反应详情

To Boc-Leu-DTrp-βAla-OEt (760 mg) obtained in Example 29-(1) was added 20% ethanedithiol/TFA (25 ml) at 0°~5° C. The reaction mixture was stirred at 0°~5° C. for 30 min, and concentrated under reduced pressure. Toluene was added to the residue and the solution was again concentrated under reduced pressure. These procedures were repeated 3 times. The resulting residue was dissolved in ether (5 ml). Addition of hexane (ca. 10 ml) caused precipitation. Filtration of a precipitate, followed by drying in vacuo gave Leu-DTrp-βAla-OEt.TFA (781 mg) as a pale yellow solid. To the solid (781 mg) was added sat. NaHCO3. Extraction with chloroform, followed by drying the organic layer over MgSO4, and concentration of the resulting solution under reduced pressure, gave the product (479 mg).

1. concentrationconcentrated under reduced pressure
2. additionToluene was added to the residue
3. concentrationthe solution was again concentrated under reduced pressure
4. dissolutionThe resulting residue was dissolved in ether (5 ml)
5. additionAddition of hexane (ca. 10 ml)
6. customprecipitation
7. filtrationFiltration of a precipitate
8. customby drying in vacuo