Chlorosulfonic acid → 4-(4-cyano-2-methoxyphenyl)-3,4-dihydro-2H-benzo[b][1,4]oxazine-7-sulfonyl chloride

Participants

Reaction Steps

To a solution of 4-(2H-benzo[b][1,4]oxazin-4(3H)-yl)-3-methoxybenzonitrile (790 mg, 2.96 mmol) in DCM (10 mL) was added chlorosulfonic acid (0.79 mL, 11.8 mmol) at 0° C. The reaction mixture was stirred at room temperature for 2 h. After completion, reaction mixture was poured into ice water (15 mL), quenched with solid sodium bicarbonate (pH˜9-10) and the aqueous layer was extracted with ethyl acetate (2×20 mL). The organic layer was dried over sodium sulfate and concentrated to get 4-(4-cyano-2-methoxyphenyl)-3,4-dihydro-2H-benzo[b][1,4]oxazine-7-sulfonyl chloride as a sticky yellow solid (220 mg, 20.3%) which was used without further purification in the next step.

Provenance & Evidence