DE1148549B - Process for the preparation of thionothiolphosphonic acid esters - Google Patents

Description

Process for the preparation of Thionothiolphosphonsäureestern Aus the German patent 833 807 is already a process for the production of Dithiophosphorsäuretriestern known that in the condensation of one or more O, O-diesters of phosphorodithioic acid with an aliphatic mercaptan and formaldehyde consists.

Furthermore, in the German patent specification 917 668 the production of neutral esters of dithiophosphoric acid by reaction of O, O-dialkyldithiophosphoric acids in the form of their alkali salts or in the presence of acid-binding agents with haloalkyl-alkylthioethers described.

The present invention now relates to a process for the preparation of thionothiolphosphonic acid esters of the general formula in which R stands for a lower alkyl radical having at least 2 carbon atoms and Ri stands for a lower alkyl group, while R2 stands for a lower alkyl, a phenyl or halophenyl radical.

It has been found that compounds of the composition given above are obtained smoothly and with good yields when one alkylthionothiolphosphonic acid O-alkyl ester of the general formula with formaldehyde and aliphatic or aromatic mercaptans of the formula HSR2.

Furthermore, the aforementioned products can also be prepared by reacting alkyl-O-alkylthionothiolphosphonic acid salts of the general formula with chloromethyl alkyl or aryl thioethers of the formula Cl-CH2-S-R2.

In the aforementioned formulas, the radicals R, Ri and R2 have those mentioned above given meaning, while Me stands for an alkali metal.

The process according to the invention is preferably carried out in the presence of inert ones organic solvent carried out. In particular, hydrocarbons are used as such, z. B. benzene, and low-boiling aliphatic nitriles (acetonitrile) in question.

However, it is also possible to carry out the reaction in an aqueous medium.

Furthermore, it has proven to be expedient to use the Allowing the reaction to proceed at a slightly to moderately elevated temperature and moreover to stir the reaction mixture for some time after the starting components have been combined.

The compounds obtained according to the invention are distinguished by an excellent insecticidal activity and in this respect are clearly superior to the products of analogous composition known from German patent specification 1,032,247, as can be seen from the results of comparative experiments summarized in the following table. Biological effect Compound Constitution Application Substance ion destruction of the No new zen quadratioa in ° / o harmful lines m% S OC2HS Miickenlarvae 0.000001 80 1 GaHi-P \ Mosquitoes 0.001 100 S-CH2-S-CH (CHs) a (according to the invention) CO S Miickenlarvae 0.001 0 2 PS-CH2-S-CH (CHs2 / Mosquitoes 0.1 Q C2H50 (known from German patent specification 917 668) Due to their excellent insecticidal properties, the process products are used as crop protection or. Pesticide Use.

The following examples illustrate the claimed process: Example 1 43 g (0.25 mol) of ethylthionophosphono-O-ethyl ester-thiolic acid (boiling point, 21-38 ° C.) are suspended in 50 cc of water. 10 g (0.25 mol) of isopropyl mercaptan are added with stirring. Then 30 g of a 30% aqueous formaldehyde solution are added with further stirring. The temperature rises to 40 ° C. After the reaction has subsided, stirring is continued for a further 2 hours and the reaction product is then added to 200 cc of benzene. The benzene solution is washed through with a 3% aqueous sodium bicarbonate solution. The benzene solution is then dried over sodium sulfate. After the solvent has been distilled off, 22 g of the new ester are obtained as a pale yellow, water-insoluble oil.

Molecular weight 258: Calculated ... S 37.2 "/ o, P 12.0%; found .. S 36, 6 ° / o, P 11.9 ° / o.

Example 2 52 g (0.25 mol) of ethylthionophosphon-O-ethyl ester-thiolate of potassium are dissolved in 100 cc of acetonitrile. Then, with stirring at 60 ° C., 28 g (0.25 mol) of a-chloromethyl thioethyl ether are added. The mixture is allowed to stir for 1 hour at 60 ° C. and then the reaction product is poured into 300 cc of ice water. The solution is then taken up in 200 cc of benzene. The benzene solution is washed with water and dried over sodium sulfate. On fractionation, 47 g of the new ester with a boiling point of 74 ° C. are obtained. Yield: 77% of theory.

Aphids are killed in a concentration of 0.01% 100%.

Example 3 52 g (0.25 mol) of ethylthionophosphon-O-ethyl ester-thiolate of potassium are dissolved in 100 cc of acetonitrile. 49 g (0.25 mol) of α-chloromethyl (4-chlorophenyl) thioether are then added at 60.degree. The mixture is heated to 60 ° C. for a further hour and then worked up in the usual way. 71 g of the new ester are obtained as a yellow, water-insoluble oil. Yield: 87% of theory.

Molecular Weight 327: Calculated ... S 29.4%, P 9.5%; found .. S 29.50 / o, P 9.3%.

DLso rat orally: 10 mg / kg.

Example 4 52 g (0.25 mol) of ethylthionophosphon-O-ethyl ester-thiolate of potassium are dissolved in 100 cc of acetonitrile. 40 g of α-chloromethyl thiophenyl ether (0.25 mol) are added at 60 ° C. with stirring.

