反应详情

温度

50 °C

A sodium hydride-mineral oil suspension (54%; 3.1 g., 0.069 mole) is stirred with three 50 ml. portions of dry hexane, each portion being pipetted out to remove the mineral oil. Dimethylformamide (30 ml., previously distilled and dried over a molecular sieve) is added through a pressure equalized addition funnel while a slow stream of nitrogen is passed through the mixture. The reaction vessel is cooled in an ice-bath while diethyl methylmalonate (12 g., 0.069 mole) is added dropwise to the stirred mixture. After the addition is complete, the ice-bath is replaced by an oil bath and the temperature is raised to 50° C. To the mixture is added dropwise 2-chloro-5--phenylpyrazine (10 g., 0.053 mole) in warm dimethylformamide (55 ml.). After this addition is complete, the mixture is heated for 31/2 hours during which time the temperature is raised to 120° C. The reaction mixture is cooled to about 80° C. and water (4 ml.) is added. The mixture is concentrated to a small volume, and the residual liquid is diluted with 50 g. of ice and extracted with ether several times. The combined ether extracts are washed with 5% hydrochloric acid, then with water, and then dried and evaporated. The resulting oil is chromatographed on a column of 500 g. of Merck acid-washed alumina. Elution with benzene-hexane (4:1) through ethyl acetate-benzene (1:3) yielded diethyl α-methyl-5-phenylpyrazinylmalonate.

1. customto remove the mineral oil
2. distillation, previously distilled
3. customdried over a molecular sieve)
4. additionis added through a pressure
5. additionaddition funnel while a slow stream of nitrogen
6. additionis added dropwise to the stirred mixture
7. additionAfter the addition
8. additionAfter this addition
9. temperaturethe mixture is heated for 31/2 hours during which time the temperature
10. temperatureis raised to 120° C
11. temperatureThe reaction mixture is cooled to about 80° C.
12. concentrationThe mixture is concentrated to a small volume
13. additionthe residual liquid is diluted with 50 g
14. extractionof ice and extracted with ether several times
15. washThe combined ether extracts are washed with 5% hydrochloric acid
16. dry with materialwith water, and then dried
17. customevaporated
18. customThe resulting oil is chromatographed on a column of 500 g
19. washof Merck acid-washed alumina
20. washElution with benzene-hexane (4:1) through ethyl acetate-benzene (1:3)