[NH2:1][C:2]1[CH:3]=[C:4]([CH:10]=[CH:11][C:12]=1[NH:13][C:14](=[O:18])[CH:15]([CH3:17])[CH3:16])[C:5]([O:7]CC)=[O:6].[OH-].[Na+]>>[NH2:1][C:2]1[CH:3]=[C:4]([CH:10]=[CH:11][C:12]=1[NH:13][C:14](=[O:18])[CH:15]([CH3:16])[CH3:17])[C:5]([OH:7])=[O:6]A sample of ethyl 3-amino-4-(2-methylpropionylamino)benzoate (2.30 g, 0.0092 mol) was suspended in 1N NaOH (13.80 mL, 0.0138 mol). After stirring for 24 h at room temperature, the reaction was then heated at 50° C. for 6 h. The reaction was filtered and the filtrate acidified with 1N HCl forming an orange precipitate. The solid was collected by filtration and thin-layer chromatographic analysis (SiO2, 9:1 ethyl acetate:methanol) indicated formation of a new lower-running spot (Rf =0.1). This material was recrystallized from N-butanol. The residue was collected by filtration and then suspended in ether. The product was filtered and dried in vacuo at acetone reflux to give 0.12 g (5%) of the title compound as a beige solid, mp 159°-160° C.
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