5,6,7,8-Tetrahydrobenzo[b]thieno[2,3-d]pyrimidine-4(3H)one as a Synthon of Heterocyclic Systems

Abstract

Reaction of 5,6,7,8-tetrahydrobenzo[b] thieno[2,3-d]pyrimidin-4(3H)-one with ethyl chloroacetate afforded an ester, which upon treatment with p-chlorobenzaldehyde under various conditions and with benzylamine gave new com pounds. Chiorothienopyrimidine reacted with thiourea, benzoylhydrazine, thiosemicarbazide, semicarbazide, sodium azide and glycine, to give pyriniidinethione, 1 ,2,4-triazole, thioxo-l ,2,4-triazole, oxo- 1 ,2,4-triazole, tetrazole, and imidazole, respectively. The reaction of pyrimidinthione with β-aroylacrylic acid produced γ-ketoacid, which reacted with acetic anhydride and hydrazine hydrate to afford furanone and pyridazinone, respectively. Ethyl 2-amino-4,5,6,7- tetrahydrobenzo[b]thiophene- 3-carboxylate was utilized to synthesize the 3-aminothienopyrimidinone derivative via reaction with benzoyl chloride followed by hydrazine hydrate. An interesting condensation product was obtained by reaction of ethyl 2-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylate with ethyl cyanoacetate in DMF. © 2009 Bulgarian Academy of Sciences, Union of Chemists in Bulgaria.