U.S. patent application number 10/226657 was filed with the patent office on 2003-10-09 for glycosidase inhibitors and methods of synthesizing same.
Invention is credited to Ghavami, Ahmad, Johnston, Blair D., Pinto, Brian M..
Application Number | 20030191104 10/226657 |
Document ID | / |
Family ID | 26870587 |
Filed Date | 2003-10-09 |
United States Patent
Application |
20030191104 |
Kind Code |
A1 |
Pinto, Brian M. ; et
al. |
October 9, 2003 |
Glycosidase inhibitors and methods of synthesizing same
Abstract
A method for synthesizing Salacinol, its stereoisomers, and
non-naturally occurring selenium and nitrogen analogues thereof
having the general formula (I): 1 The compounds are potentially
useful as glycosidase inhibitors. The synthetic schemes comprise
reacting a cyclic sulfate with a 5-membered ring sugar containing a
heteroatom (X). The heteroatom preferably comprises sulfur,
selenium, or nitrogen. The cyclic sulfate and ring sugar reagents
may be readily prepared from carbohydrate precursors, such as
D-glucose, L-glucose, D-xylose and L-xylose. The target compounds
are prepared by opening of the cyclic sulfates by nucleophilic
attack of the heteroatoms on the 5-membered ring sugars. The
resulting heterocyclic compounds have a stable, inner salt
structure comprising a heteroatom cation and a sulfate anion. The
synthetic schemes yield various stereoisomers of the target
compounds in moderate to good yields with limited side-reactions.
In an alternative embodiment of the invention, the cyclic sulfate
may be similarly reacted with a 6-membered ring sugar containing a
heteroatom (X) to yield a compound having the general formula
(XII): 2
Inventors: |
Pinto, Brian M.; (Coquitlam,
CA) ; Johnston, Blair D.; (Vancouver, CA) ;
Ghavami, Ahmad; (Coquitlam, CA) |
Correspondence
Address: |
Charles D. McClung
1600 ODS Tower
601 S. W. Second Avenue
Portland
OR
97204-3157
US
|
Family ID: |
26870587 |
Appl. No.: |
10/226657 |
Filed: |
August 22, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10226657 |
Aug 22, 2002 |
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09627434 |
Jul 28, 2000 |
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6455573 |
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60174837 |
Jan 7, 2000 |
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Current U.S.
Class: |
514/183 ;
514/424; 514/438; 540/1; 548/542; 549/62 |
Current CPC
Class: |
A61P 3/10 20180101; A61P
3/08 20180101; C07D 345/00 20130101; A61P 25/28 20180101; C07D
207/12 20130101; A61P 35/00 20180101; C07D 333/46 20130101; A61P
43/00 20180101; A61P 35/04 20180101 |
Class at
Publication: |
514/183 ;
514/424; 514/438; 540/1; 548/542; 549/62 |
International
Class: |
A61K 031/4015; A61K
031/381; C07D 345/00; C07D 333/18; C07D 27/24 |
Claims
What is claimed is:
1. A non-naturally occurring compound selected from the group
consisting of compounds represented by the general formula (I) and
stereoisomers and pharmaceutically acceptable salts thereof:
27where X is selected from the group consisting of S, Se and NH;
R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are the same or
different and are selected from the group consisting of H, OH, SH,
NH.sub.2, halogens and constituents of compounds selected from the
group consisting of cyclopropanes, epoxides, aziridines and
episulfides; and R.sub.6 is selected from the group consisting of H
and optionally substituted straight chain, branched, or cyclic,
saturated or unsaturated hydrocarbon radicals.
2. The compound as defined in claim 1, wherein R.sub.1, R.sub.2,
R.sub.3, R.sub.4 and R.sub.6 are OH and R.sub.5 is H.
3. The compound as defined in claim 1, wherein R.sub.1, R.sub.2,
R.sub.3, R.sub.4 and R.sub.5 are OH and R.sub.6 is
C.sub.3H.sub.7O.sub.3.
4. A process for the production of the compound of claim 1,
comprising reacting a cyclic sulfate having the general formula
(II) with a 5-membered ring sugar having the general formula (III)
28where X is selected from the group consisting of S, Se, and NH;
R.sup.1 and R.sup.2 are selected from the group consisting of H and
a protecting group; R.sup.3 is selected from the group consisting
of H and optionally substituted straight chain, branched, or
cyclic, saturated or unsaturated hydrocarbon radicals and their
protected derivatives; and R.sup.4, R.sup.5 and R.sup.6 are the
same or different and are selected from the group consisting of H,
OH, SH, NH.sub.2, halogens and constituents of compounds selected
from the group consisting of cyclopropanes, epoxides, aziridines
and episulfides and their protected derivatives
5. The process as defined in claim 4, wherein said cyclic sulfate
is a 2,4-di-O-protected-D-or L-erythritol-1,3-cyclic sulfate.
6. The process as defined in claim 5, wherein said cyclic sulfate
is 2,4-O-Benzylidene-D-or L-erythritol-1,3-cyclic sulfate.
7. The process as defined in claim 4, wherein R.sup.3 is a
protected polyhydroxylated alkyl chain.
8. The process as defined in claim 4, wherein R.sup.4, R.sup.5, and
R.sup.6 are selected from the group consisting of OH and
OCH.sub.2C.sub.6H.sub.5.
9. The process as defined in claim 4, comprising the step of
opening the cyclic sulfate (II) by nucleophilic attack of the
heteroatom X on the sugar (III).
10. The process as defined in claim 4, wherein the coupling
reaction is carried out in a solvent selected from the group
consisting of acetone and methanol.
11. The process as defined in claim 10, further comprising the step
of adding a base to said solvent.
12. A pharmaceutical composition comprising an effective amount of
a compound according to claim 1 together with a pharmaceutically
acceptable carrier.
13. A method of treating a carbohydrate metabolic disorder in an
affected patient comprising the step of administering to said
patient a therapeutically effective amount of a compound according
to claim 1.
14. The method of claim 13, wherein said carbohydrate metabolic
disorder is non-insulin dependent diabetes.
15. A method of treating tumor cell proliferation and metastasis in
an affected patient comprising administering to said patient a
therapeutically effective amount of a compound according to claim
1.
16. A process for the production of a compound having the formula
(VI) comprising reacting a cyclic sulfate selected from the group
consisting of compounds having the formulas (VII) and (VIII) with a
sugar compound having the formula (IX) where R.dbd.H, COR,
CH.sub.2C.sub.6H.sub.5, CH.sub.2C.sub.6H.sub.4--OMe.sub.p. 29
17. A compound selected from the group consisting of compounds
represented by the general formula (XII) and stereoisomers and
pharmaceutically acceptable salts thereof: 30where X is selected
from the group consisting of S, Se and NH; R.sub.1, R.sub.2,
R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are the same or different and
are selected from the group consisting of H, OH, SH, NH.sub.2,
halogens and constituents of compounds selected from the group
consisting of cyclopropanes, epoxides, aziridines and episulfides;
and R.sub.7 is selected from the group consisting of H and
optionally substituted straight chain, branched, or cyclic,
saturated or unsaturated hydrocarbon radicals.
18. A process for the production of the compound of claim 17,
comprising reacting a cyclic sulfate having the general formula
(II) with a 6-membered ring sugar having the general formula (XI)
31where X is selected from the group consisting of S, Se, and NH;
R.sup.1 and R.sup.2 are selected from the group consisting of H and
a protecting group; R.sup.3 is selected from the group consisting
of H and optionally substituted straight chain, branched, or
cyclic, saturated or unsaturated hydrocarbon radicals and their
protected derivatives; and R.sup.4, R.sup.5, R.sup.6 and R.sup.7
are selected from the group consisting of H, OH, SH, NH.sub.2,
halogens and constituents of compounds selected from the group
consisting of cyclopropanes, epoxides, aziridines and episulfides
and their protected derivatives.
19. The process of claim 18, wherein R.sup.3 is a protected
polyhydroxylated alkyl chain or its protected derivative.
