Preliminary Study On Synthesis And Insecticidal Activities Of Benzaldehyde Benzenesulfonylhydrazone Derivatives

Acylhydrazone(-CONHN=C-)derivatives display a variety of biological properties such as insecticidal activity,antimicrobial activity,anti-inflammatory activity and antitumor activity,and have a wide range of applications in the fields of medicine and pesticides.The sulfonylhydrazone(-SO2NHN=C-),a special class of acylhydrazones,has a strong coordination ability and various coordination forms.The combination of sulfonylhydrazone with an aromatic group or other conjugated group can improve its biological activities by enhancing its coordination capacity.Here,to find more potent insecticidal compounds,we synthesized a series of benzaldehyde benzenesulfonylhydrazone derivatives as insecticidal agents.The experiment results were obtained as follows:1.By using benzaldehydes(3a-e)and benzenesulfonylhydrazides(2a-e)as starting materials,we synthesized twenty-five benzaldehyde benzenesulfonylhydrazones(4a-y).We then prepared ten phenylacrolein benzenesulfonylhydrazones(9a-j)through a series of Knoevenagel,esterification,reduction,and oxidation reactions.Among them,except compounds 4a,4f,4g,9b,9f and 9g,twenty-nine new compounds were obtained.The structures of the target compounds were identified by melting point,1H NMR or 13C NMR.2.We have discussed the methods for synthesis of intermediates.The trans configuration of C=C of 9a-j were confirmed by analyzing the corresponding coupling constants.3.We investigated insecticidal activities of thirty-five target coumpounds against Mythimna separata Walker,Bursaphelenchus xylophilus and Spodoptera litura,respectively.At the concentration of 1 mg/mL,the antifeedant activity of 4l,4m,4p,4q,4r,4v,4w,9b,9c,9e and 9h,and the final mortality rates of 4b(66.7%),4g(60.0%),4s(60.0%),4t(66.7%),4w(66.7%)and 9i(63.3%)were greater than that of toosendanin.We tested the insecticidal activity against Bursaphelenchus xylophilus,and found 4k(LC50 = 24.3 mg/L),4q(LC50=28.9 mg/L)and 9d(LC50=28.7 mg/L)showed the good insecticidal activity.Against Spodoptera litura at a concentration of 1 mg/mL,compounds 9f and 9j showed the good insecticidal activity with the mortality rates of 100.0%and 93.3%,respectively.4.Compared with benzaldehyde benzenesulfonylhydrazones(4a-j),phenylacrolein benzenesulfonylhydrazones(9a-j)showed better antifeedant activity and insecticidal activity against M.separata and S.litura,respectively;but the insecticidal activities of 9a-j against M.separata and B.xylophilus were not enhanced at all.