4-Methylmorpholine → Tert-butoxycarbonylalanine

Participants

Reaction Steps

A mixed anhydride of Boc-Ala-OH was prepared by reacting Boc-Ala-OH (10 g, 52.8 mmoles) with N-methylmorpholine (5.80 mL, 52.8 mmoles) and isobutyl chloroformate (6.8 mL, 52.85 mmoles) for 5 minutes in 50 mL of tetrahydrofuran at -20°. The reaction mixture and additional N-methylmorpholine (5.8 mL) were added to H-Pro-Obzl·HCl dissolved in 50 mL of cold CHCl3. After this mixture was stirred for 1 hour at -20° and 2 hours at 23°, it was filtered and the filtrate evaporated. The residue was dissolved in ethyl acetate and was washed sequentially with 0.2N HCl, 5% NaHCO3, and saturated aqueous NaCl. The solvent was evaporated to yield Boc-AlaPro-OBzl as an oil (14.1 g).

Provenance & Evidence