Synthesis of certain furopyrimidines as potential antitumor agents

4,5-Diphenyl-2-aminofuran-3-carbonitrile (1) was converted to 1,3-furothiaz ine (2). Thermal Oxidation of (2) afforded 1,3-oxazin-2-one derivative (3). The reaction of (3) with primary amine or hydrazine hydrate afforded 4-ami no-or 4-arylamino-5,6-diphenyl-1,2-dihydrofuro [2,3-d]-pyrimidin-2-one (5a- c). Substituted furo [2,3-d] [1,3,4]-thiadiazolo derivatives (7,8) were obt ained by the reactions of (6) with triethyl orthoacetate or acetic anhydrid e. 4-Arylidenehydrazono-5,6-diphenyl-1,2-dihydrofuro [2,3-d]-pyrimidin-2- t hiones (9a-b) were obtained by the reaction of (10) with appropriate aldehy de. 3-Methyl-8,9-diphenyl-4, 5-dihydrofuro [3,2-e] [1,2,4]-triazolo [4,3-c] -pyrimidin-5-thione (11) was prepared from the reaction of (10) with trieth yl orthoacetate or acetic anhydride. 3-Methyl-5-methylmercapto (12) derivat ive was obtained from the reaction of (11) with methyl iodide. 5-Hydrazino or arylamino products (13) were obtained via the reaction of (11) with appr opriate primary amine or hydrazine hydrate.