DE2263429C3 - 0,0-Diethyl-0- (6-fluoro-pyridyl-2) -thiophosphoric acid ester - process for its preparation and compositions containing them - Google Patents

Description

The invention relates to 0,0-diethyl-0- (6-fluoropyridyl-2Hhiophosphorsäureester with the formula

Io

S OCH,

OC ₂ H ₅

Similar compounds are disclosed in U.S. Patent 3,244,586. These compounds are used to control pests such as beetles. Flies, roach and nematodes or roundworms would be root-branch nematodes.

It has now been found that the compound O, O - diethyl - O - (6 - fluoropyridyl - 2) - thiophosphoric acid ester has an exceptionally high activity for the control of terrestrial nematodes. It has shown, that this activity towards comparable, known compounds containing other halogen atoms in the 6-position, containing halogen atoms, is superior. It has also been found that the inventive Compound is less phytotoxic and usable at much lower concentrations than that Prior art connections. The compound of the present invention also has an excellent one Residual activity. This activity allows the compound of the invention to be used in Cases where the prior art compounds cannot be used.

The compound of the invention is somewhat soluble in many common organic solvents and has very poor solubility in water.

The compound of the invention can be prepared by several methods. According to a preferred Method, the connection is made by using O.O-diethylthiophosphoric acid chloride 6-fluoro-2-hydroxypyridine is implemented in a manner known per se.

The reaction is conventionally carried out in the presence of an acid binder such as sodium, potassium, Calcium or lithium carbonate, and an inert organic liquid such as dimethylformamide. Carbon tetrachloride, chloroform, benzene, toluene, isobutyl methyl ketone or methylene dichloride carried out. Although the amounts of raw materials used are not critical, for best results it is preferred, essentially Equimolar amounts of the hydroxypyridine and thiophosphuric acid chloride starting materials to use. The reaction proceeds smoothly at atmospheric pressure and at temperatures in the range from O to KK) C with formation of the desired product and with formation of a chloride by-product. In carrying out the reaction, the reactants are mixed and brought into contact with each other in the usual way. The resulting mixture is over maintained in the range of the reaction temperature for a reaction period to complete the reaction. After the completion of the reaction, the reaction mixture is washed with water and organic The reaction medium is removed by fractional distillation under reduced pressure, where-

is obtained with the desired product as a residue will. This product can be further purified by conventional means, for example by washing with water and dilute aqueous alkali metal hydroxide, solvent extraction and recrystallization.

Using the preferred conditions, reaction times of from 1 to 10 hours are practical Completion of the reaction is sufficient. The 6-fluoro-2-hydroxypyridine used as the starting material can be obtained by diazotizing 6-fluoro-2-aminopyridine in dilute sulfuric acid. Alternatively, this connection can also be made by adding 2,6-difhiorpyridine is refluxed in aqueous sodium hydroxide for about 1 hour.

Agents according to the invention suitable for practical use as nematicids contain the compound according to the invention enuveder alone or in admixture with other pesticides. The means can also include surface-active agents, inert solid or liquid diluents and others contain inert materials, such as those used for the production of wettable powders, suspensions, emulsifiable Concentrations. Dust. Solutions. Granules, pellets or high strength agents are known. In general, very good results are obtained when the compound according to the invention is used in of the earth in amounts of about 0.12 to 1000 ppm. based on the weight of the earth.

When used in the field, the active ingredient can be found in the soil in a dosage of around 0.112 to 22.4 kg, ha and inserted through a cross-section of the earth that in the earth the presence of the We obtain a nematicid concentration of the active ingredient. In such an application, it is advisable to to distribute the active compound to a depth of at least 30 cm below the surface of the earth.

The concentration of the active ingredient in liquid milk. used to obtain the desired dosage is about 0.01 to 50 weight percent. However, a concentration as high as 90 percent by weight can be used. In the case of dusts, the effective amount can be about 1 to 20 percent by weight. In the case of agents which are used as concentrates, the active ingredient can be present in a concentration of about 5 to 95 percent by weight.
The surfactant dispersants are generally used in an amount of 1 to 20 percent by weight based on the total weight of the compound and surfactant in the formulation. Examples of suitable

organic liquid carriers are acetone, xylene, toluene, methylformamide, included. Isopropanol was added to this solution. Polyglycols, chlorinated hydrocarbons, with stirring, 477 g (4.5 mol) of finely divided sodium substances, such as methylene chloride, carbon tetrachloride carbonate. ^{This mixture was cooled to S 0} C on one or chlorobenzene and petroleum distillates, such as a diesel ice bath, and while stirring with fuel, kerosene, fuel oil, naphtha or Stoddard 5848 g (4.5 mol) of OO-diethylthiophosphoric acid-chloro solvent. The petroleum ridges are added to the latter. The mixture was stirred for 4 hours at a temperature distillate which was almost entirely below 2O5 ' ^J C at an atmosphere of 25 to 30 "C. The reactor pressure boiled and the flash point mixture then became a mixture of above 27" C generally preferred. 61 cold water and 11 benzene. The water

The aqueous preparation forms can have a to rige layer, which had a pH value of about 8,

a small amount of a water-immiscible solution was extracted twice with 500 ml parts of benzene,

means included. The benzene layers were with 500 ml of a 2%

Examples of usable dispersing and sodium hydroxide solution washed. Then became

Emulsifiers are condensation products of washing three times with 500 ml portions of water.

Alkylsnoxiden with phenols and other organic 15 The benzene layer was then dried and

Acids, alkylsarylsulfonates, polyoxyethylene derivatives filtered. The benzene was taken by evaporation

removed from sorbitol esters, complex ether alcohols or Maho- a pressure of 3 Torr at 50 ° C. That

gany soaps. remaining crude O, O-diethyl-O- (6-fluoro-2-py-

In the production of dust preparations, ridyl) thiophosphoric acid ester was obtained using an active ingredient in and on finely divided inert solids of 911 g (77% of theory). The substances such as clay, talc, chalk or plaster are dispersed. Purification by distillation resulted in a water-like manner, dust preparations that contain light-colored liquid with a refractive index of the active ingredient on various above-Ni ⁵ = 1.4953 and a boiling point of 66 "C with surface-active dispersants, such as bentonite, 0.5 microns The structure of the product was confirmed by Fuller's earth, attapulgite, or other clays, produced by infrared and nuclear magnetic resonance spectroscopy.

Example analysis:

A solution was made which calculated 508.5 g ... C 40.75, H 4.94, N 5.28%;

(4.5MoI) 6-Flu.:--2-pyridinol, dissolved in 1800 ml of Di- 30 found ... C 40.32, H 4.77, N 5.12%.

Claims (3)

Patent claims: 1. O, O-DUlthyl-O- (6-fluoro-pyridyl-2) -thiophosphoric acid ester. 2. Process for the preparation of 0,0-DiethyI-O - (6 - fluoropyridil - 2) - thiophosphoric acid ester, characterized in that mnn Ο, Ο-diethylthiophosphoric acid chloride in a manner known per se reacted with 6-fluorine-2-pyridine. 3. Nematocidal agent, characterized in that it contains 0,0-diethyI-0- (6-fluoropyridyl-2) -thiophosphoric acid ester contains as an active ingredient and an inert carrier.