A 3-step method shows the glycosidic linkages and abs. configuration of oligosaccharide moieties attached to a complex labile aglycon by measuring the split CD curves resulting from interacting benzoate chromophores on the hexopyranose ring. Thus, the chromosome units of chromomycin A3 in the oligosaccharide moiety are all 2,6-deoxy sugars and hence lack sufficient OH groups which can be benzoylated to give coupled benzoate groups. Accordingly, the anomeric position were benzoylated as well; chromomycin A3 was directly permethylated in DMF/NaH with MeI, hydrolyzed with 50% AcOH, and per-p-bromobenzoylated. The coupled CD spectra resulting from chiral interaction between the 1-benzoate groups attached to other carbons were used to det. the position of glycosidic linkages and abs. configurations.
Circular dichroic method for determining the position of glycosidic linkages of deoxy sugar moieties. Antitumor antibiotic chromomycin A3
RICCIO, Raffaele;
1982-01-01
Abstract
A 3-step method shows the glycosidic linkages and abs. configuration of oligosaccharide moieties attached to a complex labile aglycon by measuring the split CD curves resulting from interacting benzoate chromophores on the hexopyranose ring. Thus, the chromosome units of chromomycin A3 in the oligosaccharide moiety are all 2,6-deoxy sugars and hence lack sufficient OH groups which can be benzoylated to give coupled benzoate groups. Accordingly, the anomeric position were benzoylated as well; chromomycin A3 was directly permethylated in DMF/NaH with MeI, hydrolyzed with 50% AcOH, and per-p-bromobenzoylated. The coupled CD spectra resulting from chiral interaction between the 1-benzoate groups attached to other carbons were used to det. the position of glycosidic linkages and abs. configurations.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
