2-Aminoselenazoles and 2-aminothiazoles: One-pot synthesis and control of the fungus Colletotrichum lindemuthianum in common beans

BACKGROUND Anthracnose, caused by the fungus Colletotrichum lindemuthianum, increases losses in the production of common beans. As 1,3-diazoles can act against fungi by inhibiting the enzyme squalene epoxidase (SE), 2-aminoselenazoles and 2-aminothiazoles were synthesized and subjected to tests with the fungus. In addition, the interactions of the most promising substances with the enzyme SE were investigated in silico. RESULTS Seventeen compounds (eight new) were prepared by a one-pot methodology. In vitro antifungal activities of these compounds against C. lindemuthianum were determined by the minimum inhibitory concentration (MIC) method. Most treatments differed from the control (water), and six azoles with the lowest MIC values underwent an assay employing common bean plants inoculated with the fungus. Among the best results were those from 2-(3-fluorophenyl)amino-4-phenyl-1,3-thiazole (16; 2857 mu g mL(-1)), which reduced the severity of anthracnose in common beans to values statistically comparable to the commercial fungicide thiophanate-methyl (700 mu g mL(-1)). The in silico affinity of compound 16 for SE was statistically equal to those calculated for several inhibitors of this enzyme. CONCLUSIONS The results suggested that 2-(3-fluorophenyl)amino-4-phenyl-1,3-thiazole (16) could be considered a potential fungicidal lead compound for further structural optimization, which according to the in silico study acts via SE inhibition.