Description
[0001] This application is a continuation of application Ser. No.
09/627,434 filed 28 Jul. 2000, which is currently pending.
TECHNICAL FIELD
[0002] This application relates to methods for synthesizing
Salacinol, its stereoisomers, and analogues thereof potentially
useful as glycosidase inhibitors.
BACKGROUND
[0003] In treatment of non-insulin dependent diabetes (NIDD)
management of blood glucose levels is critical. One strategy for
treating NIDD is to delay digestion of ingested carbohydrates,
thereby lowering post-prandial blood glucose concentration. This
can be achieved by administering drugs which inhibit the activity
of enzymes, such as glucosidases, which mediate the hydrolysis of
complex starches to oligosaccharides in the small intestine. For
example, carbohydrate analogues, such as acarbose, reversibly
inhibit the function of pancreatic .alpha.-amylase and
membrane-bound intestinal .alpha.-glucoside hydrolase enzymes. In
patients suffering from Type II diabetes, such enzyme inhibition
results in delayed glucose absorption into the blood and a
smoothing or lowering of postprandial hyperglycemia, resulting in
improved glycemic control.
[0004] Some naturally-occurring glucosidase inhibitors have been
isolated from Salacia reticulate, a plant native to submontane
forests in Sri Lanka and parts of India (known as "Kotala himbutu"
in Singhalese). Salacia reticulate is a woody climbing plant which
has been used in the Ayurvedic system of Indian medicine in the
treatment of diabetes. Traditionally, Ayurvedic medicine advised
that a person suffering from diabetes should drink water left
overnight in a mug carved from Kotala himbutu wood. In an article
published in 1997, Yoshikawa et al. reported the isolation of the
compound Salacinol from a water-soluble fraction derived from the
dried roots and stems of Salacia reticulate..sup.1 Yoshikawa et al.
determined the structure of Salacinol, shown below, and
demonstrated its efficacy as an .alpha.-glucosidase inhibitor.
3
[0005] Yoshikawa et al. later reported the isolation from the roots
and stems of Salacia reticulate of Kotalanol which was also shown
to be effective as an .alpha.-glucosidase inhibitor..sup.2 Like
Salicinol, Kotalanol contains a thiosugar sulfonium ion and an
internal sulfate providing the counterion: 4
[0006] Kotalanol has been found to show more potent inhibitory
activity against sucrase than Salicinol and acarbose..sup.2
[0007] The exact mechanism of action of Salacinol and other
glucosidase inhibitors has not yet been elucidated. Some known
glycosidase inhibitors, such as the indolizidine alkaloids
castanospermine and swainsonine, are known to carry a positive
charge at physiological pH. 5
[0008] It is believed that the mechanism of action of some known
inhibitors may be at least partially explained by the establishment
of stabilizing electrostatic interactions between the inhibitor and
the enzyme active site carboxylate residues. It is postulated that
the compounds of the present invention, which comprise postively
charged sulfonium, ammonium, and selenonium ions, could function in
a similar manner. It is also possible that Salacinol and other
compounds of the same class may act by alteration of a transport
mechanism across the intestinal wall rather than by directly
binding to glucosidase enzymes.
[0009] Salacinol and Kotalanol may potentially have fewer long-term
side effects than other existing oral antidiabetic agents. For
example, oral administration of acarbose in the treatment of Type
II diabetes results in undesirable gastrointestinal side effects in
some patients, most notably increased flatulence, diarrhoea and
abdominal pain. As mentioned above, Salacinol has been used as a
therapy for diabetes in the Ayurvedic system of traditional
medicine for many years with no notable side effects reported.
Further, recent animal studies have shown that the oral ingestion
of an extractive from a Salacia reticulate trunk at a dose of 5,000
mg/kg had no serious acute toxicity or mutagenicity in
rats..sup.3
[0010] The Salacia reticulate plant is, however, in relatively
small supply and is not readily available outside of Sri Lanka and
India. Accordingly, it would be desirable if Salicinol, Kotalanol
and analogues thereof could be produced synthetically.
[0011] Carbohydrate processing inhibitors have also been shown to
be effective in the treatment of some non-diabetic disorders, such
as cancer. While normal cells display characteristic
oligosaccharide structures, tumor cells display very complex
structures that are usually found in embryonic tissues. It is
believed that these complex structures provide signal stimuli for
rapid proliferation and metastasis of tumor cells. A possible
strategy for therapeutic use of glucosidase inhibitors is to take
advantage of the differential rates of normal vs cancer cell growth
to inhibit assembly of complex oligosaccharide structures. For
example, the indolizidine alkaloid swainsonine, an inhibitor of
Golgi .alpha.-mannosidase II, reportedly reduces tumor cell
metastasis, enhances cellular immune responses, and reduces tumor
cell growth in mice..sup.4 Swainsonine treatment has led to
significant reduction of tumor mass in human patients with advanced
malignancies, and is a promising drug therapy for patients
suffering from breast, liver, lung and other
malignancies..sup.5,6
[0012] The compounds of the present invention may also find
application in the treatment of Alzheimer's disease due to their
stable, internal salt structure. Alzheimer's is characterized by
plaque formation in the brain caused by aggregation of a peptide,
.beta.-amyloid, into fibrils. This is toxic to neuronal cells. One
can inhibit this aggregation by using detergent-like molecules. It
is believed that the compounds of the present invention, which are
amphipathic, may demonstrate this activity.
[0013] The need has therefore arisen for a new class of glycosidase
inhibitors which may be synthesized in high yields from readily
available starting materials and which have potential use as
therapeutics.
SUMMARY OF THE INVENTION
[0014] In accordance with the invention, a compound selected from
the group consisting of non-naturally occurring compounds
represented by the general formula (I), including stereoisomers and
pharmaceutically acceptable salts thereof is disclosed, 6
[0015] where X is selected from the group consisting of S, Se, and
NH. Such compounds include stereoisomers of Salicinol. The target
compounds have a stable, internal salt structure comprising
heteroatom cation X and a sulfate anion; the substituents may vary
without departing from the invention. Preferably, R.sub.1, R.sub.2,
R.sub.3, R.sub.4 and R.sub.5 are the same or different and are
selected from the group consisting of H, OH, SH, NH.sub.2, halogens
and constituents of compounds selected from the group consisting of
cyclopropanes, epoxides, aziridines and episulfides; and R.sub.6 is
selected from the group consisting of H and optionally substituted
straight chain, branched, or cyclic, saturated or unsaturated
hydrocarbon radicals, such as alkyl, alkenyl, alkynyl, aryl, and
alkoxy substituents containing any suitable functionality.
[0016] Processes for the production of compounds of the general
formula (I) are also disclosed comprising reacting a cyclic sulfate
having the general formula (II) with a 5-membered ring sugar having
the general formula (III) 7
[0017] where X is selected from the group consisting of S, Se, and
NH; R.sup.1 and R.sup.2 are selected from the group consisting of H
and a protecting group; R.sup.3 is selected from the group
consisting of H and optionally substituted straight chain,
branched, or cyclic, saturated or unsaturated hydrocarbon radicals
and their protected derivatives; and R.sup.4, R.sup.5 and R.sup.6
are the same or different and are selected from the group
consisting of H, OH, SH, NH.sub.2, halogens and constituents of
compounds selected from the group consisting of cyclopropanes,
epoxides, aziridines and episulfides and their protected
derivatives. Preferably the cyclic sulfate is a
2,4-di-O-protected-D-or L-erythritol-1,3-cyclic sulfate, such as
2,4-O-Benzylidene-D-or L-erythritol-1,3-cyclic sulfate (i.e.
R.sup.1 and R.sup.2 comprise a benzylidene protecting group);
R.sup.3 is H or a protected polyhydroxylated alkyl chain; and
R.sup.4, R.sup.5 and R.sup.6 are selected from the group consisting
of OH and a protected OH group, such as OCH.sub.2C.sub.6H.sub.5.
