P-SULFOTETRAFLUOROPHENYL HYDROPHILIC ACTIVE ESTERS OF AMINO-ACIDS IN PEPTIDE-SYNTHESIS

Highly reactive hydrophilic (i.e., water-soluble) p-sulfotetrafluorophenyl esters (Tfs esters) are proposed for peptide synthesis in aqueous and aqueous-organic media, as well as for protein and peptide partial synthesis in an aqueous medium. These esters can serve as a basis for creating a series of protein modifying reagents. As they are analogs of the widely used pentafluorophenyl esters, the Tfs esters possess a high reactivity coupled with good stability during storage. The expression for the reaction rate (for substrates AA(1) and AA(2)) is shown to be v = k[Boc-AA(1)-OTfs][H-AA(2)-NH2](0.5) for both water and DMF, i.e., the reaction is not a simple second-order reaction. The reaction rate in water is only slightly lower than that in DMF.