DE1179760B - Insecticidal agent - Google Patents

Description

Insecticidal agents Well-known insecticidal agents are dimethyl-1-carbomethoxy-2-methylvinyl-phosphate ("Phosdrin") and the phosphoric acid esters of the general formula wherein the substituents R and Ri are alkyl, aryl or aralkyl radicals. It has also already been proposed that triester of phosdrinic acid of the general formula be used as the insecticidal active ingredient where R 'is a hydrocarbon group and R "is a halogen or hydrogen atom or a hydrocarbon group and Ri, Rs and R3 are the alcohol radicals of ester groups.

It has now surprisingly been found that the triesters of phosphoric acid of the general formula where Ri is a methyl or ethyl group, preferably a methyl group, or benzyl group and the substituent R2 is either a hydrogen atom or a methyl group, R3 is a methyl or ethyl group, preferably a methyl group, and R4 is a phenyl group optionally substituted by a nitro group in the p-position is, have a particular effectiveness as an insecticidal agent and have a better residual activity than comparable known insecticides.

The substituent Ri in the active ingredient according to the invention is preferred a methyl group. Compounds in which the substituents Ri and R2 are methyl groups and the phenyl group R4 is unsubstituted.

The compounds used as insecticidal active ingredients according to the invention can be prepared by processes known per se. For example a number of these compounds by reacting the phenyl-dialkyl-phosphite with win the corresponding Halogenacetoessigsäureester, which in turn again from the corresponding, non-halogenated acetoacetic ester was obtained. The acetoacetic ester itself is produced by known methods, e.g. B. by implementing the appropriate Alcohol with diketene or by reacting this alcohol with another acetoacetic acid ester. The substances used according to the invention can also be used by the known Schrader method produce.

The effectiveness of the active ingredient according to the invention was determined on the basis of various Try also to compare the effectiveness of the practically similarly constructed phosphoric acid esters examined.

Here, an acetone solution of the active ingredient to be investigated is used a pipette in a Petri dish, the solvent could then evaporate. The concentration of the active ingredient in the solution and the amount of solution were adjusted so that that the desired quantity of the active ingredient is achieved per dm2 area of the Petri dish was.

The dish was kept at 26.7 ° C. with 50 ° / 0 atmospheric humidity. Adult Anopheles albimanus (mosquitoes), which lasted 1 hour, served as the test insect have been exposed to the contents of the peel for a long time, at a point in time immediately 1 or 4 days after Introduction of the active ingredient. The percentage of death of the insects was determined 24 hours after their stay in the Petri dishes. There were each examined ten insects in parallel experiments.

The results are shown in Table 1.

Table I. Kill in% link mg / dm2 immediately 1 day 4 days 0.11 100 100 5 2-carbomethoxy-1-methylvinyl-dimethyl-phosphate 0.21 100 85 5 0.54 100 95 0 0.11 100 100 100 2-carbomethoxy-1-methylvinyl-methylphenyl- # 0.21 100 100 100 phosphate 0.54 100 100 100 1 0, 54 100 100 100 Acetone, I. Blank test-0 0 0 In larger test series, the same two compounds are compared after spraying a 25% emulsion on wood fiber boards. The toxicity values of these substances are determined at weekly intervals using the Anopheles albimanus (mosquitoes) as the test insect.

Table 2 Kill in% Connection Connection 1. 2. 3. 4. week 2.69 100 90 20 25 2-carbomethoxy-1-methylvinyl-dimethyl-phosphate # 2.538 100 100 65 55 2.69 100 100 100 100 2-carbomethoxy-1-methylvinyl-methylphenyl- # phosphate 5.38 100 100 100 100 The insecticidal effectiveness of 2-carboethoxy-1-methylvinyl-ethyl-pWnitrophenyl-phosphate, 2-carbomethoxy-1-methylvinyl-methyl-p-nitrophenyl-phosphate, 2-carbomethoxy-1-methylvinyi-methylphenylphosphate and 2-carbobenzyloxy-1-methylvinyl Methylphenyl phosphate was examined in Petri dishes in the above manner. Table 3 summarizes the percent kill data obtained.

