Methyl 2-(2-sulfamoylphenyl)acetate → 2H-1,2-Benzothiazin-3(4H)-one
Reaction equation
[S:1]([C:5]1[CH:10]=[CH:9][CH:8]=[CH:7][C:6]=1[CH2:11][C:12]([O:14]C)=O)(=O)(=O)[NH2:2]>[OH-].[Na+]>[S:1]1[C:5]2[CH:10]=[CH:9][CH:8]=[CH:7][C:6]=2[CH2:11][C:12](=[O:14])[NH:2]1Participants
3
Reactant 1
Product 1
Reagents, catalysts & solvents 1
Procedure
A solution of 18 g of 2-sulfamoylphenylacetic acid, methyl ester, in 125 g of 10% aqueous sodium hydroxide was stirred at room temperature for 4 hours. The mixture was filtered and the filtrate acidified by the addition of concentrated hydrochloric acid with ice-water cooling. The resulting precipitate was collected by filtration, washed with water, and dried to afford 12.5 g of 2H-1,2-benzothiazin-3(4H)-one, 1,1-dioxide as an off-white powder, m.p. 190°-195° C. NMR (CDCl3 /DMSO-d6): δ 11.3 (1H, br s, NH), 7.85 (1H, br d), 7.3-7.7 (3H, m) and 4.0 (2H, s).