STUDIES OF ESTERIFICATION OF WANG RESIN AND FMOC/tBu TYROSIN IN SOLID PHASE PEPTIDE SYNTHESIS

This paper has discussed the effect of different effects on the esterification yield of Fmoc-Tyr(t-Bu)-OH and Wang resin in symmetrical anhydride method, active ester method and 2,6-dichlorobenoyl chloride (DCB) method, respectively. The yield was lowest in symmetrical anhydride method; however, the yield was improved by other two methods. In active ester method, the yield was beyond 90% in DMA, THF, DCM and 45%DMF/THF with small amount of HOBt after 5h; While in DCB method, the highest yield was 99%, which was achieved by THF after 3h. In general, DCB method was the best method of esterification of Fmoc-Tyr(t-Bu)-OH and Wang resin.