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Paper | Regular issue | Vol 43, No. 8, 1996, pp.1613-1620
Published online, 1st January, 1970
DOI: 10.3987/COM-96-7402
One-Pot Synthesis of New Spiro- and Tricyclic Pyridazino[4,5-c]pyridazinones

Tetsuo Yamasaki, Yuji Yoshihara, Yoshinari Okamoto, Tadashi Okawara, and Mitsuru Furukawa*

*Faculty of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-hon-machi, Kumamoto 862-0973, Japan


New 1,4-dihydropyridazino[4,5-c]pyridazine-4-spiro-3’-lactones (3) were prepared by one-pot cyclization from 5-hydrazinopyridazinones (1), 4-bromo-5-hydrazinopyridazinones (5) and a-ethoxyalyllactones (2). The reaction of 5 with 2-hydroxy-3,5-diethoxycarbonylcyclopent-2-en-1-one (6) afforded cyclopenteno[c]pyridazino[4,5-c]pyridazinone (7) and 12a,13a-diethoxycarbonyl-5,8-dimethyl-1,2,5,8,11,12,12b,13a-octahydro-2,3,5,6,7,8,10,11-octaazadibenzo[a,i]fluorene(8).