Hydrochloric Acid → 4-{[4-(5-Chloro-2-methoxy-benzenesulfonyl)-3,4-dihydro-2H-benzo[1,4]oxazine-6-carbonyl]-amino}-benzoic acid

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Reaction Conditions

Reaction Steps

A solution of 4-{[4-(5-chloro-2-methoxy-benzenesulfonyl)-3,4-dihydro-2H-benzo-[1,4]oxazine-6-carbonyl]-amino}-benzoic acid ethyl ester (0.91 g, 1.72 mmol) in tetrahydrofuran (10 mL) and methanol (10 mL) was treated with 3N NaOH (5 mL, 15 mmol, 8.7 equiv.). The mixture was stirred at 45° C. for 30′. The mixture was then acidified with HCl 3N (5 mL) and the solid which precipitated was filtered, washing with water, and dried under high vacuum. 4-{[4-(5-Chloro-2-methoxy-benzenesulfonyl)-3,4-dihydro-2H-benzo[1,4]oxazine-6-carbonyl]-amino}-benzoic acid was obtained as a white solid, 0.85 g (98%). MS (ISP): m/e=501.0 (M−H); δH (300 MHz; d6-DMSO) 12.65 (1H, s), 10.35 (1H, s), 8.05 (1H, d), 7.81-7.88 (5H, m), 7.66-7.71 (2H, m), 7.19 (1H, d), 6.98 (1H, d), 3.96 (2H, m), 3.85 (2H, m), 3.53 (3H, s).

Provenance & Evidence