Cyclopentanone → (R)-Methyl 2-(cyclopentylamino)butanoate

HRID 2364662Notes

Reaction equation

HRID 2364662 reaction equation
[NH2:1][C@H:2]([CH2:7][CH3:8])[C:3]([O:5][CH3:6])=[O:4].[C:9]1(=O)[CH2:13][CH2:12][CH2:11][CH2:10]1.C([O-])(=O)C.[Na+].C(O[BH-](OC(=O)C)OC(=O)C)(=O)C.[Na+].C(=O)(O)[O-].[Na+]>ClCCl>[CH:9]1([NH:1][C@H:2]([CH2:7][CH3:8])[C:3]([O:5][CH3:6])=[O:4])[CH2:13][CH2:12][CH2:11][CH2:10]1

Participants

7

Reactant 5

HCID 8452CyclopentanoneHCID 516892Sodium BicarbonateHCID 517045Sodium AcetateHCID 5049666Sodium triacetoxyborohydrideHCID 13283514methyl (2R)-2-aminobutanoate

Product 1

HCID 57358664(R)-Methyl 2-(cyclopentylamino)butanoateYield 34%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

The crude compound methyl (2R)-2-aminobutanoate 1j (11.24 g, 0.10 mol) and cyclopentanone (8.24 g, 0.10 mol) were dissolved in 150 mL of dichloromethane, stirred for 1.5 hours followed by the addition of sodium acetate (8.04 g, 0.10 mol) and sodium triacetoxyborohydride (30.52 g, 0.14 mol), and stirred for 3 hours. The reaction solution was poured into 150 mL 10% sodium bicarbonate solution, extracted with dichloromethane (100 mL×3). The combined organic phase was washed with saturated sodium chloride solution (100 mL×3), then dried over anhydrous magnesium sulfate, filtered and the filtrate was concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography to obtain the title compound methyl (2R)-2-(cyclopentylamino)butanoate 1k (6.04 g, yield: 34.0%) as a light liquid.

Workup

  1. stirringstirred for 3 hours
  2. extractionextracted with dichloromethane (100 mL×3)
  3. washThe combined organic phase was washed with saturated sodium chloride solution (100 mL×3)
  4. dry with materialdried over anhydrous magnesium sulfate
  5. filtrationfiltered
  6. concentrationthe filtrate was concentrated under reduced pressure
  7. customThe resulting residue was purified by silica gel column chromatography

Sources & evidence

ORD record
ord-40a9d6951c0f4779a94f6e08d0065028
Source dataset
uspto-grants-2014_04
Patent number
US08691822B2

Reaction notes

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