Tropylium Salts as Reagents for Modification of Hydrazides of Monocarboxylic Acids
Reactions of electrophilic substitution at nitrogen atom in the amino group of hydrazides of nicotinic, isonicotinic and 2-furancarboxylic acids with tropylium salts proceed as disubstitution of hydrogen atoms in the amino group of hydrazide to tropylium fragment. Reactions result in formation of N ', N '-di(cyclohepta-2,4,6trien-1-yl)-nicotinohydrazide, N ', N '-di(cyclohepta-2,4,6-trien-1-yl)-isonicotinohydrazide, N ', N '-di(cyclohepta2,4,6-trien-1-yl)furan-2-carbohydrazides. Exception: by proportion of initial reagents: hydrazide of 2-furancarboxylic acid - tropylium salt (1:1) a product of monosubstitution - N '-(cyclohepta-2,4,6-trien-1-yl)furan-2carbohydrazides is produced.