Modification of Monocarboxylic Acid Hydrazides with Tropylium Salts

Abstract

Nicotinic, isonicotinic, and furan-2-carboxylic acid hydrazides reacted with 2 equiv of tropylium perchlorate or tetrafluoroborate to give the corresponding N′N′-di(cyclohepta-2,4,6-trein-1-yl) derivatives as a result of electrophilic substitution of both hydrogen atoms in the primary amino group. The reaction of furan-2-carbohydrazide with an equimolar amount of tropylium salt gave N′-(cyclohepta-2,4,6-trien-1-yl)furan-2-carbohydrazide.