[Synthesis]
General procedure for the synthesis of tert-butyl (S)-(1-hydroxy-3-(4-hydroxyphenyl)propan-2-yl)carbamate from N-tert-butyloxycarbonyl-L-tyrosine: 4.1 g of N-tert-butyloxycarbonyl-L-tyrosine (3.6 mmol) was dissolved in 80 mL of anhydrous ether under nitrogen protection. Lithium aluminum hydride (0.4 g, 0.01 mol) was then added in batches. The resulting suspension was heated to reflux and kept overnight. Upon completion of the reaction, it was cooled to room temperature, ethyl acetate was added slowly and the reaction mixture was carefully poured into concentrated sodium hydroxide solution while stirring continuously. The organic layer was separated, washed with water and dried over anhydrous sodium sulfate. After removing the solvent under reduced pressure, 0.4 g of an oily product was obtained.1H NMR (400 MHz, CDCl3) data were as follows: δ1.37 (9H, s), 2.69 (2H, d, J=6.51 Hz), 3.47 (1H, dd, J=5.27,10.85 Hz), 3.57 (1H, dd, J=3.75,10.85 Hz). 3.76 (1H, s), 5.06 (1H, d, J=7.75Hz), 6.70 (2H, d, J=8.37Hz), 6.97 (2H, d, J=8.37Hz), 7.70 (1H, br s) ppm. |
[References]
[1] Journal of Organic Chemistry, 1992, vol. 57, # 22, p. 5811 - 5812
[2] Tetrahedron Asymmetry, 2017, vol. 28, # 12, p. 1675 - 1685 |