HETEROCYCLIC SYNTHESIS WITH NITRILES: SYNTHESIS OF SOME NOVEL THIOPHENE AND THIENO[2,3-d]PYRIMIDINE DERIVATIVES

Abstract

Abstract The thiophene derivative 1 reacts with acrylic acid derivatives 2a-c to give N-alkylated derivatives 3a-c which all undergo further hydrolysis to afford N-(thien-2-yl)-β-alanine derivative 6. While 1 reacts with phenyl isothiocyanate to afford the thiourea derivative 8, it reacts with benzoyl isothiocyanate to afford the dihydrothieno [2,3-d]pyrimidine derivative 9. Compound 1 reacts also with diethyl malonate, thiourea 14a and guanidine 14b to afford the thieno[2,3-d] pyrimidine derivatives 13, 15a and 15b respectively. Benzaldehyde condenses with 1 to give the benzylidene derivative 17 which cyclizes with thioglycollic acid to afford 18.