Citric Acid → 4-((3-Chloro-4-methoxybenzyl)amino)-2-(methylthio)pyrimidine-5-carboxylic acid

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Reaction Steps

A suspension of 2-methylthio-4-(3-chloro-4-methoxybenzylamino)-5-ethoxycarbonylpyrimidine (2.00 g) obtained in Example 1 (1) in dimethylsulfoxide (10 ml) is treated with 10% aqueous sodium hydroxide solution (10 ml) at room temperature. To the reaction mixture is added dimethylsulfoxide (5 ml), and the mixture is stirred at room temperature overnight. To the resulting colorless solution is added citric acid until the solution becomes acidic. To the solution is added an excess amount of water (about 50 ml), and the resulting precipitates are collected by filtration. The precipitates are washed with isopropyl alcohol and isopropyl ether successively, and dried under reduced pressure to give 2-methylthio-4-(3-chloro-4-methoxybenzylamino)-5-carboxypyrimidine (1.864 g) as pale yellow impalpable powder, m.p. 238-240° C. (dec.).

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