Amino acids attached to 2-chlorotrityl resin
2-Chlorotrityl resins are excellent supports for the preparation of partially protected and fully deprotected peptide fragments by Fmoc batch SPPS. Cleavage can be effected by treatment with AcOH/TFE/DCM (2:2:6), 0.5% TFA in DCM or 30% HFIP in DCM, to yield protected peptide acid fragments without any loss of sensitive side-chain protecting groups. Because enantiomerization does not occur during the loading of 2-chlorotrityl resin, peptides containing C-terminal Cys and His residues can be produced free from contamination by diastereomeric side-products. These supports are useful tools for the synthesis of prolyl peptides as the bulk of the trityl handle prevents diketopiperazine formation.
