Three oxygenated cyclohexenone derivatives produced by an endophytic fungus
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Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
Published on: July 17, 2020
Yoshihito Shiono1, Tetsuya Murayama, Koetsu Takahashi
1Department of Bioresource Engineering, Faculty of Agriculture, Yamagata University, Tsuruoka, Yamagata, Japan. yshiono@tds1.tr.yamagata-u.ac.jp
Abstract:
Three cyclohexenone derivatives, (4S,5S,6S)-5,6-epoxy-4-hydroxy-3-methoxy-5-methyl-cyclohex-2-en-1-one (1), (4R,5R)-4,5-dihydroxy-3-methoxy-5-methyl-cyclohex-2-en-1-one (2), and (4R,5S,6R)-4,5,6-trihydroxy-3-methoxy-5-methyl-cyclohex-2-en-1-one (3), were isolated from unpolished rice fermented with an xylariaceous endophytic fungus (strain YUA-026). The structures of three compounds were established on the basis of spectroscopic analyses and chemical conversion. The minimum inhibitory concentrations of 1 and 3 were 100 microg/ml and 400 microg/ml against Staphylococcus aureus, 100 microg/ml and 200 microg/ml against Pseudomonas aeruginosa, and 200 microg/ml and >400 microg/ml against Candida albicans, respectively. In addition, 1 and 3 exhibited phytotoxic activity against lettuce.
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