The synthetic processes comprise the step of opening the cyclic
sulfate (II) by nucleophilic attack of the heteroatom X on the
sugar (III).
[0018] In an alternative embodiment of the invention, the cyclic
sulfate (II) may be reacted with a 6-membered ring sugar having the
general formula (XI) to yield a compound having the general formula
(XII): 8
[0019] where X is selected from the group consisting of S, Se and
NH. In this embodiment R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5
and R.sub.6 are the same or different and are selected from the
group consisting of H, OH, SH, NH.sub.2, halogens and constituents
of compounds selected from the group consisting of cyclopropanes,
epoxides, aziridines and episulfides and R.sub.7 is selected from
the group consisting of H and optionally substituted straight
chain, branched, or cyclic, saturated or unsaturated hydrocarbon
radicals. Preferably R.sup.1, R.sup.2 and R.sup.3 are as described
above in respect of compound (II) and R.sup.4, R.sup.5, R.sup.6 and
R.sup.7 are selected from the group consisting of H, OH, SH,
NH.sub.2, halogens and constituents of compounds selected from the
group consisting of cyclopropanes, epoxides, aziridines and
episulfides and their protected derivatives.
[0020] The application also relates to pharmaceutical compositions
comprising an effective amount of a compound according to formula
(I) or (XII) together with a pharmaceutically acceptable carrier
and to methods of treating carbohydrate metabolic disorders, such
as non-insulin dependent diabetes, or different forms of cancer or
Alzheimer's disease by administering to a subject in need of such
treatment an effective amount of such compounds.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] Salacinol is a naturally occurring compound which may be
extracted from the roots and stems of Salacia reticulate, a plant
native to Sri Lanka and India. This application relates to
synthetic routes for preparing Salacinol (1), and its nitrogen (2)
and selenium (3) analogues shown below. 9
[0022] This application also relates to synthetic routes for
preparing the stereoisomers of compounds (1) to (3). Such analogues
and stereoisomers (including stereoisomers of Salacinol) comprise a
new class of compounds which are not naturally occurring and may
find use as glycosidase inhibitors.
[0023] 1.0 Summary of General Synthetic Scheme
[0024] Scheme 1(a) below, shows the general synthetic scheme
developed by the inventors for arriving at the target compounds. To
synthesize different stereoisomers of Salacinol and its nitrogen
and selenium analogues (A)-(C), 5-membered-ring sugars are reacted
with sulfate-containing compounds in accordance with the invention
(in Scheme 1(a) the letters (A), (B), and (C) represent all
stereoisomers of Salacinol and its nitrogen and selenium analogues
(1), (2) and (3) respectively). The inventors followed a
disconnection approach for determining the preferred synthetic
route. A reasonable disconnection is one that gives the
5-membered-ring sugars (D) since they can be synthesized easily
from readily available carbohydrate precursors. Nucleophilic
substitution at C.sub.1 of the sulfate fragment (E) can then yield
the target molecules (Scheme 1(a)). A potential problem with this
approach is that the leaving group (L) might act later as a base to
abstract the acidic hydrogens of the sulfonium salt.sup.7 and
produce unwanted products. Therefore, the cyclic sulfate (F) may be
used instead of (E) to obviate the problems associated with leaving
group (L). Compound (G) may similarly be used as a cyclic sulfate
reagent and is a protected version of (F). 10
[0025] Scheme 1(a). Disconnection approach for the synthesis of
(A)-(C) (R.dbd.H, --CH.sub.2C.sub.6H.sub.5 and L=leaving
group).
[0026] Scheme 1(b) below shows generally the coupling reactions for
producing the target compounds (A)-(C). 11
[0027] Route 1 of Scheme 1(b) shows the general strategy of
reacting a cyclic sulfate with a 5-membered ring sugar to produce
an intermediate compound, which may include benzyl or other
protecting groups. As described in further detail below, the
intermediate compound is then deprotected to yield the target
compounds. The inventors have determined that Route 2 of Scheme
1(b), a possible side reaction, does not occur.
[0028] 2.0 Synthesis of Reagents
[0029] Cyclic sulfates and 5-membered-ring sugars were prepared in
accordance with the synthetic schemes described below. As will be
apparent to a person skilled in the art, other equivalent schemes
for producing the reagents of the invention could be
substituted.
[0030] 2.1 Cyclic sulfates
[0031] Cyclic sulfates were prepared in analogous fashion to the
ethylidene acetal..sup.8 The cyclic sulfate (7) was synthesized in
4 steps starting from D-glucose (Scheme 2).
2,4-O-Benzylidene-D-erythrithol (5) was synthesized from D-glucose
in two steps,.sup.9,10 and then treated with thionyl chloride to
yield the cyclic sulfite (6) which was oxidized to the cyclic
sulfate (7) as described by Calvo-Flores et al..sup.8 12
[0032] The enantiomer (10) was also synthesized using the same
route but starting from L-glucose (Scheme 3). 13
[0033] 2.2 Synthesis of 5-Membered-ring Heterocycles
[0034] In order to synthesize one of the 5-membered-ring sugars (D,
X.dbd.S), 1,4-anhydro-3-O-benzyl-4-thio-D-arabinitol (11), was
synthesized in 9 steps starting from D-glucose (Scheme 4)..sup.11
Benzylation of the compound (11), using benzyl bromide in DMF
yielded 1,4-anhydro-2,3,5-tri-O-benzyl-4-thio-D-arabinitol (12) in
90% yield. Compound (11) was debenzylated to give
1,4-anhydro-4-thio-D-arabinitol (13) in 97% yield using a Birch
reduction. 14
[0035] The L-isomer,
1,4-anhydro-2,3,5-tri-O-benzyl-4-thio-L-arabinitol (14) was
synthesized in 5 steps starting from D-xylose (Scheme 5)..sup.12
15
[0036] 1,4-Di-O-methanesulfonyl-2,3,5-tri-O-benzyl-D-xylitol (15)
is also a key intermediate for the synthesis of the aza and selena
sugars (16) and (17). 1,4-Dideoxy-1,4-imino-L-arabinitol
(16).sup.13 was synthesized in 7 steps starting from D-xylose
(Scheme 5). The enantiomer (19).sup.13 was synthesized in an
analogous way starting from L-xylose (Scheme 6). Compound (19) was
also synthesized in 10 steps starting from D-xylose..sup.13
1,4-Anhydro-2,3,5-tri-O-benzyl-4-seleno-D-arabinitol (20) was
synthesized in 5 steps starting from L-xylose (Scheme 6). To
synthesize compound (20), Na.sub.2Se was made in-situ by treatment
of selenium metal with sodium in liquid ammonia. 16
[0037] Scheme 6(a) below shows a more generalized scheme for
synthesizing compound (20) using other possible protecting groups
(R.dbd.COR, CH.sub.2C.sub.6H.sub.4--OMe.sub.p). 17
[0038] 3.0 Synthesis of the Target Compounds
[0039] The target compounds (1)-(3) were prepared by opening of the
cyclic sulfates by nucleophilic attack of the heteroatoms on the
5-membered rings (Scheme 1(b) above). The heteroatom gives rise to
a positively charged cation and the cyclic sulfate gives rise to a
negatively charged counterion. This internal salt structure may
explain the stability of the target compounds toward decomposition
by further nucleophilic attack.
[0040] 3.1 Synthesis of Salacinol
[0041] Salacinol (1) was synthesized by nucleophilic substitution
of the protected thio-arabinitol (12) with the cyclic sulfate (10)
(1.2 equiv) in dry acetone containing K.sub.2CO.sub.3, to give the
protected intermediate compound (21) in 33% yield. Hydrogenolysis
of the benzyl and benzylidene groups in AcOH:H.sub.2O, 4:1 afforded
Salacinol (1) in 67% yield (Scheme 7). 18
[0042] The same procedure was used to prepare intermediate compound
(22) in 79% yield from the enantiomeric cyclic sulfate (7).
