DE1139119B - Process for the preparation of dithiophosphonic ester amides - Google Patents

Description

Process for the preparation of dithiophosphonic ester amides It has been found that dithiophosphonic ester amides of the general formula be obtained when using thionophosphonic acid amide halides of the formula with phenyl mercaptans of the general formula HSR3.

In the above formulas, R denotes a saturated or unsaturated, aliphatic or a cycloaliphatic or aromatic radical, R1 and R2 are for preferably lower alkyl radicals and can also be used together with the nitrogen atom one optionally further interrupted by oxygen, sulfur or nitrogen form heterocyclic ring; R2 means one optionally through halogen atoms lower alkyl, alkyl mercapto or nitro groups substituted phenyl, while Hal is a halogen atom.

The course of the method according to the invention is explained in more detail using the following equation: The reaction according to the process is preferably carried out in the presence of inert organic solvents. As such, especially low-boiling anhydrous alcohols such. B. methanol or ethanol, but also hydrocarbons such as benzene, into consideration.

To bind the by-product formed during the reaction Hydrogen halide is the presence of acid acceptors, for example alkali hydroxides or alcoholates or tert.

Amines, appropriate in the reaction mixture. Can of course just as well also the salts of the above phenyl mercaptans as starting materials for the procedural implementation find use.

The compounds obtainable according to the invention are distinguished by very good insecticidal effectiveness with low warm-blooded toxicity. she are therefore valuable pesticides, especially in crop protection come into use.

From the German patent specification 814 152 there is already a method for the preparation of esters of thiophosphoric acid known, which is characterized is that the alkali salts of negatively substituted phenols with thiophosphoric acid amide halides implements.

Furthermore, in the German patent specification 1 032 247 the production organic phosphorus compounds by reaction of phosphorus or thiophosphoric acid-O-alkylesteramide halides with alkyl, aralkyl or aryl mercapto-alkyl mercaptans in the presence of acid binders described.

The patent-based feature of the present invention, however, consists in the unforeseeable, superior, technically useful properties of the process products which these compounds of analogous composition have compared to known compounds which can be used for the same purpose. This technical superiority of the dithiophosphonic ester amides according to the invention can be seen from the results of comparative experiments compiled in the following table: Insecticidal effectiveness killing binding constitution application active ingredient d, b pests No against concentration in 01o Ni. against in 01o 0 C2H5P X C1 spider mites 0.1 0 1 C, H, -P -C1 C1 Cl (known from US Pat. No. 2,668,839, Example 2) s 2 N (CH3) 2 spin mites 0.1 100 C2H5P \ 5MMu ½ --- (according to the invention, example 4) 0 3 [1 N (C2H5) 2 N (C2 H5) 2 Cl aphids 0.1 50 / C1 BlattlHuse o, l 50 X n Cl (known from US Pat. No. 2,668,839, Example 1) s t 7N (CH2 4 C, H, -P \ aphids aphids 0.1 100 Sv -a (according to the invention, example 6) 0 11 N (C2H5) 2 5 C2H5P \ fly maggots 0.1 100 0 - NOg (known from US Pat. No. 2,668,840, Example 2) 5 , N (CH3) 2 6 CH3P \ fly maggots 0.01 100 CH2Py5 7-CI S <-Cl (according to the invention, example 1) N (QH5) 2 7th 7 CH3P / cockroaches 0.1 0 No, (known from US Pat. No. 2,668,840, Example 1) Insecticidal effectiveness killing binding constitution application active ingredient of the pests No against concentration, olo in against in 0/0 5, N (CH3) 2 8 CH2Py \ cm3 scraping 0.1 100 (according to the invention, example 2) From the experimental data listed above it can be seen that the compounds obtainable according to the process show a significantly better insecticidal activity compared to the analogously constructed products known from US Pat. Nos. 2,668,839 and 2,668,840. In some cases, the comparative preparations prove to be completely ineffective against the insect pests mentioned, while the products of the process, when used in the same concentration, still kill the pests by 1000%.

