Abstract

A new alkylpyrrole derivative, fusariumin A (1), was isolated from the culture broth of the fungus Fusarium sp. The absolute configuration of fuasiumin A has been established as (2′R,3′R) using a combination of RDC (residual dipolar coupling)-based NMR and DFT-supported chiroptical spectroscopy. It is worth to note that in this study without the aid of the RDC analysis, an unambiguous determination of configuration and conformation was not feasible due to the excessive conformational possibilities of this open-chain compound.Electronic supplementary materialThe online version of this article (doi:10.1007/s13659-015-0084-0) contains supplementary material, which is available to authorized users.

Highlights

  • A new alkylpyrrole derivative, fusariumin A (1), was isolated from the culture broth of the fungus Fusarium sp

  • Fusarium is a large genus of filamentous fungi which widely distributed in soil and associated with plants

  • The connection of C-10/C-20/C-30/C-40 was established from the correlations from H-10 to C-20 and C-30, and from H-20 to C-40 in the HMBC spectrum (Fig. S2, Electronic supplementary material)

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Summary

Fungal Material

The determination of absolute configuration were measured at 22–25 °C using a 2 mL cuvette at 589, 578, 546, 436 and 365 nm with a Perkin Elmer model 241 polarimeter (Waltham, Massachusetts, USA). CD spectra were recorded at room temperature using a Jasco-J-810 CD spectrometer (Tokyo, Japan). Standard 1D and 2D NMR spectra of fusariumin A in CDCl3 were acquired on Bruker DRX-500 and AM-400 instruments at room temperature with TMS as internal standard (Bruker, Rheinstetten, Germany).Standard 2D NMR spectra with DMSO solvents, together with [1H,13C]-CLIP-HSQC [31], [1H,13C]HECADE [32], [1H,13C]-HSQMBC [33] and NOESY [34] spectra, which were used for determination of relative configuration, were recorded on Bruker 700 MHz with 1.7 mm PA-TXI room temperature probe head (Bruker, Rheinstetten, Germany). Silica gel (200–300 mesh, Qingdao Marine Chemical Inc., Qingdao, China), Sephadex LH-20 (Amersham Biosciences, Sweden), and RP-18 gel (40–75 lm, Fuji Silysia Chemical Ltd. Japan) were used for column chromatography (CC). Pre-coated silica gel GF254 plates (Qingdao Marine Chemical Inc., Qingdao, China) were used for TLC. Was collected in Botanic Garden of Kunming Institute of Botany, Chinese Academy of Sciences and identified by Prof. Zhu-Liang Yang (Kunming Institute of Botany, Chinese Academy of Sciences). The pH was adjusted to 6.5 before autoclaving, and the fermentation was carried out in a shaker (150 rpm) at 25 °C for 25 days

Extraction and Isolation
Molecular Mechanics and DFT Calculations
RDC Fitting
ECD Computations
ORD Computations
Full Text
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