 1042,
1012, 946, 910 and 657 cm.sup.-1. .sup.1H NMR (400 MHz,
CDCl.sub.3): .delta. 4.15 (dt, J=9.6, 5.9 Hz, 1H), 3.80 (ddd, J=l
1, 8.4, 5.6 Hz, 1H), 3.73 (ddd, J=10.9, 8.6, 5.8 Hz, 1H), 3.13 (s,
OH, 1H), 2.68 (d, J=6.2 Hz, OH, 1H), 2.47-2.57 (m, 1H), 2.09-2.29
(m, 3H), 1.93-2.04 (m, 2H), 1.64-1.67 (m, 1H), 1.38 (d, J=10.2 Hz,
1H), 1.30 (s, 3H), 0.99 (s, 3H). ##STR37## Pinanediol Bromide 13: A
mixture of 4-methylmorpholine N-oxide (NMO, 1.1 g, 9.2 mmol, 1.05
equiv), t-butanol (18.5 ml), water (3.3 ml),
hexamethylenetetraamine (3.4 g, 24 mmol, 2.8 equiv), pinene bromide
11 (2 g, 8.7 mmol), and osmium tetroxide stock solution (40 mg/ml
H.sub.2O, 0.7 ml. 0.11 mmol, 0.0125 equiv) was heated at 70.degree.
C. for 18.5 hours under argon atmosphere. TLC of the resulting dark
brown mixture showed no product spot. When the reaction was run
under milder conditions with a shorter reaction time by heating the
mixture of 4-methylmorpholine-N-oxide (NMO, 805 mg, 6.9 mmol, 1.05
equiv), t-butanol (14 ml), water (2.6 ml), hexamethylenetetraamine
(HMTA, 1.3 g, 24 mmol, 1.4 equiv), pinene bromide 11 (1.5 g, 6.5
mmol), and osmium tetroxide stock solution (40 mg/ml H.sub.2O, 0.52
ml. 0.08 mmol, 0.0125 equiv) at <65.degree. C. for 6.5 hours
under an argon atmosphere, the product was isolated as an orange
gum (905 mg, 53%) in addition to recovered starting material (334
mg, 22%). The pinanediol bromide 13 did not solidify in hexanes,
and was shown to contain a long contaminant tail underneath the
pinanediol bromide 13 by TLC.
[0103] However, the clean pinanediol bromide 13 could be obtained
by employing dihydroxylation reaction conditions for unhindered
alkenes without HMTA. A mixture of 4-methylmorpholine-N-oxide (NMO,
309 mg, 2.6 mmol, 1.2 equiv), acetone/water (9:1, 15 ml), pinene
bromide 11 (503 mg, 2.2 mmol), and osmium tetroxide stock solution
(40. mg/ml H.sub.2O, 0.07 ml. 11.7 .mu.mole, 0.05 equiv) was
stirred at room temperature for 17 days. After standard workup,
pinanediol bromide 13 was obtained as an off-white crystalline
solid (435 mg, 75%). IR (CHCl.sub.3): 3617, 3490, 3004, 2927, 2888,
1452, 1373, 1256, 1107, 1040, 1026, 957, 907 and 645 cm.sup.-1.
.sup.1H NMR (400 MHz, CDCl.sub.3): .delta. 4.08-4.15 (m, 1H),
3.51-3.66 (m, 2H), 3.03 (s, OH, 1H), 2.62 (d, J=6.2 Hz, OH, 1H),
2.48-2.57 (m, 1H), 2.20-2.30 (m, 2H), 2.04-2.15 (m, 2H), 1.92-1.99
(m, 1H), 1.66 (ddd, J=14.2, 5.2, 2.5 Hz, 1H), 1.37 (d, J=10.3 Hz,
1H), 1.30 (s, 3H), 0.98 (s, 3H). ##STR38## Pinanediol Thiol 14 and
Disulfide 15: To a solution of pinanediol chloride 12 (300 mg, 1.4
mmol) in anhydrous THF (2.7 ml), hexamethyldisilathiane
([TMSi].sub.2S, 0.35 ml, 1.6 mmol, 1.2 equiv) was added at
-5.degree. C. under argon atmosphere. The resulting mixture was
then treated with 1M solution of tetrabutylammonium fluoride (TBAF,
1.5 ml, 1.5 mmol, 1.1 equiv) in tetrahydrofuran (THF), containing
5% of water. The color of the mixture changed from yellow to green
during the addition of TBAF. The reaction remained incomplete after
5 hours of stirring at room temperature. Saturated NH.sub.4Cl
solution was added, the mixture was then extracted 3 times with 50%
EtOAc/hex. The combined organic extract was washed with saturated
NaHCO.sub.3 solution, and dried over anhydrous Na.sub.2SO.sub.4.