The following examples illustrate the claimed process: Example 1 37 g (0.25 mol) of p-chlorophenyl mercaptan are dissolved in 100 cc of anhydrous ethanol. An ethanolic sodium ethyate solution containing 0.25 mol of sodium in dissolved form is added to this solution, the mixture is then heated to 400 ° C. for 20 minutes and then 40 g (0.25 mol) of dimethylaminomethyl thionophosphonic acid chloride (bp 65) are added while stirring vigorously ° C). The reaction mixture is then stirred for a further 1 hour at 40 ° C. and then poured into 200 cc of ice water.

The precipitated oil is taken up in 200 cc of benzene. The benzene layer is separated and dried with sodium sulfate. After the benzene has been distilled off 54 g of the new ester are obtained. Yield 820 / o of theory.

Calculated for Mol 266: N 5.3, C1 13.4, S 24.0, P 11.60 /,; found ... N4.9, Cd 14.0, S24.3, P 10.80 / 0.

Average oral toxicity in rats 250 mg / kg.

Example 2 Under similar conditions, from 31 g of thiocresol and 40 g of dimethylaminomethylthionophosphonic acid chloride, 35 g of dimethylaminomethylthionophosphonic acid -5- (4-methylphenyl) - ester is obtained as a colorless, water-insoluble oil. Yield 570 / o of theory.

Calculated for mole 245: N 5.7, S 26.1, P 12.6%; found ... N 5.0, S26.5, P 11.7 O / o.

Average oral toxicity in rats 500 mg / kg.

Example 3 From 28 g of thiophenol and 40 g of dimethylaminomethyl-thionophosphonic acid chloride, 31 g of dimethylaminomethyl-thionophosphonic acid-S-phenyl ester with a boiling point of 0.01 102 ° C. are obtained. Yield 540 / c of theory.

Average oral toxicity in rats 100 mg / kg.

Example 4 37 g of p-chlorophenyl mercaptan are dissolved in 100 cc of anhydrous alcohol. A sodium ethylate solution containing 0.25 mol of sodium in dissolved form is added with stirring. At 40 "C, 43 g (0.25 mol) of dimethylaminoethyl-thionophosphonic acid chloride (boiling point 72" C) are added dropwise. It is kept at room temperature for a further hour and then worked up in the usual way. This gives 44 g of S- (4-chlorophenyl) dimethylaminoethylthionophosphonic acid ester.

The new ester crystallizes from ligroin in colorless needles, which show a melting point of 74 to 75 "C. Yield 63O / o of theory.

Average toxicity rat orally 500 mg / kg.

Example 5 Under similar conditions, from 31 g of p-thiocresol and 44 g of dimethylaminoethyl-thionophosphonic acid chloride, 40 g of dimethylaminoethyl-thionophosphonic acid - S - (4 - methylphenyl) - ester with a boiling point of 0.01 109 "C. Yield 62% of theory.

Average oral toxicity in rats 1000 mg / kg.

Example 6 From 28 g of thiophenol and 44 g of dimethylaminoethylthionophosphonic acid chloride, 37 g of dimethylaminoethylthionophosphonic acid S-phenyl ester with a boiling point of 0.01-104 "C. Yield 610 /, of theory.

Average oral toxicity in rats 250 mg / kg.

Claims (1)

PATENT CLAIM: Process for the preparation of dithiophosphonic acid ester amides, characterized in that thionophosphonic acid amide halides of the general formula in which R is a saturated or unsaturated aliphatic or a cycloaliphatic or aromatic radical, R1 and R2 are preferably lower alkyl radicals and, together with the nitrogen atom, can also form a heterocyclic ring which is optionally further interrupted by oxygen, sulfur or nitrogen, while Hal is a Halogen atom, with phenyl mercaptans of the general formula HS - R3 in which R3 denotes a phenyl radical optionally substituted by halogen atoms, lower alkyl, alkyl mercapto or nitro groups, to compounds of the general formula converts, where R, R1, R2 and R3 have the meaning given above. Considered publications: German Patent Specifications No. 814 152, 1,032 247; U.S. Patent Nos. 2,668,839, 2,668,240.