Oxidative Cyclisation Based One-Pot Synthesis of 3-Substituted[1,2,4]triazolo[4,3-b]pyridazines Using Me4NBr/Oxone

ABSTRACT. A facile one-pot syhthesis of 3-substituted triazolopyridazine and thieno-triazolopyridazine derivatives is described. This protocol involves the preparation of heteroaryl hydrazone from the aldehyde and pyridazinohydrazine deriva-tive followed by subjecting the intermediate directly to oxidative cyclization to assemble the desired 1,2,4-triazloe moiety by employing the mixture of Me4NBr and oxone. This condition is efficient and is able to tolerate wide range of functional groups. Key words: 1,2,4-Triazolopyridazine, Tetramethylammonium bromide, Oxone, Aromatic aldehyd