Sodium Bicarbonate → 3-(2-Oxo-1,2,5,6-tetrahydropyridin-4-yl)-2-phenylpyrazolo[1,5-a]pyridine

HRID 466011Notes

Reaction equation

[C:1]1([C:7]2[CH:15]=[C:10]3[CH:11]=[CH:12][CH:13]=[CH:14][N:9]3[N:8]=2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[NH:16]1[CH2:21][CH2:20][C:19](=O)[CH2:18][C:17]1=[O:23].C(=O)([O-])O.[Na+]>S(=O)(=O)(O)O.C(O)(=O)C>[O:23]=[C:17]1[CH:18]=[C:19]([C:15]2[C:7]([C:1]3[CH:2]=[CH:3][CH:4]=[CH:5][CH:6]=3)=[N:8][N:9]3[CH:14]=[CH:13][CH:12]=[CH:11][C:10]=23)[CH2:20][CH2:21][NH:16]1

Participants

Conditions

Temperature: 135 °C

Procedure

A mixture of 2-phenylpyrazolo[1,5-a]pyridine (0.50 g, 2,4-piperidinedione (0.292 g), concentrated sulfuric acid (1 drop) and acetic acid (0.5 ml) was heated at 135° C. for 13.5 hours. A saturated aqueous solution of sodium hydrogen carbonate (20 ml) was added to the reaction mixture and the mixture was extracted with chloroform (20 ml×2). The combined extract was washed with a saturated aqueous solution of sodium chloride (20 ml) and dried over magnesium sulfate. The solvent was evaporated in vacuo. The residue was purified by column chromatography on silica gel using a mixture of chloroform and ethyl acetate (9:1) and recrystallized from ethyl acetate to give crystals of 3-(2-oxo-1,2,5,6-tetrahydropyridin-4-yl)-2-phenylpyrazolo[1,5-a]pyridine.

Workup

extractionthe mixture was extracted with chloroform (20 ml×2)
extractionThe combined extract
washwas washed with a saturated aqueous solution of sodium chloride (20 ml)
dry with materialdried over magnesium sulfate
customThe solvent was evaporated in vacuo
customThe residue was purified by column chromatography on silica gel using
additiona mixture of chloroform and ethyl acetate (9:1)
customrecrystallized from ethyl acetate

Sources & evidence

ORD record: ord-107a60501a1e4e338f58c4fd604a95cb
Source dataset: uspto-grants-1992_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05155114

Reaction notes

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