A mixture containing 0.85 g of N-[(4,6-dimethoxypyrimidin-2-yl)aminocarbonyl]-2-carboxybenzenesulfonamide in 50 ml of anhydrous tetrahydrofuran was treated with 40 ml of 1.4 molar solution of methyl lithium (low halide, Aldrich) in ether at 25° under a nitrogen atmosphere. The mixture was stirred for 4 hours at 25° and was then poured into 500 ml of water containing 10 ml of concentrated hydrochloric acid. The precipitated oil was extracted into methylene chloride and the oil on evaporation of solvent was purified by preparative thin layer chromatography on silica gel (Analtec, 2000 micron, 20×20 plates) by elution with ethyl acetate/hexane in a one to one ratio. The isolated product was recrystallized from a 1-chlorobutane and hexane mixture to give 0.1 g, m.p. 126°-8°. The infrared absorption showed a broadened carbonyl peak at 1710 cm-1, and the absence of the 3500 and 3400 cm-1 peaks of the starting material. The nuclear magnetic resonance spectrum showed peaks at 2.6 ppm S, 3H, ##STR32## 4.0 ppm, S, 6H, CH3O of pyrimidine; 5.7 ppm S, 1H, pyrimidine proton at position 5; and 7.3-7.7 ppm and 8.0 ppm M, 4H, aromatic, which are constitent with the desired structure.