Deprotection as before gave compound (23) in 59% yield (Scheme 8).
Compound (23) is a diastereomer of Salacinol (1). 19
[0043] Compound (24) was prepared in 40% yield from (7) and the
enantiomeric thio-ether (14) (Scheme 9). Deprotection in 80% yield
gave the enantiomer of Salacinol (25). 20
[0044] To reduce the number of synthetic steps, the inventors
attempted the coupling reactions with the deprotected
thio-arabinitols. Thus, the partially deprotected compound (11) was
reacted with the cyclic sulfate (10) in acetone, to give compound
(26) in 32% yield. Deprotection yielded Salacinol (1) in 36% yield
(Scheme 10). 21
[0045] The fully-deprotected thio-arabinitol (13) was not soluble
in acetone and the reaction in methanol produced several
products.
[0046] 3.2 Synthesis of Selenium Analogues
[0047] The seleno-analogue intermediate (27)
(R.dbd.CH.sub.2C.sub.6H.sub.5- ) was made starting from the
seleno-arabinitol (20) (R.dbd.CH.sub.2C.sub.6H.sub.5) and the
cyclic sulfate (10) in excellent yield 86% (Scheme 11), but NMR
spectroscopy showed the presence of two isomers in a ratio of 7:1
that differed in stereochemistry at the stereogenic selenium
center. The isomers were separable by analytical HPLC. The
inventors have assigned the name "Blintol" to the new selenium
analogue (3). 22
[0048] The seleno-analogue intermediate (28)
(R.dbd.CH.sub.2C.sub.6H.sub.5- ) was made starting from the
seleno-arabinitol (20) (R.dbd.CH.sub.2C.sub.6H.sub.5) and the
cyclic sulfate (7) in excellent yield 97% (Scheme 12); a mixture of
two isomers in a ratio of 3:1 that differed in stereochemistry at
the stereogenic selenium center was obtained. The isomers were
separable by analytical HPLC. 23
[0049] Compound (29) is a diastereomer of Blintol (3).
[0050] 3.3 Synthesis of Nitrogen Analogues
[0051] The nitrogen analogue intermediate (30) was made by the
reaction of the deprotected imino-arabinitol (19) with the cyclic
sulfate (10) in a good yield 72% (Scheme 13). Compound (19) was not
soluble in acetone so the reaction was performed in dry methanol. A
side product (19%) which was identified to be the product of
methanolysis of the cyclic sulfate was obtained. The inventors have
assigned the name "Ghavamiol" to the new nitrogen analogue (2).
Compound (30) was deprotected to give Ghavamiol (2) in 64% yield.
24
[0052] The enantiomer intermediate (31) was made by the reaction of
the deprotected imino-arabinitol (16) with the cyclic sulfate (7)
in a good yield 72% (Scheme 14). A side product (21%) which was
identified to be the product of methanolysis of the cyclic sulfate
was obtained. Compound (31) was deprotected to give compound (32)
in 77% yield. Compound (32) is the enantiomer of Ghavamiol (2).
25
[0053] 4.0 Alternative Synthetic Scheme
[0054] In an alternative embodiment of the invention, target
compounds having potential application as glycosidase inhibitors
may be synthesized in the manner described above using 6-membered
rather than 5-membered ring heterocycles as reagents. As in the
embodiments described above, the cyclic sulfate (described above)
is opened in the coupling reaction due to nucleophilic attack of
the heteroatoms (i.e. X.dbd.S, Se, N) on the ring sugars. As will
be apparent to a person skilled in the art, the general formulas
for the 6-membered sugar reagent and resulting target compound are
as shown below. 26
[0055] The 6-membered ring target compound shares the same internal
salt structure as the 5-membered ring embodiment. The substituent
groups may vary as described above without departing from the
invention.
5.0 EXAMPLES
[0056] The following examples will further illustrate the invention
in greater detail although it will be appreciated that the
invention is not limited to the specific examples.
[0057] 5.1 Experimental Methods
[0058] Optical rotations were measured at 20.degree. C. .sup.1H and
.sup.13C NMR spectra were recorded at 400.13 and 100.6 MHz for
proton and carbon respectively. All assignments were confirmed with
the aid of two-dimensional .sup.1H,.sup.1H (COSYDFTP) or
.sup.1H,.sup.13C (INVBTP) experiments using standard Bruker pulse
programs. MALDI-TOF mass spectra were obtained for samples
dispersed in a 2,5-dihydroxybenzoic acid matrix using a Perseptive
Biosystems Voyager-DE instrument. Silica gel for chromatography was
Merck kieselgel 60. High resolution mass spectra were LSIMS (Fab),
run on a Kratos Concept H double focussing mass spectrometer at
10000 RP.
[0059] 5.2 Preparation of Intermediates
5.2.1 Example 1
Preparation of Cyclic Sulfate (7) (Scheme 2)
[0060] Step 1--2,4-O-Benzylidene-D-erythritol (5).
[0061] Compound (5) was prepared from 4,6-O-benzylidene-D-glucose
(4) according to standard procedures..sup.9,10 Compound (5) has
been mentioned by MacDonald et al.,.sup.10 without
characterization, which is therefore dealt with here. Mp
138-139.degree. C.; [.alpha.].sub.D -44.degree. (c 1.0, MeOH);
.sup.1H NMR (CD.sub.3OD): .delta.7.53-7.28 (5H, m, Ar), 5.53 (1H,
s, H-5), 4.2 (1H, dd, J=10.1, 3.6 Hz, H-4a), 3.92 (1H, dd, J=12.1,
1.7 Hz, H-1a), 3.74 (1H, dd, J=12.1, 5.7 Hz, H-1b), 3.67-3.55 (3H,
m, H-3, H-2, H-4b); .sup.13C NMR (100.6 MHz, CD.sub.3OD):
.delta.139:52 (C.sub.ipso), 129.77 (C.sub.para), 128.99, 127.49
(4C.sub.ortho+meta), 102.36 (C-5), 84.22 (C-3), 72.21 (C-4), 62.76
(C-1), 62.59 (C-2); MALDI-TOF MS: m/e 211 (M.sup.++H), 233
(M.sup.++Na). Anal. Calcd for C.sub.11H.sub.14O.sub.4: C, 62.83; H,
6.72. Found: C, 62.96; H, 6.55.
[0062] Step 2--2,4-O-Benzylidene-D-erythritol-1,3-cyclic Sulfite
(6).
[0063] A solution of the diol (5) (4.5 g, 21 mmol) and Et.sub.3N
(11 mL, 4 equiv) in dry CH.sub.2Cl.sub.2 (90 mL) was added dropwise
to a solution of SOCl.sub.2 (2.4 mL, 1.5 equiv) in dry
CH.sub.2Cl.sub.2 (60 mL), with stirring in an ice-bath under an
N.sub.2 atmosphere. Stirring was continued at 0.degree. C., until
TLC (hex:EtOAc, 4:1) showed complete disappearance of the starting
material. The mixture was diluted with CH.sub.2Cl.sub.2 (150 mL)
and washed with H.sub.2O (150 mL) and brine (150 mL). The organic
solution was dried (Na.sub.2SO.sub.4) and concentrated on a rotary
evaporator. The product was purified by flash chromatography
[hex:EtOAc, 4:1+0.1% Et.sub.3N] to give a mixture of two
diastereomers (4.5 g, 82%). One of the isomers was selectively
recrystallized from EtOAc:hex. Mp 137-139.degree. C.;
[.alpha.].sub.D +32.degree. (c 1.0, CH.sub.2Cl.sub.2); .sup.1H NMR
(CD.sub.2Cl.sub.2): .delta.7.48-7.36 (5H, m, Ar), 5.68 (1H, s,
H-5), 5.04 (1H, ddd, J=10.4, 9.5, 5.0 Hz, H-3), 4.80 (1H, dd,
J=10.4, 10.4 Hz, H-1a), 4.24 (1H, dd, J=10.5,5.0 Hz, H-4e), 4.18
(1H, ddd, J=10.4, 9.5, 4.8 Hz, H-2), 4.06 (1H, dd, J=10.4, 4.8 Hz,
H-1e), 3.89 (1H, dd, J=10.5,10.4 Hz, H-4a); .sup.13C NMR (100.6
MHz, CD.sub.2Cl.sub.2): .delta.137.14 (C.sub.ipso), 129.74
(C.sub.para), 128.65, 126.50 (4C.sub.ortho+meta), 102.72 (C-5),
73.56 (C-2), 68.16 (C-4), 63.90 (C-3), 60.18 (C-1). Anal. Calcd for
C.sub.11H.sub.12O.sub.5S: C, 51.55; H, 4.72. Found: C, 51.80; H,
4.66.
