An alternative solid phase peptide fragment condensation protocol with improved efficiency

The success of solid phase peptide synthesis is often limited by the aggreg ation of the growing peptide chains on the resin. Working from the results of a study of model coupling reactions in solution between Z-Gly-Phe-OH and H-Phe-OBzl, we have achieved higher efficiency in the repetitive solid pha se fragment condensation of VGVAPG, in a 3:1 chloroform-phenol solvent syst em, using diisopropylcarbodiimide (DIC) as coupling agent, and a combinatio n of 3-hydroxy-3,4-dihydro-4-oxo-1,2,3-benzotriazine (HODhbt) and its tetra butyl ammonium salt as additive, than in DMF with DIC and HODhbt alone. Cop yright (C) 2001 European Peptide Society and John Wiley & Sons, Ltd.