3-Hydrazino-5,6,7,8-tetrahydro-6-pyrido(4,3-c)pyridazinecarboxylic acid ethyl ester 39715-29-2 Ethyl 7,8-dihydro-3-hydrazinopyrido(4,3-c)pyridazine-6(5H)-carboxylate Pyrido(4,3-c)pyridazine-6(5H)-carboxylic acid, 7,8-dihydro-3-hydrazino-, ethyl ester