Methyl tyrosinate hydrochloride → Tyr(3-tBu)-OMe
Reaction equation
[NH2:1][C@H:2]([C:11]([O:13][CH3:14])=[O:12])[CH2:3][C:4]1[CH:9]=[CH:8][C:7]([OH:10])=[CH:6][CH:5]=1.Cl>C(OC(C)(C)C)(=O)C>[NH2:1][C@H:2]([C:11]([O:13][CH3:14])=[O:12])[CH2:3][C:4]1[CH:5]=[CH:6][C:7]([OH:10])=[C:8]([C:4]([CH3:9])([CH3:5])[CH3:3])[CH:9]=1Participants
3
Reagents, catalysts & solvents 1
Procedure
To a solution of Tyr-OMe.HCl (500 g, 2.16 mol) in tert-butyl acetate (4500 ml), 70% HCl4 (278 ml, 3.24 mol) was added and stirred for 4.5 days at room temperature. The reaction mixture was evaporated under reduced pressure; the thus obtained residue was dissolved in ethyl acetate, poured into a saturated aqueous NaHCO3 solution and stirred. The organic layer was collected and washed with a saturated aqueous NaHCO3 solution and saturated brine, dried over anhydrous magnesium sulfate and evaporated to remove the solvent under reduced pressure. The thus obtained residue was mixed with ether (950 ml) and at room temperature, stirred overnight. The thus precipitated crystals were collected by filtration to give Tyr(3-tBu)-OMe (242 g, 45%).