One pot synthesis of 4,5-dibromo-3,6-diarylpyridazine from 1,4-diarylbuta-1,3-diyne

Abstract

Pyridazines are an important scaffold present in various pharmacophores due to their significant physiochemical features of drug molecules. Laboratory synthesis of pyridazines is highly important because their natural sources are very rare. A one-pot two-step methodology has been developed for the synthesis of 4,5-dibromo-3,6-diarylpyridazines starting from easily available starting material 1,4-diarylbuta-1,3-diynes. The reaction goes through the electrophilic addition of Br⁺ ion with alkyne bonds followed by nucleophilic addition of hydrazine and then intramolecular cyclization.