4-t-Butyl-N-[2,6-dichloro-5-(2-methoxyphenoxy)-4-pyrimidinyl]benzenesulfonamide (5) (482 mg; 1.0 mmol) was dissolved in dimethyl sulfoxide (5 ml). Morpholine (175 mg; 2.0 mmol) was added to the solution, and the resultant mixture was stirred overnight at 100° C. After being cooled, the reaction mixture was poured into water, made acidic with hydrochloric acid, and extracted with ethyl acetate, being washed with water, dried over anhydrous sodium sulfate, and evaporated. The residue was purified by silica gel column chromatography (ethyl acetate:hexane=1:2), to thereby obtain 240 mg (yield: 45%) of the title compound as a white powder.
