Pan Chengqian, Shi Yutong, Chen Xuegang, Chen Chen-Tung Arthur, Tao Xinyi, Wu Bin
Ocean College, Zhejiang University, Hangzhou 310058, China.
Institute of Marine Geology and Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan, Republic of China.
Org Biomol Chem. 2017 Feb 1;15(5):1155-1163. doi: 10.1039/c6ob02374f.
Three new quinazoline derivatives (1-3), one new oxepin-containing natural product (4) and four new cyclopenin derivatives (5-7 and 9) have been isolated from an EtOAc extract of the Taiwan Kueishantao hydrothermal vent crab-associated fungus Aspergillus versicolor XZ-4. Their planar structures were established by HRMS, 1D and 2D NMR spectroscopic data analyses. The absolute configurations for compounds 1 and 4 were determined by chiral phase HPLC analysis of their hydrolysis products. The absolute configurations of 2, 3 and 7 were defined mainly by comparison of the quantum chemical TDDFT calculated and the experimental ECD spectra, and the absolute configuration of 5 was deduced from comparison of the optical rotation values reported in the literature. The presence of two atropisomers of 5 was established by NOE analyses. The Ile & Val units in compounds 1-3 allowed the assignment of a new quinazoline skeleton and it's the first time the configuration of isoleucine in the quinazoline skeleton was defined. A series of 7-methoxy cyclopenin derivatives were reported for the first time in this study. The bioevaluation of compounds 5, 7, 8 and 9 revealed inhibitory activities against E. coli at MIC values around 32 μg mL.
从台湾龟山岛热液喷口蟹相关真菌杂色曲霉XZ - 4的乙酸乙酯提取物中分离出三种新的喹唑啉衍生物（1 - 3）、一种新的含氧杂环庚三烯天然产物（4）和四种新的环戊菌素衍生物（5 - 7和9）。通过高分辨质谱、一维和二维核磁共振光谱数据分析确定了它们的平面结构。通过对化合物1和4水解产物的手性相高效液相色谱分析确定了其绝对构型。化合物2、3和7的绝对构型主要通过量子化学TDDFT计算和实验电子圆二色光谱的比较来确定，化合物5的绝对构型则通过与文献报道的旋光值比较推导得出。通过NOE分析确定了化合物5存在两种阻转异构体。化合物1 - 3中的异亮氨酸和缬氨酸单元有助于确定一种新的喹唑啉骨架，并且首次确定了喹唑啉骨架中异亮氨酸的构型。本研究首次报道了一系列7 - 甲氧基环戊菌素衍生物。化合物5、7、8和9的生物活性评价显示，它们对大肠杆菌具有抑制活性，最低抑菌浓度值约为32 μg/mL。
