Diethyl Oxalate → Ethyl 3-cyclopentyl-3-oxopropanoate

HRID 1063809

Reaction equation

HRID 1063809 reaction equation
[Na].C(O[C:5](=O)[C:6]([O:8][CH2:9][CH3:10])=[O:7])C.[CH:12]1([C:17](=[O:19])C)[CH2:16][CH2:15][CH2:14][CH2:13]1>C(O)C>[CH2:9]([O:8][C:6](=[O:7])[CH2:5][C:17]([CH:12]1[CH2:16][CH2:15][CH2:14][CH2:13]1)=[O:19])[CH3:10]

Participants

5

Reactant 3

HCID 7268Diethyl OxalateHCID 22326Cyclopentyl methyl ketoneHCID 5360545Sodium

Product 1

HCID 11159709Ethyl 3-cyclopentyl-3-oxopropanoate

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent2×

Conditions

Temperature
60 °C

Procedure

Sodium pellets (3.1 g, 135 mmol) were dissolved in ethanol (100 ml) under nitrogen at room temperature and a solution of diethyloxalate (18.4 ml, 135 mmol) and 1-cyclopentylethanone (16.7 g, 149 mmol) was added dropwise at room temperature over 30 minutes. The reaction was diluted with ethanol (100 ml), heated to 60° C. and stirred at this temperature for 2 hours. After cooling to room temperature the reaction was poured onto ice-cold 2N HCl (200 ml) and extracted with diethylether (300 ml) and ethyl acetate (300 ml). The combined organic extracts were dried over MgSO4, concentrated under reduced pressure and the residue was purified by flash column chromatography on silica gel eluting with pentane:ethyl acetate (6:1, by volume) to give 3-cyclopentyl-3-oxo-propionc acid ethyl ester (23.8 g) as an orange oil. 1H NMR (400 MHz, CDCl3): δ=14.38-14.65 (1H, brs), 6.83 (1H, s), 4.30-4.39 (2H, quart), 2.82-2.92 (1H, quin), 1.83-1.96 (2H, m), 1.57-1.83 (6H, 2×m), 1.33-1.40 (3H, t) ppm. LRMS (electrospray): m/z [M−H]+ 211.

Workup

  1. temperatureAfter cooling to room temperature the reaction
  2. additionwas poured onto ice-cold 2N HCl (200 ml)
  3. extractionextracted with diethylether (300 ml) and ethyl acetate (300 ml)
  4. dry with materialThe combined organic extracts were dried over MgSO4
  5. concentrationconcentrated under reduced pressure
  6. customthe residue was purified by flash column chromatography on silica gel eluting with pentane:ethyl acetate (6:1, by volume)
  7. customto give 3-cyclopentyl-3-oxo-propionc acid ethyl ester (23.8 g) as an orange oil

Sources & evidence

ORD record
ord-1201cb2fc16e4c0cb08428a9b1d66098
Source dataset
uspto-grants-2005_11
Patent number
US06967204B2

Linked notes

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