[0064] Step 3--2,4-O-Benzylidene-D-erythritol-1,3-cyclic Sulfate
(7).
[0065] The cyclic sulfite (6) (3.5 g, 14 mmol) was dissolved in a
mixture of MeCN (50 mL) and CCl.sub.4 (50 mL), and NaIO.sub.4 (4.1
g, 1.5 equiv) and RuCl.sub.3.H.sub.2O (50 mg) were added followed
by H.sub.2O (50 mL). The mixture was stirred vigorously at rt until
TLC (hex:EtOAc,4:1) showed complete disappearance of the starting
material. The mixture was diluted with Et.sub.2O (200 mL) and
washed with H.sub.2O (200 mL) and brine (200 mL). The organic
solution was dried (Na.sub.2SO.sub.4) and concentrated on a rotary
evaporator. The product was purified by flash chromatography
[hex:EtOAc, 4:1+0.1% Et.sub.3N] to yield a white solid (3.5 g,
95%). A portion of the product was recrystallized from EtOAc:hex.
Mp 115-125.degree. C. (dec); [.alpha.].sub.D +4.degree. (c 1.0,
CHCl.sub.3); .sup.1H NMR (CD.sub.2Cl.sub.2): .delta.7.48-7.37 (5H,
m, Ar), 5.65 (1H, s, H-5), 4.86 (1H, ddd, J=10.2, 9.8, 5.0 Hz,
H-3), 4.76 (1H, dd, J=10.7, 10.5 Hz, H-1a), 4.65 (1H, dd,
J=10.5,5.0 Hz, H-1e), 4.44 (1H, dd, J=10.5, 5.0 Hz, H-4e), 4.25
(1H, ddd, J=10.7, 9.8, 5.0 Hz, H-2), 3.97 (1H, dd, J=10.5,10.2 Hz,
H-4a); .sup.13C NMR (100.6 MHz, CD.sub.2Cl.sub.2): .delta.136.32
(C.sub.ipso), 130.03 (C.sub.para), 128.74, 126.52
(4C.sub.ortho+meta), 102.98 (C-5), 75.74 (C-3), 73.19 (C-1), 71.68
(C-2), 67.64 (C-4); MALDI-TOF MS: m/e 273 (M.sup.++H), Anal. Calcd
for C.sub.11H.sub.12O.sub.6S: C, 48.52; H, 4.45. Found: C, 48.43;
H, 4.39.
5.2.2 Example 2
Preparation of Thio-arabinitol (Scheme 4)
[0066] 1,4-Anhydro-2,3,5-tri-O-benzyl-4-thio-D-arabinitol(12).
[0067] A mixture of 1,4-anhydro-3-O-benzyl-4-thio-D-arabinitol (1.0
g, 4.2 mmol) and 60% NaH (0.85 g, 5 equiv) in DMF (20 mL) was
stirred in an ice-bath for 1 h. A solution of benzyl bromide (1.9
mL, 3.8 equiv) in DMF (5 mL) was added and the solution was stirred
at rt for 3 h. The mixture was added to ice-water (150 mL) and
extracted with Et.sub.2O (150 mL). The organic solution was dried
(Na.sub.2SO.sub.4) and concentrated. The product was purified by
flash chromatography [hex:EtOAc, 4:1] to give a syrup (1.6 g, 90%).
[.alpha.].sub.D +5.degree. (c 1.6, CHCl.sub.3); .sup.1H NMR
(CDCl.sub.3): .delta.7.38-7.23 (15H, m, Ar), 4.64-4.45 (6H, m,
CH.sub.2Ph), 4.19 (1H, dd, J=8.9, 4.6 Hz, H-2), 4.11 (1H, dd,
J=7.2, 3.8 Hz, H-3), 3.69 (1H, dd, J=8.8, 7.6 Hz, H-5a), 3.57 (1H,
ddd, J=7.5, 6.4, 3.6 Hz, H-4), 3.50 (1H, dd, J=8.9, 6.3 Hz, H-5b),
3.08 (1H, dd, J=11.4, 5.1 Hz, H-1a), 2.91 (1H, dd, J=11.4, 4.6 Hz,
H-1b). .sup.13C NMR (100.6 MHz, CDCl.sub.3): .delta.138.16, 138.06,
137.88 (3C.sub.ipso), 128.40-127.59 (15C.sub.Ar), 85.08 (C-3),
85.04 (C-2), 73.01 (CH.sub.2Ph), 72.34 (C-5),
71.85,71.50(2CH.sub.2Ph), 48.99 (C-4), 33.10 (C-1). Anal. Calcd for
C.sub.26H.sub.28O.sub.3S: C, 74.25; H, 6.72. Found: C, 74.18; H,
6.53.
5.2.3 Example 3
Preparation of Seleno-arabinitol (Scheme 6)
[0068] 1,4-Anhydro-2,3,5-tri-O-benzyl-4-seleno-D-arabinitol
(20).
[0069] Selenium metal (1.1 g, 14 mmol) was added to liquid NH.sub.3
(60 mL) in a -50.degree. C. bath and small pieces of Na (0.71 g)
were added until a blue color appeared. A small portion of selenium
(20 mg) was added to remove the blue color. NH.sub.3 was removed by
warming on a water bath and DMF was added and removed under high
vacuum to remove the rest of NH.sub.3. A solution of the mesylated
compound (18) (7.4 g, 12.7 mmol) in DMF (100 mL) was added and the
mixture was stirred under N.sub.2 in a 70.degree. C. bath for 3 h.
The mixture was cooled and the solvent was removed on high vacuum.
The product was partitioned between CH.sub.2Cl.sub.2 (150 mL) and
water (50 mL), and the organic solution was washed with water (50
mL) and brine (50 mL) and dried (MgSO.sub.4). The product was
purified by flash chromatography (hex:EtOAc, 3:1) to give a yellow
oil (4.74 g, 80%). [.alpha.].sub.D +220.degree. (c 1.3,
CHCl.sub.3); .sup.1H NMR (CDCl.sub.3): .delta.7.22-7.48 (15H, m,
Ar), 4.67, 4.61 (2H, 2d, J=11.8 Hz, CH.sub.2Ph), 4.56, 4.48 (2H,
2d, J=12.1 Hz,CH.sub.2Ph), 4.53, 4.50 (2H, 2d, CH.sub.2Ph), 4.22
(1H, dd, J=10.1, 5.1 Hz, H-2), 4.07 (1H, dd, J=4.6, 4.6 Hz, H-3),
3.85 (1H, dd, J=9.2, 7.6 Hz, H-5a), 3.77 (1H, ddd, J=7.5, 6.9, 4.5
Hz, H-4), 3.53 (1H, dd, J=9.1, 6.8 Hz, H-5b), 3.11 (1H, dd, J=10.4,
5.1 Hz, H-1a), 2.96 (1H, dd, J=10.4, 5.3 Hz, H-1b). .sup.13C NMR
(100.6 MHz, CDCl.sub.3): .delta.138.24, 138.21, 138.06
(3C.sub.ipso), 128.40-127.60 (15C.sub.Ar), 85.93 (C-2), 85.63
(C-3), 72.96 (C-5, CH.sub.2Ph), 72.14,71.50(2CH.sub.2Ph), 42.59
(C-4), 23.96 (C-1). Anal. Calcd for C.sub.26H.sub.28O.sub.3Se: C,
66.65; H, 6.03. Found: C, 66.49; H, 6.05.
