Acetic Anhydride → 4-Phenylpyridin-2-ol
Reaction equation
[C:1]1([C:7]2[CH:12]=[CH:11][N+:10]([O-])=[CH:9][CH:8]=2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[H-].[Na+].C(OC(=O)C)(=[O:18])C>>[C:1]1([C:7]2[CH:12]=[CH:11][NH:10][C:9](=[O:18])[CH:8]=2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1Participants
Procedure
A solution of 4-phenylpyridine-N-oxide (8.55 g, 50 mmol) in acetic anhydride (250 ml) was heated under reflux for sixteen hours. Acetic anhydride was then removed under vacuum and the residue was dissolved in absolute ethanol (200 ml) and 80% sodium hydride (1.5 g, 50 mmol) was added in small portions. The mixture was stirred for 2 hours under nitrogen, then evaporated and the residue was dissolved in ethyl acetate and dilute hydrochloric acid. The phases were separated and the aqueous phase was basified (sodium bicarbonate) and re-extracted (ethyl acetate). The aqueous phase was filtered to give the solid product which was recrystallised from ethyl acetate/methanol to give pure product, 3.76 g, Mp 226°-230° C. The combined organic extracts were evaporated to give a further quantity (1.58 g) of impure product.
Workup
- temperatureunder reflux for sixteen hours
- customAcetic anhydride was then removed under vacuum
- dissolutionthe residue was dissolved in absolute ethanol (200 ml)
- customevaporated
- dissolutionthe residue was dissolved in ethyl acetate
- customThe phases were separated
- extractionre-extracted (ethyl acetate)
- filtrationThe aqueous phase was filtered
- customto give the solid product which
- customwas recrystallised from ethyl acetate/methanol
- customto give pure product, 3.76 g, Mp 226°-230° C
- customThe combined organic extracts were evaporated
Sources & evidence
- ORD record
- ord-319339b9443c43f19c9c4d57f2573208
- Source dataset
- uspto-grants-1993_02
- Patent number
- US05189047
Reaction notes
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