摘要:
The Trp-His-Gly-Arg derived macrocycle 4 of moroidin 1 containing the unusual tryptophan C-2 histidine N-1 link has been synthesised in protected form. The key steps are displacement of a 2-chloroindole with a histidine derived nucleophile, a Horner-Wadsworth-Emmons reaction followed by asymmetric hydrogenation to establish the tryptophan side chain, and incorporation of the Gly-Arg dipeptide by peptide coupling. (C) 2003 Elsevier Science Ltd. All rights reserved.