5.2.4 Example 4
General Procedure for the Synthesis of the Protected Sulfonium,
Selenonium and Ammonium Sulfates (21), (22), (24), (26), (27),
(28), (30), (31) (Schemes 7 -14).
[0070] The thio, aza or selenosugar (3 mmol) and the cyclic sulfate
(1.2 equiv) were dissolved in dry acetone (in the case of (21),
(22), (24), (26), (27) and (28)) or dry methanol (in the case of
(30) and (31)) (0.5 mL) and anhydrous K.sub.2CO.sub.3 (7 mg) was
added. The mixture was stirred in a Caries tube in an oil-bath
(75.degree. C.) overnight. The solvent was removed under reduced
pressure and the product was purified by column chromatography.
[0071]
1-((1',4'-Anhydro-2',3',5'-tri-O-benzyl-4'-thio-D-arabinitol)-4'-S--
yl)-2,4-O-benzylidene-1-deoxy-L-erythritol-3-sulfate (21).
[0072] Column chromatography [CHCl.sub.3:MeOH, 10:1+0.1% Et.sub.3N]
of the crude product gave an amorphous solid (33%). [.alpha.].sub.D
-11.9.degree. (c 1.7, CH.sub.2Cl.sub.2); .sup.1H NMR
(CD.sub.2Cl.sub.2): .delta.7.49-7.12 (20H, m, Ar), 5.54 (1H, s,
H-5), 4.59 (1H, ddd, J=9.9, 5.4, 4.5 Hz, H-3), 4.55-4.33 (8H, m,
4CH.sub.2Ph, H-2', H-4a, H-1a, H-3'), 4.29 (1H, dt, J=9.5, 3.0 Hz,
H-2), 4.25 and 4.15 (2H, 2d, J=11.9 Hz, CH.sub.2Ph), 4.04 (1H, m,
H-1'a) 4.02-3.95 (2H, m, H-4', H-1b), 3.78 (1H, dd, J=10.7, 10.7
Hz, H-4b), 3.74 (1H, dd, J=13.6, 3.8 Hz, H-1'b), 3.62 (1H, dd,
J=9.9, 8.6 Hz, H-5'a), 3.54 (1H, dd, J=9.9, 7.2 Hz, H-5'b);
.sup.13C NMR (100.6 MHz, CD.sub.2Cl.sub.2): .delta.137.34, 137.24,
136.56, 136.39 (4C.sub.ipso), 129.73-126.62 (20C.sub.Ar), 101.95
(C-5), 83.75 (C-3'), 82.82 (C-2'), 76.80 (C-2), 73.73, 72.84, 72.52
(3CH.sub.2Ph), 69.54.(C-4), 67.01 (C-5'), 66.48 (C-3), 65.27
(C-4'), 49.67 (C-1), 48.28 (C-1'); MALDI-TOF MS: m/e 693
(M.sup.++H). Anal. Calcd for C.sub.37H.sub.40O.sub.9S.sub.2: C,
64.14; H, 5.82. Found: C, 63.88; H, 5.83.
[0073]
1,4-(1',4'-Anhydro-2',3',5'-tri-O-benzyl-4'-thio-D-arabinitol)-4'-S-
-yl)-2,4-O-benzylidene-1-deoxy-D-erythritol-3-sulfate (22).
[0074] Column chromatography [CHCl.sub.3:MeOH, 10:1+0.1% Et.sub.3N]
of the crude product gave an amorphous solid (79%). [.alpha.].sub.D
-46.9.degree. (c 0.65, CH.sub.2Cl.sub.2); .sup.1H NMR
(CD.sub.2Cl.sub.2): .delta.7.43-7.10 (20H, m, Ar), 5.49 (1H, s,
H-5), 4.62-4.34 (11H, m, CH.sub.2Ph, H-3, H-4a, H-2', H-1a, H-3'),
4.30-4.21 (2H, m, H-2, H-4'), 3.96 (1H, dd, J=9.7, 6.2 Hz, H-5'a),
3.90 (1H, dd, J=13.3, 3.4 Hz, H-1b), 3.82 (1H, dd, J=9.8, 9.8 Hz,
H-5'b), 3.79-3.71 (2H, m, H-1'a, H-4b), 3.51 (1H, dd, J=13.2, 3.9
Hz, H-1'b); .sup.13C NMR (100.6 MHz, CD.sub.2Cl.sub.2):
.delta.137.62, 137.27, 136.48, 136.29 (4C.sub.ipso), 129.80-126.56
(20C.sub.Ar), 102.16 (C-5), 84.25 (C-3'), 82.56 (C-2'), 77.07
(C-2), 74.02, 72.74 (3CH.sub.2Ph), 69.75 (C-4), 67.19 (C-5'), 66.82
(C-3), 65.76 (C-4'), 50.41 (C-1), 49.60 (C-1'); MALDI-TOF MS: m/e
693 (M.sup.++H). Anal. Calcd for C.sub.37H.sub.40O.sub.9S.sub.2: C,
64.14; H, 5.82. Found: C, 64.16; H, 5.73.
[0075]
1-((1',4'-Anhydro-2',3',5'-tri-O-benzyl-4'-thio-L-arabinitol)-4'-S--
yl)-2,4-O-benzylidene-1-deoxy-D-erythritol-3-sulfate (24).
[0076] Column chromatography [CHCl.sub.3:MeOH, 10:1+0.1% Et.sub.3N]
of the crude product gave an amorphous solid (40%). [.alpha.].sub.D
+14.3.degree. (c 1.4, CH.sub.2Cl.sub.2); .sup.1H NMR
(CD.sub.2Cl.sub.2): .delta.7.49-7.12 (20H, m, Ar), 5.55 (1H, s,
H-5), 4.60 (1H, ddd, J=9.8, 5.5, 4.5 Hz, H-3), 4.55-4.44 (5H, m,
3CH.sub.2Ph, H-2', H-4a), 4.42 (1H, dd, J=13.3, 2.3 Hz, H-1a),
4.39-4.34 (2H, m, CH.sub.2Ph, H-3'), 4.28 (1H, dt, J=9.8, 2.9 Hz,
H-2), 4.24 and 4.14 (2H, 2d, J=11.9 Hz, CH.sub.2Ph), 4.10 (1H, d,
J=13.4 Hz H-1'a), 3.98-3.90 (2H, m, H-4', H-1b), 3.78 (1H, dd,
J=10.5, 10.5 Hz, H-4b), 3.67 (1H, dd, J=13.4, 3.8 Hz, H-1'b), 3.62
(1H, dd, J=9.9, 8.7 Hz, H-5'a), 3.53 (1H, dd, J=9.9, 7.2 Hz,
H-5'b); .sup.13C NMR (100.6 MHz, CD.sub.2Cl.sub.2): .delta.137.32,
137.26, 136.48, 136.25 (4C.sub.ipso), 129.79-126.64 (20C.sub.Ar),
102.06 (C-5), 83.96 (C-3'), 82.74 (C-2'), 76.93 (C-2), 73.81,
72.97, 72.57 (3CH.sub.2Ph), 69.59 (C-4), 67.07 (C-5'), 66.36 (C-3),
66.31 (C-4'), 49.96 (C-1), 48.52 (C-1'). Anal. Calcd for
C.sub.37H.sub.40O.sub.9S.sub.2- : C, 64.14; H, 5.82. Found: C,
64.13; H, 5.74.
[0077]
1-((1',4'-Anhydro-3'-O-benzyl-4'-thio-D-arabinitol)-4'-S-yl)-2,4-O--
benzylidene-1-deoxy-L-erythritol-3-sulfate (26).
