Synthesis And Biological Activity Of Cyanoacrylate Compounds Containing Nitrogen And Oxygen Heterocyclic Structures

Cyanoacrylates have always been a research hotspot those days,with a special focus on herbicidal activity.It belongs to the PSII electron transfer inhibitor and is a highly effective and low toxicity herbicide.In order to further filter out the cyanoacrylate compounds with good biological activity,high efficiency,low toxicity and environmentally friendly,2-cyanoacrylate were used as a leading compound to design and synthesize 67 novel cyanoacrylates compounds with isoxazole,oxadiazole or pyrimidine heterocyclic moieties,comprising 32 containing isoxazole moieties,19 containing oxadiazole moieties and 16 containing pyrimidine moieties.All target compounds were confirmed by NMR and elemental analysis.The effects of different reactant ratio,reaction temperature,reaction time and solvent on the yield of some intermediates and target compounds were investigated.The optimum reaction conditions were screened by comparative experiments.The results of preliminary bioassay are shown as followed:1.The herbicidal activity of the cyanoacrylate compound I containing isoxazole heterocycles is not obvious.Only Im(R1 = 3,4-F2,R2 = CH3)showed good activity at 1500 g / ha concentration,can inhibit broadleaf weeds to reach 100%,as good as a control drug.In addition,Ib and Ic have a good inhibitory activity against HepG2 cells,especially compound Ib(IC50 = 3.2?mol/L)is significantly higher than the control drug Sorafenib(IC50 = 16.2 ?mol/L).2.The herbicidal activity of the cyanoacrylate compound II containing isoxazole heterocycles is remarkably improved.At the dose of 1500 g / ha,compounds IIi,IIj,and IIp not only exhibited a 100% inhibition rate for broadleaf weeds(Abutilon theophrasti Medic,Amaranthus retroflexus,Eclipta prostrata)as well as against the control compound NK9717,but also showed more than 50% inhibition rate on the gramineous weeds(Digitaria sanguinalis,Echinochloa crus-galli,Setaria viridis);At the dose of 750 g / ha,the inhibitory rates of compounds IIe and IIm on Abutilon theophrasti Medic and Amaranthus retroflexus were 100%,while the control compound was only 90% and 80%.3.The herbicidal activity of the cyanoacrylate compound III containing the oxadiazole structure was very high.In particular,the inhibitory rate of compound IIId on Amaranthus retroflexus,Eclipta prostrata and Echinochloa crus-galli was 100%,80% and 70%,respectively.And the inhibitory rate of compound IIIj on Abutilon theophrasti Medic,Amaranthus retroflexus was 100% at the dose of 375 g / ha.The compounds of R1 = 4-Cl have better herbicidal activity than the compounds of R1 = 4-F and R1 = 2,4-Cl2.4.The herbicidal activity of the cyanoacrylate compound IV containing the pyrimidine structure was good,and more than 75% of the compound exhibited a significant inhibitory effect on the grass weeds(Digitaria sanguinalis,Echinochloa crus-galli).The compounds IVk,IVl have an inhibitory effect on six weeds.