Hydrochloric Acid → 5-(Benzyloxy)-4-oxo-1,4-dihydropyridine-2-carboxylic acid
Reaction equation
[O:1]=[C:2]1[C:7]([O:8][CH2:9][C:10]2[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=2)=[CH:6]O[C:4]([C:16]([OH:18])=[O:17])=[CH:3]1.[OH-].[NH4+:20].Cl>>[O:1]=[C:2]1[C:7]([O:8][CH2:9][C:10]2[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=2)=[CH:6][NH:20][C:4]([C:16]([OH:18])=[O:17])=[CH:3]1Participants
Procedure
300 g (1.22 mol) of 4-oxo-5-(phenylmethoxy)-4H-pyran-2-carboxylic acid was put into a flask and 5 l of 33% ammonium hydroxide was carefully added with stirring. The reaction mixture was then stirred under reflux. After 3 hours, one additional liter of 33% ammonium hydroxide was added slowly. Stirring was continued for further 2 hours under reflux. The reaction solution was then evaporated until the product crystallized. The product was transferred back into the reaction flask and water added until a clear solution was obtained (approximately 5 l, pH 6.38). This solution was stirred vigorously while concentrated hydrochloric acid was added dropwise until a pH of 3 was obtained. The precipitated white product was removed by filtration, thoroughly washed with water and dried. Yield: 273 g.
Workup
- stirringThe reaction mixture was then stirred
- temperatureunder reflux
- stirringStirring
- waitwas continued for further 2 hours
- temperatureunder reflux
- customThe reaction solution was then evaporated until the product
- customcrystallized
- additionadded until a clear solution
- customwas obtained (approximately 5 l, pH 6.38)
- additionwas added dropwise until a pH of 3
- customwas obtained
- customThe precipitated white product was removed by filtration
- washthoroughly washed with water
- customdried
Sources & evidence
- ORD record
- ord-ee518e2f571a476b881d464d821846ae
- Source dataset
- uspto-grants-1988_02
- Patent number
- US04723002
Reaction notes
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