[0078] Column chromatography [CHCl.sub.3:MeOH, 10:1+0.1% Et.sub.3N]
of the crude product gave an amorphous solid (32%).; .sup.1H NMR
(CD.sub.2Cl.sub.2): .delta.7.49-7.26 (10H, m, Ar), 6.22 (1H, d,
J=4.4 Hz, 2'-OH), 5.54 (1H, s, H-5), 4.96 (1H, br-s, H-2'), 4.64
(1H, d, J=11.6 Hz, CH.sub.2Ph), 4.64-4.62 (1H, m, 5'-OH), 4.56 (1H,
d, J=11.6 Hz, CH.sub.2Ph), 4.54-4.48 (1H, m, H-3), 4.46 (1H, dd,
J=10.5, 5.4 Hz, H-4a), 4.33-4.25 (3H, m, H-3', H-2, H-1'a), 4.12
(1H, dd, J=13.5, 2.6 Hz, H-1a), 4.12-4.09 (1H, m, H-4'), 4.01 (1H,
dd, J=13.5, 3.4 Hz, H-1b), 3.92-3.82 (2H, m, H-5'a, H-5'b), 3.78
(1H, dd, J=10.5, 10.1 Hz, H-4b), 3.67 (1H, dd, J=13.5, 3.9 Hz,
H-1'b); .sup.13C NMR (100.6 MHz, CD.sub.2Cl.sub.2): .delta.136.92,
136.73 (2C.sub.ipso), 129.97-126.61 (10C.sub.Ar), 102.32 (C-5),
88.45 (C-3'), 76.61 (C-2), 76.22 (C-2'), 72.96 (CH.sub.2Ph), 71.24
(C-4'), 69.27 (C-4), 66.96 (C-3), 60.51 (C-5'), 52.43 (C-1'), 48.30
(C-1); MALDI-TOF MS: m/e 513 (M.sup.++H). Anal. Calcd for
C.sub.23H.sub.28O.sub.9S.sub.2: C, 53.89; H, 5.51. Found: C, 53.64;
H, 5.34.
[0079]
1-((1',4'-Anhydro-2',3',5'-tri-O-benzyl-4'-seleno-D-arabinitol)-4'--
Se-yl)-2,4-O-benzylidene-1-deoxy-L-erythritol-3-sulfate (27).
[0080] Column chromatography [CHCl.sub.3:MeOH, 15:1] of the crude
product gave an amorphous solid (86%). NMR showed the presence of
two isomers (7:1) at the stereogenic selenium center which were
separated on analytical HPLC [acetonitrile/H.sub.2O]. Anal. Calcd
for C.sub.37H.sub.40O.sub.9SSe: C, 59.99; H, 5.45. Found: C, 59.91;
H, 5.44.
[0081]
1-((1',4'-Anhydro-2',3',5'-tri-O-benzyl-4'-seleno-D-arabinitol)-4'--
Se-yl)-2,4-O-benzylidene-1-deoxy-D-erythritol-3-sulfate (28).
[0082] Column chromatography [CHCl.sub.3:MeOH, 15:1] of the crude
product gave an amorphous solid (96%). NMR showed the presence of
two isomers (3:1) at the stereogenic selenium center which were
separated on analytical HPLC [acetonitrile/H.sub.2O]. Anal. Calcd
for C.sub.37H.sub.40O.sub.9SSe: C, 59.99; H, 5.45. Found: C, 59.91;
H, 5.37.
[0083]
1-((1',4'-Dideoxy-1',4'-imino-D-arabinitol)-4'-N-yl)-2,4-O-benzylid-
ene-1-deoxy-L-erythritol-3-sulfate (30).
[0084] A mixture of 1,4-Dideoxy-1,4-imino-D-arabinitol (19) (100
mg, 0.7 mmol) and 2,4-O-benzylidene-L-erythritol-1,3-cyclic sulfate
(10) (235 mg, 1.2 equiv) were dissolved in dry MeOH (0.5 mL) and
anhydrous K.sub.2CO.sub.3 (15 mg) was added. The mixture was
stirred in a Caries tube in an oil-bath (75.degree. C.) overnight.
The solvent was removed under reduced pressure and column
chromatography [CH.sub.2Cl.sub.2:MeOH, 4.5:1] of the crude product
gave an amorphous solid (219 mg, 72%). .sup.1H NMR (CD.sub.3OD):
.delta.7.53-7.30 (5H, m, Ar), 5.61 (1H, s, H-5), 4.53 (1H, dd,
J=11.1, 5.2 Hz, H-4a), 4.25 (1H, m, H-2), 4.20 (1H, ddd, J=9.8,
5.2, 4.4 Hz, H-3), 4.11 (1H, br-s, H-2'), 3.99-3.84 (4H, m, H-1a,
H-3', H-5'a, H-5'b), 3.82 (1H, dd, J=10.7, 9.8 Hz H-4b) 3.58 (1H,
m, H-1'a), 3.55-3.42 (2H, m, H-1'b, H-4'), 3.38 (1H, m, H-1b);
.sup.13C NMR (100.6 MHz, CD.sub.3OD): .delta.138.72 (C.sub.ipso),
130.12 (C.sub.para), 129.21, 127.39 (4C.sub.ortho+meta), 102.33
(C-5), 78.01 (C-4', C-3', C-2), 76.31 (C-2'), 70.29 (C-4), 69.02
(C-3), 62.64 (C-1'), 60.51 (C-5'), 58.46 (C-1); MALDI-TOF MS: m/e
428 (M.sup.++Na) ,406 (M.sup.++H); HRMS. Calcd for
C.sub.16H.sub.23O.sub.9SN (M+H): 406.1179. Found: 406.1192.
[0085]
1-((1',4'-Dideoxy-1',4'-imino-L-arabinitol)-4'-N-yl)-2,4-O-benzylid-
ene-1-deoxy-D-erythritol-3-sulfate (31).
[0086] A mixture of 1,4-Dideoxy-1,4-imino-L-arabinitol (16) (80 mg,
0.6 mmol) and 2,4-O-benzylidene-D-erythritol-1,3-cyclic sulfate (7)
(190 mg, 1.2 equiv) were dissolved in dry MeOH (0.5 mL) and
anhydrous K.sub.2CO.sub.3 (10 mg) was added. The mixture was
stirred in a Caries tube in an oil-bath (75.degree. C.) overnight.
The solvent was removed under reduced pressure and column
chromatography [CH.sub.2Cl.sub.2:MeOH, 5:1] of the crude product
gave an amorphous solid (175 mg, 72%). .sup.1H NMR (CD.sub.3OD):
.delta.7.52-7.31 (5H, m, Ar), 5.62 (1H, s, H-5), 4.53 (1H, dd,
J=10.9, 5.2 Hz, H-4a), 4.28 (1H, m, H-2), 4.20 (1H, ddd, J=9.7,
5.1, 4.6 Hz, H-3), 4.14 (1H, br-s, H-2'), 4.03 (1H, m, H-1a),
3.98-3.84 (3H, m, H-3', H-5'a, H-5'b), 3.81 (1H, dd, J=10.9, 10 Hz
H-4b) 3.63 (1H, m, H-1'a), 3.55-3.42 (2H, m, H-1'b, H-4'), 3.38
(1H, m, H-1b); .sup.13C NMR (100.6 MHz, CD.sub.3OD): .delta.138.66
(C.sub.ipso), 130.15 (C.sub.para), 129.23, 127.40
(4C.sub.ortho+meta), 102.34 (C-5), 77.81 (C-4'), 77.52 (C-3', C-2),
76.19 (C-2'), 70.27 (C-4), 68.92 (C-3), 62.68 (C-1'), 60.41 (C-5'),
58.61 (C-1); MALDI-TOF MS: m/e 428 (M.sup.++Na) 406
(M.sup.++H).
5.2.5 Example 5
General Procedure for the Deprotection of the Protected Sulfonium
Sulfates (Schemes 7-10) and Ammonium Sulfates (Schemes 13-14)
[0087] The protected compound was dissolved in AcOH:H.sub.2O, 4:1
(3 mL) and stirred with Pd-C (80 mg) under H.sub.2 (52 psi). After
60 h the reaction mixture was filtered through a pad of Celite,
which was consequently washed with MeOH. The combined filtrates
were concentrated and the residue was purified by column
chromatography.
