Study On The Synthetic Process Of Tebufenpyrad And Tolfenpyrad

Pyrazoleamide insecticide and acaricide is a sort of fungicide with low toxicity, high efficiency and broad spectrum, and has no cross resistance with other insecticide and acaricide that has been marketed in our country. And it degradates rapidly in plant, soil and water. Pyrazole insecticide and acaricide is a new-type insecticide with market potential because it has the features of protection, cure, eradication, penetrateon and non-mutagenesis. The synthetic methods of N-(4-tert-butylbenzyl)-4-chloro-3-ethyl-l-met hyl-5-pyrazolemethylamide (Tebufenpyrad) and 4-chloro-3-ethyl-l-methyl-N-{[4-(4-meth ylphenoxy)-phenyl]-1-H-pyrazole-5-carboxamide} (Tofenpyrad) were investigated in this paper.Ethyl propionyl pyruvate which was an intermediate of tebufenpyrad was synthesized from diethyl oxalate and 2-butanone by the Claisen reaction. Ethyl 1-methyl-3-ethyl-5-py-razolecarbonylate was synthesized from propionyl pyruvate by the Knorr reaction;The synthesis of ethyl 4-chloro-3-ethyl-l-methyl-5-pyrazolecarbonylate was halogenation by the 4-reaction, hydrolyzed reaction, acylation reaction, and 4-chloro-3-ethyl-1-methyl-5-pyrazolecarbonyl chloride was synthesized; N-(4-tert-butylbenzyl)-4-chloro-3-ethyl-l-met-hyl-5-pyrazolemethylamide was synthesized from 4-chlor-3-ethyl-l-methyl-5-pyrazol-ec carbonyl chloride and 4-tert-butylbenzylamine by the condensation. Based on diethyl oxalate, total yield is 50.9%(Literature 43%).4-chlor-3-ethyl-l-methyl-5-pyrazolecarbonyl chloride which was an intermediate of tebufenpyrad was synthesize from 4-chlor-3-ethyl-l-methyl-5-pyrazolecarbonyl by the acylation reaction,4-chloro-3-ethyl-1-methyl-N-{[4-(4-methylphenoxy)-phenyl]-1 H-pyra-zole-5-carboxamide} was synthesized from 4-chlor-3-ethyl-l-methyl-5-pyrazolecarbonyl chloride and 4-(4-methylphenoxy)benzylamine of sodium borohydride reduction by the condensation. Based on diethyl oxalate, total yield is 31.89%(Literature 30.08%).The chemical structures of Tebufenpyrad and Tofenpyrad had been characterized by 'H-NMR.