The organic solution was filtered through a silica gel plug,
eluting with 0.about.4% MeOH in CH.sub.2Cl.sub.2, to give a
colorless gum (284 mg) as a mixture of unreacted starting material
chloride 12, thiol 14 and disulfide 15. Unlike the protected
acetonide analogue, the thiol 14 and disulfide 15 were inseparable
by silica column. The assignment of 14 and 15 was based on TLC and
.sup.1H NMR spectrum. Thiol 14 showed a characteristic blue stain
instantly on the TLC plate at room temperature when contacted with
a 10% solution of phosphomolybdic acid (PMA) in MeOH; the stain of
the disulfide 15 was visualized only after the plate was heated. In
the .sup.1H NMR spectrum, the signal multiplicity from the
methylene protons on the carbon bearing the sulfur atom should be
more complex for thiol 14 than disulfide 15, due to the extra
vicinal coupling to the thiol proton. The methylene signals
appeared at 2.72 ppm (m, 5 lines, 2H) and 2.87 ppm (m, 4 lines, 2H)
for thiol 14 and disulfide 15, respectively. The ratio of the
starting material 12, thiol 14 and disulfide 15 was estimated as
1.4:1:3.5, based on the integrals of one of the geminal methyl
protons at 0.98, 0.976 and 0.96 ppm respectively. ##STR39##
Pinanediol Thiol 14 and Disulfide 15: A mixture (275 mg) of thiol
14 and disulfide 15 in a 1.68:1 ratio was also obtained by the same
reaction with pinanediol bromide 13 (335 mg, 1.3 mmol),
[TMSi].sub.2S (0.32 ml, 1.5 mmol, 1.2 equiv) and 1M TBAF solution
(1.4 ml, 1.4 mmol, 1.1 equiv) in THF containing 5% water. The
reaction was complete after 2 hours of stirring at room
temperature. The thiol 14 was the predominate product in this
faster reaction, as opposed to the slow reaction with chloride 12.
Contemplated Synthesis of Pinanediol w/C11 Thiol Linker or w/Ether
C8 Thiol Linker
PROPHETIC EXAMPLE
[0104] The present teachings also contemplate adaptation of the
preceding methods to construct pinanediols with a linker thiol of
C5-C16 chain length for surface modification of gold via
self-assembled monolayers (SAMs). Chain elongation of nopylhalides
(e.g., such as compound 11) to a C6-C12 derivative, followed by
oxidation to the pinanediol derivative, and conversion of the
C6-C12 side chain to an alkyl sulfide and/or disfulfide,
exemplifies the general synthetic method contemplated for
pinanediol thiol linker compounds of the general formula:
##STR40##
[0105] In some embodiments, SAM surfaces can be generated from
thiols. In some embodiments, SAM surfaces can be generated from the
disulfide. In some embodiments, SAM surfaces can be generated from
mixtures of thiol and disulfide.
[0106] Disulfide cis-diols can be converted to the sulfide
analogues just prior to SAM surface modification by reaction of the
disulfide with tris(2-carboxyethyl)phosphine hydrochloride
(TCEP.HCl). TCEP.HCl is a water-soluble reducing agent that
exhibits better stability and more effective reductive capability
than dithiothreitol (DTT) or 2-mercaptoethanol. The agent retains
its reductive activity in a broad pH range (pH 5 to >pH 7.5) and
typically can be used in a molar excess quantity. An example of
disulfide reduction immediately prior to SPR detection is reduction
by TCEP.HCl of thiolated-ssDNA just before application to bare Au
surfaces.
CONJUGATION EXAMPLES
Conjugation Example 1
Pinanediol/m-Dansylaminophenylboronic Acid
[0107] FIG. 1 is a schematic of covalent conjugation of
surface-bound pinane acetonide (bound to poly-D-Lys Plates) with
borate (m-dansylaminophenylboronic acid). Two sets of triplicates
were run in 96-well, poly-D-lysine coated polystyrene plates (Sigma
M 5682, Sigma-Aldrich, St. Louis, Mo.). The 70-150 kDa polymer
provides a uniform net of positively charged ammonium groups, which
were neutralized with NaHCO.sub.3 washes (.times.3, pH 7) to
primary amines and coupled with the pinane acetonide NHS ester (1
hr). (Pinane acetonide NHS ester was synthesized by TSTU activation
and isolated as a precipitate for use in the coupling reaction.)
