Diisopropylethylamine → HCID 131724516, compound

Participants

Reaction Steps

Fmoc-(D)Phe(4-Cl)-OH (844 mg, 2 mmol) was coupled to 2-chlorotritylchloride resin (Alexis, 0.75 g, 1 mmol) in the presence of diisopropylethylamine (2 mmol 0.35 ml) in DMF (8 ml) by an automated procedure on an Applied Biosystems 430A peptide synthesiser. After 1 hour at ambient temperature, the resin was filtered and washed with DMF. After deprotection with 20% piperidine in DMF (two treatments with 15 ml), the resin was thoroughly washed with DMF (5×10 ml). Fmoc-NMe(D)Phe-OH (803 mg, 2 mmol) was coupled to the resin-bound H-(D)Phe(4-Cl) by the standard HBTU/HOBt chemistry similar to that used in example 3. After extensive washing with DMF, the deprotection procedure described above was repeated to give H-NMe(D)Phe-(D)Phe(4-Cl)-resin. Fmoc-(D)Lys(BOC)-OH (938 mg, 2 mmol) was coupled by the HATU procedure (see J Chem Soc. Chem Comm. 1994, 201). After 1 hour at ambient temperature the resin as filtered and washed with DMF. After deprotection and extensive washing with DMF, cyclohexane carboxylic acid (256 mg, 2 mmol) was coupled by standard HBTU/HOBt chemistry similar to that described above to the resin bound tripeptide to give cyclohexyl-(D)Lys(BOC)-NMe(D)Phe-(D)Phe(4-Cl) on the resin. The peptide resin was collected and washed with methanol and dried, in vacuo, at 50° C. Yield 1.337 g (gain 587 mg).

Provenance & Evidence