Ligand-Controlled Copper-Catalyzed Highly Regioselective Difluoromethylation of Allylic Chlorides/Bromides and Propargyl Bromides

Highly regiodivergent copper-catalyzed allylic/propargylic difluoromethylation reactions by employing different ligands are described. When 5,6-dimethyl-1,10-phenanthroline was used as the ligand, exclusively α-difluoromethylated products were obtained, while γ-selective difluoromethylated products were generated when N-heterocyclic carbene-SIPr was used as the ligand. Likewise, high α- vs. γ-selectivities were achieved in the presence of similar copper catalysts for the reactions of propargyl bromides. Moreover, a copper-catalyzed asymmetric allylic difluoromethylation reaction with moderate to good enantioselectivity by the use of chiral ligands was developed.

Research on controllable alkaline soil degradation of 5-substituted chlorsulfuron

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.

Design, Synthesis, Structure-Activity Relationship and Insecticidal Activities of Trifluoromethyl-Containing Sulfiliminyl and Sulfoximinyl Phthalic Acid Diamide Structure

Due to a novel mode action,low toxicity to mammals and low residue characteristics,phthalic acid diamides have aroused considerable interests in agricultural chemistry.With introduction of N-cyano,N-trifluoroacetyl,N-carbamoylsulfiliminyl and sulfoximinyl substituents into phthalamides,12 novel derivatives containing trifluoromethyl moiety were designed and synthesized.All title compounds were characterized by ^(1)H NMR and high-resolution mass spectrometry.The preliminary results of biological activity assessment indicated that some title compounds exhibited moderate to good insecticidal activities against oriental armyworm(Pseudaletia separata Walker).In particular,Va gave higher activity against oriental armyworm and diamondback moth.The present work reported that the new trifluoromethylated diamides incorporating N-trifluoroacetylsulfoximinyl moieties are potential lead compounds for further structure optimization,providing some insight into the relating structure-activity relationship.

Sorption and desorption of pymetrozine on six Chinese soils

Pymetrozine is a selective insecticide with a unique chemical structure and mode to control hemipteran and homopteran. While pymetrozine has brought great benefits to crop production by killing insects, its residues in soil may have a detrimental effect on environment. Therefore, it is of great importance to investigate its behaviors in soil. In this study, the sorption and desorption of pymetrozine on six Chinese soils were investigated using a batch equilibrium approach to understand its mobile behavior in the soils. Both sorption and desorption isotherms ofpymetrozine were in good agreement with the Freundlich model. The sorption coefficient KF varied between 3.37 and 58.32 mL. g-1 and the sorption isotherms were nonlinear, with 1/n ranging from 0.57 to 0.91. A regression equation was proposed to predict the solption of pymetrozine on six different soil samples： log KF = 4.3708 - 4.5709 × log （pH in 0.01mol·L-1 CaC12） ＋ 0.4700 × log OC% ＋ 0.0057 × sand （%） ＋ 0.0022 × CEC（clay）, with R2 = 0.9982. The organic carbon content of soil positively affected the sorption ofpymetrozine, but soil pH had a negative effect on the sorption. Additionally, effects of CaC12 concentration, soil to solution ratio and pesticide form were investigated. The sorption was promoted with an increase in soil to solution ratio and a decrease in CaC12 concentration. The possible variation of the five formulated products of pymetrozine was also investigated.