38275-34-2

61727-33-1

38275-34-2

3A. General procedure for the synthesis of 5-chloro-2-(methylsulfonyl)pyrimidine-4-carboxylic acid: 5-chloro-2-(methylthio)pyrimidine-4-carboxylic acid (8.0 g, 39 mmol) was mixed with acetic acid (30 mL) and stirred, and 25% aqueous hydrogen peroxide (11.5 mL, 85 mmol) was added slowly dropwise over a controlled time period of 1 hour. The reaction mixture was stirred continuously at room temperature for 4 days. After completion of the reaction, the mixture was filtered and the resulting solid was washed with cold water (2 x 50 mL) and dried to afford the target compound 5-chloro-2-(methylsulfonyl)pyrimidine-4-carboxylic acid (5.8 g, 63% yield) as a white solid.1H NMR (400 MHz, CDCl3) δ 8.57 (s, 1H), 2.71 (s, 3H).