Syntheses Of Halogenated Heterocyclic Pesticide Intermediates

In recent years, a new force suddenly rises for heterocyclic compounds, andgradually become the mainstream research and development of new pesticides. In theworld of the new pesticide patents, heterocyclic compounds accounted for90%. It ischanges in the structure of heterocyclic compounds, so that the development potential isvery great by the pesticide companies attention.Benzofurans and indoles are widely used as high activity, broad-spectrum, lowtoxicity and safety pesticides because that have good biological activity, so that havebecome substitutes for traditional pesticides. Therefore, synthesis of the heterocycliccompounds is more attention.This paper mainly studied on the synthesis of benzofurans, benzothiophenes andindoles. The main research contents are as follows:1. Study on a highly efficient cesium carbonate-promoted intramolecular cyclizationof gem-dibromoolefns has been developed for the synthesis of2-bromobenzofurans(thiophenes);2. Study on facile synthesis of2-bromoindoles by cesium carbonate-catalyzedintramolecular cross-coupling of gem-dibromoolefins;3. Study on facile synthesis of2-bromoindoles by composite alkali-catalyzedetherification reaction of gem-dibromoolefins and thiophenols;4. The structures of the compounds were confirmed by high resolution massspectrometry,1H and13C NMR; then to explore the reaction mechanism;5. Optimization of reaction conditions, and resulting the good yields; extendingcompounds, explore the applicability of this method.In short, this paper introduces that a highly efficient cesium carbonate-promotedintramolecular cyclization of gem-dihalovinyls has been developed for the synthesis ofhalogenated benzofurans, halogenated benzothiophenes, halogenated indoles and sulfide compounds that containing benzofuran structure unit. There are25compoundsare new compounds in the synthesis of52compounds. The present method is feasiblethat has advantages of availability of reagents, broad substrate scope, operationalsimplicity, mild reaction conditions, high regioselectivity, excellent yields of theproducts.