Citrifurans A–D, Four Dimeric Aromatic Polyketides with New Carbon Skeletons from the Fungus Aspergillus sp.

• DOI: 10.1021/acs.orglett.7b01823
• Publication Date: 2017-07-20T15:39:18Z
• Authors: Guo-Ping Yin; Ya-Rong Wu; Ming-Hua Yang; Tian-Xiao Li; Xiao-Bing Wang; Miao-Miao Zhou; Jian-Li Lei; Ling-Yi Kong
• Keywords: Lipopolysaccharides; Molecular Structure; Cell Survival; Pigments, Biological; Nitric Oxide; 01 natural sciences; 0104 chemical sciences; Mice; Aspergillus; RAW 264.7 Cells; Polyketides; Animals; Benzopyrans; Furans; Dimerization

Citrifurans A-D (1-4), metabolized by an Aspergillus sp., are unusual dimers of azaphilone and furanone derivatives. Michael addition was thought to be the pivotal procedure in their biosynthesis, and different addition sites generated two new different carbon skeletons. Their structures were elucidated on the basis of spectroscopic methods, single-crystal X-ray diffraction, chemical conversion, and electronic circular dichroism analyses. Compounds 1-3 showed moderate inhibitory activities against LPS-induced NO production in RAW 264.7 macrophages with IC50 values of 18.3, 22.6, and 25.3 μM, respectively.