Water → 1-Bromo-4-phenylbutan-2-one

Participants

Reaction Conditions

Reaction Steps

A freshly prepared solution of bromine (258.9 g) in methanol (600 mL) was added dropwise during 1 h 20 min to a stirred solution of benzylacetone (222.3 g) in methanol (600 mL) at 7-10° C. An exothermic reaction took place, and to maintain the necessary temperature (7-10° C.), the flask should be immersed in a ice-water bath. When orange-red color of bromine disappeared, water (1500 mL) was added to the mixture and the obtained mixture was stirred overnight. The organic layer (on the bottom) was separated, water phase was extracted with dichloromethane (2×600 mL). The combined organic layers were dried over sodium sulfate, filtered and evaporated under reduced pressure. The oily residue was dissolved in hexane (2500 mL) and the obtained solution was kept overnight at −10° C. Precipitated fine crystals (needles) were filtered off, washed on filter with cold hexane, dried under reduced pressure at room temperature to give 1-bromo-4-phenyl-2-butanone (213.0 g, 63% yield), mp 39-40° C. 1H NMR (CDCl3) δ 2.95-3.00 (m, 4H); 3.83 (s, 2H); 7.16-7.30 (m, 5H).

Provenance & Evidence