16677-29-5

16652-64-5

501-53-1

86827-18-1

General procedure for the synthesis of the compound (CAS: 86827-18-1) from O-benzyl-L-tyrosine and benzyl chloroformate: (S)-O-benzyl-tyrosine (8.14 g, 30 mmol) was dissolved in THF (60 mL) and cooled to 0 °C. Subsequently, an aqueous solution of NaOH (3 g, 75 mmol) was added (60 mL). A solution of benzyl chloroformate (4.65 mL, 5.63 g, 33 mmol) in THF (30 mL) was slowly added dropwise at 0 °C. The reaction mixture was stirred at 0 °C for 2 h, then gradually warmed to room temperature and continued stirring overnight. After the reaction was completed, water (50 mL) was added and the pH was adjusted to 1-2 with 10% HCl, then the aqueous phase was extracted with EtOAc (3 × 100 mL). The organic phases were combined, washed with brine (2 × 100 mL) and dried over Na2SO4. The solvent was removed by concentration under reduced pressure to give pure (S)-N-Benzyloxycarbonyl-O-benzyl-tyrosine (11.57 g, 95% yield) as a pale yellow solid, melting point: 128-130°C. The product could be used in the next reaction without further purification.1H NMR (400 MHz, CDCl3) δ: 2.85 (dd, J = 13.2, 8.4 Hz, 1H, CH2), 3.10 (dd, J = 13.2, 12.0 Hz, 1H, CH2), 4.43 (dd, J = 12.0, 8.4 Hz, 1H, CH). 4.80 (d, J = 12.4 Hz, 1H, CH2O), 4.82 (s, 2H, CH2O), 5.00 (d, J = 12.4 Hz, 1H, CH2O), 5.60 (d, J = 4.8 Hz, 1H, NH), 6.65-7.35 (m, 14H, ArH).13C NMR (100 MHz, CDCl3) δ : 36.9, 56.2, 66.8, 69.8, 114.8, 127.5, 127.83, 127.89, 127.93, 128.4, 128.5, 128.9, 130.3, 136.2, 137.0, 156.6, 157.7, 177.5. HRMS (ESI) C24H24NO5 [M + H ]+ m/z calculated value: 406.1649; measured value: 406.1641.