Hydrogen Bromide → Methyl 5-bromo-4-oxopentanoate

Participants

Reaction Conditions

Reaction Steps

30 ml of trimethylsilyldiazomethane (2 M solution in diethyl ether) was added drop wise to a solution of 3-carbomethoxy propionylchloride (3.75 g, 30.5 mmol) in acetonitrile (75 ml) over a period of 10 mins at room temperature. The mixture was then stirred for 1 h. The reaction was cooled to 0° C. and 10g of 33% HBr in acetic acid was added slowly over 20 min, then the reaction was warmed to room temperature and stirred for 16 h. The solvent was removed in vacuo without heating and the residue was dissolved in ethyl acetate (100 ml), washed with 50 ml of saturated sodium bicarbonate solution and then 50 ml of brine. The organics were passed through a phase separator to remove any water and the solvent removed in vacuo. The resultant crude material was purified by kuglerhor distillation under reduced pressure (˜3 mbar, 150° C.) to give 5-bromo-4-oxo-pentanoic acid methyl ester (7g).

Provenance & Evidence