Table 3 Compound Dosiemng Killing in% residual activity mgfflni immediately after 3 days 2-Carboethoxy-1-methylvinyl-ethyl-prnitrophenyl-0, 012 * 100 35 15 phosphate 2-carbomethoxy-1-methylvinyl-methyl-p-nitro-0, 016 * 100 30 0 phenyl phosphate 2-carbomethoxy-1-methylvinyl-methylphenyl-0.027 * 100 100 phosphate 2-carbobenzyloxy-1-methylvinyl-methylphenyl- 0.54 * 100 95 ** phosphate * Dosage in each case 10 times the LD50 dosage for the test compound.

** After 4 days instead of 3 days.

Tables 1 and 2 show that the compound according to the invention is 2-carbomethoxy-1-methylvinylmethylphenylphosphate has a far higher residual activity than the known insecticide 2-carbomethoxy-1-methylvinyl-dimethyl-phosphate "Phosdrin". If one continues the in Table 3 for 2-carbobenzyloxy-1-methylvinyl-methylphenylphosphate Killing after 4 days with that for phosdrin after 4 days in Table 1 compares, then it is clearly shown that the first-mentioned connection in this one Is far superior to phosdrine. The killing after 4 days by the two Nitrophenyl compounds mentioned in Table 3 were determined by drawing up mortality-time curves established. From these curves it was found that the percent kill after 4 Days for the two compounds was about 30 and 20 ° / n, respectively. If you have this Data with the kill listed in Table 1 after 4 days with Phosdrin in one Comparing dosage of 0.11 mg / dm2 shows that the compounds according to the invention have a higher residual activity than phosdrine. The phosdrine dose of 0.11 mg / dm2 Like all the dosages in Table 3, this corresponds to ten times the LDso dosage.

Investigations were also carried out on the residual activity of the first two compounds and of the phosdrin from Table 3 against the American bean beetle Epilachna varivetis Mulsant on bean plants. The active ingredient was sprayed on with five times the LD 50 and the larvae were exposed 7 days later. When the percentage mortality was counted after 44 to 46 hours, the following picture emerged: Table 4 R4O O H3C H / OC = CCOORI kill Rs-O in ° / o Ri-CaHs, R4-CaH5, R-C6H4N0890 Ri = CHs, R4 = CHs, Rs = C6H4NO2 65 Ri = CHs, R4-CH3, Rs = CH30 Table 5 below shows the superiority of the active compounds according to the invention over compounds of the formula In this comparison, the long-term effect is particularly important. Spotted spider mites served as the test insect. The percentage mortality was determined after the animals were exposed 7 days after application of the active ingredient.

Table 5 dosage R1 R2 R3 R4 R5 10 # LD50 20 # LD50 40 # LD50 * CH3 H CH3 CH3 CH3 0 59 78 * C2H5 H CeHs CHs CHs 81 80 93 CH2-C H CH3 CH3 C6H5 89 96 99.8 * Comparative substance.

Nevertheless, the superiority of the insecticidal agents according to the invention based particularly on its long-term effectiveness, its initial toxicity is also of special interest. Table 6 shows the Initial toxicity of the invention Compounds with respect to those of phosdrine, which are arbitrarily set equal to 100 is.

Table 6 Greens Blattella Leucania beetle ca unipuncta C2Hs H CH3 C2H5 02N {> 9,200 115 CH3 H I-CHs-CHs OsN 62 1280 155 continuation Gr r Ri Rz Rs R4 Rs! Spurge-B) atte)) a Leucania I. jtafer Germanica unipuncta CH3 H-CHs-CHs <6 100 83 CH2 H CH3 CH3 3 100- C2H5 H / CH3 1 CH3 1 3 100 22 (Comparative substance)

Claims (1)

Claim: Insecticidal agent containing a phosphoric acid triester, one ester group of which is derived from a substituted 3-oxy-2-alkenylic acid ester, as active ingredient, characterized in that the active ingredient is a phosphoric acid triester of the formula is. where the substituent Ri is either a methyl or ethyl group, preferably a methyl group, or a benzyl group and the substituent R2 is either a hydrogen atom or methyl, the substituent I; t3 is a methyl or ethyl group, preferably a methyl group, and R4 is a phenyl group which is optionally substituted by a nitro group in the p-position. Documents considered: German Auslegeschrift No. 1,035,392; U.S. Patent No. 2,685,552; British Patent No. 786 322.