p-Toluenesulfonic acid → L-leucine cyclopentyl ester tosylate

HRID 548215Notes

Reaction equation

HRID 548215 reaction equation
[NH2:1][C@H:2]([C:7]([OH:9])=[O:8])[CH2:3][CH:4]([CH3:6])[CH3:5].[C:10]1([CH3:20])[CH:15]=[CH:14][C:13]([S:16]([OH:19])(=[O:18])=[O:17])=[CH:12][CH:11]=1.CC[CH2:23][CH2:24][CH2:25][CH2:26][CH3:27]>C1CCCCC1.C1(O)CCCC1>[C:10]1([CH3:20])[CH:11]=[CH:12][C:13]([S:16]([OH:19])(=[O:17])=[O:18])=[CH:14][CH:15]=1.[CH:23]1([O:8][C:7](=[O:9])[C@@H:2]([NH2:1])[CH2:3][CH:4]([CH3:6])[CH3:5])[CH2:24][CH2:25][CH2:26][CH2:27]1

Participants

6

Reactant 3

HCID 6101p-Toluenesulfonic acidHCID 6106L-LeucineHCID 8900Heptane

Product 1

HCID 86633653L-leucine cyclopentyl ester tosylateYield 85%

Reagents, catalysts & solvents 2

HCID 7298CyclopentanolCatalystHCID 8078CyclohexaneSolvent

Procedure

To a suspension of (S)-leucine (15 g, 0.11 mol) in cyclohexane (400 ml) was added cyclopentanol (103.78 ml, 1.14 mmol) and p-toluene sulfonic acid (23.93 g, 0.13 mol). The suspension was heated at reflux to effect solvation. After refluxing the solution for 16 hours it was cooled to give a white suspension. Heptane (500 ml) was added to the mixture and the suspension was filtered to give the product as a white solid (35 g, 85% yield). 1H NMR (300 MHz, MeOD), δ: 1.01 (6H, t, CH3×2, J=5.8 Hz), 1.54-2.03 (11H, m, 11×CH), 2.39 (3H, s, CH3), 3.96 (1H, t, CH, J=6.5 Hz), 5.26-5.36 (1H, m, CH), 7.25 (2H, d, ArH x 2, J=7.9 Hz), 7.72 (2H, d, ArH×2, J=8.3 Hz).

Workup

  1. temperatureThe suspension was heated
  2. temperatureat reflux
  3. temperatureAfter refluxing the solution for 16 hours it
  4. temperaturewas cooled
  5. customto give a white suspension
  6. filtrationthe suspension was filtered

Sources & evidence

ORD record
ord-52f25e54db2d4fab94879ede7f6a48fd
Source dataset
uspto-grants-2011_05
Patent number
US07939666B2

Reaction notes

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