Bromine → 10-chloro-2-(4-chlorophenyl)-5,6-dihydro-[1]benzothiepino[5,4-c]pyridazin-3(2H)-one

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Reaction Steps

To a mixture of 3.0 g of 10-chloro-2-(4-chlorophenyl)-4,4a,5,6,-tetrahydro-[1]benzothiepino[5,4-c]pyridazin-3(2H)-one obtained in Example 10 in 90 ml of acetic acid is added 0.4 ml of bromine at 40°-50° C. and stirred for 30 minutes at the same temperature. The mixture is concentrated under reduced pressure and to the residue is added water. The precipitated crystals are collected by filtration, dissolved in chloroform and the solution is washed with water. The organic layer is dried over anhydrous magnesium sulfate and the solvent is distilled off. The crude product obtained is purified by column chromatography and recrystallized from chloroformmethanol to give 2.4 g of 10-chloro-2-(4-chlorophenyl)-5,6-dihydro-[1]benzothiepino[5,4-c]pyridazin-3(2H)-one, melting at 215°-217° C.

Provenance & Evidence