Synthesis of acyclo-C-nucleosides: 2-(alditol-1-yl)-5-methylthio- and -5-benzylthio-1,3,4-thiadiazoles

Condensation of S-methylhydrazinecarbodithioate or S-benzylhydrazinecarbodithioate with aldopentoses or aldohexoses gave the corresponding aldehydo-sugar S-methylhydrazonecarbodithioates of S-benzylhydrazonecarbodithioates. Oxidative cyclization of these hydrazones with bromine in acetic acid gave the corresponding 2-(alditol-1-yl)-5-alkylthio-1,3,4-thiadiazoles. Acetylation of the latter gave the corresponding per-O-acetyl derivatives which were also obtained by one-pot preparation by treatment of the hydrazones with bromine and sodium acetate in acetic acid followed by acetic anhydride. Some of the prepared compounds were tested for antimicrobial activity against Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Candida albicans. While hydrazones showed significant activity against these organisms, the thiadiazoles were devoid of antimicrobial activity.