6 新規エンドセリン拮抗物質Stachybocin類の構造決定(口頭発表の部)

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In the course of our screening for endothelin antagonists from microorganisms, we found new compounds stachybocins A(1), B(2) and C(3) from the fermentation broth of Stachybotrys sp. They were extracted with EtOAc and then purified by aluminum oxide and silica gel column chromatographies. The molecular formula of stachybocins were determined to be C_<52>H_<70>N_2O_<10> (1) and C_<52>H_<70>N_2O_<11> (2 and 3) by HR FAB-MS and NMR data. The ^<13>C-NMR spectrum of 1 confirmed the presence of 52 carbons including 46 signals of the pairs or equivalent carbons. All one-bond ^1H-^<13>C connectivities were established by the HSQC spectrum using a pulse-field-gradient (PFG) technique. PFG DQF-COSY and HMBC experiments of 1 generated partial structures 1-a and 1-b in Fig. 3. Further detailed analysis of ^<13>C-^1H long range spin couplings enabled to connect these units to give the total structure of 1 as shown in Fig. 1. 2 and 3, monohydroxy derivatives of 1, showed similar ^1H and ^<13>C NMR spectra each other. Detailed analysis of HMBC spectral data established that 2 and 3 have an additional hydroxy group at C-17 and C-17', respectively. The relative stereochemistry of the sesquiterpene portion of the stachybocins was deduced by the NOESY data. The absolute configuration of C-24 was determined to be S by isolation of L-lysine from 1 by Jones oxidation followed by acid hydrolysis.
天然有機化合物討論会の論文
1994-09-20