Features of reactions of (E)-1-(β-aroylvinyl)pyridinium bromides with binucleophiles

Abstract

Regardless of pH and a solvent nature the reactions of (E)-1-(β-aroylvinyl)pyridinium bromides with hydrazine led to the formation of pyrazole derivatives. The salts reacted with thiourea via intermediate formation of 4-arylpyrimidine-2-thiol to give (Z)-2-[(β-aroylvinyl)sulfanyl]-4-arylpyrimidines. In the case of N,N'-diphenylthiourea the reaction provided 6-aryl-3-aroyl-1-phenylpyridinium bromides. Pyridine hydrobromide liberated in the reaction course has a major influence on the process chemoselectivity.