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Synthesis of 4-aryl-5-hydroxy- and 5-aryl-4-hydroxypyridazin-3(2H)-ones and their use in the preparation of 4,5-diarylpyridazin-3(2H)-ones and hitherto unknown isochromeno[3,4-d]pyridazinediones

2002; Elsevier BV; Volume: 58; Issue: 48 Linguagem: Inglês

10.1016/s0040-4020(02)01285-1

1464-5416

Bert U. W. Maes, Katrien Monsieurs, Kristof T. J. Loones, Guy L. F. Lemière, R. Dommisse, Péter Mátyus, Zsuzsanna Riedl, György Hajós,

Phenothiazines and Benzothiazines Synthesis and Activities

Easily accessible 2-substituted 4-aryl-5-methoxy- and 2-substituted 5-aryl-4-methoxypyridazin-3(2H)-ones were transformed into the corresponding aryl-hydroxypyridazin-3(2H)-ones by alkaline hydrolysis. The use of these compounds in the synthesis of 2-substituted 4,5-diarylpyridazin-3(2H)-ones with two differently substituted aryl groups was investigated. Two aryl-hydroxypyridazin-3(2H)-ones, 2-(2-benzyl-5-hydroxy-3-oxo-2,3-dihydropyridazin-4-yl)benzaldehyde and 2-(1-benzyl-5-hydroxy-6-oxo-1,6-dihydropyridazin-4-yl)benzaldehyde, were transformed into 2-benzyl-1H-isochromeno[3,4-d]pyridazine-1,6(2H)-dione and 3-benzyl-3H-isochromeno[3,4-d]pyridazine-4,6-dione, respectively, via oxidation of the formyl group with KMnO4 followed by lactonization.