Synthesis and Herbicidal Activity of Phenoxypropionic Acid Derivatives with Imidazo(1,2-a)pyridine Moiety.

Phenoxypropionic acid derivatives (Ia-s) with an imidazo[1,2-a]pyridine moiety were synthesized and their herbicidal activities were examined. The activities were affected dramatically by the substituents on the imidazo[1,2-a]pyridine ring, and good substituents to enhance the herbicidal activity were a cyano group at the 3-position and a chlorine atom at the 6-position. Among the compounds, n-propyl 2-[4-(6-chloro-3-cyano-2-imidazo[1,2-a]pyridinvloxy)phenoxy]propionate(Iq) was most active against gramineous weeds and the activity was comparable to that of the commercial herbicide fluazifop-butyl.