GB847244A - Octahalogeno-endomethylene-tetrahydrophthalans and a process for their production - Google Patents

Abstract

The invention comprises 1:3:4:5:6:7:10:10-octahalogeno- 4:7-endomethylene-4:7:8:9-tetra -hydrophthalans of the general formula: <FORM:0847244/IV(b)/1> in which X denotes a halogen atom which is either chlorine or fluorine, at least two and not more than four of the six halogen atoms so denoted being fluorine atoms, and a process for the preparation thereof wherein a 4:5:6:7:10: 10-hexahalogeno-4:7-endomethylene-4:7:8:9-tetrahydrophthalan of the formula : <FORM:0847244/IV(b)/2> wherein X is as defined above is chlorinated to introduce a chlorine atom into each of the 1 and 3 positions. The chlorination may be carried out until the product contains an average of 1,7 to 2,5 chlorine atoms in the tetrahydrofuran ring of the molecule. The products are employed as active ingredients in insecticidal compositions (see Group VI). The chlorination may be carried out by passing chlorine into a boiling solution of the hexahalogeno-phthalan in carbon tetrachloride or other suitable inert solvent or by treatment with other chlorinating agents, e.g., sulphuryl chloride or chlorosuccinimide. The chlorination may also be effected without a solvent, e.g., in the presence of aluminium chloride. The reaction may be carried out at room or elevated temperature and whilst irradiating, e.g. with ultraviolet light and/or in the presence of a catalyst, e.g. ferric chloride, arsenic trichloride or a free-radical forming substance such as benzoyl peroxide or azoisobutyronitrile. The chlorination may be effected batchwise or continuously. Examples are furnished in which are prepared 10:10-difluoro-1:3:4:5:6:7-hexachloro-4:7-endomethylene-4:7:8: 9- tetrahydrophthalan and 4:5:10:10-tetrafluoro-1:3:6:7-tetrachloro 4:7-endomethylene-4:7:8:9- tetrahydrophthalan. Hexahalogeno-endomethylene-tetrahydrophthalans employed as starting materials are obtained by a dione synthesis between 2,5-dihydrofuran and a hexahalogeno-cyclopentadiene in which at least two and not more than four of the six halogen atoms are fluorine and the remainder are chlorine. 10:10-Difluoro-4:5:6:7-tetrachloro -4:7-endomethylene-4:7:8:9-tetrahydrophthalan and 4:5:10:10-tetrafluoro-6:7-dichloro-4:7-endomethylene-4:7:8:9 -tetrahydrophthalan are so prepared. Specification 772,212 is referred to.ALSO:Insecticidal compositions comprise 1:3:4:5:6: 7:10:10-octa-halogen-4:7-endomethylene-4:7:8: 9-tetrahydrophthalans having the general formula: <FORM:0847244/VI/1> in which X denotes a halogen atom which is either chlorine or fluorine, at least two and not more than four of the six halogen atoms so denoted being fluorine atoms (see Group IV(b)) diluted with petroleum ether. Specification 772,212 is referred to.