反应详情

温度

100 °C

Ethyl veratroylacetate (4.5 g) was added dropwise under stirring at 60°-70° C. to a suspension of 2-aminopyridine (0.84 g) in polyphosphoric acid (13.7 g). The reaction mixture was stirred at 100° C. for 3 hrs and poured into ice-water (50 ml). The aqueous solution was extracted with chloroform, washed with water, dried and evaporated to give dark oily residue which was chromatographed on silica gel using n-hexaneethyl acetate. The fractions were evaporated and the resulting residue was triturated with ethanol-isopropyl ether to give 2-(3,4-dimethoxyphenyl)-4-oxo-4H-pyrido[1,2-a]pyrimidine (3.8 g).

1. extractionThe aqueous solution was extracted with chloroform
2. washwashed with water
3. customdried
4. customevaporated
5. customto give dark oily residue which
6. customwas chromatographed on silica gel using n-hexaneethyl acetate
7. customThe fractions were evaporated
8. customthe resulting residue was triturated with ethanol-isopropyl ether