Chemical Modifications of 12-Methoxy-<i>N</i>-methylvoachalotine (12-MMV): Enhancing Efficacy against Phytopathogenic Fungi

The development of new fungicides against phytopathogenic fungi is crucial due to the increasing resistance toward traditional agrochemicals and the need for sustainable agricultural practices. This study reports the isolation of 12-methoxy-N-methylvoachalotine (12-MMV) from the bark of Tabernaemontana catharinensis and the synthesis of 17 derivatives. These compounds were tested against three phytopathogenic fungal strains: Fusarium solani, Fusarium graminearum, and Cercospora kikuchii. The derivatives demonstrated varied efficacy, indicating the potential of 12-MMV modifications for the development of new antifungal agents to target agricultural pathogens. Compound 5 emerged as a promising agent due to its activity against all three tested phytopathogenic fungi. Additionally, compounds 7, 9, and 17 showed selective activity against Fusarium strains.