|
Series of new chiral N-substituted benzotriazol-1-yl derivatives were synthesized and their fungicidal activities in vitro against gray mold(Botrytis cinerea), black spot(Alternaria kikuchiana) and phytophthora blight(Phytophthora capsici) were measured by the agar medium dilution method. The substituents effects between the fungicidal activities (obs. pI_(50)) and a various physicochemical parameters of phenoxy or thiophenoxy group(X) & alkyl or phenyl group(Y) were analyzed by the multiple regression technique. From the analyzed substituent effects, the structure-activity relationship(SAR) equations shows that the antifungal activities depend on the parameters for the optimal molecular hydrophobicity((∑logP)_(opt.)), Van der Waals (∑Vw$gt;0) volume(Å^(-3)) and inductive constant with electron withdrawing group(σ_IY$gt;0). The activity in affected by the inductive effect (σ_IY$gt;σ_RX) of Y-group rather than the X-group. The phenoxy substituents, 1, showed higher antifungal activity than the thiophenoxy substituents, 2. For 1, polar substituent constant(σ^*) was an important factor in determining the activity. And the tribromomethyl substituent, 1g showed the highest activity against the three fungi.
|