p-Toluenesulfonic acid monohydrate → 4-Chloro-1-(m-tolyl)butan-1-one

Participants

Reaction Steps

A solution of Example 91A (2.56 g, 16.9 mmol), TsOH.H2O (3.2 g, 16.9 mmol) and pyridine hydrochloride (3.88 g, 33.8 mmol) in CH3CN (60 mL) was heated at 160° C. for 3 hours under microwave and the CH3CN was removed by reduced pressure to give a residue, which was re-dissolved in ethyl acetate (100 mL). The resulting organic solution was washed with aqueous NaHCO3 (50 mL) and brine (50 mL), dried over MgSO4, filtered, and concentrated to give a black oil. The oil was purified by chromatography on silica gel column (petroleum ether:ethyl acetate=20:1) to give the title compound (1.56 g, 50%). LC-MS (M+H): m/z 197. 1H NMR (400 MHz, CDCl3): δ ppm 7.765-7.786 (m, 2H), 7.354-7.397 (m, 2H), 3.679 (t, J=6.2 Hz, 2H), 3.170 (t, J=6.2 Hz, 2H), 2.419 (s, 3H), 2.194-2.260 (m, 2H).

Provenance & Evidence