Synthesis And Insecticidal Activity Of A Novel Class Of Chiral Ester Derivatives

The research and development of chiral pyrethroids is an important and difficult area in modern pyrethroids.Chiral pesticides is in its infancy in China,due to the lack of chiral pesticides which process the independent intellectual property rights,chiral pyrethroids and its related intermediates are mainly imported,however,construction of the chiral intermediates is the key step to solve the problem of the synthesis of chiral pyrethroids.On the other hand,in recent years,essential oils have attracted much attention in many areas especially in plant protection area owning to their excellent biological activity,but these compounds are unstable to light and heat,moreover,they are difficult to extract,slow to become effective,short-lived after application,easy to decompose,etc.Currently,the crude extracts of plants have been mainly used in its mixture with chemical pesticides at home and abroad,but chemical modification and structural transformation of the active ingredients of essential oils are rare in the literatures.In view of the above,in order to develop natural plant source green pesticide with a higher activity,we introduced the active essential oil molecules into the pyrethroid backbone to improve their stability and bioavailability.The contents are as follows:1.45 unreported essential oils oriented chiral ester derivatives have been designed and synthesized by splicing the 7 essential oil molecules such as thymol,carvacrol,eugenol with the chiral carboxylic acid intermediate which were obtained by camphor sultam introduced asymmetric conjugate addition.The chemical structures of these compounds were characterized by 1H NMR?ESI-MS?13C NMR,etc.Insecticidal activity test against Plutella xylostella shows that 22 target compounds' activity have been significantly improved in comparing with the essential oil molecules,wherein,the compound IV-A1-R,IV-A1-S,IV-A2-R,IV-A2-S,IV-A3-R,IV-B1-S,IV-B2-S shows a higher level of activity in contrast to the commercialized specie--D-trans-Phenothrin at the concentration of 3.7 ppm,and this activity level is comparable with that of the Esfenvalerate control;moreover,insecticidal activity between enantiomeric compounds also show some differences,especially when the substituent in the chiral center is a large steric hindrance group,the activity of the S configuration compounds are superior to that of the R configuration enantiomers(the IV-B1?IV-B4 serie).2.23 unreported tetrafluorobenzyl alcohol oriented chiral ester derivatives have been synthesized by esterifying the chiral carboxylic acid intermediate with the tetrafluorobenzyl alcohol.The insecticidal activity indicates that some of the target compounds show comparable activity with Esfenvalerate.In addition,the enantiomeric isomers with an R configuration are superior to the activity of the corresponding compound of the S configuration.