Dicyclohexylcarbodiimide → cyclo(-DTrp-DAsp-Thz-DVal-Leu-)

Participants

Reaction Steps

Thz-DVal-Leu-resin which was prepared from Fmoc-Leu-resin in the same manner described in Example 4, was unpacked from a reaction column and allowed to react with 2.5 equivalents of the symmetrical acid anhydride of Fmoc-nAsp(OtBu)(prepared previously from Fmoc-DAsp(OtBu) and DCC) and DMAP(10 mg) in DMF at room temperature for 3 h with occasional shaking. After removal of excess reagents, the resin was washed successively with DMF, tert-amyl alcohol, acetic acid, tert-amyl alcohol and DMF, and repacked in a reaction column. The further solid-phase peptide synthesis was performed by the standard protocol described in Example 4. The resulting DTrp-DAsp(OtBu)-Thz-DVal-Leu-resin was treated in the same manner described in Example 4 to give the title compound.

Provenance & Evidence