反应详情

Step AAH (6): To a soln of 3-(3-(2-phenyl-1,3-dioxolan-2-yl)propyl)-1H-pyrazol-5(4H)-one (1.1 g, 4.01 mmol) in acetonitrile (15 mL) was added trichloroborane (1.0 M in CH2Cl2, 10.02 mL, 10.02 mmol) at −10° C. under nitrogen. The mixture was allowed to warm to rt, and stirred at rt for 6 h. The reaction was quenched with 50 mL of aqueous 0.1 N HCl (50 mL). The mixture was extracted with dichloromethane (3×80 mL). The organic layer was washed with brine, dried over Na2SO4, filtered and concentrated in vacuo. The product was purified using silica gel column chromatography (60% EtOAc/hexanes) to afford 7-phenyl-4,5-dihydropyrazolo[1,5-a]pyridin-2-ol (510 mg, 60% yield) as a solid. LC-MS (M+H)+ 213.06. 1H NMR (500 MHz, methanol-d4) δ ppm 7.42-7.53 (m, 2 H) 7.29-7.40 (m, 3 H) 5.55 (s, 1 H) 5.50 (t, J=4.88 Hz, 1 H) 2.86 (t, J=7.63 Hz, 2 H) 2.35-2.45 (m, 2 H).

1. customThe reaction was quenched with 50 mL of aqueous 0.1 N HCl (50 mL)
2. extractionThe mixture was extracted with dichloromethane (3×80 mL)
3. washThe organic layer was washed with brine
4. dry with materialdried over Na2SO4
5. filtrationfiltered
6. concentrationconcentrated in vacuo
7. customThe product was purified