4-(2-Oxopyrrolidin-1-yl)benzoic acid → Trans-4-(2-oxo-pyrrolidin-1-yl)cyclohexanecarboxylic acid
Reaction equation
[N:1]1([C:7]2[CH:15]=[CH:14][C:10]([C:11]([OH:13])=[O:12])=[CH:9][CH:8]=2)[CH2:5][CH2:4][CH2:3][C:2]1=[O:6]>[C].[Rh].CO>[N:1]1([CH:7]2[CH2:8][CH2:9][CH:10]([C:11]([OH:13])=[O:12])[CH2:14][CH2:15]2)[CH2:5][CH2:4][CH2:3][C:2]1=[O:6]Participants
Reactant 1
Product 1
Reagents, catalysts & solvents 2
Procedure
4-(2-Pyrrolidon-1-yl)benzoic acid (4.0 g, 0.0195 mol), 5% rhodium-carbon catalyst (2.8 g, 3.0% mol) and methanol (80 mL) are charged in an autoclave (300 mL) and stirred at room temperature for 5 hours under hydrogen pressure (50 atm, conversion rate >99%, cis:trans=50:50). The reaction solution is cooled, filtrated to collect the catalysts, and washed with methanol. The filtrate is concentrated under reduced pressure, and the resulting crystals are washed with methanol to give 4-(2-pyrrolidon-1-yl)cyclohexylcarboxylic acid as a mixture of cis and trans isomers (3.4 g, 82.5%, cis:trans=79:21). A portion (3.0 g) is dissolved in methanol (15 mL) under heating, and cooled. The resulting crystals are washed with cooled methanol to give cis-4-(2-pyrrolidon-1-yl)cyclohexylcarboxylic acid (700 mg, >99% de). The tertiary structure of cis-4-(2-pyrrolidon-1-yl)cyclohexylcarboxylic acid was confirmed by X-ray structure analysis. Mp: 188° C.
Workup
- temperatureThe reaction solution is cooled
- filtrationfiltrated
- customto collect the catalysts
- washwashed with methanol
- concentrationThe filtrate is concentrated under reduced pressure
- washthe resulting crystals are washed with methanol
Sources & evidence
- ORD record
- ord-b4fe6b4a48894227869200f82af7c37e
- Source dataset
- uspto-grants-2008_10
- Patent number
- US07439368B2
Reaction notes
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