Synthesis of n-glycosylthioureas, N-glycosylrhodanines, and N-glycosyl-2-aminothiazoles and their antimicrobial activity

A method for obtaining N-β-D-glucopyranosylthioureas was found in the aminolysis of N-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)-5-aralkylidenerhodanines. Aminolysis of the triacetylated or tribenzoylated ribosylrhodanines generally did not give ribosylthioureas but resulted in glycosidic cleavage, although N-(2,3,5-tri-O-benzoyl-β-D-ribofuranosyl)thioureas were obtained using morpholine and hydroxylamine. Ring closure of N-β-D-glucopyranosylthiourea with ethyl bromopyruvate gave ethyl 2-(N-β-D-glucopyranosyl)aminothiazole-4-carboxylate, and ammonolysis led to the corresponding 4-carboxamide. Antimicrobial screening against five microorganisms showed that N-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)rhodanine and the glucosylaminothiazole-4-carboxylate had the broadest spectrum of inhibitory activity, although the thioureas usually showed inhibition of some organisms.