Hydrochloric Acid → Leu-Pro-OBn

Participants

Reaction Steps

To a flask containing Boc-Leu-Pro-OBn (113.8 g, 272 mmol) a solution of hydrogen chloride in dioxane (209 ml, 5.3 N) was added and the stirring was continued for 5 h or until total conversion by TLC (disappearance of starting material; Rf=0.47 (hex-EtOAc 2:1, silica). The solution was concentrated under reduced pressure and the resulting oil was chased with CHCl3 (3×50 ml), CHCl3-MTBE (30 ml-50 ml), MTBE (50 ml) and hex (50 ml). The residue was dried under vacuum (16 h) to remove residual HCl, to give the title compound as a white solid. A5 (96.4 g, 100%) was used directly without further purification in the next step. [α]D22−85.21 (c=1, CHCl3).

Provenance & Evidence