ABSTRACT
The present work covers novel herbicidal lead structures that contain a 2,3-dihydro[1,3]thiazolo[4,5-b]pyridine scaffold as structural key feature carrying a substituted phenyl side chain. These new compounds show good acyl-ACP thioesterase inhibition in line with strong herbicidal activity against commercially important weeds in broadacre crops, e.g., wheat and corn. The desired substituted 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines were prepared via an optimized BH3-mediated reduction involving tris(pentafluorophenyl)borane as a strong Lewis acid. Remarkably, greenhouse trials showed that some of the target compounds outlined herein display promising control of grass weed species in preemergence application, combined with a dose response window that enables partial selectivity in certain crops.
ABSTRACT
Novel synthetic lead structures interacting with RCAR/(PYR/PYL) receptor proteins were identified based on the results of a high-throughput screening campaign of a large compound library followed by focused SAR studies of the three most promising hit clusters. Whilst indolinylmethyl sulfonamides 8y,z and phenylsulfonyl ethylenediamines 9y,z showed strong affinities for RCAR/ (PYR/PYL) receptor proteins in wheat, thiotriazolyl acetamides 7f,s exhibited promising efficacy against drought stress in vivo (wheat, corn and canola) combined with confirmed target interaction in wheat and arabidopsis thaliana. Remarkably, binding affinities of several representatives of 8 and 9 were on the same level or even better than the essential plant hormone abscisic acid (ABA).
