反应详情

Concentrated sulfuric acid (768 mL) was added slowly to ethanol (1.6 L) with cooling (exothermic reaction!). 4-Methyl-5-nitropyridine-2-carbonitrile (62.4 g, 0.38 mol) was added to the cold solution. After the addition was complete, the solution was refluxed under nitrogen for 2 h. Part of the solvent (500 mL) was removed using an oil pump at 30° C. The remaining thick solution was poured onto ice (1 kg). After stirring for 15 min, the mixture was extracted with ether (2×1 L) and multiple times with dichloromethane. At first, the organic layer was the TOP layer. As the extraction continued, the organic layer changed from the top layer to the bottom layer due to change in density as less ethanol was extracted. The combined organic extracts were dried (magnesium sulfate) and concentrated. Recrystallization from hexanes yielded 44.4 g (56%) of the desired product. 1H NMR (300 MHz, CDCl3) δ ppm 1.46 (t, 3H, J=7.5 Hz), 2.71 (s, 3H), 4.51 (q, 2H, J=7.5 Hz), 8.13 (s, 1H), 9.22 (s, 1H). LCMS: (APCI, M+H+)=209

1. temperaturewith cooling
2. custom(exothermic reaction!)
3. additionAfter the addition
4. temperaturethe solution was refluxed under nitrogen for 2 h
5. customPart of the solvent (500 mL) was removed
6. customat 30° C
7. additionThe remaining thick solution was poured onto ice (1 kg)
8. extractionthe mixture was extracted with ether (2×1 L) and multiple times with dichloromethane
9. extractionAs the extraction
10. extractionwas extracted
11. dry with materialThe combined organic extracts were dried (magnesium sulfate)
12. concentrationconcentrated
13. customRecrystallization from hexanes