DE1059918B - Process for the preparation of insecticidally active derivatives of piperonyl alcohol - Google Patents

Description

Process for the preparation of insecticidally active derivatives of piperonyl alcohol It is known that polyethers which are insecticidally active and, in particular, synergistically active on insecticides of the pyrethrum class and which contain a methylenedioxyphenyl ring are obtained if a methylenedioxybenzene is substituted in the nucleus by a haloalkyl radical, and if desired also nucleus-bound aliphatic May contain hydrocarbon residues, reacts with sodium alcoholates of glycol or polyglycol ethers. It is also known that the same polyethers are obtained if one uses sodium salts of oxy compounds of the general formula: in which A represents a hydrogen atom or an alkyl radical and R represents a divalent aliphatic hydrocarbon radical, in particular a methylene group, allows a chloride of glycol or polyglycol ethers to act.

It has now been found that insecticidally active derivatives of piperonyl alcohol of the general formula can be used in which R denotes a methyl group and R1 denotes an alkyl or aryl group or a saturated aliphatic hydrocarbon radical interrupted by ether-like bonded oxygen atoms, or R and R1 together form a chain consisting of three or four CH, groups which is optionally substituted by alkyl or alkoxy radicals obtained when piperonyl alcohol is reacted with cyclic or open-chain vinyl ethers, advantageously in the presence of acidic compounds which accelerate the reaction.

Of the cyclic vinyl ethers that are suitable for the reaction are for example 2,3-dihydrofuran, 2,3 - dihydropyran, 2 - alkoxy -2,3 - dihydrofuran, Called 2-alkoxy-2,3-dihydropyran and 2-alkoxy-4-methyl-2,3-dihydropyran. As an open chain Vinyl ethers are z. B. vinyl ethyl ether, vinyl butyl ether, vinyl phenyl ether, vinyl ethyl glycol ether, Vinyl ethyl diglycol ether, vinyl methyl triglycol ether and vinyl butyl diglycol ether are used.

The reaction takes place at normal or at elevated temperature, z. B. at temperatures between 15 and 120 ° C. Solvents or diluents, e.g. B. ethers such as diethyl ether, tetrahydrofuran, dioxane, hydrocarbons such as butane, Hexane, cyclohexane, benzene or benzene homologues can be present during the reaction be. If necessary, when working in the presence of the diluent, the application increased pressure may be required.

The implementation is z. B. carried out in such a way that one to the Piperonyl alcohol, which is for example crossed from piperonal by a so-called Cannizzaro's reaction can be obtained easily and in good yields, or to solutions of the piperonyl alcohol in one of the solvents mentioned with stirring introduces the vinyl ether in the calculated amount or in a slight excess. Particularly it is advantageous to work in the presence of a substance which accelerates the reaction. If the reaction is carried out without the use of a catalyst, then it is advisable to work at higher temperatures for a faster conversion, z. B. at above 100 ° C. As reaction accelerating, acidic compounds come z. B. inorganic acids such as concentrated hydrochloric acid, sulfuric acid, also Boron trifluoride, boron trifluoride etherate, aluminum chloride, zinc chloride and antimony trichloride into consideration. The catalytically active acidic substances are advantageous only in small amounts Quantities applied. For example, traces of these substances are enough to reduce the Effect implementation. From the reaction mixture, the acetals become more common per se Way won, e.g. B. after neutralizing the catalyst and washing the reaction mixture with water by distillation.

The resulting insecticidally active derivatives of piperonyl alcohol are particularly suitable as an additive to other pesticides all such 3 pyrethrum class, e.g. from pyrethrum and allethrin, to significantly increase their effectiveness.

The parts given in the examples are parts by weight.

EXAMPLE 1 1 part of alcohol saturated with hydrogen chloride, 1000 parts of ether and 400 parts of vinyibutyl diglycol ether are added to 300 parts of piperonyl alcohol, and the mixture is heated to the boil. After the mixture has been refluxed for 15 minutes, the reaction mixture is allowed to cool and washed neutral with soda solution and water. The washed solution is distilled.

After distilling off the ether, 360 parts of les 1- (3 ', 4'-methylenedioxyphenyl) -3-methyl-2,4,7,10-tetra-) xatetradecane are obtained as a colorless liquid from bp S 63 to 560C. .

Example 2 Into the mixture of 200 parts of piperonyl alcohol, 350 parts Ether and 2 parts of boron fluoride ether are stirred into 200 parts of 2,3-dihydrofuran entered, iie mixture is heated and refluxed for 1 hour. Allow to cool and wash the: reaction mixture with soda solution and water up to to neutral reaction. The solvent is distilled off and the residue is fractionated distilled. 70 parts of 2- (3 ', 4'-methylenedioxybenzyloxy) -tetrahydrohan are obtained as a colorless liquid with a boiling point of 2 102 to 104 ° C. Example 3 In the mixture of 200 parts of 2,3-dihydropyran and., 5 parts of 35 ° / jger aqueous hydrochloric acid are used 25 ° C entered 300 parts of piperonyl alcohol with stirring within half an hour. The mixture is heated to 70 ° C. and, with further stirring, a further 1/2 hour. kept at this temperature. The reaction mixture is allowed to cool and is distilled it after having washed it neutral with dilute sodium hydroxide solution and water and using it dried anhydrous sodium sulfate. The distillation gives 380 parts 2 - (3 ', 4'-methylenedioxybenzyloxy) - tetrahydropyran as a colorless oil from Kp.o, p 130 to 136 ° C.

Claims (1)

PATENT CLAIM: Process for the preparation of insecticidally active derivatives of piperonyl alcohol of the general formula in which R is a methyl group and R1 is an alkyl or aryl group or a saturated aliphatic hydrocarbon radical interrupted by ether-like bonded oxygen atoms or R and R1 together form a chain consisting of three or four CH, 7 groups, which is optionally substituted by alkyl or alkoxy radicals, characterized in that piperonyl alcohol is reacted with cyclic or open-chain vinyl ethers, advantageously in the presence of acidic compounds which accelerate the reaction.