RECYCLIZATION OF 2-IMINO-2H-1-BENZOPYRANS BY THE ACTION OF NUCLEOPHILIC REAGENTS. 4. USE OF 2-(N-AROYLHYDRAZONO)COUMARIN-3-CARBOXAMIDES FOR THE SYNTHESIS OF 3-(1,3,4-OXADIAZOL-2-YL)COUMARINS

Abstract

A new method for the synthesis of 3-(1,3,4-oxadiazol-2-yl)coumarins is proposed. It is based on the recyclization of 2-(N-aroylhydrazono)coumarin-3-carboxamides, which are readily obtained by the reaction of 2-iminocoumarin-3-carboxamides with arenecarboxylic hydrazides in an acidic medium. Advantages of the given method over alternative synthetic schemes were shown. Proposals on the mechanism of reaction were made.

Authors: S. N. Kovalenko, K. M. Sytnik, V. M. Nikitchenko, S. V. Rusanova, V. P. Chernykh, and A. O. Porokhnyak

English Translation in Chemistry of Heterocyclic Compounds, 1999, 35 (2), pp 167-170

http://link.springer.com/article/10.1007/BF02251703