An efficient and economical technology for the anchoring of Boc-protected amino acids via the carboxy terminal to chloromethyl Merrifield resin, using K₂CO₃/KI as the base reagent, was investigated. 2.5 equiv. Boc-AA-OH, 2.5 equiv. K₂CO₃, 0.01 equiv. KI and 1.0 equiv. resin were mixed in DMF. The reaction was completed after 25 h at 70℃. Each of the twenty-eight N-blocked amino acids was attached to Merrifield chloromethyl resin to give the N-Boc-esterified resin preparations. The mean values of yields were based on both weight gain of the resin and the nitrogen content respectively. Most yields of the desired derivatized resin esters were close to quantitative level. Four amino acids with different bulk of side chain were compared in the resin loading experiment under seven different conditions, such as KOH, Cs₂CO₃, TEA/KI, DCHA/KI, DIPA/KI, Cs₂CO₃/KI and K₂CO₃/KI. The efficiency of K₂CO₃/KI in related reaction was the same as that of Cs₂CO₃/KI, except for Boc-Asn-OH. Considering the facility and economy, K₂CO₃/KI promoted process would be more suitable for large scale production of chloromethyl resin bound Boc-amino acids.

Key words: peptide, chloromethyl resin (Merrifield resin), solid-phase synthesis, Boc-protected amino acid