Synthesis and biological activity of new quinoxaline antibiotics of echinomycin analogues
作者:Yun Bong Kim、Yong Hae Kim、Ju Youn Park、Soo Kie Kim
DOI:10.1016/j.bmcl.2003.09.086
日期:2004.1
Novel quinoxaline antibiotics having the methylenedithioether bridge as an analogue of echinomycin have been synthesized by insertion of methylene moiety between -S-S- bond. The compound 1a shows remarkable cytotoxicities against human tumor various cell lines, and is active VRE (vancomycin-resistant enterococci) within MIC range 0.5-8 microg/mL. According to the eukaryotic or prokaryotic data, 1a
Synthesis of des-n-tetramethyltriostin a from C-terminal Z-d-serine tetra-and octadepsipeptide intermediates
作者:Madhup K. Dhaon、Joseph H. Gardner、Richard K. Olsen
DOI:10.1016/0040-4020(82)85045-x
日期:1982.1
derived from 6, furnished linear octadepsipeptide 9, which upon cyclization and disulfide formation gave the bicyclic octadepsipeptide 11, a known synthetic precursor to 1. The degree of racemization incurred in the alanine and valine residues of selected depsipeptides was measured and the results compared with those obtained in previous studies. It was concluded that alanine, perhaps because of sequence