P-39 Pseudodeflectusinの合成と構造決定(ポスター発表の部)

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In the course of our program for the constructon of small molecule library from natural resources, we isolated pseudodeflectusin (1), a new isochroman derivative, from a culture broth of Aspergillus pseudodeflectus. The structure was elucidated by a spectroscopic means as 9-hydroxy-7-methyl-2-(methylethylidine)-furano[3,2-H]isochroman-3-one. 1 exhibited cytotoxicity against several human cancer cell lines from the stomach (NUGC-3), cervix (HeLa-S3), and peripheral blood (HL-60), but did not have an effect on flattened epothelium cells such as A549 and DLD-1. The LD_<50> values for NUGC-3, HeLa-S3 and HL-60 were 49, 47, 39μM, respectively. We observed a marked increase in LDH leakage and a significant decrease in the intracellular gluthathione by treatment of 1 with HeLa-S3. We proposed the structure of 1 by spectral analysis. However, Proksch et al. have isolated aspergione B (2), tricyclic chromone derivative, whose NMR spectroscopic data (^1H, ^<13>C spectra) were in good accordance with those of 1. To clarify the structure of 1 and the absolute configuration at C-7, we started the synthetic studies on pseudodeflectusin (1). δ-Lactone 7 was prepared from o-anisic acid by the ortho lithiation of 4 and alkylation of propylene oxide. 7 was converted into β-keto ester 12 by the intramolecular cyclization of 11. Decarboxylation, followed by condensation with 2,2-dimethoxypropane gave 14. Finally reduction of 14 with DIBAL gave 1. The ^1H-NMR spectrum of our synthetic 1 was identical with that of natural 1. Thus, we were able to confirm the structure of pseudodeflectusin as 1.
天然有機化合物討論会の論文
2005-09-15

P-39 Pseudodeflectusinの合成と構造決定(ポスター発表の部)

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