The Research In The Synthesis Of Cycloprothrin-A Pesticide Of Pyrithriod Kind

Pyrithriods are a group of insecticides characterized as broad-spectrum, efficient and pro-environmental, which is in accordance with the demand of our society to the development of modem pesticides. Cycloprothrin, as a member of this group, shows priority to other congeneric compounds in the use against paddy pests for its lower toxicity to hydrophily animals. The need of Cycloprothrin in our country is growing rapidly, while there is neither domestic manufacturer nor report about the synthesis of this compound. So researching work in the synthesis of the title compound is of great, significance.This paper, based on summarization of references, has accomplished the design of the synthetic route of Cycloprothrin and improved the reported technics. 4-Hydroxybenzeneacetic was employed as inceptive material, via a six-step reaction including Williamson etherization,esterfication, Claisen condensation, Aldol condensation, carbene addition,and hydrolyzation, an important intermediate compound—2,2-dichloro-1- (4-ethyoxy phenyl) cyclopropanecarboxylic acid was obtained. After another intermediate compound—(RS)-α-Cyano-3-phenoxybenzyl alcohol was made from 3-phenoxybenzaldehyde, the two intermediate compounds were condensed to generate the final product, which was identified by means of ~1H-NMR, MS, IR to be the target compound—Cycloprothrin, with the total yield of about 35% and the purity of 90% or more.In this paper, besides the title compound another seven intermediate compounds were also obtained, including 4-Ethoxyphenylacetic acid, Ethyl-4-ethoxy phenyl acetate, Diethyl-(4-ethoxyphenyl)oxobutanedioic acid, Ethyl-2-(4-ethoxyphenyl)propenoate, Ethyl-2,2-Dichloro-1-(4-ethy-oxyphenyl) cyclopropanecarboxylic acid, 2,2-dichloro-1-(4-ethyoxy phenyl) cyclopropanecarboxylic acid and (RS)-α-Cyano-3-phenoxyben-zyl alcohol. The structure and purity of each of these compounds above were also confirmed.Different synthetic methods were compared in this paper and the reaction conditions were also studied and optimized, which offered a satisfactory result for the synthesis process. A feasible technics to the synthesis of Cycloprothrin was at last established, characterized by low cost, cheap and easily gained materials and convenient operating process.The new technics has. gained a higher yield compared with the reported route and possesses a broad foreground of industrialization.