The mixture is heated to 60 ° C. for a further hour and then worked in the usual manner on. 67 g of the new ester are obtained as pale yellow, water-insoluble oil. Yield: 92% of theory.

Molecular Weight 292: Calculated ... S 32.8%, P 10.60 / o; found ... p 32.7 ° / o, P 10.3 ° / o.

DLso on the rat orally: 5 mg / kg.

Example 5 43 g of ethylthionophosphon-O-ethyl ester thiolic acid (0.25 mol) are suspended in 50 cc of water.

To this are added 23 g (0.25 mol) sec while stirring.

Butyl mercaptan. Then 30 g of a 30% are added with stirring aqueous formaldehyde solution. The internal temperature rises to 40 ° C.

The mixture is kept at 40 ° C. for a further 2 hours and then worked in the customary manner on. 32 g of the new ester are obtained as pale yellow, water-insoluble oil. Yield: 47% of theory.

Molar weight 272: calculated ... S 35.4 "/ o, P 11.4%; found. S 34, 4 ° / o, P 11, 3 ° / o.

Oral DL5o rat: 100 mg / kg.

Example 6 A solution of 92 g (0.5 mol) of isopropylthionophosphon-O-ethyl ester-thiolic acid (boiling point, 41 ° C.) in 200 cc of benzene is added at 20 ° C. to a sodium ethylate solution which contains 1 mol of dissolved sodium, and then 56 g of α-chloromethyl thioethyl ether are added dropwise at 20 to 25 ° C. with stirring to the reaction mixture, which is stirred for 4 hours at room temperature to complete the reaction and then mixed with 200 cc of benzene.

The benzene solution is washed with water and separated from the aqueous solution Phase off and dry them with sodium sulfate. After distilling off the solvent llg (86% of theory) of isopropylthionophosphonic acid O-ethyl-S-ethylmercaptomethyl ester obtained as water-insoluble, colorless oil with a boiling point of 90 ° C. The mean toxicity the compound (DLso) is 10 mg per os in rats per kilogram of animal. To fly or spider mites become 100 or 95% with 0.001% solutions of the ester killed, while 0.1% solutions have a 100% systemic effect.

Example 7 100 g (0.5 mole) sec. Butyl-thionophosphono-O-ethyl ester-thiolic acid (boiling point o, oi 51 ° C) are dissolved in 200 cc of benzene. A sodium ethylate solution containing 0.5 mol of sodium in dissolved form is added to the resulting solution at 20 ° C. and 56 g of α-chloromethyl thioethyl ether are then added dropwise to the reaction mixture at 20 ° C. while stirring. To complete the reaction, the mixture is stirred for a further 5 hours at room temperature and then 200 cc of benzene are added. The benzene solution is washed with water, then separated from the aqueous phase and dried with sodium sulfate. In the fractional distillation of the solution, after evaporation of the solvent, 116 g (corresponding to 65% of theory) are added sec. Butyl-thionophosphonic acid-O-ethyl-S-ethylmercaptomethyl ester with a boiling point of 94 ° C.

The compound shows a medium toxicity in the rat per os (DLso) of 250 mg per kilogram of animal. The ester acts in a concentration of 0.1% kills 100% on caterpillars, and 0.01% igue solutions kill flies 100%, while the systemic effect 0.1% solutions are also 100% is.

Example 8 97 g of chloromethyl (3-chlorophenyl) thioether are added to a solution of 104 g (0.5 mol) of äthylthionophosphon-O-ethyl-thiolic acid potassium in 300 ccm of acetonitrile with stirring at 50 ° C. The mixture is then heated to 60 ° C. for a further hour and then worked up as described in Example 8. 138 g (840% of theory) of ethylthionothiolphosphonic acid 0-ethyl-S- (3-chlorophenylmercaptomethyl) ester are obtained as colorless oil.

Analysis for a molecular weight of 327: Calculated ... C110, 9%, S 29.4%, P 9.5%; found .. Cl 10.7%, S 29.00 / o, P 8.9%.

Example 9 104 g (0.5 mol) of äthylthionophosphon-O-äthylthiolsaures potassium are dissolved in 300 cc of acetonitrile. 97 g of chloromethyl (2-chlorophenyl) thioether are added to this solution with stirring at 45 ° C., the mixture is stirred for a further 1 hour at 80 ° C. and then worked up as described in Example 8. The yield is 148 g (91% of theory) of ethylthionothiolphosphonic acid S- (2-chlorophenylmercaptomethyl) ester, which is obtained as water-insoluble, colorless oil.

Claims (1)

Claim: Process for the preparation of thionothiolphosphonic acid esters, characterized in that alkylthionothiolphosphonic acid-O-alkyl esters of the general formula with formaldehyde and aliphatic or aromatic mercaptans of the general formula HSR2 or that one alkyl-O-alkylthionothiolphosphonic acid salts of the general formula with chloromethyl alkyl or aryl thioethers of the general formula Cl-CH2-S-R2 to form compounds of the general formula reacted, where in the aforementioned formulas R is a lower alkyl radical having at least 2 carbon atoms, Ri is a lower alkyl radical, while R2 is a lower alkyl, a phenyl or halophenyl radical and Me is an alkali metal. Considered printing steps: German patent specifications No. 833 807, 917 668, 1 032 247.