反应详情

To a cold (0° C.) solution of 4-(4-methylpent-1-ynyl)-2-(methylthio)pyrimidine (2.5 g, 12 mmol) in acetonitrile (40 mL) was added 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) (2.7 mL, 18 mmol) and 1-aminopyridinium iodide (3.49 g, 15.7 mmol). The resultant dark solution was allowed to warm to room temperature and stirred vigorously. The mixture was heated to 50° C. for 18 h then cooled to room temperature. Water was added and the mixture concentrated in vacuo. The residue was partitioned between water and ether. The organic layer was washed with brine. The aqueous layer was extracted with ether and the combined organics were dried over magnesium sulfate. Filtration and concentration followed flash chromatography on silica gel (6:1 to 4:1 to 2:1 hexane-ethyl acetate) provided 2-isobutyl-3-[2-(methylthio)pyrimidin-4-yl]pyrazolo[1,5-a]pyridine (2.0 g, 56%) as a yellow solid. 1H NMR (CDCl3) δ 8.51–8.48 (m, 2H), 8.36 (d, 1H), 7.35 (t, 1H), 7.19 (d, 1H), 6.91 (t, 1H), 3.04 (d, 2H), 2.68 (s, 3H), 2.20 (m, 1H), 1.03 (d, 6H); MS m/z 299 (M+1).

1. temperatureThe mixture was heated to 50° C. for 18 h
2. temperaturethen cooled to room temperature
3. concentrationthe mixture concentrated in vacuo
4. customThe residue was partitioned between water and ether
5. washThe organic layer was washed with brine
6. extractionThe aqueous layer was extracted with ether
7. dry with materialthe combined organics were dried over magnesium sulfate
8. filtrationFiltration and concentration