Structural revision of isovalertatins M03, M13, and M23 isolated from the culture of Streptomyces luteogriseus.

Three aminooligosaccharides, isovalertatins M03 (1), M13 (2), and M23 (3) were isolated and purified from the culture filtrate of Streptomyces luteogriseus. Their physicochemical properties, liquid chromatographic behavior, and spectroscopic data were in full accordance with the reported compounds [Xu, Q.; Wang, Q.; Lu, D. CN Patent 1100756, 1995; Chem. Abstr. 1995, 123, 110278n], but their structures were reinvestigated and revised by spectroscopic methods, including ESI multistage mass spectrometry and 2-dimensional NMR techniques.