Synthesis, crystal structure and herbicidal activity of novel 1,2,3-thiadiazole substituted 2-cyanoacrylates

A series of novel 2-cyanoacrylates containing the 1,2,3-thiadiazole ring moiety were synthesized and characterized by H-1 NMR, C-13 NMR, elemental analysis and, in one case, by X-ray crystallography. Most of these cyanoacrylates exhibited good herbicidal activities. In particular, (Z)-methoxyethyl- and (Z)-ethoxyethyl-2-cyano-3-isopropyl-3-(4-methyl-1,2,3-thiadiazol-5-yl) methylaminoacrylate 9h and 9g showed 100% herbicidal activities against rape and amaranth pigweed at a dose of 1.5 kg/ha. 2-Cyanoacrylates containing the thiadiazole ring are a new variation of this class of compound which still retain herbicidal activities.