126173-94-2

60-18-4

67-63-0

126173-94-2

1. dissolve L-tyrosine (100 g, 552 mmol) in 2-propanol (1.00 L). 2. Concentrated sulfuric acid (60 mL) was added slowly and dropwise to the above solution. 3. The reaction mixture was stirred at 80 °C for 48 hours. 4. Upon completion of the reaction, the reaction solution was concentrated under reduced pressure. 5. Saturated aqueous potassium bicarbonate was added to the concentrated residue with thorough stirring. 6. The solid product was collected by filtration. 7. The solid product was dried under reduced pressure to afford isopropyl (S)-2-amino-3-(4-hydroxyphenyl)propionate (129 g, 85% yield) as a white solid. 8. 8. Product characterization data: 1H NMR (CD3OD, 400 MHz): δ 7.01 (d, J = 8.0 Hz, 2H), 6.71 (d, J = 8.4 Hz, 2H), 4.96-4.90 (m, 1H), 3.62 (t, J = 6.8 Hz, 1H), 2.91-2.80 (m, 2H), 1.15 (d, J = 6.4 Hz, 6H). 6.4 Hz, 6H).MS (ESI) m/z 224 (M + H)+.