Water → 3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylic acid

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Reaction Steps

3-Oxo-3,4-dihydro-2H-benzo[1,4]thiazine-6-carboxylic acid methyl ester (6.74 g) was suspended in tetrahydrofuran (100 mL) and 2M sodium hydroxide (30 mL) was added followed by water (20 mL). The solution was stirred for 2.5 hours, evaporated to half volume and acidified with 2M hydrochloric acid. The product was collected, washed with water and dried in vacuo, to give a white solid (6.2 g).

Provenance & Evidence