4-Methylmorpholine → Z-Asp(OtBu)-Leu-OBzl

Participants

Reaction Steps

Z-Asp(OtBu)-OH (10.23 g) in THF (50 mL) was added N-methylmorpholine (3.30 mL) and isobutyl chloroformate (3.90 mL) at −20° C. After 10 min, the reaction mixture was added to the solution of H-Leu-OBzl (11.81 g in 50 mL HCl3) at −20° C., followed by addition of triethylamine (4.18 mL). The resulting mixture was allowed to warm to room temp. After filtering off the salt, the filtrate was concentrated to an oil. The oil was dissolved in 100 mL of ethyl acetate; washed with 0.2 N HCl, 5% NaHCO3 and sat. NaCl; dried over Na2SO4. After filtration, the solvent was evaporated to give Z-Asp(OtBu)-Leu-OBzl as an oil of 14.81 g.

Provenance & Evidence