Synthesis and Study of the Antifungal Activity of 1-(2-Cyanophenyl)-3-heterylureas

In the treatment and prevention of fungal infections of plants, along with fungicides, inducers of systemic plant resistance, also called elicitors, have become particularly important in recent years. In this work, a method was developed for the synthesis of new 3,4-dichloroisothiazol-5-yl and 4-methyl-1,2,3-thiadiazol-5-yl ureas 1,2, containing a 2-cyanophenyl substituent, structurally similar to a known synthetic elicitors isotianil and tiadinil. The protective properties of the obtained compounds on cucumber and pepper leaves infected with B. cinerea, as well as their fungicidal properties against B. cinerea, were studied. It has been established that disubstituted ureas 1,2 exhibit very low fungicidal activity against this fungus, about 11%. At the same time, study on plant leaves showed that compound 2 effectively inhibited the development of gray mold on both cucumber and pepper leaves with an inhibition rate of more than 90%, which was similar to tiadinil. Compound 1 was effective only on cucumber leaves (96.50±0.01%). Isotianil in the experiment showed an average degree of protection – 62.48±1.04% on cucumber leaves and 56.50±1.29% on pepper leaves.