DE1273253B - Low-toxic pest repellants - Google Patents

Description

Low-toxicity pesticides The invention relates to new low-toxicity pesticides which, as active ingredients, are compounds of the formula contain. in which R ', R ", R"' hydrogen, halogen or a lower alkyl radical, Rl to R6 optionally substituted alkyl, cycloalkyl, aralkyl, aryl or heterocyclic radicals, where R 1 to R6 can be identical or different, and X represents a sulfur or oxygen atom, are suitable as active ingredients for pesticides. With a good insecticidal effect and plant tolerance, they have an extremely low toxicity towards warm-blooded animals. For example, while the toxicity of most known and already commercially available thio- or dithiophosphoric acid esters is between 2.3 and 500 mg / kg perorally, the thio- or dithiophosphoric acid esters produced by the process according to the invention still show an oral application of 5 (X) O to 1 () () () O mSkg rat no symptoms whatsoever In this formula, R ', R ", R"' denote hydrogen, halogen or a lower alkyl radical, R1 to R6 optionally substituted alkyl, cycloalkyl, aralkyl -, aryl or heterocyclic radicals, where R1 to R6 can be identical or different. X has the meaning S or 0.

It has been found that the compounds of the formula The new compounds according to the invention can be prepared by adding 1 mol of a 1,3,5-tris-acryloyl-hexahydro-s-triazine of the formula which is easily accessible from acrylonitrile or substituted acrylonitrile and formaldehyde in which R 'R ", R"' denote hydrogen, halogen or a lower alkyl radical, on 3 mol of identical or different thiol or thionothiol phosphoric acid esters which form the group or have accumulated. The addition of 1,3,5-tris-acryloyl-hexahydro-s-triazines to phosphoric acid esters of the above general constitution already takes place at room temperature with a positive exotherm. The reaction is preferably carried out at a temperature in the range from 20 to 150 ° C. and in the presence of inert solvents or diluents such as chloroform, dimethylformamide, benzene, acetonitrile, acetone, methyl ethyl ketone Amines such as triethylamine, etc. In addition, a polymerization retarder such as hydroquinone can also be used to prevent polymerization of the 1,3,5-trisacryloyl-hexahydro-s-triazines.

The esters are obtained in very good form by the process described Yields and high purity as partially light yellow and practically odorless Ule, partly also as colorless crystalline substances.

The active compounds according to the invention are used in pesticides customary formulations, for example as dusts, sprinklers or sprays, if appropriate also used in combination with other active ingredients.

example 1 47.4 g (0.3 mol) of dithiophosphoric acid O, O-dimethyl ester are stirred at 25 ° C. Hunter to give a solution of 24.9 g (O, r mol) of 1,3,5-tris-acryloyl-hexahydro-s Triazine, 0.2 g of hydroquinone and 0.3 ml of triethylamine are added dropwise to 200 ml of chloroform, the temperature rising to about 60 ° C. The mixture is left to stir at 600 ° C. for a further 2 hours and, after cooling, is washed with 100% sodium carbonate solution and Water, dried with sodium sulfate, filtered and distilled to a residue in vacuo, giving 65 g (91% of theory) of the new ester as pale yellow, viscous oil.

Example 2 24.9 g (0.1 mol) of 1,3,5-tris-acryloyl-hexahydros-triazine are dissolved in 150 ml of chloroform. 55.8 g (0.3 mol) of dithiophosphoric acid O, O-diethyl ester are added at 20 "C. with stirring, the temperature rising to about 55" C. The mixture is stirred for a further 3 hours at 50 ° C. and the solvent is distilled off in vacuo. The oily residue is washed with 100/0 sodium carbonate solution and water, a thick crystal paste being formed. 68.5 g (85.5 g) are recrystallized from ethanol % of theory) colorless crystals are obtained. M.p. 58 "C. Example 3 To a solution of 24.9 g (0.1 mol) of 1,3,5-trisacryloyl-hexahydro-s-triazine, 0.1 g of hydroquinone and 0.3 ml of triethylamine in 200 ml of chloroform, with stirring at 20 "C. , 2 g (0.3 mol) of dithiophosphoric acid O, O-diisopropyl ester are added dropwise. The mixture is heated to 70 ° C. for a further hour and worked up as in Example 1. 82 g (92% of theory) of the new ester are obtained in the form of a light yellow oil. Example 4 24.9 g (0.1 mol) of 1,3,5-tris-acryloyl-hexahydros-triazine are dissolved in 150 ml of chloroform. For this purpose 51 g (0.3 mol) of O, O-diethyl-thiolphosphorus are added. acid ester was added dropwise at 25 "C. The temperature rises to 50" C. The mixture is heated to 60 to 70 ° C. for a further 3 hours and worked up in the customary manner. 47 g (63% of theory) of the new ester are obtained as a yellow oil.

Example 5 14.5 g (0.05 mol) 1,3,5-tris- (a-methyl-acryloyl) -hexahydro-s-triazine are suspended in 70 ml of acetone. At 20 ° C., 23.7 g (0.15 mol) of dithiophosphoric acid O, O-dimethyl ester are added with stirring.

After a short time, with a temperature rise of up to about 35 ° C., the product becomes clear Solution one. The mixture is stirred for 4 hours at 50 to 60 ° C. and the process is carried out in the customary manner on. 27 g of the new ester are obtained as a light yellow viscous U1. Yield: 71% of theory.

Example 6 The insecticidal testing of some selected compounds took place on flies (Musca domestica) and on grain beetles (Sitophilus granarius) in acetone solution (details of the amount of active ingredient in sg / cm2), on rice flour beetle larvae (Tribolium confusum) as an active ingredient in wheat flour (indication of the percentage of active ingredient in the flour).

The efficiency was on grain weevils and flies after 18 hours, detected on rice flour beetle larvae after 1 day of exposure.

The following table provides information on the biological effectiveness of some products obtained according to the invention. Amount of active ingredient Connection application after against (in Fg / cm2 grad or ° / °) (in0 / 0) Example 1 M. domestica 12.5 100 T. confusum 0.2 100 Example 5 M. domestica 12.5 100 T. confusum 0.5 100 Example 4 M. domestica 12.5 100 S. granarius 130 90 T. confusum 0.5 100

Claims (1)

Claim: Low-toxicity pesticides, characterized in that they are compounds of the formula as active ingredient in which R ', R ", R"' are hydrogen, halogen or a lower alkyl radical, Rl to R «s are optionally substituted alkyl, cycloalkyl, aralkyl, aryl or heterocyclic radicals and X is sulfur or oxygen, the compounds may be symmetrical or asymmetrical.