Boron trifluoride → HCID 18446599, compound

HRID 1269030Notes

Reaction equation

[Cl:1][C:2]1[N:7]2[N:8]=[C:9]([C:11]3[CH:16]=[CH:15][N:14]=[CH:13][CH:12]=3)[CH:10]=[C:6]2[CH:5]=[CH:4][CH:3]=1.[C:17](OC(=O)C)(=[O:19])[CH3:18].B(F)(F)F>C(#N)C>[Cl:1][C:2]1[N:7]2[N:8]=[C:9]([C:11]3[CH:16]=[CH:15][N:14]=[CH:13][CH:12]=3)[C:10]([C:17](=[O:19])[CH3:18])=[C:6]2[CH:5]=[CH:4][CH:3]=1

Participants

Conditions

Temperature: 80 °C

Procedure

To a solution of 7-chloro-2-(4-pyridinyl)pyrazolo[1,5-a]pyridine (2.0 g, 8.7 mmol) in acetonitrile (50 mL) at room temperature was added acetic anhydride (2.0 mL, 21 mmol). Boron trifluoride diethyletherate (5.3 mL, 42 mmol) was added dropwise and the resulting solution was heated at 80° C. for 12 hours. The reaction mixture was cooled to room temperature and quenched by the dropwise addition of saturated sodium bicarbonate. The reaction mixture was extracted with ethyl acetate, and the organic phase phase washed with brine, dried (magnesium sulfate), filtered and concentrated. The residue was purified by silica gel chromatography (5:95 methanol-dichloromethane) to give 1-[7-chloro-2-(4-pyridinyl)pyrazolo[1,5-a]pyridin-3-yl]ethanone (1.53 g, 65%) as a red foam. 1H NMR (CDCl3): δ 8.82 (m, 2H), 8.45 (d, 1H), 7.62 (m, 2H), 7.54 (t, 1H), 7.25 (d, 1H), 2.26 (s, 3H); MS m/272 (M+1).

Workup

temperatureThe reaction mixture was cooled to room temperature
customquenched by the dropwise addition of saturated sodium bicarbonate
extractionThe reaction mixture was extracted with ethyl acetate
washthe organic phase phase washed with brine
dry with materialdried (magnesium sulfate)
filtrationfiltered
concentrationconcentrated
customThe residue was purified by silica gel chromatography (5:95 methanol-dichloromethane)

Sources & evidence

ORD record: ord-e86ad3e586184069a566952cd601e6b9
Source dataset: uspto-grants-2007_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07199120B2

Reaction notes

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