Peculiarities of the reactions of a,b-unsaturated g-bromoketones with hydrazine derivatives

Abstract

The reaction result of a,b-unsaturated g-bromoketones with hydrazines depends on the structure of the reagents. Reaction with hydrazine hydrate leads to the mixture of 3,5- di(R)pyridazine, 3,6-di(R)pyridazine and 2,4-di(R)-1H-pyrrol-1-amine derivatives. The formation of three types of products is due to the structure of the unsaturated aliphatic ketone. Two competing reaction schemes of ketones with hydrazines are considered, which include condensation or Michael-type addition in the first stage. The main products of the reactions of halogen-substituted derivatives of g-bromodipnone with arylhydrazines are 1,3,5-triaryl-1,6-dihydropyridazines, which easily form aromatic salts under reaction conditions (when heated in EtOH).