Synthesis of 2-Arylfuro[3,2-c]pyridines and Their Derivatives

Abstract

A series of 2-arylfuro[3,2-c]pyridines was synthesized. 3-(5-Aryl-2-furyl)propenoic acids 1a-1h were converted to the acid azides 2a-2h, which in turn were cyclized to give 2-arylfuro[3,2-c]pyridine-4(5H)-ones 4a-4h by heating in Dowtherm. The pyridones 4a-4f were aromatized with phosphorus oxychloride to the 2-aryl-4-chlorofuro[3,2-c]pyridines 5a-5f, which were reduced with zinc and acetic acid to the title compounds 6a-6f. Reacted with phosphorus(V) sulfide, the pyridones 4a-4f yielded the corresponding thiones 7a-7f.