Synthesis and Antimicrobial Activity of 1,3,4-Oxadiazoline, 1,3-Thiazolidine, and 1,2,4-Triazoline Double-Tailed Acyclo C-Nucleosides

[Image: see text] The condensation products of terphthaloyl bishydrazide with two equivalents of various monosaccharide aldoses were found to have a bis(sugarhydrazone) form or bis-glycosylhydrazide structure or coexist in tautomeric equilibrium depending on the sugar configuration. The condensation products were substantially utilized as 3-acetyl-1,3,4-oxadiazoline, 1,3-thiazolidine, and 4-amino-1,2,4-triazoline double-tailed acyclo C-nucleosides synthons. The preliminary antimicrobial activities of representative examples of the prepared compounds were evaluated.