Example 4. Preparation of (2S,3S,5S)-5-amino-2-(N-((5-thiazolyl)-methoxycarbonyl)amino)-1,6-diphenyl-3-hydroxyhexane: (2S,3S,5S)-5-(tert-butoxycarbonylamino)-2-(N-5-thiazolylcarbonylmethoxycarbonyl)amino-1,6-diphenyl-3-hydroxyhexane (1.2g, 6.2 mmol) was dissolved in 4N HCl/dioxane solution (12 mL) and the reaction was stirred for 3 hours at room temperature. After completion of the reaction, the mixture was concentrated under vacuum and the residue was ground with EtOAc and filtered to give a white solid product (0.93 g, 98.2% yield). The product was characterized by 1H NMR (300MHz, DMSO-D6): δ 1.58 (t, J = 6.3Hz, 2H), 2.54-2.68 (m, 1H), 2.72-2.93 (m, 3H), 3.41-3.55 (m, 1H), 5.13 (s, 2H), 7.04-7.47 (m, 11H), 7.84 (s, 1H), 9.07 (s, 1H). 1H), 9.07 (s, 1H); MS (ESI) m/z 426.1 (M + H)+.
