187753-74-8Relevant articles and documents
Probing host-selective phytotoxicity: Synthesis of destruxin B and several natural analogues
Ward,Gai,Lazny,Pedras
, p. 7832 - 7840 (2007/10/03)
The syntheses of the host-selective phytotoxin destruxin B [cyclo(βAla-Hmp-Pro-Ile-MeVal-MeAla), Hmp = (2R)-2-hydroxy-4-methylpentanoic acid], and the closely related natural analogues homodestruxin B (MeVal→MeIle), desmethyldestruxin B (MeVal→Val), hydroxydestruxin B (Hmp→Dhmp, Dhmp = (2R)-2,4-dihydroxy-4-methylpentanoic acid), and hydroxyhomodestruxin B (MeVal→MeIle, Hmp→Dhmp) are described. In each case, the MeAla-βAla linkage was formed by cyclization and the precursor linear hexadepsipeptides were formed by condensing two three-residue fragments. Radiolabeled samples of destruxin B, homodestruxin B, and hydroxydestruxin B were prepared by coupling [3-14C]-β-alanine to the appropriate pentadepsipeptide followed by cyclization. A noteworthy feature of the synthesis involves the novel use of a Boc-hydrazide protecting group on dipeptides with a C-terminal N-methylalanine residue to inhibit the otherwise facile dioxopiperazine formation during peptide coupling.