The covalently attached pinane acetonide was then deprotected to
the pinanediol with a 1:1 TFA/H.sub.2O incubation (2 hrs). After
neutralization washes (dil NaHCO.sub.3.times.1, H.sub.2O.times.1),
incubation of the pinanediol modified wells with
m-dansylaminophenylboronic acid (5 mM in EtOH, M Probes D-2281,
Molecular Probes, Inc. Eugene, Oreg.), followed by EtOH washes to
remove residual, uncomplexed boronic acid, resulted in dansyl
fluorescence at 530 nm (ex 360 nm) with S/N=8. Control wells
containing 5 mM dansylaminophenylboronic acid, followed by removal
of the fluorophore solution and EtOH washes (.times.3) showed a 50%
increase over background (blank wells).
[0108] FIG. 2 shows the fluorescence signal and signal-to-noise
ratios in control wells (originally containing the
dansylaminophenylboronic acid solution ) and wells containing
pinane diol (bound to poly-D-Lys Plates) conjugated to borate
(m-dansylaminophenylboronic acid). In FIG. 5, "blank" is the signal
for an empty well; "Solvent A" is the signal for a well containing
ethanol; "Solvent C" is the signal for a well containing 20%
H.sub.2O/CH.sub.3CN; and "5 mM D-BA/wash" is the signal for a blank
well washed with -dansylaminophenylboronic acid in EtOH, followed
by 3.times.EtOH washes, with EtOH added for analysis. The columns
"coupling A" and "coupling B" are the signal for wells where pinane
acetonide NHS ester is covalently attached in solvent C to a well,
washed w/ solvent C.times.2 followed by TFA/H.sub.2O incubation,
then washed w/ dil NaHCO.sub.3.times.1, washed w/ H.sub.2O.times.1,
incubated w/5 mM m-dansylaminophenylboronic acid in EtOH, followed
by 3.times.EtOH washes, and EtOH is added for analysis. The columns
"coupling A:BA S/N" and "coupling B:BA S/N" are the signal to noise
ratios of the respective conjugated wells versus the respective
solvent-washed blank wells. These signal to noise ratios ranged
from about 5.33 to about 5.46.
Conjugation Example 2
Constrained Cis-diol/borate Conjugation for SPR
[0109] On a bare gold surface plasmon resonance chip (available for
Affinity Chip SPR Analyzer model 8500, Applied Biosystems, Foster
City, Calif.), constrained diol
((1R,2R,3S,5R)-2-(2-mercaptoethyl)-6,6-dimethylbicyclo[3.1.1]heptane-2,3--
diol): ##STR41## was spotted using was spotted on a MicroSys
spotter (Cartesian Dispensing Systems, presently Genomic Solutions)
with a SMP 10B pin (Telechem), in phosphate buffered saline (PBS)
with less than about 1% dimethylformamide (DMF). Concentrations of
about 1, 5, 25, 100, and 200 .mu.M were spotted in the presence and
absence of 1 mM tris (2-carboxyl-ethyl) phosphine (TCEP). TCEP is
typically used in place of dithiothreitol (DTT) as a non
thiol-based reductant. Controls of bovine serum albumin (BSA) and
PBS with 1 mM TCEP were also spotted. All solutions were spotted in
replicates of nine. The chip was then incubated in a humid
environment for about 1 hour.
[0110] After spotting, the chip was assembled, loaded onto the SPR
analyzer, and individual reference spots were assigned adjacent to
the left of spotted material. The chip was blocked with about 10 mL
of 0.5 mM capped mercapto-PEG-2000. PBS with 0.05% Tween-20 (PBST),
was used to equilibrate the chip for 60 minutes at a flow rate of
0.5 mL/min in order to minimize drift effects.
[0111] A solution of 3.5 mL m-dansylaminophenylboronic acid (DAPB,
molecular weight 370.23 g/mol, catalog number D-2281, Molecular
Probes, Eugene, Oreg.): ##STR42## 20 .mu.M in PBST, was allowed to
re-circulate over the equilibrated chip for 30 minutes at a flow
rate of 0.5 mL/min. During this time association of DAPB could be
observed with the constrained diol spotted at 25 .mu.M.
Dissociation was allowed to take place over a period of 30 minutes
with a flow rate of 0.5 mL/min.
[0112] Results
[0113] FIG. 3 shows binding curves could be observed for 20 .mu.M
DAPB binding to the immobilized constrained diol at concentrations
of 25 .mu.M.
[0114] FIG. 4 shows the presence or absence of TCEP did not appear
to have a significant effect upon end-point binding. At the lower
concentrations of 1 and 5 .mu.M, no binding above background levels
could be observed. Beginning at concentrations of 100 .mu.M DAPB, a
detrimental effect upon binding at the higher spotted densities of
the constrained diol was observed.
[0115] Two reasons can account for this effect. At the higher
densities over-saturation of the gold surface can occur. The
presence of binding to adjacent reference spots suggested this
outcome. Also, at very high densities, a tightly packed layer of
constrained diol can hinder the reaction of DAPB. The negative
end-point signal at 200 .mu.M spotted constrained diol indicates
that binding to the reference spots is greater than binding to the
densely spotted material (FIG. 2).
