Hydrochloric Acid → 3-Oxo-3,4-dihydro-2H-1,4-benzoxazine-6-carboxylic acid

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Reaction Conditions

Reaction Steps

To a solution of 18 (1.0 mmol) in dioxane (4 mL) was added aqueous LiOH (1 M, 4 mL, 4.0 mmol). The solution was stirred at 23° C. for 1 h and then quenched with aqueous HCl (4 M, 2 mL, 8 mmol). The resulting solid was isolated by filtration, washed with water and dried in vacuo to give a white solid: 1H NMR (DMSO-d6, 400 MHz): δ=12.81 (s, 1H), 10.88 (s, 1H), 7.48-7.54 (m, 2H), 7.01 (d, J=8.3 Hz, 1H), 4.67 ppm (s, 2H). ESI-MS: m/z 194.0 (M+H)+.

Provenance & Evidence