Acetonitrile → 2-Bromo-3-chloro-1-(2-trimethylsilylethoxymethyl)-1,5-dihydropyrrolo[2,3-d]pyridazin-4-one

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Reaction Steps

To 30 ml of acetonitrile solution containing 903 mg (3.00 mmol) of 3-chloro-1-(2-trimethylsilylethoxymethyl)-1,5-dihydropyrrolo[2,3-d]pyridazin-4-one obtained in Reference example 16-(c) was added 703 mg (3.95 mmol) of N-bromosuccinimide at room temperature, and the mixture was stirred for 8.5 hours. After completion of the reaction, ethyl acetate was added to the reaction mixture, and the mixture was washed successively with a saturated aqueous solution of sodium hydrogencarbonate, 5% aqueous sodium hydrogen sulfite solution and then a saturated aqueous solution of sodium chloride, dried over anhydrous magnesium sulfate and concentrated under reduced pressure. To the obtained concentrate were added diisopropyl ether and cyclohexane, precipitated solid was collected by filtration. The obtained solid was washed with cyclohexane and then with hexane, and dried under reduced pressure to obtain 943 mg of the title compound as a pale yellowish solid. (Yield: 83%)

Provenance & Evidence