Hydrochloric Acid → 4-Methyl-6-trifluoromethyl-3,4-dihydro-2H-benzo[1,4]oxazine-2-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

To a solution of 6-trifluoromethyl-3,4-dihydro-2H-benzo[1,4]oxazine-2-carboxylic acid ethyl ester (650 mg, 2.4 mmol) in anhydrous DMF (7 mL) was added K2CO3 (816 mg, 5.9 mmol), followed by iodomethane (294 μL, 4.7 mmol). The reaction was heated in the microwave (300 W, 150° C.) for 1 hour. After cooling, the mixture was poured into water (50 mL), acidified with 2N HCl and extracted with EtOAc (3×50 mL). The combined organics were washed with brine (3×50 mL), dried (MgSO4), filtered and concentrated. Flash chromatography (0 to 12% MeOH in DCM) gave the title compound (90 mg, 10%) as a beige solid. m/z=262.1 (M+1), r.t.=3.28 mins. 1H NMR (400 MHz; d6-DMSO) δ 6.93-6.86 (3H, m), 4.85 (1H, s), 3.45-3.36 (2H, m), 2.86 (3H, s).

Provenance & Evidence