[0088]
1-(1',4'-Anhydro-4'-thio-D-arabinitol)-4'-S-yl)-1-deoxy-L-erythrito-
l-3-sulfate (1).
[0089] Column chromatography [CHCl.sub.3:MeOH:H.sub.2O, 7:3:1] of
the crude product gave an amorphous solid (67%). [.alpha.].sub.D
+2.1.degree. (c 0.48, MeOH); .sup.1H NMR (pyridine-d5): .delta.5.25
(1H, ddd, J=7.4, 3.8, 3.6 Hz, H-3), 5.14-5.09 (2H, m, H-3', H-2'),
5.00 (1H, m, H-2), 4.78 (1H, dd, J=13.0, 4.9 Hz H-1a), 4.70 (1H, m,
H-4'), 4.63 (1H, dd, J=13.0, 4.0 Hz H-1b), 4.61 (1H, dd, J=11.8,
3.7 Hz H-4a)4.53 (2H, m, H-5'a, H-5'b),4.38 (1H, dd, J=11.8, 3.8 Hz
H-4b), 4.32 (2H, br-s, H-1'a, H-1'b); .sup.13C NMR (100.6 MHz,
pyridine-d5): .delta.79.14 (C-3), 79.06 (C-3'), 78.18 (C-2'), 72.30
(C-4'), 67.44 (C-2), 62.05 (C-4), 59.98 (C-5'), 52.46 (C-1), 50.35
(C-1'). HRMS. Calcd for C.sub.9H.sub.18O.sub.9S.sub.2 (M+H):
335.0471. Found: 335.0481.
[0090]
1-((1',4'-Anhydro-4-thio-D-arabinitol)-4'-S-yl)-1-deoxy-D-erythrito-
l-3-sulfate (23).
[0091] Column chromatography [CHCl.sub.3:MeOH:H.sub.2O, 7:3:1] of
the crude product gave an amorphous solid (59%). [.alpha.].sub.D
-35.6.degree. (c 0.86, MeOH); .sup.1H NMR (pyridine-d5):
.delta.5.19 (1H, ddd, J=8.0, 4.1, 3.6 Hz, H-3), 5.17-5.12 (2H, m,
H-2', H-3'), 5.00 (1H, ddd, J=8.0, 5.3, 4.1 Hz, H-2), 4.83 (1H, dd,
J=13.0, 5.1 Hz H-1a), 4.78 (1H, m, H-4'), 4.65 (1H, dd, J=11.9, 3.8
Hz H-4a), 4.64-4.57 (2H, m, H-5'a, H-5'b),4.53 (1H, dd, J=13.0, 4.1
Hz H-1b), 4.40 (1H, dd, J=11.9, 3.8 Hz H-4b), 4.29 (1H, dd, J=12.7,
39 Hz H-1'a), 4.17 (1H, dd, J=12.7, 2.6 Hz H-1'b); .sup.13C NMR
(100.6 MHz, pyridine-d5): .delta.79.46 (C-3), 79.38 (C-3'), 78.94
(C-2'), 71.94 (C-4'), 67.52 (C-2), 62.02 (C-4), 60.26 (C-5'), 52.64
(C-1), 51.01 (C-1'). HRMS. Calcd for C.sub.9H.sub.18O.sub.9S.sub.2
(M+H): 335.0471. Found: 335.0486.
[0092]
1-(1',4'-Anhydro-4'-thio-L-arabinitol)-4'-S-yl)-1-deoxy-D-erythrito-
l-3-sulfate (25).
[0093] Column chromatography [CHCl.sub.3:MeOH:H.sub.2O, 7:3:1] of
the crude product gave an amorphous solid (80%). [.alpha.].sub.D
+1.1.degree. (c 1.5, MeOH); .sup.1H NMR (pyridine-d5): .delta.5.23
(1H, ddd, J=7.4, 3.8, 3.7 Hz, H-3), 5.11 (1H, m, H-3'), 5.10 (1H,
m, H-2'), 4.98 (1H,m, H-2), 4.76 (1H, dd, J=11.7, 3.7 Hz H-1a),
4.70 (1H, m, H-4'), 4.63 (1H, dd, J=11.7, 3.8 Hz H-1b), 4.60 (1H,
dd, J=11.8, 3.7 Hz H-4a)4.51 (2H, m, H-5'a, H-5'b),4.35 (1H, dd,
J=11.8, 4.0 Hz H-4b), 4.31 (2H, m, H-1'a, H-1'b); .sup.13C NMR
(100.6 MHz, pyridine-d5): .delta.79.38 (C-3, C-2'), 78.41 (C-3'),
72.51 (C-4'), 67.63 (C-2), 62.23 (C-4), 60.21 (C-5'), 52.60 (C-1),
50.57 (C-1'), HRMS. Calcd for C.sub.9H.sub.18O.sub.9S.sub.2 (M+H):
335.0471. Found: 335.0466.
[0094]
1-((1',4'-Dideoxy-1',4'-imino-D-arabinitol)-4'-N-yl)-1-deoxy-L-eryt-
hritol-3-sulfate (2).
[0095] Column chromatography [CHCl.sub.3:MeOH:H.sub.2O, 7:3:1] of
the crude product gave an amorphous solid (64%). .sup.1H NMR
(CD.sub.3OD): .delta.4.26-4.20 (2H, m H-2, H-3), 4.15 (1H, m,
H-2'), 3.98 (1H,br-s, H-3'), 3.94-3.87 (3H,m, H-5'a, H-5'b, H-4'a),
3.81 (1H, dd, J=12.0, 3.5 Hz H-4b), 3.74-3.62 (2H, m, H-1a, H-1'a),
3.49-3.42 (1H, m, H-1'b),3.40-3.35 (1H, m, H-4'), 3.15 (1H, m,
H-1b); .sup.13C NMR (100.6 MHz, CD.sub.3OD): .delta.81.17 (C-3),
78.27 (C-3'),77.86 (C-4'), 76.19 (C-2'), 68.07 (C-2), 62.57 (C-1'),
61.67(C-4), 60.72 (C-1, C-5'). HRMS. Calcd for
C.sub.9H.sub.18O.sub.9SN (M+H): 318.0859. Found: 318.0863.
[0096]
1-((1',4'-Dideoxy-1',4'-imino-L-arabinitol)-4'-N-yl)-1-deoxy-D-eryt-
hritol-3-sulfate (32).
[0097] Column chromatography [CHCl.sub.3:MeOH:H.sub.2O, 7:3:1] of
the crude product gave an amorphous solid (77%). .sup.1H NMR
(CD.sub.3OD): .delta.4.25 (1H, m H-2), 4.23(1H, m, H-3), 4.16 (1H,
br-s, H-2'), 3.99 (1H,br-s, H-3'), 3.94-3.87 (3H,m, H-5'a, H-5b',
H-4a), 3.81 (1H, dd, J=12.1, 3.6 Hz H-4b), 3.77-3.64 (2H, m, H-1a,
H-1'a), 3.55-3.39 (2H, m, H-1'b, H-4'), 3.22 (1H, m, H-1b);
.sup.13C NMR (100.6 MHz, CD.sub.3OD): .delta.81.18 (C-3), 78.23
(C-3', C-4'), 76.10 (C-2'), 68.05 (C-2), 62.66 (C-1'), 61.88(C-4),
60.49 (C-1, C-5'). HRMS Calcd for C.sub.9H.sub.18O.sub.9SN (M+H):
318.0859. Found: 318.0856.
[0098] As will be apparent to those skilled in the art in the light
of the foregoing disclosure, many alterations and modifications are
possible in the practice of this invention without departing from
the spirit or scope thereof. Accordingly, the scope of the
invention is to be construed in accordance with the substance
defined by the following claims.
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