Synthesis And Fungicidal Activity Of 4-methyl-5-imidazole Amides

In recent years,the use of pesticides has increased crop yields,it has also resulted negative impact to the environment and the human itself.Taking the fungicide as an example,improper use has led to an increase in the emergence of resistance and make the effect of fungicidal lower.Therefore,it is necessary to make new environmentally friendly,new fungicides with high fungicidal activity.As a long-lasting fungicide structure,amide still plays a important role in agriculture.And the amide structure has excellent stability,the hydrolysis reaction is difficult to occur,and therefore has the advantages of good patent drug stability.The fungicidal mechanism of amide-based pesticides has been confirmed in many studies.It acts in the mitochondria and inhibits the tricarboxylic acid cycle by inhibiting the succinate dehydrogenase(SDH)competition,thereby inhibiting the fungal respirationto fungal death.The succinate dehydrogenase inhibitor(SDHI)has been classified as a new class of pesticide fungicides in the 1990 s according to its mechanism of action.It is gaining more and more people‘s attention due to its good effect and the increasing market share.Throughout the compound structure of the fungicide,a large number of nitrogen-containing compounds have a certain fungicidal activity.Based on the existing literature,two biologically active structures of imidazole and amide have been selected as research targets.With reference to the imidazoles and amide fungicides listed in recent years,a total of 12 kinds have been synthesized through molecular rationalization design and active substructure splicing.1.Cyclization of 2-chloro-acetoacetate and formamide as starting materials gives4-methyl-1H-imidazole-5-carboxylic acid ethyl ester.After hydrolysis,4-methyl-1Himidazole-5-carboxylic acid is obtained.Amidation reaction with substituted aniline and benzylamine gives the desired product 4-methyl-N-phenyl-1H-imidazole-5-carboxamide series and N-benzyl-4-Methyl-1H-Imidazole-5-carboxamide.The structure of the synthesized compound was characterized by FTIR,1H NMR,and 13 C NMR.2.The mycelial growth rate method was used to determine the antifungicidal activity of the target compound against Botrytis cinerea,Rhizoctonia solani and Strawberry anthracnose.The fungicidal biological activity of the composition was compared using chlorothalonil and fluopicolide as control agents.Most of the compounds have certain fungicidal activity against the three tested bacteria.Some of the compounds,such as Ic~Ig,and Ⅱ series Ⅱa and Ⅱd,showed excellent inhibition performance against Sclerotium,which were superior to the commercially available control agents.The experimental results showed that the target compound had certain antifungicide activity against S.sclerotiorum,Botrytis cinerea and Colletotrichum orbiculare,and the fungicidal activity of Compound Ic was significant.It has a high inhibitory effect on Botrytis cinerea;Id have the highest fungicidal activity among the synthesized compounds.It can continue to be studied as a lead compound for amide fungicides.It also has been provided experience for the synthesis of future amide fungicide compounds.According to the calculation of biostatistics,all the 12 target compounds,the half-effect concentration of compound Ib on EC50 was the lowest,up to 0.16 μg /m L,and the chlorothalonil was 8.0 μg /m L under the same conditions.In addition,compound Id,Ie,If,Ih had better effect to S clerotinia.Compound Ⅰa,Ⅰh,Ⅱb,Ⅱc also had a better effect concentration to Colletotrichum orbiculare than the commercial fungicide,among which compound Ⅱc had the best effect,with the better efficacy 2.6 times that of chlorothalonil and 3 times that of flumidamide.