反应详情

A solution of 1,4-dihydro-2-methoxy-6-methyl-4-(3-nitrophenyl)-5-pyrimidinecarboxylic acid, ethyl ester (0.96 g., 3.0 mmole), dry triethylamine (1.25 ml., 9.0 mmole), and dimethylaminopyridine (36 mg., 0.3 mmole) in dichloromethane (12 ml.) under argon is treated with pivaloyl chloride (0.44 ml., 3.6 mmole). After stirring for 45 minutes at room temperature, the reaction mixture is evaporated. The residue is taken up in tetrahydrofuran/methanol (10 ml. each) and treated with 2N hydrochloric acid (6.0 ml., pH 1). After stirring at room temperature for 3.0 hours, the reaction is quenched with saturated sodium bicarbonate, partially evaporated and extracted with ethyl acetate. The organic phase is washed with saturated sodium chloride and evaporated. Flash chromatography and crystallization from dichloromethane/isopropyl ether gives the title compound as white crystals (420 mg. , m. p. 155°-156°. TLC(silica gel; ethyl acetate:hexane, 1:1)Rf =0.67.

1. customthe reaction mixture is evaporated
2. additioneach) and treated with 2N hydrochloric acid (6.0 ml., pH 1)
3. stirringAfter stirring at room temperature for 3.0 hours
4. customthe reaction is quenched with saturated sodium bicarbonate
5. custompartially evaporated
6. extractionextracted with ethyl acetate
7. washThe organic phase is washed with saturated sodium chloride
8. customevaporated
9. customFlash chromatography and crystallization from dichloromethane/isopropyl ether