Synthesis and evaluation of antimicrobial activity of some pyrimidine glycosides

Reaction of ethyl 4-thioxo-3,4-dihydropyrimidine-5-carboxylate derivatives 1a,b and ethyl 4-oxo-3,4-dihydropyrimidine-5-carboxylate 1c with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide in KOH or TEA afforded ethyl 2-aryl-4-(2′,3′,4′,6′-tetra-O-acetyl-β-D- glucopyranosylthio or/ oxy)-6-methylpyrimidine-5-carboxylate 6a-c. The glucosides 6a and 6b were obtained by the reaction of 1a and 1b with peracetylated glucose3 under MW irradiation. Mercuration of 1a followed by reaction with acetobromoglucose gave the same product 6a. The reaction of 1a-c with peracetylated ribose 4 under MW irradiation gave ethyl 2-aryl-4-(2′, 3′,5′-tri-O-acetyl-β-D-ribofuranosylthio)-6-methylpyrimidine-5- carboxylate 8a-c. The deprotection of 6a-c and 8a-c in the presence of methanol and TEA/H2O afforded the deprotected products 7a-c and 9a-c. The structure were confirmed by using 1H and 13CNMR spectra. Selected members of these compounds were screened for antimicrobial activity.