| Research Abstract |
(1) Studies on a New Stereoselective Synthesis of D-Gluco-pyranose-Type Phospha-Sugars from D-Xylose. D-Xylose was efficiently converted in 5 steps into a key intermediate 3-O-benzyl-5-deoxy-5- (ethoxy) phenylphosphinyl-1,2-O-isopropylidene-D-xylof-uranose. This was led to a phospha-sugar 3-O-benzyl-5-deoxy-5-phenylphosphinyl-D-xylopyranoses, which were purified as 1,2,4-tri-O-acetyl derivatives. After conversion into the corresponding 1,2,4-tri-O-methyl derivatives, methylation with methyl iodide in the presence of a base KHMDS provided 3-O-benzyl-5,6-di-deoxy-5- [(R) - and (S) -phenylphosphinyl] -a- and -b-D-glucopyranoses. Improvement of the yield of each steps as well as the selective benzyloxymethylation is under investigation. (2) New Synthetic Studies on L-Arabinofuranose- and 2-Deoxy-D-ribose-Type Phospha-Sugars. Dimethyl L-tartrate is converted into 1,4-di-O-mesyl-2,3-di-O-methyl-L-threitol, which was treated with phenyl-phosphine in the presence of NaH in DMSO,providing a phospha-sugar (3S,4S) -3,4-di-O-methyl-1-phenylphosphorane-2,3-diol. This was readily led to the 1-oxide with hydrogen peroxide. In contrast, the Arbuzov reaction of 1,4-dibromo- (or 1,4-diiodo-) 1,4-dideoxy-2,3-di-O-methyl-L-threitol with diethyl phosphonite turned out to afford 4,5-dimethoxy-2-oxo-2-phenyl-1,2-oxaphosphorinane in 89% yield. Similarly prepared was (1R/S,3S) -1-phenyl-phosphoran-3-ol-l-oxide from L-maleic acid. The one-carbon elongation for these 1-oxides to the title phospha-sugars are under investigation. (3) Competitive Enzyme Inhibition. As a preliminary result, 5-deoxy-5- [(R) - and (S) -phenylphosphinyl] -b-D-xylopyranoses showed a weak inhibitory activity against b-glucosidase. This study remains to be inverstigated further in datail.
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