Synthesis and biological evaluation of MS-347a derivatives against plant pathogenic fungi based on a strategy of laeA gene introduction

Our group previously identified MS-347a (1) as a new fungicide candidate from the culture broth of the mutant strain, Aspergillus sp. KTF-0058, which had the laeA gene inserted. This mutant strain was able to produce a sufficient supply of 1, allowing for its use to investigate the structure-activity relationship. To this end, we synthesized 11 derivatives and evaluated their antifungal activity. Among these derivatives, the aldehyde derivative exhibited superior antifungal potency as compared to 1, and some acyl derivatives were able to maintain the antifungal activity of 1 despite significant structural changes. From these results, it is found that the aldehyde derivative is one of the most promising fungicidal candidates, and the introduction of acyl groups could be utilized to create chemical probes for target-identification experiments.