Synthesis and Herbicidal Evaluation of 3‐N‐Substituted Amino‐6‐benzyloxypyridazine Derivatives

Abstract

A variety of 3‐N‐substituted amino‐6‐benzyloxypyridazine derivatives were designed and synthesized in satisfactory yields. Their structures were confirmed by IR, 1H‐NMR, and elemental analysis; compound 5j was further determined by X‐ray diffraction crystallography. Their herbicidal activities were evaluated through barnyard grass and rape cup tests in laboratory bioassays. Most of the title compounds 5 displayed moderate herbicidal activities against the dicotyledonous plant Brassica campestris L. The most active compounds in the laboratory were also evaluated in the greenhouse.

Morpholine Derivatives in Agrochemical Discovery and Development

“…Most of the patent reports were often accompanied by a pyridazine or pyridazinone group when synthesizing herbicidal agents, in which compounds 34 – 37 − all exhibited significant activity (Figure ). Zhang and his colleagues showed that all of the target compounds, namely, compounds 34a – 34e , demonstrated elevated rates of inhibition for the dicotyledonous plant Brassica campestris than those for the monocotyledonous plant Echinochloa crus-galli. Additionally, they discovered that these compounds exhibited superior selectivity toward dicotyledonous plants, specifically B.…”

“…The prevalence of morpholine structures in herbicides is predominantly documented through patents, whereas academic research publications on the subject are comparatively scarce. Most of the patent reports were often accompanied by a pyridazine or pyridazinone group when synthesizing herbicidal agents, in which compounds 34 – 37 − all exhibited significant activity (Figure ). Zhang and his colleagues showed that all of the target compounds, namely, compounds 34a – 34e , demonstrated elevated rates of inhibition for the dicotyledonous plant Brassica campestris than those for the monocotyledonous plant Echinochloa crus-galli.…”

Pyridazine Chemistry in Crop Protection

“…The anilinopyridazine 17 and the phenoxypyridazine 18 showed both excellent post‐emergent activity against Brassica campestris (field mustard) and Amaranthus retroflexus (redroot pigweed). The same two weeds are fully controlled under pre‐emergence conditions by the 2‐fluoropyridazine 19 . The pyrazole‐substituted pyridazine 20 displayed good efficacy against B. campestris and Echinochloa crus‐galli (barnyard grass) , and the pyrrolidinone‐bearing pyridazine 21 showed strong pre‐ and post‐emergent activity against a variety of different economically important weeds .…”