Water → N-isobutyl-3-bromopyrrolidine-2-one

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Reaction Steps

In a 1.5-liter 4-necked flask, equipped with a stirrer, reflux condenser, thermometer and argon inlet, 54.4 g NaOH pearls (1.36 mol) and 9.26 g tetrabutylammonium-hydrogensulfate (27.3 mmol) were suspended at room temperature under argon in 500 ml dichloromethane. To this suspension 36.6 g isobutylamine (500 mol) were added. Under stirring 100.0 g 2-bromo-4-chlorobutyric acid chloride (400 mol, product of Example 1) in 100 ml dichloromethane were added in 10 min. After the first three minutes of addition reflux of the mixture was reached and maintained during the addition. Reflux of the mixture was continued for 2.0 h. After the first 10 minutes, the initially yellowish suspension turned purple, then gradually faded into gray. After completed reflux, the mixture was allowed to cool to room temperature during 15 min., a mixture of 50 g ice in 250 ml deionized water was added under stirring during 1 min., and the phases were separated. The organic phase was first washed with a solution of 60 g ammonium chloride in 300 ml deionized water, then with 300 ml deionized water, and finally evaporated to yield 84.3 g of N-isobutyl-3-bromopyrrolidine-2-one as a dark oil.

Provenance & Evidence