Formic Acid → N-(tert-Butoxycarbonyl)-O-{[(3S)-3-[(tert-butoxycarbonyl)amino]-4-oxo-4-{[2-(tritylsulfanyl)-ethyl]amino}butyl]carbamoyl}-L-tyrosine

Participants

Reaction Steps

98 mg (0.1 mmol) of the compound from example 15A was dissolved in approx. 4 ml tetrahydrofuran. 70 μl (0.5 mmol) Triethylamine, 19 μl (0.5 mmol) formic acid and 11 mg (0.01 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 67 mg (79% of theory) product.

Provenance & Evidence