chemistry and biology of novel amin0 sugars and amino-sugar analogs

294 Pages·1999·13.32 MB·English

CHEMISTRY AND BIOLOGY OF NOVEL
AMIN0 SUGARS AND AMINO-SUGAR ANALOGS
MARK ANTHONY SZAREK
A thesis submitted to the Department of Chemistry
in conformity with the requirernents for
the degree of Doctor of Philosophy
Queen's University
Kingston, Ontario, Canada
July, 1998
copyright (B Mark Anthony Szarek, 1998
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ABSTRACT
A synthesis of a series of 2-acetamidopentoses ("2-acetamido-2,4-dideoxy-xylose"
derivatives). narnely, methyl2-acetamido-2,4-dideoxy-a-a nd P-L-fhreo-
pentopyranosides, rnethyi 2-acetamido-3-O-acetyl-2,4-dideoxy-a- and P-L-threo-
pentopyranosides, 2-acetamido-2,4-dideoxy-L-threo-pentopyrosaen d 2-acetamido- 1.3-
di-O-acetyi-2,4-dideoxy-a,P-L-ihreo-pentoposes,w as achieved fiom D-xylose. The
six 2-acetamidopentoses were evaluated for their inhibition of de novo glycoconjugate
biosynthesis in female, Swiss White mouse hepatocytes in culture.
The synthesis of 1,5,6-trideoxy-6,6-difluoro1-, 5-imino-D-glucitol ( 1,6-dideoxy-
6,6-difluoronojirimycin)w as achieved fiom L-sorbose. The formation of the C-5
difluoromethyl group was accomplished by difluorination of a carbonyl group by DAST.
The results of in vitro enzymic evaiuation indicate that 1,5,6-trideoxy-6,6-difluoro1-.5 -
imino-D-glucitol is a competitive inhibitor of yeast a-glucosidase (Ki= 7.5 mM) and a
noncornpetitive inhibitor of alrnond P-glucosidase (K,= 8.7 mM).
1.2,5-Trideoxy- 1, 5-imino-D-erythro-pentitolh ydrochlonde was synthesized fiom
2-deoxy-ribose. The results of in vitro enzyrnic evaluation indicate that 12,5-ûideoxy-
1, 5-imino-D-eryrhro-pentitolh ydrochloride is a potent competitive inhibitor of almond fi-
glucosidase (K,= 35 pm and a weak competitive inhibitor of A. niger a-gaiactosidase
(Ki= 3.8 mM).
1,2,5-Tndeoxy-1 , 5-imino-D-threo-pentitolh ydrochloride was synthesized fiom
1,2,5-trideoxy- 1, 5-irnino-D-erythro-pentitolh ydrochloride or 1,2,5,6-tetrahydropyridine.
.
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The results of in vitro enzymic evaiuation indicate that 1 -2,s-hideoxy- 1 ,5-imino-D-fhreo-
pentitol hydrochloride is a weak noncornpetitive inhibitor of yeast a-glucosidase (Ki= 1.1
mM), and a weak cornpetitive inhibitor of almond P-glucosidase (Ki = 1.2 mM) and A.
mm.
niger a-gaiactosidase (Ki = 19.4
The synthesis of 3-[(3 R,4S)-34-dihydroxy- 1- piperidinyl]- 1- propanesulfonic acid.
sodium salt was achieved by the treatment of 1,2,5-trideoxy-1 ,5-imino-D-erythro-pentitol
with 1,3-propane sultone.
(4S,SR)-2-(Nitromethyl)-4,5-piperidinediol was synthesized fiom 5-mino-2 5-
dideoxy-D-erythro-pentono-1 ,5-lactam. The results of in viîro enzymic evaluation
indicate that (4S,5R)-2-(nitromethyl)-4,5-pipendinediol is a cornpetitive inhibitor of
almond P-glucosidase (Ki= 0.49 mM).
