ClC1C2C=CC=CC=2SN=1.[O:11]=[S:12]1(=[O:30])[C:16]2[CH:17]=[CH:18][CH:19]=[CH:20][C:15]=2[C:14]([NH:21][CH2:22][CH2:23][CH2:24][C:25]([O:27]CC)=[O:26])=[N:13]1.Cl.C(OC(=O)CCCN)C.C(N(CC)CC)C>O1CCOCC1>[O:11]=[S:12]1(=[O:30])[C:16]2[CH:17]=[CH:18][CH:19]=[CH:20][C:15]=2[C:14]([NH:21][CH2:22][CH2:23][CH2:24][C:25]([OH:27])=[O:26])=[N:13]15.68 g. (28.1 mM) of 3-chloro-1,2-benzisothiazole, 1,1-dioxide (prepared as in Example 1), 4.8 g. (28.1 mM) of ethyl-4-aminobutyrate hydrochloride and 7.84 ml. (56.2 mM) of triethylamine are refluxed in 100 ml. of dioxane for one hour. The solvent is evaporated and the residue refluxed in 1% hydrochloric acid for 2.5 hours. The product crystallizes out overnight at room temperature. The product, 4-[(1,1-dioxo-1,2-benzisothiazol-3-yl)amino]butanoic acid is filtered out, washed with water, and recrystallized from 150 ml. water, yield 4.2 g., m.p. 200°-202°.
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