C([O:3][C:4]([C:6]1[N:7]=[C:8]([CH3:18])[S:9][C:10]=1[NH:11][C:12]1[CH:13]=[N:14][CH:15]=[CH:16][CH:17]=1)=[O:5])C.[OH-].[K+]>CO.O>[CH3:18][C:8]1[S:9][C:10]([NH:11][C:12]2[CH:13]=[N:14][CH:15]=[CH:16][CH:17]=2)=[C:6]([C:4]([OH:5])=[O:3])[N:7]=1A solution of 2-methyl-5-(pyridin-3-ylamino)-thiazole-4-carboxylic acid ethyl ester (0.24 g, 0.90 mmol) in methanol (1.6 ml) was treated with a 2.55 N solution of KOH in water (1.06 ml). The mixture was stirred at 55° C. for 40 min then cooled to room temperature. The volatiles were evaporated and the residue dissolved in water (2.00 ml) and treated with HCl 1N under vigorous stirring until pH 5 was reached. The mixture was stirred for 1 h, then the solids were filtered, washed with water and dried under high vacuum to yield 2-methyl-5-(pyridin-3-ylamino)-thiazole-4-carboxylic acid (0.15 g, 70%) as a light yellow solid, MS (ISP): m/e=234.1 (M−H).
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