Oxidation of 2-Cyanothioacrylamides with Sodium Nitrite in Acidic Medium

Abstract

(E)-3-Aryl-2-cyanoprop-2-entioamides, prepared by Knoevenagel condensation between aromatic aldehydes and cyanothioacetamide, react with sodium nitrite in acetic acid to form (2E,2′E)-2,2′-(1,2,4-thiadiazole-3,5-diyl)bis[3-arylacrylonitriles]. A possible mechanism and limitations of the reaction are discussed. Molecular docking was carried out in order to search for possible protein targets for the obtained 1,2,4-thiadiazoles. One of the compounds showed a pronounced antidote effect against the herbicide 2,4-D in a laboratory experiment on sunflower seedlings and under field conditions.