Piperidine → (2S,4S)-1-(((9H-Fluoren-9-yl)methoxy)carbonyl)-4-hydroxypyrrolidine-2-carboxylic acid

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Reaction Steps

Peptides were synthesised using a CS-Bio 336S, a CS-Bio 336X and a Multipep peptide synthesis machine (Intavis AG Bioanalytical Instruments, Germany). Standard amino acids were purchased from CS-Bio in their Fmoc-N-α-protected form. Fmoc-trans-4-hydroxy-(L)-proline was obtained from Merck. Fmoc-cis-4-hydroxy-(L)-proline, Fmoc-cis-3-hydroxy-(L)-proline and Fmoc-trans-3-hydroxy-(L)-proline were prepared as described in the synthetic section. Peptide synthesis was carried out in dimethylformamide (DMF) using diisopropylcarbodiimide (DIC) and 1-hydroxybenzotriazole (HOBt) as activating reagents, and piperidine as Fmoc deprotection reagent. DIC was used as 0.5 M solution in DMSO, and HOBt as a 0.5 M solution in DMF. Typically, synthesis was carried out on a 0.1 mmol scale, using MBHA Rink Amide resin (loading 0.45 mmol/g), 1 mmol of protected amino acids (10× molar excess), and 1 mmol of activating reagents (DIC, HOBt). Parallel peptide synthesis for screening was performed on Tentagel S-RAM resin. Amino acids were pre-activated by addition of DIC/HOBt for 30 min prior to addition to the resin. After addition to the resin, the activated amino acid was allowed to react with the resin/growing peptide chain for 2 h, prior to removal and washing of the resin. Fmoc deprotection was performed using 20% piperidine, 20% DMSO in 60% DMF, followed by extensive washing of the resin, and addition of the next amino acid.

Provenance & Evidence