Water → Cyclopentanone

HRID 968332Notes

Reaction equation

HRID 968332 reaction equation
O.C1(C)C=CC(S(O)(=O)=O)=CC=1.C[O:14][C:15]1(OC)[CH2:19][CH2:18][CH2:17][CH:16]1[O:20][C:21](=[O:38])[C@@H:22]([NH:30][C:31]([O:33][C:34]([CH3:37])([CH3:36])[CH3:35])=[O:32])[CH2:23][C:24]1[CH:29]=[CH:28][CH:27]=[CH:26][CH:25]=1.O.C(=O)([O-])O.[Na+]>CC(C)=O>[O:14]=[C:15]1[CH2:19][CH2:18][CH2:17][CH:16]1[O:20][C:21](=[O:38])[C@@H:22]([NH:30][C:31]([O:33][C:34]([CH3:36])([CH3:35])[CH3:37])=[O:32])[CH2:23][C:24]1[CH:25]=[CH:26][CH:27]=[CH:28][CH:29]=1.[C:15]1(=[O:14])[CH2:19][CH2:18][CH2:17][CH2:16]1

Participants

7

Reactant 4

HCID 962WaterHCID 516892Sodium BicarbonateHCID 521998p-Toluenesulfonic acid monohydrateHCID 11047485HCID 11047485, compound

Product 2

HCID 8452CyclopentanoneHCID 10970084HCID 10970084, compound

Reagents, catalysts & solvents 1

HCID 180AcetoneSolvent

Procedure

4-Toluenesulphonic acid monohydrate (1.7 g, 9.2 mmol) was added to a stirred solution of (2S)-2-tert-butoxycarbonylamino-3-phenylpropionic acid 2,2-dimethoxycyclopentyl ester (36 g, 91.6 mmol) in acetone (450 ml) at ambient temperature. The solution was stirred for 3 days then water (600 ml) and saturated aqueous sodium hydrogen carbonate solution (200 ml) were added, then the product was extracted into ethyl acetate (600 ml). The aqueous phase was extracted with ethyl acetate (2×400 ml), then the combined ethyl acetate solutions were washed with saturated aqueous sodium chloride solution (2×150 ml), dried (Na2SO4) and the solvent removed in vacua. The residue (18.05 g) was purified by flash chromatography over silica gel eluting with a gradient of heptane:ethyl acetate 3:1→2:1. Appropriate fractions were combined and the solvents removed in vacuo to leave (2S)-2-tert-butoxycarbonylamino-3-phenylpropionic acid 2-oxocyclopentyl ester as a colourless oil (18.05 g, 40% from cyclopentanone). TLC (single UV spot, Rf=0.25, heptane:ethyl acetate 7:3), analytical HPLC with main broad peak Rt=17.9-19.2 mins, HPLC-MS (main broad UV peak with Rt=9.04-9.24 mins, 248.1 [M−Boc+2H]+, 370.2 [M+Na]+, 717.3 [2M+Na]+).

Workup

  1. extractionthe product was extracted into ethyl acetate (600 ml)
  2. extractionThe aqueous phase was extracted with ethyl acetate (2×400 ml)
  3. washthe combined ethyl acetate solutions were washed with saturated aqueous sodium chloride solution (2×150 ml)
  4. dry with materialdried (Na2SO4)
  5. customthe solvent removed in vacua
  6. customThe residue (18.05 g) was purified by flash chromatography over silica gel eluting with a gradient of heptane:ethyl acetate 3:1→2:1
  7. customthe solvents removed in vacuo

Sources & evidence

ORD record
ord-add924ee654741dfab0dc22e00d4c51e
Source dataset
uspto-grants-2005_10
Patent number
US06958358B2

Reaction notes

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