Sulfuric Acid → 4-Dimethylamino-phenylboric acid

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Reaction Steps

A solution of the corresponding Grignard compound is prepared from 16.8 g 4-bromo-N,N-dimethyl-aniline and 2.04 g of magnesium in 150 ml of tetrahydrofuran. This is now slowly added dropwise while stirring at -60° to a solution of 9.4 ml of trimethylborate in 50 ml of tetrahydrofuran under argon. Subsequently, the mixture is stirred at room temperature overnight. The mixture is poured on to ice-water, adjusted to pH 3-4 with dilute sulphuric acid and extracted with diethyl ether. The extract is dried, evaporated and the residue is recrystallized from water. 5.6 g (40%) of 4-dimethylamino-phenylboric acid are obtained. Mass spectrum: peaks inter alia at m/e: 164 (M±H, 100%).

Provenance & Evidence