A NOVEL RESIN LINKER FOR SOLID-PHASE PEPTIDE SYNTHESIS WHICH CAN BE CLEAVED USING TWO SEQUENTIAL MILD REACTIONS

The interest in developing new linkers for solid-phase peptide and organic synthesis has increased tremendously as a result of the rapid development of combinatorial chemistry. Herein, we report the development of a new redox-sensitive linker for solid-phase peptide synthesis. This linker can be readily cleaved under mild conditions by using two sequential mild reactions, a reduction followed by a base (Bu4N+F-)-catalyzed cyclic ether formation. By using this new linker, two short peptides, a tetrapeptide [Boc-Trp-Ala-Gly-Gly-OH] and a pentapeptide [Boc-Asn-Ala-Ser(OBn)-Gly-Glu(OBn)-OH)], were synthesized. Because the cleavage does not use acidic conditions, this resin linker provides an alternative when acidic conditions are not desirable. Furthermore, the cleavage conditions do not affect most of the side chain protecting group. Therefore, the peptides synthesized can be used for the segment synthesis of larger peptides without the need to reprotect the side chain functional groups.