Studies on a new immunoactive peptide, FK-156. IV. Synthesis of FK-156 and its geometric isomer.

Abstract

For the structural confirmation of FK-156, 2 possible structures, 1 and its geometric isomer 2, were synthesized. Di-Z-meso-diaminopimelic acid (4) was converted into 14 via a sequence of reactions involving, as key steps, an enzyme-mediated asymmetric hydrolysis (6 .fwdarw. 7), followed by carbobenzyloxylation using a Cu chelate procedure (7 .fwdarw. 8). Condensation of 14 and the appropriately protected lactoyl dipeptide 17 and removal of the protecting groups of the resulting 18 afforded 1. Protection of 7 to 22, followed by coupling to glycine via an azide method, gave 25. Derivatization of 25 to 29 and condensation with 17 gave 30, which was deprotected to yield 2. Compound 1 was identical in all respects with the natural product.