Synthesis and herbicidal activity of novel α,α,α‐trifluoro‐m‐tolyl pyridazinone derivatives

Abstract

A series of novel alpha,alpha,alpha-trifluoro-m-tolyl pyridazinone derivatives was synthesised. Herbicidal activities of the two intermediate compounds and 15 pyridazinone derivatives were evaluated through barnyardgrass and rape cup tests and Spirodela polyrrhiza (L.) Schleiden tests. Selected compounds were also evaluated under greenhouse conditions. Bleaching activities were observed at 10 microg ml(-1) and some compounds exhibited herbicidal activities at a rate of 300 g ha(-1). The relationship between crystal structures and herbicidal activities is discussed through a comparison of two compounds (5a and 5f).

Synthesis and herbicidal activities of novel 4-(3-trifluoromethylphenyl)-2H-pyridazin-3-one derivatives

“…In our previous research, we reported that compound 1a showed a better bleaching activity [17], with Chl inhibition of 90% at 10 μg/mL, and this compound quite fitted into the characteristics of an optimized inhibitor of phytoene desaturase which has a 3-trifluoromethyl phenyl ring, a central heterocycle ring, and additional substituents [16]. Therefore, in this research, we modified compound 1a by introducing some groups into the benzyl ring to give compounds 1.…”

“…To a mixture of 80% sodium hydride (1.5 mmol) in 20 mL of dry DMF was added 6-methyl-4-(3-trifluoromethylphenyl)-2H-pyridazin-3-one [17] (1.0 mmol) at 0 °C. After the resulting mixture was stirred for 0.5 h, substituted benzyl chloride (1.0 mmol) was added and the reaction mixture was stirred at 10°C for 1 h. Then it was poured into water (40 mL) and extracted with ether (3 × 20 mL).…”

“…Most of the typical and efficient bleaching compounds possess a central five or six-membered heterocycle carrying one or two substituted benzene rings, and one of the benzene rings mostly links a meta-trifluoromethy group [16]. It is also noticed that Nsubstituted pyridazinone derivatives represent better bleaching activities [17].…”

Synthesis and Herbicidal Activity of 2-Substituted-6-methyl-4-phenyl-3(2H)-pyridazinone

“…对以上化合物我们采用了油菜平皿法和稗草小杯 法进行初步活性测试, 并以文献 [23]中报道的活性最高 的化合物 5b, 5k 做对照, 结果见表 3. Table 1 Selected bond lengths, bond angles and torsional angles for compound 4e …”

“…这些 PDS 抑制剂的结构多样, 但几乎所有化合 物中都有 3-三氟甲基苯基 [9～18] . 在此基础上, 我们设计 合成了一系列哒嗪类化合物 [19～22] , 并发现化合物 5 具有 较好的白化作用和除草效果 [23] . 同时我们又注意到商 品化的 Difunon 和呋草酮(flurtamone)是典型的苯基呋喃 酮类 PDS 抑制剂, 但 Difunon 苯环上并没有 3-三氟甲基 取代基 [11] .…”