Hydrazine, dihydrochloride → Ethyl 3-oxo-6-(pyridin-2-yl)-2,3-dihydropyridazine-4-carboxylate

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Reaction Steps

Working as in example 19 for the preparation of ethyl 6-[4-(benzyloxy)phenyl]-3-oxo-2,3-dihydropyridazine-4-carboxylate, but starting with 31.1 g of diethyl hydroxy(pyridin-2-oxoethyl)malonate, 11.55 g of hydrazine dihydrochloride and 700 cm3 of ethanol, and after purification by chromatography on silica gel (particle size 40-63 μm, under an argon pressure of 150 kPa), eluting with dichloromethane, followed by recrystallization from ethanol, 6.9 g of ethyl 6-pyridin-2-yl-3-oxo-2,3-dihydropyridazine-4-carboxylate were obtained in the form of a yellow solid melting at 182° C.

Provenance & Evidence