Synthesis and reactions of biologically active 1,2,3,4-tetrahydro-4-oxo-2-thiobenzofuro[3,2-d]pyrimidine derivatives

Abstract

A series of 3-alkyl-1,2,3,4-tetrahydro-2-thio-4-oxobenzofuro [3,2-d] pyrimidines (2a-e) were prepared by the reaction of ethyl-3-aminobenzofuran-2-carboxylate with various isothiocyanates. The compounds 2a-e were methylated using methyl iodide and the resulting methylthio compounds (3a-e) were subjected to nucleophilic displacement reaction by hydrazine. The hydrazine compounds (4a-e) on treatment with sodium nitrite in acetic acid gave fused tetracyclic heterocycles containing tetrazolo ring (5a-e) whereas the reaction with triethylorthoformate gave fused tetracylic heterocycles containing triazole ring (6a-e) Treatment of 2a-e with chloroacetic acid gave 7a-e. The structure of all the compounds have been confirmed by spectral data. All products were screened for antimicrobial activity.