Synthesis and Fungicidal Activities of Novel Tertiary Alcohol Ergosterol Biosynthesis Inhibitors Based on Phenazine-1-carboxylic Acid

Abstract

During our previous research using natural product phenazine-1-carboxylic acid as the lead compound to develop new pesticides, the phenazine-1-methanol had been found to exhibit excellent fungicidal activity. According to the above fact, a new class of phenazine-1-aryl(5-pyrimidine)methanol derivatives were designed and synthesized by using phenazine-1methanol as a secondary lead compound, and referring to ergosterol biosynthesis inhibitor fenarimol. The bio-assays showed that compounds 6a～6p displayed moderate fungicidal activities against Thanatephorus cucumeris and Phytophthora capsici. An interesting result is that the fungicidal activities of some of the target compounds against Phenazine-1-carboxylic-Acid (PCA) specific spectrum Thanatephorus cucumeris are greatly reduced, while against fenarimol characteristic spectrum wheat powdery mildew (Erysiphe graminis) retain moderate or strong control effects. The above bio-assays results indicated the mode of action of compounds 6a～6p may be different from that of PCA, but similar to fenarimol. Therefore, further ergosterol biosynthesis inhibition experiment proved that the target compounds had the same mode of action as commercially available fungicide fenarimol.