Synthesis
General procedure for the synthesis of tert-butyl (S)-(1-hydrazino-1-oxo-3-phenylpropan-2-yl)carbamate from N-Boc-L-phenylalanine methyl ester: Hydrazine hydrate (170 μL, 3.44 mmol) was added to a methanol (5.4 mL) solution of N-Boc-L-phenylalanine methyl ester (300 mg, 1.07 mmol). The reaction mixture was stirred at room temperature overnight. Upon completion of the reaction, the solvent was concentrated under reduced pressure by rotary evaporator. The resulting residue was first ground with hexane (2×) and then with a minimum volume of 2:3 hexane/methanol solvent mixture (2×) to afford the target product (S)-(1-hydrazino-1-oxo-3-phenylpropan-2-yl)carbamic acid tert-butyl ester in white solid form (195 mg, 65% yield). The structure of the product was confirmed by 1H NMR (CDCl3) δ 7.41-7.25 (m, 3H), 7.20 (d, J = 6.8 Hz, 2H), 4.39-4.21 (m, 1H), 3.07 (d, J = 7.0 Hz, 2H), 1.42 (s, 9H) and mass spectrometry (ESI+) m/z 280.3 ([M+H]+).
References
[1] New Journal of Chemistry, 2018, vol. 42, # 6, p. 4344 - 4351
[2] Journal of Organic Chemistry, 1995, vol. 60, # 10, p. 3112 - 3120
[3] Angewandte Chemie - International Edition, 2016, vol. 55, # 32, p. 9422 - 9426
[4] Angew. Chem., 2016, vol. 55, # 32, p. 9569 - 9574,6
[5] Patent: WO2013/192286, 2013, A1. Location in patent: Paragraph 00281
