Thiophenylhydrazonoacetates in heterocyclic synthesis

Abstract

Abstract Benzo[b]thiophen‐2‐yl‐hydrazonoesters 4 were synthesized by coupling of 2‐diazo‐4,5,6,7‐tetrahydrobenzo[b]thiophene‐3‐carboxamide ( 1 ) with either ethyl cyanoacetate or ethyl acetoacetate. The reactivity of 4 toward a variety of nitrogen nucleophiles was investigated to yield pyrazole, isoxazole, pyrimidine, triazine, pyrazolopyridine, and pyrazolopyrimidine derivatives. © 2003 Wiley Periodicals, Inc. 15:15–20, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/.hc10205