Hydrochloric Acid → Z-Leu-Asp(OtBu)-Leu-OH

Participants

Reaction Steps

The H-Asp(OtBu)-Leu-OH (3.02 g), sodium bicarbonate (1.68 g), and 30 mL of water were mixed to give a mixture of pH 8. Z-Leu-OSu (3.63 g) in dioxane (30 mL) was added to the mixture and was stirred at room temp for 2 h. The reaction mixture was acidified by addition of conc. HCl to pH 1.0, then was extracted with ethyl acetate (30 mL×3). The combined extracts were dried over Na2SO4, filtered, and concentrated. The crude product was dissolved in methanol and chromatographed on a column of Sephadex™ LH20 to yield Z-Leu-Asp(OtBu)-Leu-OH as a foamy solid (4.43 g).

Provenance & Evidence