Methyl tyrosinate hydrochloride → Tyr(3-tBu)-OMe

To a solution of 25.0 g (0.108 mol) of Tyr-OMe.HCl in 500 ml of tert-butyl acetate, 18 ml (0.204 mol) of 70% HClO4 was added and the mixture was stirred at room temperature for 4 days. The reaction mixture was concentrated under reduced pressure and the resulting residue was dissolved in 400 ml of ethyl acetate; thereafter, the solution was poured into 800 ml of a saturated aqueous solution of NaHCO3 and the mixture was stirred. The organic layer was taken out and washed first with a saturated aqueous solution of NaHCO3, then with saturated brine, dried with anhydrous sodium sulfate, and the solvent was distilled off under reduced pressure. To the resulting residue, 500 ml of ether was added and the mixture was stirred overnight at room temperature. The precipitating crystals were recovered by filtration to give Tyr(3-tBu)-OMe in the amount of 10.9 g (40%).

1. concentrationThe reaction mixture was concentrated under reduced pressure
2. dissolutionthe resulting residue was dissolved in 400 ml of ethyl acetate
3. additionthereafter, the solution was poured into 800 ml of a saturated aqueous solution of NaHCO3
4. stirringthe mixture was stirred
5. washwashed first with a saturated aqueous solution of NaHCO3
6. dry with materialwith saturated brine, dried with anhydrous sodium sulfate
7. distillationthe solvent was distilled off under reduced pressure
8. additionTo the resulting residue, 500 ml of ether was added
9. stirringthe mixture was stirred overnight at room temperature
10. filtrationThe precipitating crystals were recovered by filtration

ORD record

ord-c610bccacce549df8a2b88113edc4ce4

Source dataset

uspto-grants-2001_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06255285B1