Dicyclohexylcarbodiimide → N-[2-(4,6-Dimethoxypyrimidin-2-yl)acetyl]-2-methoxycarbonylbenzylsulfonamid

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Reaction Steps

A solution of 1.9 g of (4,6-dimethoxypyrimidin-2-yl)acetic acid in 40 ml of absolute dichloromethane is added dropwise at 0° C. to 2° C. to a solution of 1.9 g of dicyclohexylcarbodiimide, 100 mg of 4-dimethylaminopyridine and 2.1 g of 2-methoxycarbonylbenzylsulfonamide in 40 ml of absolute dichloromethane. Stirring is continued for 1 hour at 0° C., and the mixture is allowed to come to room temperature and stirred for another 0.5 hour. The solids are filtered off, and the filtrate is concentrated in a rotary evaporator. 100 ml of 2 N sodium carbonate solution are added to the residue, the mixture is stirred for 0.5 hour at room temperature, and the solids are filtered off with suction. The sodium carbonate alkaline phase is extracted twice using diethyl ether, and a pH of 2-3 is established using concentrated hydrochloric acid. Stirring is continued for 15 minutes, the solids are filtered off with suction, the filter residue is washed once with water and twice with ether, and dried in vacuo. This gives 2.4 g of N-[2-(4,6-dimethoxypyrimidin-2-yl)acetyl]-2-methoxycarbonylbenzylsulfonamide of melting point 98°-101° C.

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