13C-NMR Spectra and Streochemistry of Isoechinulins A,B and C |
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| Authors: | Hiromichi Nagasawa Akira Isogai Akinori Suzuki Saburo Tamura |
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| Institution: | Department of Agricultural Chemistry, The University of Tokyo, Bunkyo-ku, Tokyo 113, Japan |
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| Abstract: | 13C-NMR spectra of isoechinulins A, B and C, metabolites from Aspergillus ruber, were fully assigned on the basis of chemical shifts and multiplicities and comparison with their analogues. Taking advantage of the symmetrical structure of the diketopiperazine ring, the stereochemistry of the trisubstituted carbon-carbon double bond in a dehydrotryptophyl moiety was determined as Z (cis) by measuring the coupling constants,  | |
| Keywords: | glycoside hydrolase family 31 α-glucosidase substrate specificity transglycosylation specificity branched oligosaccharide |
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