Synthesis and antifungal activity of 7-methyl-7-hydroxy-2,3-benzo[c]octa-1,6-olide

Abstract

The racemic 7-methyl-7-hydroxy-2,3-benzo[c]octa-1,6-olide, the analog of natural product (6R)-3,7-dimethyl-7-hydroxy-2-octen-1,6-olide, was totally synthesized using easily available (E)-2-(2-carboxyvinyl)benzoic acid as a raw material in nine-step reactions including three key steps of Wittig reaction, epoxidation, and cyclization, with an overall yield of 10.3%. The bioassay results showed that ( ± )-2 exhibited stronger antifungal activity than the natural product ( ± )-1 and (R)-1 against Alternaria solani with an EC₅₀ value of 27.36 μg/ml.

Keywords::

• 7-methyl-7-hydroxy-2,3-benzo[c]octa-1,6-olide
• total synthesis
• lactonization of epoxy carboxylic acid
• antifungal activity

Acknowledgments

This project was co-founded by the National Key Technologies R&D Program (No. 2011BAE06B04), Natural Science Foundation of China (No. 21172254), National Hi-Tech R&D Program of China (2011AA10A202), and Chinese Universities Scientific Fund (2012YJ131).