Synthesis of ‘Reversed’ Pyrimidine and Pyrazolo[1,5-a]pyrimidine-C-Nucleoside Analogues from Push-Pull Functionalized α-d-xylo-Hept-5-ulofuranurononitrile

Abstract

3-O-Benzyl-6-deoxy-1,2-O-isopropylidene-6-[bis(meth­ylsulfanyl)methylene]-α-d-xylo-hept-5-ulofuranurononitrile (1) was reacted with acetamidinium chloride, S-methylisothiouronium sulfate, and guanidinium chloride, respectively, in the presence of triethylamine to furnish the 2-substituted 4-(3-O-benzyl-1,2-O-isopropylidene-α-d-xylo-tetrofuranos-4-yl)-6-methylsulfanylpyrimidine-5-carbonitriles 2a-c. Treatment of 1 with different 5-aminopyrazole-4-carboxylic acid derivatives yielded the 8-(3-O-benzyl-1,2-O-isopropylidene-α-d-xylo-tetrofuranos-4-yl)-6-methylsulfanylpyrazolo[1,5-a]pyrimidine-3,7-dicarboxylic acid derivatives 3a-c.

Key words

enzyme inhibitors - C-nucleosides - monosaccharide derivatives - cyclization - pyrazoles

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