Hydrogen Bromide → 5-Bromo-3,3-dimethylpentanoic Acid

Participants

Reaction Conditions

Reaction Steps

A stream of dry hydrogen bromide gas (made from 83.3 m) of tetralin and 71 ml of bromine) was bubbled through a stirred solution of 3,3-dimethylpent-4-enoic acid (80 g, 0.625 mol) in dry light petroleum b.p. 40°-60° C. (940 ml) together with benzoyl peroxide (6.4 g, 0.025 mol) until it was saturated (about 2 hours) whilst the reaction mixture was maintained at the temperature between 10°-20° C. by occasional cooling. After completion of the reaction, the mixture was cooled down to -10° C. and the solid product was collected (near quantitative yield). The product was sufficiently pure by NMR spectroscopy to be used directly in the next step synthesis. However, a pure product was obtained after recrystallised from light petroleum spirit m.p. 53°-55° C. 1H NMR δ3.43 (2H, t), 2.27 (2H, s), 2.10 (2H, t), and 1.08 (6H, s).

Provenance & Evidence