反应详情

A 200 mL round-bottom flask equipped with air cooled reflux condenser outfitted with a nitrogen inlet adapter was charged with 1-(2-methylpyridin-4-yl)-5,7,8,9-tetrahydro-1H-spiro[cyclohepta[f]indazole-6,2′-[1,3]dioxolane] (82, R1=2-methylpyridin-4-yl) (3.26 g, 9.72 mmol) and PTSA (2.31 g, 12.2 mmol) in acetone (49 mL). The mixture was heated to reflux. After 24 h, the reaction was diluted with additional acetone (50 mL) and water (2.5 mL) was added. After 1 h the reaction was cooled before adding sat. aq. NaHCO3 (30 mL). The mixture was then concentrated under reduced pressure. EtOAc (70 mL) was added, and after separating the layers, the aqueous phase was extracted with EtOAc (2×25 mL). The combined organic phases were washed with brine (75 mL), dried over Na2SO4, filtered, and concentrated under reduced pressure to give 1-(2-methylpyridin-4-yl)-5,7,8,9-tetrahydrocyclohepta[f]indazol-6(1H)-one (6, R1=2-methylpyridin-4-yl) (2.8 g, 99%); LC/MS, method 3, Rt=1.71 min, MS m/z 292 (M+H)+. 1H NMR (400 MHz, CDCl3) δ 8.65-8.60 (m, 1H), 8.20-8.16 (m, 1H), 7.71 (s, 1H), 7.69-7.65 (m, 1H), 7.63-7.59 (m, 2H), 3.85 (s, 2H), 3.21-3.11 (m, 2H), 2.71 (s, 3H), 2.62-2.54 (m, 2H), 2.14-1.94 (m, 2H).

1. customA 200 mL round-bottom flask equipped with air
2. temperaturecooled
3. temperaturereflux condenser
4. customoutfitted with a nitrogen inlet adapter
5. temperatureThe mixture was heated to reflux
6. additionwas added
7. temperatureAfter 1 h the reaction was cooled
8. concentrationThe mixture was then concentrated under reduced pressure
9. additionEtOAc (70 mL) was added
10. customafter separating the layers
11. extractionthe aqueous phase was extracted with EtOAc (2×25 mL)
12. washThe combined organic phases were washed with brine (75 mL)
13. dry with materialdried over Na2SO4
14. filtrationfiltered
15. concentrationconcentrated under reduced pressure