Syntheses of Carbocyclic Analogs of Nucleoside and Bioactive Pseudo-Sugars from Carbohydrate

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During the course of studies on highly effective utilization of naturally abundant carbohydrates, we have developed versatile conversion methods starting from carbohydrates leading to optically active pseudo-hexopyranoses and pseudo-pentafuranoses. Furthermore, in the examination of the chemical behavior of pseudo-nitrofuranoses, a new synthetic method for optically active pseudo-aminosugars has been developed. We have also found that pseudo-glycosides such as carbocyclic nucleoside analogs are successfully synthesized by use of Michael-type addition reactions to nitro-olefin derivatives as key reactions. In these reaction pathways, all six carbons of initial hexoses and substituents at C-2, 3, 4 (in pseudo-hexopyranose derivatives) or at C-3, 4 (in pseudo-pentafuranose derivatives) with their configurations, have been preserved.As an extension of these synthetic studies, we have converted D-glucose and D-glucuronolactone to optically active pseudo-hexopyranoses : pseudo-alpha-D-glucopyranose and pseudo-beta-L-idopyranose and optically active pseudo-pentafuranoses : pseudo-alpha- and -beta-D-arabinofuranoses and pseudo-beta-L-xylofuranose. Furthermore, bioactive pseudo-aminosugars : validamine, epi-validamine, and valienamine, have been synthesized via common reaction intermediates used in pseudo-hexopyranose synthesis. In addition, we have prepared three new optically active cyclohexane analogs of nucleoside : (-)-9-pseudo-beta-D-glucopyranosyladenine, (-)-9-pseudo-beta-L-idopyranosyladenine, and also have synthesized optically active cyclopentane analogs of nucleoside : (+)-cyclaradine, (-)-aristeromycin, and (+)-9-pseudo-beta-L-xylofuranosyladenine which are known to exhibit various important bioactivity such as antiviral and antitumor.