[0116] FIGS. 5A and 5B show that both negative controls (BSA and
PBS with 1 mM TCEP) exhibited no DAPB binding.
[0117] The binding of DAPB to immobilized constrained diol has been
observed in three separate experiments. The SPR results suggest
that a real binding event for a small molecule was observed. The
high density surface afforded by constrained diol may account for
the ability to detect a 370 Dalton species by the 8500 systems
under flow. The smallest analyte detected previously under flow
using this particular SPR analyzer was a peptide of about 1000
Daltons.
[0118] The association rate of DAPB with constrained diol can seem
slow. Detailed kinetic analyses were not possible but the
association rate appears to be in order of .about.10E2
M.sup.-1s.sup.-1. Steric problems may potentially explain the slow
association. Dissociation, on the other hand, appears to be slow
and blends in with the instrument drift (some of the dissociation
curves appear to drift up).
Conjugation Example 3
Constrained Borate /cis-diol Conjugation for SPR
[0119] On a bare gold surface plasmon resonance chip (available for
Affinity Chip SPR Analyzer model 8500, Applied Biosystems, Foster
City, Calif.), 4-mercaptophenylboronic acid (Aldrich, St. Louis,
Mo.) was spotted on a MicroSys spotter (Cartesian Dispensing
Systems, presently Genomic Solutions) with a SMP 10B pin
(Telechem), in phosphate buffered saline (PBS) with 50% ethanol.
Concentrations of about 100, 200, and 500 .mu.M were spotted. All
solutions were spotted in replicates of three. The chip was then
incubated in a humid environment for about 1 hour.
[0120] After spotting, the chip was assembled, loaded onto the SPR
analyzer, and individual reference spots were assigned adjacent to
the left of spotted material. The chip was blocked with 1 mM capped
mercapto-PEG-2000. Buffer solution, either PBST (phosphate buffer
saline (PBS), pH 7.4 with 0.05% Tween-20), sodium acetate buffer
(50 mM sodium acetate, 100 mM sodium chloride, pH 5.5), or
carbonate buffer (200 mM sodium carbonate-bicarbonate, pH 9.4), was
used to equilibrate the chip for 60 to 90 minutes at a flow rate of
0.5 mL/min in order to minimize drift effects.
[0121] A solution of 2.5 mL pinanediol acetate: ##STR43## 100 .mu.M
in PBST, sodium acetate buffer, or carbonate buffer was allowed to
re-circulate over the equilibrated chip for 30 to 60 minutes at a
flow rate of 0.5 mL/min. During this time, association of
pinanediol acetate could be observed with the immobilized
4-mercaptophenylboronic acid. Dissociation was allowed to take
place over a period of 30 minutes with a flow rate of 0.5
mL/min.
[0122] Results
[0123] FIG. 6A shows affinity traces observed for 100 .mu.M
pinanediol acetate binding to the immobilized
4-mercaptophenylboronic acid. The buffer used was 50 mM sodium
acetate, 100 mM sodium chloride, pH 5.5.
[0124] FIG. 6B shows affinity traces observed for 100 .mu.M
pinanediol acetate binding to the immobilized
4-mercaptophenylboronic acid. The buffer used was phosphate
buffered saline with 0.05% Tween-20, pH 7.4.
[0125] FIG. 6C shows affinity traces observed for 100 .mu.M
pinanediol acetate binding to the immobilized
4-mercaptophenylboronic acid. The buffer used was sodium
carbonate-bicarbonate buffer pH 9.4.
[0126] This set of experiments demonstrates that the
cis-diol-borate conjugation can be achieved by first immobilizing
the borate-containing compound, and then capturing the constrained
cis-diol derivative under flow. The conjugation was observed at pH
5.5, pH 7.4, and pH 9.4. In all cases, the dissociation rate was
less than 10.sup.-5 s.sup.-1 and could not reliably measured
relative to the instrument and/or surface drift rate. The
association rates observed were less than or equal to 10
M.sup.-1s.sup.-1.
[0127] The section headings used herein are for organizational
purposes only and are not to be construed as limiting the subject
matter described in any way.
[0128] All literature and similar materials cited in this
application, including but not limited to, patents, patent
applications, articles, books, treatises, and internet web pages,
regardless of the format of such literature and similar materials,
are expressly incorporated by reference.
[0129] While the present teachings are described in conjunction
with various embodiments, it is not intended that the present
teachings be limited to such embodiments. On the contrary, the
present teachings encompass various alternatives, modifications,
and equivalents, as will be appreciated by those of skill in the
art.
* * * * *