Synthesis of RP 56142: a new immunoactive peptide
RP 56142, a new immunoactive peptide was synthesized on large scale (ca. 500 g)viaL-2,6-diaminopimelic acid which was prepared by chemical or biochemical synthesis. The key derivative, N6-benzyloxycarbonyl-L-2,6-diaminopimelamic acid was synthesized by two methods. In the first, we used a copper chelate procedure. In the second, we selectively deblocked the amine at the α-position to the free carboxylic group by the N-carboxyanhydride method. Condensation of N6-benzyloxycarbonyl-L-2,6-diaminopimelamic acid and the appropriately protected lauroyl dipeptide and removal of the protecting groups afforded RP 56142.