Dicyclohexylcarbodiimide → HCID 178501441, compound

Participants

Reaction Steps

840 mg of Boc-Pro-His-Pro-Phe-His-OH, 600 mg of H-Sta-Val-Tyr-Lys(Boc)-OMe (from stage 1.5) and 250 mg of HONB are dissolved in 6 ml of DMF, cooled to 0°, and 290 mg of DCCI are added. The whole is stirred for 6 hours at 0° and for 24 hours at 25° the DCH is filtered off, and the filtrate is concentrated to dryness by evaporation. The residue is dissolved in 18.8 ml of MeOH, 0.6 ml of glacial acetic acid and 0.6 ml of H2O, heated for 1 hour at 60°, concentrated to approximately 3 ml, and the peptide is precipitated in the form of greasy material with 20 ml of diisopropyl ether. It is purified by Craig partitioning in the system MeOH/0.1N AcOH/ethylene chloride/chloroform (10:3:8:4) over 750 stages; K=0.75. The chromatographically pure middle fraction is isolated by strong concentration and lyophilisation, yielding Boc-Pro-His-Pro-Phe-His-Sta-Val-Tyr-Lys(Boc)-OMe in the form of an amorphous powder; Rfn (B)=0.38; Rf (I)=0.46; Rf (C)=0.64.

Provenance & Evidence