Fate of Fluazinam in Pepper and Soil After Application

To discover the fate of fluazinam after its application in pepper field, an efficient residual analytical method for determining fluazinam in pepper and soil was developed. The samples were extracted by acetone, cleaned up by solid-phase extraction （SPE） florisil cartridge, and determined by gas chromatography with electronic capture detector （ECD）. The recoveries ranged from 80 to 94.6%, with repeatability relative standard deviation ≤9.3% at spiking levels of 0.1-1 mg kg^-1. The residue dynamics of fluazinam in pepper and soil were studied in a field plot. The experiment data showed that the halflives of fluazinam in peppers and soils were 2.5-3.7 days and 1.2-4.2 days, respectively. When the pepper was treated by fluazinam 50% suspension concentrate （SC） at 495 g ha^-1 4 times at 7-day intervals, the fluazinam in pepper on the 7th day after the last application was all below 0.06 mg kg^-1, which was below the maximum residue limit （MRL） fixed in Korea （0.3 mg kg^-1）. It is implied that fluazinam in pepper is nonpersistent. The results suggested that fluazinam 50% SC should be used in a pepper field at most for 4 times, and the pre-harvest interval should be 7 days.

The Enantiomer Separations of Allethrone and Propargyllone Using Two Long Chain Acylated b-Cyclodextrin Derivatives as CGC Capillary Stationary Phases

Using two b-cyclodextrin derivatives (CDs) with long chain of acyl groups as chiral stationary phases (CSPs) of capillary gas chromatography (CGC), the enantiomers of racemic allethrone and propargyllone were well resolved after derived with acetyl chloride. The enantiomer excess values (e.e.%) of 1S-allethrone and 1S-propargyllone were also determined successfully using these CDs.

Synthesis,structural characterization and solubility of 2-(1-substituted-1,11-undecylidene)-5-arylimino-△~3 -1,3,4-thiadiazolines

A series of novel 2-（1-substituted-1,11-undecylidene）-5-arylimino-△^3-1,3,4-thiadiazolines （4） were synthesized and their structure was characterized by ^1H NMR, ^13C NMR and elemental analysis. Their solubility in both polar and non-polar solvents is significantly improved owing to the introduction of ethyl or methylthio group at cyclododecyl ring as compared with parent compounds [1, 2-（1,11-undecylidene）-5-arylimino-△^3-1,3,4-thiadiazolines]. However, their fungicidal activity against Rhizoctonia solani is less than that of parent compounds. X-ray diffraction analysis of a representative compound （4d） showed that the conformation of 12-membered ring is still [3333], in which the ethyl group present at the side-exo position and the thiadiazoline ring at the comer carbon. The thiadiazoline plane is perpendicular to the cyclododecyl one.

Design, Synthesis, and Insecticidal Activity of 1,5-Diphenyl-l-pentanone Analogues

Three series of novel 1,5-diphenyl-l-pentanone derivatives were designed and synthesized. Their structures were characterized by IR, IH NMR techniques, and elemental analysis. The insecticidal activities of the new compounds were preliminarily evaluated. The bioassay results indicated that the compounds Xll--X30 displayed better aphicidal activity against Aphis gossypii than compounds X1--X10 and the lead compound （E）-l,5-diphenyl-1- penten-1-one （A）. The inhibitory rates of compounds X6 and X29 were 100% against Plutella xylostella （L.） at 600 mgoL 1. Compounds X12, X13, X19, X24, X25, X26 and X27 showed higher insecticidal activity against Tetranychus cinnabarinus （Boisduval） at 600 mgoL 1 than the lead compound （A）. Keywords Stellera chamaejasme L, （E）-l,5-diphenyl-l-penten-l-one, analogue, synthesis, design, insecticidal activity

Design and synthesis of chitin synthase inhibitors as potent fungicides

Chitin is a structural component of fungal cell walls but is absent in vertebrates,mammals,and humans.Chitin synthase is thus an attractive molecular target for developing fungicides.Based on the structure of its donor substrate,UDP-N-acetyl-glucosamine,as well as the modelled structure of the bacterial chitin synthase NodC,we designed a novel scaffold which was then further optimized into a series of chitin synthase inhibitors.The most potent inhibitor,compound 13,exhibited high chitin synthase inhibitory activity with an IC（50） value of 64.5 μmol/L All of the inhibitors exhibited antifungal activities against the growth of agriculturally-destructive fungi,Fusarium graminearum,Botrytis cinerea.and Colletotrichum lagenarium.This work presents a new scaffold which can be used for the development of novel fungicides.