Diisopropylethylamine → N5-[(4-{(2S)-3-(Allyloxy)-2-[(tert-butoxycarbonyl)amino]-3-oxopropyl}phenoxy)carbonyl]-N2-(tert-butoxycarbonyl)-L-ornithyl-S-trityl-L-cysteinamide

Participants

Reaction Conditions

Reaction Steps

1.20 g (2.07 mmol) of the compound from example 9A was dissolved in 48 ml dichloromethane. 0.750 g (2.07 mmol) S-Trityl-L-cysteinamide, 0.36 ml (2.07 mmol) N,N-diisopropylethylamine and 0.787 g (2.07 mmol) HATU were added. The reaction mixture was split into 3 portions. The portions were heated for 30 min in a sealed tube at 60° C. in a microwave synthesizer. From the combined 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. 400 ml silica gel. Solvents used were dichloromethane/ethyl acetate 2/1, dichloromethane/ethyl acetate 1/1. The product-containing fractions were combined and concentrated to dryness under reduced pressure. This gave 1.30 g (1.5 mmol, 56% of theory, 82% purity) of the desired product.

Provenance & Evidence