Etify A. Bakhite
Assiut University, Egypt
Title: Fused thieno[2,3-b]pyridines: Synthesis, characterization and biological activities of new condensed pyridothienopyrimidines
Biography
Biography: Etify A. Bakhite
Abstract
Reaction of 4-aryl-3-cyano-5-ethoxycarbonyl-6-methylpyridine-2(1H)-thiones 3a,b with chloroacetonitrile gave the corresponding 3-aminothieno[2,3-b]pyridine-2-carbonitriles 5a,b. Condensation of 5a,b with triethyl orthoformate produced the methanimidate derivatives 7a,b. Treatment of 7a,b with hydrazine hydrate at room temperature resulted in the formation of ethyl 3-amino-9-aryl-3,4-dihydro-4-imino-7-methylpyrido[3’,2’:4,5]thieno[3,2-d]pyrimidine-8-carboxylates 8a,b. 3-Amino-4-(4-methoxyphenyl)-5-ethoxycarbonyl-6-methylthieno[2,3-b]pyri-dine-2-carboxamide (6) was prepared and reacted with triethyl orthoformate to give pyrimidine-4(3H)-one derivative 15. Chlorination of 15 with phosphorus oxychloride gave 4-chloropyrimidine 16, which in turn was reacted with hydrazine hydrate to produce ethyl 4-hydrazino-9-(4-methoxyphenyl)-7-methylpyrido[3’,2’:4,5]thieno [3,2-d]pyrimidine-8-carboxylate (18). Compounds 8a,b and 18 were used as precursors for synthesizing other new pyridothienopyrimidines as well as triazolopyridothieno-pyrimidines, and pyridothienopyrimidotriazinoindoles. Structural formulas of all newly synthesized compounds were confirmed by elemental and spectral (IR, N MR and mass) analyses.