Synthesis and fungicidal activity of phenanthridinotriazines: A structure–activity relationship study

摘要

AbstractA series of analogous tetracyclic 1, 12b‐dihydro‐4H‐1,2,4‐triazino4,3‐f phenanthridines and 4H,12bH‐1,2,5‐oxadiazino5,6‐fphenanthridines was prepared and tested for control of Erysiphe graminis f. sp. tritici (the causal agent of powdery mildew in wheat). Several analogs showed exceptional activity at doses as low as 6.25 mg litre−1with substituted analogsVII, X, andXIVbeing the most potent. Singly substituted tetrahydrotriazinyl or oxadiazenyl rings with lipophilic aromatic components appeared to be the key requirements for optimal powdery mildew control. Substitution of the heterocyclic ring with multiple groups at