Hydrochloric Acid → 4-Bromo-6-isopropyl-2-methyl-1H-indene

Participants

Reaction Conditions

Reaction Steps

To a solution of 22.2 g (83.2 mmol) of 7-bromo-5-isopropyl-2-methyl-1-indanone in 120 ml of THF-methanol (2:1, vol.), 5.06 g (133 mmol) of NaBH4 was added with vigorous stirring over 3 h at 0° C. This mixture was stirred overnight at room temperature; then, 300 ml of cold water was added, and the resulting mixture was acidified with 1 M HCl to pH 1. The organic layer was separated, and the aqueous layer was extracted with 3×150 ml of dichloromethane. The combined organic fractions were dried over K2CO3 and evaporated to dryness, and 200 ml of toluene was added to the yellowish oil obtained. This toluene solution was treated with a catalytic amount of pTolSO3H (ca. 0.2 g) for 1 h at reflux, cooled to room temperature, and evaporated to dryness. The crude product was purified using flash chromatography on Silica Gel 60 (40-63 μm, d 40 mm, l 400 mm; eluent: hexanes). Yield 19.6 g (94%) of 4-bromo-6-isopropyl-2-methyl-1H-indene.

Provenance & Evidence