CH490423A - Process for the production of new phosphoric acid esters - Google Patents

Description

  

  



  Process for the production of new phosphoric acid esters
The present invention relates to the preparation of phosphoric acid esters of the general formula
EMI1.1
 where R1 and R2 are identical or different lower alkyl radicals, X is an oxygen or sulfur atom, R8 is hydrogen, lower alkyl or halogen and R4 is a lower alkoxy radical or alkyl radical or an optionally substituted aryl radical.



   A lower alkoxy radical for R4 is, for example, a methoxy, ethoxy, propoxy, isopropoxy, or butoxy radical, and a lower alkyl radical, for example, a methyl, ethyl, propyl or butyl radical.



   In the aryl radical - which is preferably phenyl, halogen atoms, nitro groups, cyano groups, rodan groups, trifluoromethyl groups and / or alkyl or alkoxy groups can be present as substituents.



  Those compounds of the general formula (I) in which R1, R2 and R3 are as defined above and R4 is a lower alkyl radical or alkoxy radical, preferably the methyl or methoxy radical, have particularly favorable properties.



  Those compounds should also be emphasized in which R5 is methyl and X is oxygen.



  The new phosphoric acid esters of the formula I have a killing effect on various insects such as. B. Orthoptera (cricket, grasshopper, cockroach), coleoptera (grain beetle, bacon beetle, meal beetle), diptera (flies, back), homoptera (aphids), aphaniphtera (fleas), hymenoptera (ants), lepidoptera (Prodenia, Limantria) and various others Insect species. They also have an acaricidal effect.



   According to the invention, the new phosphoric acid esters of the general formula I are prepared by reacting an alkali metal salt of an oxymethylene compound of the formula
EMI1.2
 wherein R3 and R4 have the meaning given above and wherein Me is an alkali metal atom such as. B.



  Sodium or potassium means with a phosphoric acid or thiophosphoric acid ester halide of the formula
EMI1.3
 prepared, in which R1, R2 and X have the meaning given above and Hal is a halogen atom.



   The conversion can be carried out in a solvent, for example in benzene, xylene, dioxane, etc. Many of the esters so produced can be purified by high vacuum distillation.



   Phosphoric acid esters of the formula
EMI2.1
 in which R1, R ", R3 and R4 have the meaning given above, can also be prepared in the customary manner by reaction of a phosphite of the formula
EMI2.2
 in which R1 and R2 have the meaning mentioned and R5 is a lower alkyl radical with an α-halogenated α-formylcarbonyl compound of the formula
EMI2.3
 be prepared, where Hal is halogen, preferably chlorine or bromine, and R3 and R4 correspond to the above definition.



   In the following example, parts are parts by weight and temperatures are given in degrees Celsius.



   example 1
145 parts of the sodium salt of ethyl oxymethylene propionate are slurried in 600 parts by volume of absolute benzene and 165 g of diethyl chlorophosphate are added dropwise over a period of 30 minutes, while stirring and cooling with ice. The reaction is allowed to finish overnight at room temperature. The mixture is then washed successively with 200 parts by volume of water, 2 × 50 parts by volume of saturated sodium bicarbonate solution, the benzene solution is dried over sodium sulfate and the benzene is evaporated off in vacuo. The residue (151 parts) is distilled in a high vacuum. The phosphoric acid ester of the formula is obtained in this way
EMI2.4
 which boils below 0.08 mm at 118-121 OC.



   The following phosphoric acid esters are obtained in the same way
EMI2.5
 
EMI3.1

Example 2
15 parts of a-formylchloroacetic acid ethyl ester are placed in 20 parts by volume of chlorobenzene and heated to the boil. 14 parts of trimethyl phosphite are added dropwise in the course of 5 minutes and the reaction mixture is kept under reflux for a further 1 hour. After this time, 4 parts of methyl chloride have been collected in a cold trap over the reflux condenser. The solution is evaporated in vacuo at a bath temperature of 950 and gives 22.2 parts of an easily mobile oil of the formula as residue
EMI3.2
 from boiling point 0 Kp 0.02 105-110.

 

Claims (1)

PATENT CLAIM Process for the preparation of phosphoric acid esters of the general formula EMI3.3 where R1 and R2 are identical or different lower alkyl radicals, X is an oxygen or sulfur atom, R3 is hydrogen, alkyl or halogen and R4 is a lower alkoxy radical, an alkyl radical or an optionally substituted aryl radical, characterized in that an alkali salt of an oxymethylene compound is used the formula EMI4.1 wherein Me is an alkali metal atom with a phosphoric acid or thiophosphoric acid halide of the formula IV EMI4.2 wherein Hal represents a halogen atom. implements.