Sodium hydride → 4,5-dichloro-3-hydroxy-3-(2-methoxy-5-methylphenyl)-1,3-dihydro-2H-indol-2-one

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Reaction Steps

Under nitrogen atmosphere, to a suspension of 0.31 g NaH in THF (40 ml), under ice bath conditions, was added 1.50 g of 4,5-dichloroisatin, which is the compound described in the specifications of U.S. Pat. No. 4,146,718, and the reaction mixture was stirred for 1 hour. Thereafter, a solution of bromo(2-methoxy-5-methylphenyl) magnesium in THF (20 ml) prepared beforehand was added dropwise over 20 minutes. The solution was stirred at the same temperature for 4 hours. Then a saturated aqueous solution of NH4Cl was added, and the reaction mixture was stirred at room temperature for 30 minutes. Liquid separation was performed, the aqueous layer was extracted with EtOAc, the combined organic layer was washed with saturated brine, dried over Na2SO4, then, the drying agent was separated by filtration and the solvent was evaporated under reduced pressure. The obtained residue was washed by stirring in IPE and the solid was collected by filtration to obtain 1.23 g of the title compound (yellow solid).

Provenance & Evidence