Synthesis and antimicrobial activity of acyclo C-nucleosides: 3-(alditol-1-yl)-7-oxo-5-phenyl-1,2,4-triazolo[4,3-a]pyrimidines

Condensation of 2-hydrazino-4-oxo-6-phenylpyrimidine (1) with aldopentoses 2a-d or aldohexoses 2e-g gave the corresponding aldehydo-sugar (4-oxo-6-phe nylpyrimidin-2-yl)hydrazones 3a-g which were acetylated to the correspondin g poly-O-acetyl-aldehydo-sugar (3-acetyl-4-oxo-6-phenylpyrimidin-2-yl)hydra zones 4a-g. The latter compounds underwent oxidative cyclization with bromi ne in acetic acid and in the presence of sodium acetate to the correspondin g 8-acetyl-3-(poly-O-acetyl-alditol-t-yl)-7-oxo-5-phenyl-1,2,4-triazolo[4,3 -a]pyrimidines 6a-g. Compounds 6a-g were also obtained by consecutive one-p ot oxidative cyclization/acetylation in which the parent hydrazones 3a-g we re treated with bromine/acetic acid/sodium acetate followed by acetic anhyd ride. Deacetylation of 6a-g with ammonium hydroxide in methanol gave the ti tle compounds 7a-g. The antibacterial and antifungal activities of compound s 3c, 3f, 7c and 7f are reported.