Formic Acid → N-[(2S)-2-[(tert-Butoxycarbonyl)amino]-4-{[(4-{(2S)-2-[(tert-butoxycarbonyl)amino]-2-carboxyethyl}phenoxy)carbonyl]amino}butanoyl]-S-trityl-L-cysteinylglycinamide

Participants

Reaction Steps

60 mg (0.031 mmol) of the compound from example 16A was dissolved in approx. 3 ml tetrahydrofuran. 22 μl (0.16 mmol) Triethylamine, 6 μl (0.16 mmol) formic acid and 4 mg (0.003 mmol) tetrakis(triphenylphosphin)palladium(0) were added. The reaction mixture was stirred over night at room temperature. The reaction was diluted with approx. 5 ml water and twice extracted with approx. 5 ml dichloromethane. The combined organic phases were extracted with brine, dried over sodium sulfate and concentrated to dryness under reduced pressure. The raw product was purified by preparative RP-HPLC on a C18 column with a water/methanol gradient to yield 26 mg (86% of theory) product.

Provenance & Evidence