DE1178425B - Process for the preparation of O-alkyl-O-cyclohexyl-S-alkylthiolphosphoric acid esters - Google Patents

Description

Process for the production of O-alkyl-O-cyclohexyl4-alkylthiolphosphoric acid esters Addition to the application: F 35839 IV b / 12 ob Auslegeschrift 1172667 The subject of the main patent application F 35839 IVb / l2 0 (German Auslegeschrift 1172667) is a process for the production of O, O- Dialkyl-S-alkylthiol phosphoric acid esters, which is characterized in that unsymmetrical O, O-dialkyl phosphites of the general formula in which R is a branched alkyl radical, while R1 is a straight-chain alkyl radical, converted with sulfur and alkalis, preferably ammonia, into the corresponding O, O-dialkylthiophosphoric acid salts and these then with alkyl or aryl mercaptoalkyl, N-alkyl or N, N-dialkylaminoalkyl, cyanoalkyl, alkoxycarbonylalkyl, alkylmercaptocarbonylalkyl, N-alkyl or N, N-dialkylaminocarbonylalkyl or aralkyl halides or the corresponding tosylates.

According to the process claimed in the main patent application, compounds of the general composition are obtained obtain.

In the latter formula, R and R1 have the same meaning as above, while R2 is an alkyl or aryl mercaptoalkyl, N-alkyl or N, N-dialkylaminoalkyl, Cyanoalkyl, alkoxycarbonylalkyl, alkylmercaptocarbonylalkyl, N-alkyl or. N, N-dialkylaminocarbonyl or represents an aralkyl radical.

The invention relates to a process for the preparation of O-alkyl-O-cyclohexyl-S-alkylthiol phosphoric acid esters of the general formula where R 'stands for a cyano, ethyl mercapto or N-methylaminocarbonyl group and the index n has the value 1 or 2.

In the course of further processing of the subject matter of the main patent application, it was found that O-methyl-O-cyclohexylphosphite is also amenable to the aforementioned reaction with sulfur and alkalis, preferably ammonia, and that the O-methyl-O-cyclohexylthiophosphoric acid salts of the constitution formed as intermediates with cyanoalkyl, ethylmercaptoalkyl or N-methylaminocarbonylalkyl halides of the general formula Hal - (CH2) n - or. the corresponding tosylates can be alkylated.

In the latter formula, the symbols R 'and n have the above meaning, while Me stands for an alkali metal ion or the ammonium group and Hal stands for a halogen atom represents.

The process according to the invention is preferably carried out in the presence of inert ones organic solvent and at a moderately elevated temperature (40 to 80 ° C) carried out. The solvents used are in particular special low molecular weight aliphatic Alcohols or nitriles, e.g. B. methanol and acetonitrile in question.

It has also been found to be useful to add the reaction mixture after the initial components have been combined in order to complete the implementation some time (1 to 2 hours) while heating to the specified temperatures to stir. The process products are then obtained in particularly good yields as well as in excellent purity.

The O-alkyl-O-cyclohexyl-S-alkylthiol phosphoric acid esters obtainable according to the process usually occur in the form of colorless to pale yellow viscous ulcers, which are Allow to distill under greatly reduced pressure without decomposition.

How to draw the compounds described in the main patent application the products which can be prepared according to the present invention are also excellent insecticidal properties; they are therefore used as pesticides, mainly used in crop protection and in the hygiene sector.

Compared to the thiophosphoric acid esters known from German Auslegeschrift 1012112 of analogous constitution and the same direction of action, the compounds obtainable according to the process prove to be clearly superior. This surprising, technically valuable superiority of the process products can be seen from the results of comparative experiments compiled in the following table: Insecticidal effectiveness - Compound (constitution) active ingredient killing of Use against concentration pests %% O HOLES w ll / caterpillars 0.01 100 HO-P H> cOp flies 0.1 100 Mosquito larvae 0.0001 50 S CH2 - CH2 - CH2-C112-SC2H5 (according to the procedure, example 2) O OC 11 / caterpillars 0.004 100 HO-P H> = OP flies 0.02 80 Mosquito larvae 0.0001 50 5- CH2 - SC2 grain weevils 0.01 100 (according to the procedure, example 4) o OC2Hs 11 / caterpillars 0.1 30 HO-P H to OP flies 0.1 0 Mosquito larvae 0.001 50 5- CH - CH2 - SC2H grain beetles 0.1 75 (known from German exposition 1 012 112, Example 3) From the above test results it can be seen that when used against the different insect species, at least the amount of active ingredient one to two powers of ten higher is required for the analogously constructed comparative preparation when used against the different insect species higher active ingredient concentration only achieves a fraction of the effectiveness of the process products.

