Revision of the structure of isochaetoglobosin D based on NMR analysis and biosynthetic consideration

• Published in: RSC advances Vol. 1; no. 4; pp. 23969 - 23974
• Main Authors: Wang, Yan-duo, Li, Yuan-yuan, Tan, Xiang-mei, Chen, Lin, Wei, Zhong-qi, Shen, Li, Ding, Gang
• Format: Journal Article
• Language: English
• Published: 23.06.2020
• ISSN: 2046-2069
• DOI: 10.1039/d0ra04108d

Isochaetoglobosin D b is a new chaetoglobosin possessing a unique 3,4-substituted pyrrole ring isolated and named by Qiu et al. , and it is different from any one of the 14 sub-types in the macrocyclic ring of chaetoglobosins classified in our previous work. Its chemical shift values, coupling constants and biosynthetic consideration implied that the proposed structure of isochaetoglobosin D b was incorrect. In this report, based on detailed NMR data analysis together with biosynthetic consideration, the structure of isochaetoglobosin D b is suggested to be revised to that of penochalasin C. The NMR spectra of penochalasin C measured in the same solvent (DMSO- d 6 ) as that of isochaetoglobosin D b supported the above conclusion. The results imply that reasonable biosynthetic consideration could complement spectroscopic structural determination, and also support that the 1 H-NMR rule of chaetoglobosin summarized in our previous work can provide help for dereplication and rectification. Isochaetoglobosin D b is a new chaetoglobosin possessing a unique 3,4-substituted pyrrole ring isolated and named by Qiu et al. , and it is different from any one of the 14 sub-types in the macrocyclic ring of chaetoglobosins classified in our previous work.