Hydrochloric Acid → 5,8-Dimethyl-6-bromothiochroman-4-one

Participants

Reaction Steps

A solution of 4.07 g (0.021 mol) of the title compound of Step B in 25 mL of methylene chloride was added dropwise to a mixture of 7.07 g (0.053 mol) of aluminum chloride (purchased from Aldrich Chemical Company) and 25 mL of methylene chloride. The suspension was stirred for approximately 15 minutes, 1.14 mL (0.022 mol) of bromine (purchased from Janssen) was added dropwise and the mixture was refluxed for 10 minutes. The hot mixture was poured into 10 mL of concentrated hydrochloric acid containing 75 g of ice, stirred for 10 minutes, diluted with 50 mL of water, and extracted with diethyl ether (2×200 mL). The organic layer was washed with water (2×200 mL), dried (Na2SO4), filtered and evaporated to dryness. The crude product was chromatographed over silica gel eluting with ethyl acetate:hexane (5% 95%) to yield 2.62 g of the title compound of Step C as a solid melting at 87-88° C. 1H NMR (CDCl3): δ2.3 (s,3H), 2.6 (s,3H), 3.0 (m,2H), 3.2 (m,2H), 7.45 (s,1H).

Provenance & Evidence