Synthesis of 7-benzyl-3-oxo-7h,1,2,3,4,5,6-hexahydropyrrolo[2,3-c]pyridazine

7-Benzyl-3-oxo-7H,1,2,3,4,5,6-hexahydropyrrolo[2,3-c]pyridazine was synthesized from 1-benzyl-2, 3-dioxopyrrolidine through the corresponding 3-hydroxy, 3-chloro, 3-(diethoxycarbonyl) methyl, and 3-ethoxycarbonylmethyl derivatives. The Fischer cyclization of cyclohexanone 5-chloro-2-pyridazylhydrazone, which leads to 2-chloro-1,9a-diaza-5,6,7,8-tetrahydrocarbazole, was studied.