反应详情

5.6 g of 1,3-dimethyl-5-hydroxypyrazole (50 mmol) was added to a suspension of 7.7 g 2-chloro-6-cyanopyridine (55 mmol) and 7.6 g K2CO3 (55 mmol) in 50 ml N,N-dimethylformamide and heated to reflux with vigorous stirring for 5 hours. After cooling, the mixture was poured into water (100 ml) and the aqueous layer extracted 3 times with each 100 ml ethyl acetate. The combined extracts were dried with anhydrous magnesium sulphate and the solvent was removed in vacuo. The residue was purified by flash silica gel column chromatography using hexane/ethyl acetate 7/3. The title compound was obtained after recrystallisation from isopropanol as 5.9 g (55%) of white crystals of m.p. 95° C.

1. temperatureheated
2. temperatureto reflux
3. temperatureAfter cooling
4. extractionthe aqueous layer extracted 3 times with each 100 ml ethyl acetate
5. dry with materialThe combined extracts were dried with anhydrous magnesium sulphate
6. customthe solvent was removed in vacuo
7. customThe residue was purified by flash silica gel column chromatography