Six new P-6A analogues were synthesized in liquid phase using THF and DMF solvents, using an active reagent of isobutyl chloroformate and mixed anhydride method in every preparation step. The yield was more than60% in every step of synthesizing peptides. Their structures were characterized by MS and elemental analysis. The examination of optical activities displayedthat the first one was right rotation and the others kept left rotation to polarized light.

Key words: fibrin mass, degraded occlusive thrombus reagent, P-6A analogue, mixed anhydride method, peptide synthesis in liquid phase