The following examples provide an overview of what is claimed Procedure.

example 1 a) 178 g (1 mol) of O-methyl-O-cyclohexyl phosphite (boiling point 7 mm / 124 ° C.) are dissolved in 200 cc of methanol. 32 g of sulfur are added to this solution with stirring and anhydrous ammonia is then passed in at 40 to 45 ° C. until the solid components have dissolved. The solvent is then distilled off in vacuo. 150 g (660/0 of theory) O-methyl-O-cyclohexylthiophosphoric acid ammonium. b) 38 g of α-chloroacetonitrile are added to a solution of 114 g (0.5 mol) of O-methyl-O-cyclohexylthiophosphoric acid ammonium in 250 cc of acetonitrile with stirring at 65 to 70 ° C., and the mixture is then heated for a further 1 hour 80 "C and pour the reaction mixture into 300 ccm of ice water. The excreted DI is taken up in 200 cc of benzene, the benzene solution is washed with water and then dried over sodium sulfate. In the subsequent fractional distillation, 70 g (56% of theory) of O-methylo-cyclohexyl-5-cyanomethylthiolphosphoric acid ester with a boiling point of 0.01 mm / 104 ° C. are obtained.

Example 2 114 g (0.5 mol) of O-methyl-O-cyclohexylthiophosphoric acid ammonium are dissolved in 250 cc of acetonitrile, 63 g of 2-ethylmereaptoethyl chloride are added to this solution with stirring at 80 ° C., and the mixture is then stirred for a further hour at the stated temperature and then works it up as described in Example 1, b), 115 g (770/0 of theory) of O-methyl-O-cyclohexyl-S- (2-ethylmercapto-ethyl) -thiolphosphoric acid ester of boiling point 0 are thus obtained .01 mm 112 "C obtained.

Example 3 114 g (0.5 mol) of O-methyl-O-cyclohexylthiophosphoric acid ammonium are dissolved in 250 cc of acetonitrile. 67 g of 2-chloropropionitrile are added to this solution with stirring at 80 ° C., the reaction mixture is then stirred for a further 2 hours at the stated temperature, then worked up in the manner described in Example 1, b) and obtained 56 g (430/0 theory) O-methyl-O-cyclohexyl-S- (2-cyanoethyl) -thiolphosphoric acid ester with a boiling point of 0.01 mm / 108 ° C.

Example 4 A solution of 114 g (0.5 mol) of O-methyl-O-cyclohexylthiophosphoric acid ammonium in 250 cc of acetonitrile is mixed with 56 g of ethyl mercaptomethyl chloride at 50 to 60 ° C. while stirring.

The mixture is then heated to 60 ° C. for a further hour and worked them then, as in Example 1, b) described on. It will be 74g (520 / o of theory) O-methyl-O-cyclohexyl-S- (ethylmercaptomethyl) -thiolphosphoric acid ester with a boiling point of 0.01 mm / 106 ° C.

Example 5 In a manner analogous to that described in the preceding examples, 114 g (0.5 mol) of O-methyl-O-cyclohexylthiophosphoric acid ammonium is converted into O-methyl-O-cyclohexylthiolphosphoric acid-S- ( N-methyl-carbaminylmethyl) ester was obtained as a pale yellow, viscous 51 soluble in plenty of water. The yield is 97 g (590/0 of theory).

Analysis for a molecular weight of 281: Calculated. . N 4.90 / 0, S 11.4%, P 11.0%; found ... N4.9%, S11.50 / 0, P 11.2%.

The compound has a moderate toxicity in the rat per os (DL50) of 50 mg per kilogram of animal.

Claims (1)

Claim: Modification of the process for the preparation of O, O-di-alkyl-S-alkylthiolphosphoric acid esters according to patent application F 35839 IVb / l2 o (German Auslegeschrift 1 172 667), characterized in that, instead of O, O-dialkyl phosphites, O -Methyl-O-cyclohexylphosphite in a manner known per se with sulfur and alkalis, preferably ammonia, is reacted and the resulting O-methyl-O-cyclohexylthiophosphoric acid salts are then converted into the O- Methyl-O-cyclohexyl-S-alkylthiol phosphoric acid ester of the formula converted, in which n has the value 1 or 2 and R 'stands for a cyano, ethyl mercapto or N-methylaminocarbonyl group.