Iodine → 5-Chloro-3-hydroxy-3-(2-methoxyphenyl)indolin-2-one

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Reaction Conditions

Reaction Steps

Magnesium turnings (40 g, 1.65 mol) are introduced into diethyl ether (100 ml) and, while stirring, a solution of 2-bromoanisole (206 ml, 1.65 mol) in diethyl ether (450 ml) is added dropwise. The reaction can be initiated, if necessary, by adding iodine crystals. During the addition, the reaction mixture should boil gently. After the addition, the mixture was stirred at room temperature for 1 hour. A slurry of 5-chloroisatin (75 g, 0.41 mol) in THF (750 ml) was added to the Grignard solution while cooling slightly (temperature 18-24° C.), and the mixture was stirred at room temperature for 30 min. The reaction mixture was stirred into ammonium chloride solution and extracted several times with ethyl acetate. The combined organic phase was washed four times with water, dried over magnesium sulfate and concentrated under reduced pressure. The remaining residue was stirred with 2-propanol. The resulting precipitate was filtered off, washed with 2-propanol and diethyl ether and dried. 106 g of the desired intermediate were obtained.

Provenance & Evidence