HCID 86622990, compound → HCID 86622991, compound

Participants

Reaction Steps

(1R,2R)-1-Methyl-2-(2-methylpropanoyloxy)propyl (2S)-3-(3,4-dihydroxyphenyl)-2-[(tert-butoxy)carbonylamino]propanoate (18) (6.7 g, 15 mmol) was dissolved in 20 ml of 4M HCl in 1,4-dioxane. The resulting mixture was stirred at room temperature for 60 min. dioxane and then evaporated completely under reduced pressure. The residue was dissolved in acetonitrile (20 mL). The solution was stirred at room temperature. The product was crystallized as hydrogen chloride salt, which was collected by filtration and dried under vacuum to give the title compound (9) (4.1 g, 75% yield). m.p.: 164.7-166.2° C. 1H NMR (400 MHz, CD3OD): δ 1.15 (d, 3H, J=6.8 Hz), 1.16 (d, 3H, J=6.8 Hz), 1.18 (d, 3H, J=6.8 Hz), 1.19 (d, 3H, J=6.4 Hz), 2.55 (m, 1H, J=6.8 Hz), 3.03 (dd, 1H, J=12.4, 6.8 Hz), 3.07 (dd, 1H, J=14.4, 6.8 Hz), 4.20 (t, 1H, J=6.8 Hz), 4.96 (m, 1H), 5.05 (m, 1H), 6.57 (dd, 1H, J=2, 8 Hz), 6.67 (d, 1H, J=2 Hz), 6.74 (d, 1H, J=8 Hz). MS (ESI) m/z 340.1 (M+H)+ and 338.1 (M−H), de>98% (by HPLC on Chiralpak column).

Provenance & Evidence