Diisopropylethylamine → (2S)-4-{[(4-{(2S)-3-(Allyloxy)-2-[(tert-butoxycarbonyl)amino]-3-oxopropyl}phenoxy)carbonyl]-amino}-2-[(tert-butoxycarbonyl)amino]butanoic acid

Participants

Reaction Conditions

Reaction Steps

4.0 g (8.22 mmol) of the compound from example 1A was dissolved in 60 ml dichloromethane. 1.795 (8.22 mmol) (2S)-4-Amino-2-[(tert-butoxycarbonyl)amino]butanoic acid and 1.43 ml (8.22 mmol) N,N-diisopropylethylamine were added. The reaction mixture was split into 3 portions. The portions were heated for 30 min in a sealed tube at 75° 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. 600 ml silica gel. Solvents used were dichloromethane/ethyl acetate 4/1, dichloromethane/ethyl acetate 1/1, dichloromethane/methanol 4/1 and dichloromethane/methanol 1/1. The product-containing fractions were combined and concentrated to dryness under reduced pressure. This gave 4.02 g (6.54 mmol, 80% of theory) of the desired product.

Provenance & Evidence