Hydrochloric Acid → (S)-Cyclopentyl 4-methyl-2-(4-nitrobenzylamino)pentanoate

HRID 1509968Notes

Reaction equation

HRID 1509968 reaction equation
[NH2:1][C@H:2]([C:7]([O:9][CH:10]1[CH2:14][CH2:13][CH2:12][CH2:11]1)=[O:8])[CH2:3][CH:4]([CH3:6])[CH3:5].[N+:15]([C:18]1[CH:25]=[CH:24][C:21]([CH:22]=O)=[CH:20][CH:19]=1)([O-:17])=[O:16].C(O[BH-](OC(=O)C)OC(=O)C)(=O)C.[Na+].Cl.[OH-].[Na+]>C(Cl)Cl.C(O)(=O)C>[CH3:5][CH:4]([CH3:6])[CH2:3][C@H:2]([NH:1][CH2:22][C:21]1[CH:24]=[CH:25][C:18]([N+:15]([O-:17])=[O:16])=[CH:19][CH:20]=1)[C:7]([O:9][CH:10]1[CH2:11][CH2:12][CH2:13][CH2:14]1)=[O:8]

Participants

8

Reactant 5

HCID 313Hydrochloric AcidHCID 5414-NitrobenzaldehydeHCID 14798Sodium HydroxideHCID 5049666Sodium triacetoxyborohydrideHCID 53718217(S)-cyclopentyl 2-amino-4-methylpentanoate

Product 1

HCID 57658402(S)-Cyclopentyl 4-methyl-2-(4-nitrobenzylamino)pentanoateYield 45.2%

Reagents, catalysts & solvents 2

HCID 176Acetic AcidCatalystHCID 6344DichloromethaneSolvent

Procedure

To a solution of cyclopentyl L-leucinate (2.00 g, 10.0 mmol) and 4-nitrobenzaldehyde (3.04 g, 20.0 mmol) in DCM (40 ml) was added glacial acetic acid (2 drops). The solution was allowed to stir at RT for 1 h whereupon sodium triacetoxyborohydride (6.40 g, 30.2 mmol) was added in a single a portion. After stirring for 3 h, the solution was poured on to aq. 1M HCl, allowed to stir for 30 min, neutralised with aq. 1M NaOH and extracted with DCM. The combined organics were washed with water and brine, dried over MgSO4, and evaporated under reduced pressure. The crude material was purified by chromatography (5% EtOAc/isohexane) to furnish the title compound as an oil (1.51 g, 45%). m/z 335.1 [M−H]+.

Workup

  1. additionwas added in a single a portion
  2. stirringto stir for 30 min
  3. extractionextracted with DCM
  4. washThe combined organics were washed with water and brine
  5. dry with materialdried over MgSO4
  6. customevaporated under reduced pressure
  7. customThe crude material was purified by chromatography (5% EtOAc/isohexane)

Sources & evidence

ORD record
ord-8d37a22e3a1c4ecdb436fcb1cbb0f2f7
Source dataset
uspto-grants-2012_07
Patent number
US08211900B2

Reaction notes

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