Isolation, antimicrobial activity, and absolute configuration of the furylidene tetronic acid core of pestalotic acids A-GElectronic supplementary information (ESI) available: 1H, 13C NMR, CD spectra of 1-7, and detailed computational data for 1. CCDC 859983. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c2ob25469g

• Main Authors: Zhang, Fan, Ding, Gang, Li, Li, Cai, Xiaoyue, Si, Yikang, Guo, Liangdong, Che, Yongsheng
• Format: Article
• Language: English
• ISSN: 1477-0520; 1477-0539
• DOI: 10.1039/c2ob25469g

Natural products possessing the 3-(furan-2(5 H )-ylidene)furan-2,4(3 H ,5 H )-dione (furylidene tetronic acid) skeleton are rare and were encountered only as fungal metabolites. The configurational assignment of the furylidene tetronic acid core using conventional approaches remained a challenge. Pestalotic acids A-G ( 1-7 ) are new furylidene tetronic acid derivatives isolated from a plant endophyte Pestalotiopsis yunnanensis . The structure of 1 was elucidated by combination of NMR experiments, X-ray crystallography, and ECD calculations. Compounds 3 and 7 showed significant antimicrobial activity. Isolation of new furylidene tetronic acids ( 1-7 ) from an endophyte and absolute configuration assignment by ECD calculations.