5-Chloro-2-methoxybenzene-1-sulfonyl chloride → 4-(5-chloro-2-methoxy-benzenesulfonyl)-3,4-dihydro-2H-benzo[1,4]oxazine-6-carboxylic acid methyl ester

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Reaction Steps

To a solution of 5-chloro-2-methoxy-benzenesulfonyl chloride (4.7 g, 19.7 mmol, 1.05 equiv.) in dichloromethane (60 mL) and pyridine (25 mL) was added a solution of 3,4-dihydro-2H-benzo[1,4]oxazine-6-carboxylic acid methyl ester (3.6 g, 18.8 mmol, 1 equiv.) in dichloromethane (60 mL). The mixture was stirred at room temperature overnight then the solvent was removed. The residue was purified by flash chromatography to yield 4-(5-chloro-2-methoxybenzenesulfonyl)-3,4-dihydro-2H-benzo[1,4]oxazine-6-carboxylic acid methyl ester as a pink solid, 7.12 g (95%), MS (ISP): m/e=398.0 (M+H+.); δH (300 MHz; CDCl3) 8.24 (1H, s), 8.07 (1H, s), 7.72 (1H, dd), 7.48 (1H, dd), 6.91 (1H, d), 6.89 (1H, d), 4.10 (2H, m), 3.91 (2H, m), 3.88 (3H, s), 3.63 (3H, s).

Provenance & Evidence