Dicyclohexylcarbodiimide → Benzyl N-(2-oxopentanoyl)prolinate

HRID 34529

Reaction equation

HRID 34529 reaction equation
Cl.[NH:2]1[CH2:16][CH2:15][CH2:14][C@H:3]1[C:4]([O:6][CH2:7][C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=1)=[O:5].C1(N=C=NC2CCCCC2)CCCCC1.C(N(C(C)C)CC)(C)C.[O:41]=[C:42]([CH2:46][CH2:47][CH3:48])[C:43](O)=[O:44]>ClCCl>[O:41]=[C:42]([CH2:46][CH2:47][CH3:48])[C:43]([N:2]1[CH2:16][CH2:15][CH2:14][C@H:3]1[C:4]([O:6][CH2:7][C:8]1[CH:9]=[CH:10][CH:11]=[CH:12][CH:13]=1)=[O:5])=[O:44]

Participants

6

Reactant 4

HCID 10868DicyclohexylcarbodiimideHCID 745632-Oxovaleric acidHCID 81531Diisopropylethylamine2×HCID 2733413Proline benzyl ester hydrochloride

Product 1

HCID 53809756Benzyl N-(2-oxopentanoyl)prolinate

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

8.8 g benzyl prolinate hydrochloride, 9.78 g dicyclohexylcarbodiimide and 6.12 g diisopropylethylamine were reacted together in 50 mL dichloromethane at 0°. 5.51 g 2-oxopentanoic acid in 10 mL dichloromethane was added dropwise at 0°. The pH of the reaction was adjusted to between 8 and 9 with diisopropylethylamine. The reaction mixture was stirred for four hours at 0°, then room temperature overnight. The next day, the reaction mixture was filtered, concentrated to dryness, and partitioned between ethyl acetate and water. The organic layer was washed with 5% sodium bisulfate, 5% sodium bicarbonate, and saturated sodium chloride solutions, and dried with magnesium sulfate. The organic layer was concentrated to give a yellow oil. The oil was then passed through a silica gel column and eluted with ethyl acetate/hexane (4:6) and ethyl acetate/hexane (1:1). Benzyl N-(2-oxopentanoyl)prolinate, [α]D25 -56.9, was isolated.

Workup

  1. customroom temperature overnight
  2. filtrationThe next day, the reaction mixture was filtered
  3. concentrationconcentrated to dryness
  4. custompartitioned between ethyl acetate and water
  5. washThe organic layer was washed with 5% sodium bisulfate, 5% sodium bicarbonate, and saturated sodium chloride solutions
  6. dry with materialdried with magnesium sulfate
  7. concentrationThe organic layer was concentrated
  8. customto give a yellow oil
  9. washeluted with ethyl acetate/hexane (4:6) and ethyl acetate/hexane (1:1)

Sources & evidence

ORD record
ord-1518e2ac8a1d43678cc8596fcb89ca73
Source dataset
uspto-grants-1988_08
Patent number
US04762821

Linked notes

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