STRUCTURAL DETERMINATION OF ARYLHYDRAZONO -6-METHYL-ALPHA, GAMMA-PYRONONE AND STUDY OF ITS RING-CLOSURE REACTION

3-Aryl hydrazono-6-methyl-alpha,gamma-pyronone is an important interme diate for the synthesis of a series of dihydro-pyridazones. This inter mediate was separated and purified for the first time. By X-ray diffra ction method, its crystalline structure was elucidated. NMR monitoring technique was applied to investigate the following ring-closure react ion under acidic and basic conditions, It was proposed that there unde rwent a mechanism as first by a lactone ring-opening then followed by a dehydrating cyclization reaction.