Citric Acid → 5-Hydroxypyridine-2-carboxylic acid ethyl ester
Reaction equation
[OH:1][C:2]1[CH:3]=[CH:4][C:5]([C:8]([OH:10])=[O:9])=[N:6][CH:7]=1.S(=O)(=O)(O)O.[OH-].[Na+].C(=O)(O)[O-].[Na+].[C:23](O)(=O)[CH2:24]C(CC(O)=O)(C(O)=O)O>C(O)C>[CH2:23]([O:9][C:8]([C:5]1[CH:4]=[CH:3][C:2]([OH:1])=[CH:7][N:6]=1)=[O:10])[CH3:24]Participants
7
Conditions
- Temperature
- 0 °C
Procedure
To a stirred solution of 5-hydroxy-pyridine-2-carboxylic acid (1.25 g, 9.0 mmol) in ethanol (40 mL) was added concentrated sulfuric acid (3 mL, 56.3 mmol) and the resulting solution heated at reflux under an atmosphere of argon for 20 h. The solution was then cooled to 0° C. then sodium hydroxide (2 N, 55 mL) was added. Saturated aqueous sodium bicarbonate and 10% w/w citric acid solution were then added to bring the pH to 7 and the resulting solution concentrated to ˜70 mL). The resulting mixture was extracted with ethyl acetate (3×50 mL) and the combined organic extracts dried, filtered and concentrated to afford the title compound (829 mg, 55%) as an off white solid. MS: m/e=168.3 [M+H]+.
Workup
- temperaturethe resulting solution heated
- temperatureat reflux under an atmosphere of argon for 20 h
- concentrationthe resulting solution concentrated to ˜70 mL)
- extractionThe resulting mixture was extracted with ethyl acetate (3×50 mL)
- customthe combined organic extracts dried
- filtrationfiltered
- concentrationconcentrated
Sources & evidence
- ORD record
- ord-695dd40b2f02493e8d1869c5f6c59c17
- Source dataset
- uspto-grants-2013_04
- Patent number
- US08415379B2
Reaction notes
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