Treatment of sodium methyl5-deoxy-2,3-0-isopropylidene-5-C-sulfonato-~-~-
ribofiiranoside and sodium 5-deoxy-2,3-0-isopropylidene-5-C-sulfonato-a-D-
xylofuranose with Montmodlonite K10 clay in methanol gave anomeric mixtures of
methyl glycosides. namely sodium methyl 5-deoxy-5-C-sulfonato-CC$-D-ribofuranosides
and sodium methyl5-deoxy-5-C-sdfonato-a,~xylofuranosidesT he results of in vitro
evaluation of amyloid P-peptide aggregation in the presence of each of these two
carbohydrate sdfonates indicate that they may inhibit peptide aggregation.

ACKNOWLEDGMENTS
1 wish to express my sincere appreciation to my SupeMsor and uncle, Professor
W. A. Szarek, for his guidance, encouragement, and support during the course of this
research.
1 would like to thank my fellow lab mates and members of the Thatcher lab not
only for their help and advice but dso for their friendship over the pst few years. in
particular. 1 thank Andy Vaino for the lunch time battles on the chess board, the core
members of the "the wall" gang, Jennifer Artz, Alison Borrajo, Colin Ferguson, Andy
Vaino, Vance Williams, and Chnstopher Yamold for their friendship, and Dr. Xianqi
Kong for our enlightening conversations.
1 wish to acknowledge Dr. Christopher Yamold for his prelirninary work on the
nitroenamine project. I would like to thank Ali Berkin for performing the biological
assays for our glycoconjuagte project. 1 wodd like to express rny thanks to Dr. Paul
Fraser of the Center for Research in Neurodegenerative Diseases at the University of
Toronto for conducting the arnyloid aggregation studies, Dr. Aleksander Roszak of the
University of Glasgow for performing the X-ray crystallographic study, and Dr. Greg
Thatcher for the use of the Beckman DU 7400 spectrophotometer for the glycosidase
studies. 1 wish to thank the members of the Facuity and Staff of the Department of
Chemistry for their help and friendship; in particular, 1 thank Dr. Dave Axelson and Ms.
Sue Blake for their help and discussions conceming NMR matters and Dr. Donal
Macartney, Coordinator of Graduate Studies, for his kindness and assistance during my
graduate career in the Department of Chemistry.
Lastly, 1 wish to express my many thanks to my fiancée, Lynn, for al1 of her help,
encouragement, support and love.
STATEMENT OF ORIGINALITY
The synthesis and biologicai evaluation of novel amino sugars and arnino-sugar
analogs are listed as follows.
Enantiomerically pure samples of methyl2-acetamido-2,4-dideoxy-aa-n d P-L-
threo-pentopyranosides, methyl2-acetamido-3-O-acetyl-2,4-dideoxy-aa-n d P-L-threo-
pentopyranosides, 2-acetamido-2,4-dideoxy-L-threo-pentopyr, and 2-acetamido- 1,3-
di-O-acetyl-2,4-dideoxy-a,p-threo-pentoposes were prepared. These molecules
were evaluated for their inhibition of glycoconjugate biosynthesis in female, Swiss White
mouse hepatocytes. The synthetic routes are novel, and the results fiom the chemistry
and biological evaluations will be published.
The synthesis of 1,5,6-trideoxy-6,6-difluoro1-, 5-irnino-D-glucitol (1,6-dideoxy-
6,6-difluoronojirimycin)a nd 1.5,6-trideoxy-6.6-difluoro-1 .5-imino-D-glucitol
hydrochloride was achieved fiom L-sorbose. These two novel compounds were analyzed
for their glycosidase activity and they were found to be inhibitors of yeast a-glucosidase
and almond P-glucosidase. The synthesis of the compounds and the results of the
biological evaluations have been published already in Curbohydrnte Research.
