148550-51-0

Step 2: Synthesis of ethyl 2-(methylsulfonyl)pyrimidine-5-carboxylate (121); Sulfide 120 (0.424 g, 2.14 mmol) was dissolved in dichloromethane (DCM, 9 mL), and a DCM (9 mL) solution of 3-chloroperoxybenzoic acid (mCPBA, 2.0 g) was slowly added. The reaction mixture was stirred at room temperature for 100 min. Upon completion of the reaction, the reaction was quenched with aqueous Na2S2O3, diluted with DCM and washed with saturated NaHCO3 solution. The organic phase was dried over anhydrous MgSO4, filtered and concentrated to give the target product 121 (0.374 g, 76% yield). [0726] MS: m/z 230.1 (calculated), 230.9 (measured).

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