Water → HCID 54533981, compound

Participants

Reaction Steps

1.01 equivalents of H-Leu-OH (Mw=131.2) was first silylated with 2.10 equivalents TMA (Mw=145.12) at about 50° C. until a clear solution was obtained. The solution was cooled to room temperature and diluted with isopropyl acetate. 1.00 equivalent of the Boc-Ile-OSu solid (Mw=328.26; 100.0%) was then added to silylated H-Leu-OH solution. The reaction mixture was further stirred at room temperature for at least 8 hours. After the completion of the reaction was confirmed by HPLC, the solution was quenched by adding DMAPA and water, washed with KHSO4 (1.00 equivalent) in 500 ml 5% (weight) aqueous NaCl solution; 500 ml 5% (weight) aqueous NaCl solution, and water. After evaporation of the isopropyl acetate in vacuo, the excess of water was eliminated by azeotropic distillation with isopropyl acetate. The peptide precipitated during the concentration. The concentrated suspension was then diluted in cyclohexane. The precipitate was stirred at room temperature for at least 10 min, filtered and finally dried in vacuum at 45° C. The dried precipitate yielded (based on NMR content) 80% of Boc-Ile-Leu-OH as white solid.

Provenance & Evidence