To develop novel sulfonylurea herbicides, a series of chlorsulfuron derivatives was designed and synthesized through introducing tetrahydrophthalimide substructure taken from protoporphyrinogen IX oxidase（PPO） inhibitors onto the critical 5-position of the classical benzene ring. The structures of title compounds were confirmed by infrared spectroscopy, ultraviolet spectroscopy, 1H and 13C NMR spectrometry, mass spectrometry and elemental analysis. In addition, the crystal structure of compound I1-5 was further determined by X-ray diffraction analysis. Bioassay results showed that individual compounds exhibited good herbicidal activities, especially compound I1-8, which displayed 100% inhibition rate against Echinochloa crusgalli at 150 g/ha（1 ha=104 m2） with the method of foliage spray in the pot experiment.
Sulfonylurea（SU） has become one class of the most important herbicides worldwide due to their ultralow application rate and mammalian toxicity. Recently application licenses of 3 classical SU herbicides chlorsulfuron, metsulfuron-methyl and ethametsulfuron were suspended due to their undesirable long persistence which is incompatible with the particular rotation planting system in China. Our previous study has discovered that electron-donating groups, especially dimethylamino and diethylamino substituents, on the 5 th position of the benzene ring in chlorsulfuron, greatly accelerated its degradation rate in an acidic soil（p H 5.41）. Owing to the natural slower degradation of SUs in alkaline soil,dimethylamino and diethylamino substituted chlorsulfuron Ia and Ib were further studied in an alkaline soil（p H 8.46） with chlorsulfuron as a control. The experimental data indicated that the half-life of degradation（DT50） of Ia was 3.36 days while Ib was 6.25 days which amounted to 30 and 15 folds faster than chlorsulfuron（DT5084.53 days）, respectively. The research confirmed that our newly-designed structures Ia and Ib can hasten their degradation rate in alkaline soil as well as in acidic soil. This structural modification of the classical SU provided an opportunity to control the degradation rate to reduce their impact on relevant environment and ecology.
Shaa ZhouXuewen HuaWei WeiMinggui ChenYucheng GuSha ZhouHaibin SongZhengming Li
Sulfonylureas（SUs） are potent and selective inhibitors of acetohydroxyacid synthase and has been used as herbicides. Some SUs also displayed other biological activities. In order to discuss the antifungal activity of SUs, a series of novel SUs containing aryl-substituted pyrimidine moieties was designed and synthesized. The preliminary bioassay showed that the title compounds exhibited moderate to favorable fungicidal activities in vivo. Especially, compound 9b exhibited more efficacy than the controls against five fungi at 25 mg/L. These promising results indicate that an aryl group on pyrimidine ring is favorable for antifungal activity and SUs are potential inhibitors for some phytopathogenic fungi.
Since sulfonylurea is one of the most potent acetohydroxyacid synthase（AHAS） inhibitors, a series of novel sulfonylureas containing an oxime ether moiety was designed and synthesized and their chemical structures were determined by means of 1H nuclear magnetic resonance（NMR）, 13C NMR and high-resolution mass spectrometry（HRMS）. In the herbicidal bioassay, several compounds showed moderate to good herbicidal activities against dicotyledons, but their activities against monocotyledons decreased. The in vitro antifungal activity was tested at a dosage of 50 mg/L. And the results show that compounds 71, 7m and 7n exhibit promising antifungal activities against six common plant pathogenic fungi. Further investigations on molecular modification are in progress.
