Diisopropylethylamine → N-[(4-{(2S)-3-(Allyloxy)-2-[(tert-butoxycarbonyl)amino]-3-oxopropyl}phenoxy)carbonyl]-3-[(tert-butoxycarbonyl)amino]-L-alanyl-S-trityl-L-cysteinamide

Participants

Reaction Steps

1.23 g (2.23 mmol) of the compound from example 24A was dissolved in 25 ml dichloromethane. 0.81 g (2.23 mmol) S-Trityl-L-cysteinamide, 0.39 ml (2.23 mmol) N,N-diisopropylethylamine and 0.85 g (2.23 mmol) HATU were added. The reaction mixture was stirred at room temperature for 3 h. From the reaction mixture the solvent was removed by rotary evaporation (approx. 40° C., approx. 200 mbar, approx. 30 min.). The raw product was dissolved in dichloromethane and chromatographed over approx. 70 ml silica gel. Solvents used were dicloromethane/methanol 20/1 to dichloromethane/methanol 5/1. The product-containing fractions were combined and concentrated to dryness under reduced pressure. This gave 2.38 g (2.03 mmol, 91% of theory, 76% purity) of the desired product.

Provenance & Evidence