Synthesis of antiviral acyclic C-nucleosides incorporating thiazolo-1,3,4-oxa(thia) diazole or thiazolo-1,2,4-triazole structure as a nucleobase

N-4-arylthiosemicarbazones of D-glucose and D-xylose undergo addition-condensation with thioglycollic acid to furnish 3-(3-arylthioureido)-2- (D-glucopentyl or D-xylobutyl)-4-thiazolidinones 4a-d, which on intramolecular chemoselective heterocyclization with cone. H2SO4 and KI/I-2 yield 2-arylamino-5-(D-glucopentyl or xylobutyl)-5H-thiazolo[4,3-b]-1,3,4-thiadiazoles 5a-d and 2-arylamino-5-(D-glucopentyl or D-xylobutyl)-5H-thiazolo [4,3-b]-1,3,4-oxadiazoles 6a-d, respectively. Compounds 6a-d on treatment with hydrazine hydrate afford 1-amino-2-arylamino-5-(D-glucopentyl or D-xylobutyl)-5H-thiazolo [3,4-b]-1,2,4-triazoles 7a-d. Compounds 7b and 7d display 100% in vitro disease control (equivalent to Virazole) against C. amaranticolor at 1000 ppm concentration.