Acetic Acid → 2-bromo-5,6,7,8-tetrahydro-4H-cyclohepta[b]thiophen-4-one

Participants

Reaction Conditions

Reaction Steps

To a solution of 5,6,7,8-tetrahydro-4H-cyclohepta[b]thiophen-4-one (4.96 g, 29.8 mmol) in water (23.0 mL, 1200 mmol) and acetic acid (23.0 mL, 4000 mmol) at −5° C. was added a solution of bromine (1.6 mL, 31 mmol) in acetic acid (3.2 mL, 56 mmol) dropwise and the reaction mixture was stirred at −5° C. for 1 hr. The reaction mixture was quenched into aqueous sodium acetate, ethyl acetate (30 mL) was added, the organic layer was separated, and the aqueous layer was extracted with ethyl acetate (3×10 mL). The combined organic layers were washed with brine, dried over MgSO4, filtered, concentrated and dried under high vacuum to afford 7.3 g product as a brownish solid (99.0% yield). LCMS: (FA) ES+ , 246. 1H NMR (300 MHz, CDCl3) δ: 7.35-7.36 (br s, 1H), 2.98-3.0 (m, 2H), 2.68-2.73 (m, 2H), 1.85-2.0 (m, 4H).

Provenance & Evidence