Boron tribromide → Erbstatin

Participants

Reaction Steps

To a stirred solution of (E)-N-[2-(2,5-dimethoxyphenyl) ethenyl] formamide (2.071 g, 10 mmol) in anhydrous dichloromethane (100 ml) is added, at -78° C. under nitrogen over a period of 10 min, a 1.0M solution of boron tribromide in dichloromethane (30 ml, 30 mmol). The resulting mixture is stirred for another 1 h at -78° and then allowed to warm to room temperature. After stirring for 1.5 h at 20°-25° C. the mixture is cooled to -10° C. and then quenched by the dropwise addition of water (100 ml) over a 10 min period. After addition of ethyl acetate (100 ml) the organic layer is separated, washed with water, dried with Na2SO4 and evaporated under vacuum to dryness. After venting with nitrogen the residue is dissolved in 80 ml of CHCl3 /MeOH 10% and the solution diluted with CHCl3 (60 ml) to faint turbidity. The mixture is kept for 5 h at 0°-5° C., the precipitate filtered and dried at 20°-25° C. under vacuum. Thus 14.34 g (80% yield) of pure title compound is obtained with m.p. 149°-153° C.

Provenance & Evidence