Ammonia → 2-Amino-3,4-dihydro-3-oxo-2H-1,4-benzothiazine

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Reaction Steps

Anhydrous ammonia gas was bubbled for one hour through a suspension of 500 mg (2.5 mmol) of 2-chloro-3,4-dihydro-3-oxo-2H-1,4-benzothiazine (prepared by the method of Worley, et al; J. Org. Chem., 40, 1731-1734 (1975)) in 5 mL of methylene chloride. The mixture was filtered through Celite and the filtrate evaporated under vacuum. The residue was triturated with 20 mL of chloroform, filtered and the filtrate evaporated under vacuum. Purification by flash chromatography on silica, eluting with ethyl acetate, afforded 185 mg (1.0 mmol, 41%) of the product. 1H NMR (200 MHz, CDCl3): 2.00 (br s,2H), 4.68 (br s,1H), 6.9-7.4 (m,4H), 9.05 (br s,1H). FAB-MS: calculated for C8H8N2OS 180; found 181 (M+h,54%).

Provenance & Evidence