Carbon Disulfide → 6-Acetyl-8-fluoro-3,4-dihydroquinolin-2(1H)-one

Participants

Reaction Conditions

Reaction Steps

To a stirring solution of 8-fluoro-3,4-dihydroquinolin-2(1H)-one (1.6 g, 9.69 mmol) and acetyl chloride (1.722 mL, 24.22 mmol) in carbon disulfide (20 mL, 9.69 mmol) at 0° C. was added in portions aluminum chloride (6.59 g, 49.4 mmol). The reaction mixture was stirred at 100° C. without a condensor until the solvent evaporated, then a condensor was fitted in place and stirring continued at 100° C. for 4 h. After cooling, the reaction contents were carefully poured into ice water and partitioned between DCM and water. The aqueous layer was extracted with DCM (3×150 mL). The combined organic washes were dried over MgSO4 and concentrated under vacuum to a tan solid. This was purified by flash chromatography on silica gel using 1% MeOH in DCM to give 6-acetyl-8-fluoro-3,4-dihydroquinolin-2(1H)-one as a yellow solid (1.6 g, 80%). 1H NMR (400 MHz, CHLOROFORM-d) δ ppm 7.72 (br. s., 1H), 7.68-7.60 (m, 1H), 2.76-2.58 (m, 2H), 2.58-2.50 (m, 2H), 1.58 (s, 13H). LCMS: R.T.=1.335 min; [M+H]+=208.0.

Provenance & Evidence