N-Heterocyclic carbene-catalyzed enantioselective(dynamic) kinetic resolutions and desymmetrizations

N-heterocyclic carbene-catalyzed enantioselective kinetic resolutions,dynamic kinetic resolutions,and desymmetrization reactions are systematically reviewed.The content is organized according to the activation modes involved in these transformations.Future advances within this highly active research field are discussed from our perspectives on the topic.

Synthesis, Nematicidal Activity, and 3D-QSAR of Novel 1,3,4-Oxadiazole/ Thiadiazole Thioether Derivatives

Forty one novel 1,3,4-oxadiazole/thiadiazole thioether derivatives containing phenoxy moiety were designed and synthesized. Bioassay demonstrated that some of them showed remarkable activities against Tylenchufus semipenetruns in vitro and in vivo. Compounds 20, 21, 35 and 39 showed excellent lethal activities after treatment for 48 h in vitro, with LC50 values of 13.4±1.8, 11.7±2.5, 13.7±2.4 and 13.31.1 mg.L-1, respectively, which were obviously superior to fosthiazate （49.1±2.8 mg.L-1） and avermectin （26.6±2.3 mg.L-1）. Compound 23. can effectively control the citrus nema- tode disease caused by T. semipenetruns at 200 mg.L-1 in vivo with （68±3）% inhibitory effect, which was even better than that of avermectin （（63±2）%）. The CoMFA and CoMSIA models of three-dimensional quantitative structure-activity relationships （3D-QSARs） were established. The compound 33 was designed based on the 3D-QSAR models with more vigorous nematicidal activities in vitro （LC50：9.8±1.4 mg.L-1） and in vivo （（70±5）%）. These results demonstrated that compound 33 can be considered as a potential nematicide.

Design, Synthesis, and Antiviral Activity of Novel Chalcone Derivatives Containing a Purine Moiety

To find new antiviral agents,novel chalcone derivatives containing a purine moiety were designed and synthesized by combining bioactive substructures.The antiviral activities of the derivatives against tobacco mosaic virus （TMV） and cucumber mosaic virus （CMV） were evaluated.Results showed that most of the derivatives showed antiviral activities.Compounds 3n and 3p exhibited excellent curative,protective and inactivation activities against TMV,with the EC50values of 452.4,416.2,241.2 and 438.7,418.6,261.7 μg·mL-1,respectively,which were better than those of ribavirin （585.8,436.0 and 268.7 μg·mL-1）.Compounds 3n and 3p showed remarkable curative and protective activities against CMV.Compound 3n showed a moderate affinity to TMV coat protein,with binding constant Ka and Kd values of 1.5 × 104 L·mol-1 and 79.8 μmol·L-1,respectively.These findings provided an important structural insight for further designs of highly active chalcone derivatives and a basis for further study on their mechanism of action.