General procedure for the synthesis of methyl (R)-2-amino-3-(4-hydroxyphenyl)propanoate hydrochloride from methanol and D-tyrosine: (2R)-2-amino-3-(4-hydroxyphenyl)propanoic acid (49) (1.07 g, 5.9 mmol) was dissolved in methanol, and the reaction was completed to give methyl (2R)-2-amino-3-(4-hydroxyphenyl)propanoate (50) . The product characterization data were as follows: melting point 176°C (literature values in agreement); 1H NMR (DMSO-d6) δ: 6.82 (d, J = 8.4 Hz, 2H, ArH3' and ArH5'), 4.13 (t, J = 6.9 Hz, 1H, H2), 3.83 (s, 3H, OCH3), 3.22 (dd, J = 6.0, 14.4 Hz. 1H, 3Ha), 3.12 (dd, J = 6.9, 14.7 Hz, 1H, 3Hb). Mass spectrum (chemical ionization, positive ion mode) m/z: 196 (100%) [M+]. High Resolution Mass Spectrometry (HRMS) calculated value of C10H14NO3: 196.0974, measured value: 196.0985.
