p-Toluenesulfonic acid monohydrate → D-Alanine trans-2-Methylcyclohexyl Ester p-Toluenesulfonate

HRID 986612Notes

Reaction equation

HRID 986612 reaction equation
[CH3:1][C@@H:2]1[CH2:7][CH2:6][CH2:5][CH2:4][C@H:3]1[O:8][C:9](=[O:23])[C@@H:10]([CH3:22])[NH:11]C(OCC1C=CC=CC=1)=O.O.[C:25]1([CH3:35])[CH:30]=[CH:29][C:28]([S:31]([OH:34])(=[O:33])=[O:32])=[CH:27][CH:26]=1>CO.[Pd]>[C:25]1([CH3:35])[CH:26]=[CH:27][C:28]([S:31]([OH:34])(=[O:32])=[O:33])=[CH:29][CH:30]=1.[CH3:1][C@@H:2]1[CH2:7][CH2:6][CH2:5][CH2:4][C@H:3]1[O:8][C:9](=[O:23])[C@@H:10]([CH3:22])[NH2:11]

Participants

5

Reactant 2

HCID 521998p-Toluenesulfonic acid monohydrateHCID 53726750N-Benzyloxycarbonyl-D-alanine trans-2-Methylcyclohexyl Ester

Product 1

HCID 86741945D-Alanine trans-2-Methylcyclohexyl Ester p-Toluenesulfonate

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 887MethanolSolvent

Procedure

N-Benzyloxycarbonyl-D-alanine-trans-2-methylcyclohexyl ester (14.7 g, 47.5 mmol) and p-toluenesulfonic acid monohydrate (9.04 g, 47.5 mmol) were dissolved in 135 mL MeOH. The methanolic solution was hydrogenated over 2.51 g of 10% Pd/C at 40 psi in a Parr apparatus for 1 hour. The catalyst was removed by filtration through a Celite pad and the filtrate was concentrated under reduced pressure. The salt was precipitated by addition of ether. Yield: 13.8 g in 2 crops (81%) mp 145°-147°. Tlc on silica gel (CHCl3 :MeOH:HOAc=45:5:1) indicated a single ninhydrin positive spot. 250 MHz nmr (CD3OD, ppm) 0.92 (d, 3H, J=6.25 Hz, trans-2-methyl), 1.09-1.99 (m, 7H, aliphatic cyclohexyl protons), 1.53 (2d, 3H, β--CH3 of Ala), 2.37 (s, 3H, CH3 --Ar--SO3H), 4.09 (2q, 1H, J=7.35 Hz, 2.57 Hz; α--H of Ala), 4.51 (m, 1H, α--H of alcohol); 7.22, 7.69 (ABq, 4H, J=8.46 Hz, CH3 --ArH4 --SO3H).

Workup

  1. customThe catalyst was removed by filtration through a Celite pad
  2. concentrationthe filtrate was concentrated under reduced pressure
  3. customThe salt was precipitated by addition of ether

Sources & evidence

ORD record
ord-d41eed071a264b34835fb25298608415
Source dataset
uspto-grants-1987_12
Patent number
US04714619

Reaction notes

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