1, l,5-Trideoxy- 1, 5-imino-D-erythro-pentitohly drochloride was determined to be
a potent competitive inhibitor of aimond P-glucosidase (Ki= 35 pM) and a weak
competitive inhibitor of A. niger a-galactosidase (Ki= 3.8 mM). Yeast a-glucosidase and
jack bean a-mannosidase were not inhibited by 1,2,5-trideoxy-l ,5-imino-o-eryrhro-
pentitol hydrochloride.
vii
The synthesis of 1,2,5-trideoxy- 1, 5-imino-D-threo-pedtoi hydrochloride was
achieved. The results of in vitro enzymic evaluation indicate that 1,2,5-trideoxy- 13 -
imino-D-threo-pentitol hydrochloride is a weak noncornpetitive inhibitor of yeast a-
glucosidase (Ki = l. l mM), and a weak competitive inhibitor of almond P-glucosidase (Ki
= 1.2 mM) and A. niger a-galactosidase (Ki= 19.4 rnM). 1,2,5-Trideoxy-1 , 5-imino-D-
threo-pentitol hydrochloride did not inhibit jack bean a-mannosidase. The D-threo
compound is novel, and the results from the chemistry of this project and biological
evaluations will be published.
Pure samples of 3-[(3R,4S)-3,4-dihydroxy-1 - piperidinyl]- l -propanesulfonic acid,
sodium salt, 3-[(R)-3-hydroxy- 1- piperidinyl]- 1- propanesulfonic acid, and 3 -(4-hydroxy- 1 -
piperidiny1)- 1- propanesulfonic acid were prepared. The results of in vitro enzymic
evaluation indicate that these sulfonic acid derivatives do not inhibit yeast a-glucosidase,
aimond P-glucosidase, or jack bean a-mannosidase. A crude sample of 3-(1 ,S-dideoxy-
1, 5-irnino-D-glucit-N-y1)1-- p ropanesulfonic acid, sodium salt was prepared. Al1 of these
compounds are novel.
The synthesis of (4S,SR)-4,5-0-isopropylidene-2-(nitrome~,5-
pipendinediol, the precursor to (4S,SR)-2-(nitromethylene)-4,S-piperidhedioi was
achieved. (4S.SR)-2-(NitromethyI)-4,5-piperidinediol was prepared in a good yield. The
results of in vitro enzymic evaluation indicate that (4S,SR)-2-(nitromethy1)-4,s-
piperidinediol is a competitive inhibitor of almond P-glucosidase (Ki= 0.49 mM) and
inhibits yeast a-glucosidase (50% at 8.2 mM). The compounds are the fust examples of
azasugar-type compounds incorporating the nitrovinyl amine functionalit y or nitromet hy 1
Vml..l l
functionality. The chemistry and biology were reported by the author at the 2 12th
American Chemical Society National Meeting in Orlando, Florida, in August 1996; the
work will also be submitted for publication.
5 - A m i n o - 2 , 5 - d i d e o x y - [ ( S ) - 3 , 4 - 0 - ( 2 , 2 , 2 - 0 -
1,s-lactarn was synthesized, and its structure was confirmed by X-ray cry stallography.
The compound is novel and its formation is an interesting example of stereoselective
acetal formation. The work, including X-ray structure, will be published.
The novel carbohydrate sulfonates, sodium methyl 5-deoxy-5-C-sulfonato-a,P-~-
ribofiiranosides and sodium methyl 5-deoxy-5-C-sulfonato-a$-D-xylofuranosides,w ere
obtained. The results of in vitro evaluation of arnyloid P-peptide aggregation in the
presence of these two carbohydrate sulfonates indicate that they may inhibit peptide
aggregation. Similarly, 3-[(3 R,4S)-3,4-dihydroxy- 1- pipendinyl]- 1- propanesuifonic acid,
sodium salt. a sulfonated azasugar-type compound, may inhibit in vitro AB-peptide
aggregation. These results are being incorporated into a mmuscnpt in preparation that
will include results obtained on additional compounds by other workers in this laboratory.