CA1047497A - Heterocyclic derivative - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
O,O-Dimethyl 2-diethylaminopyrimidin-4-yl phosphoro-thionate, and compositions comprising it, are pesticidal.

Description

~o47~7 This invention relates to a novel pyrimidine derivative, which is useful as an insecticide.
Accordingly the invention provides 0,0-dimethyl

2-diethylaminopyrimidin-4-yl phosphorothionate This compound, which is a member of a group of compounds broadly disclosed in U.K. patent specification serial No.1,019,227, is distinguished from other closely related 2-aminopyrimidin-4-yl phosphorus ;esters, including some specifically recited in the above identified specification, by a markedly lower toxicity to mammals. This feature permits the use of the compound as an insecticide in many instances where the closely related compounds cannot be used, for example, in the disinfestation of human and animal dwellings and food stores.
The favourable mammalian toxicity of the compound of this invention, and the toxicities of several closely related compounds, measured as the single dose L.D.50 for female rats measured in milligrams of 2~ substance orally administered per kilogram of live body weight is given in the foliowing table.

Compound ¦ L D 50(mg/kg) 0,0-Dimethyl 2-diethylaminopyrimidin- 800 4-yl phosphorothionate 0,0-Diethyl 2-dimethylaminopyrimidin- 100-200 4-yl phosphate 0-_-Butyl 2-dimethylaminopyrimidin-4- 12.5-25 yl methylphosphonate -- ~

- , . : , .' TABLE 1 (continued) Compound ~ L.D.50(mg/kg) 0,0-Diethyl 2-ethylaminopyrimidin-4-yl ~ 1.5-3.0 phosphate 0~0-Diethyl 2-(N-ethyl-N-methylamino) 25-50 pyrimidin-4-yl phosphorothionate 0,0-Diethyl 2-dimethylaminopyrimidin-4- 25-50 yl phosphorothionate 0,0-Diethyl 2-diethylaminopyrimidin-4-yl 10-50 phosphorothionate 0,0-Diethyl 2-diethylaminopyrimidin-4-yl ca.10 phosphate 0,0-Diethyl 2-ethylaminopyrimidin-4-yl ca.10 phosphorothionate The invention compound may be prepared by treating 2-diethylamino-4-hydroxypyrimidine, or an alkali metal salt thereof, with dimethylphosphorochloridothionate, preferably in a diluent or solvent, and optionally in the presence of a base. Suitable solvents are ketones, for example, acetone, or methyl isobutyl ketone, and esters, for example, ethyl acetate, but any nonreacting solvent or diluent may be used.
Suitable bases include alkali metal carbonates, for example potassium carbonate, and tertiary amines, for example triethylamine or diethylaniline. The reaction between the hydroxypyrimidinederivative and the halophosphorus compound may be accelerated or completed by heating, for example by refluxing the -mixture of reactants and solvent or diluent at the . .

~0474g7 reflux temperature of the solvent or diluent.
In use the compound may be applied in an undiluted form to combat insect pests, but is best applied in association with a diluent or carrier in the form of a composition.
In a further aspect therefore the invention provides pesticidal compositions comprising 0,0-dimethyl 2-diethylaminopyrimidin-4-yl phosphorothionate in association with a diluent or carrier material.
The compositions may be in the form of granules wherein the active ingredient is absorbed on a porous granular material, for example pumice.
Alternatively the compositions may be in the form of liquid preparations to be used as dips or sprays, which are generally aqueous dispersions or emulsions of the active ingredient in the presence of one or more known wetting agents, dispersing agents or emulsifying agents. These compositions are prepared by dissolving the active ingredient in a suitable solvent, for example, a ketonic solvent such as diacetone alcohol, and adding the mixture so obtained to water which may contain one or more known wetting, dispersing or emulsifying agents.
The compositions which are to be used in the form of aqueous dispersions or emulsions are generally supplied in the form of a concentrate containing a high proportion of the active ingredient or ingredients, the said concentrate to be diluted with water before use.

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~04~497 These concentrates are often required to withstand storage for prolonged periods and after such storage, to be capable Or dilution with water in order to form aqueous preparations which remain homogeneous for a sufficient time to enable them to be applied by conventional spray equipment. The concentrates may contain 10-85% by weight of the active ingredients. When diluted to form aqueous preparations, such preparations may contain varying amounts of the active ingredient depending upon the purpose for which they are to be used.
For agricultural or horticultural purposes, an aqueous preparation containing between 0.0001%
and 0.1% by weight of the active ingredient or ingredients may be used.
The compositions of the present invention, may, if desired, also comprise in addition to the compound of the present invention, at least one other biologically-active ingredient, for example an insecticide, or a fungicide.
In use the compositions are applied to the pests, to the locus of the pests, to the habitat of the pests, or to growing plants liable to infestation by the pests, by any of the known means Or applying pesticidal compositions, for example - by dusting ~r spraylng.

~0474~7 The compound of the invention and compositions comprising it are very toxic to wide varieties of insect and other invertebrate pests, including, for example the following:-Tetran~chus telarius (red spider mites) Aphis fabae (aphids) Megoura viceae (aphids) Aedes aegypti (mosquitos) Musca dome~tica (houseflies) Pieris brassicae (white butterfly, larvae) Plutella maculipennis (diamond back moth, larvae) Phaedon cochleariae (mustard beetle) Calandra granaria (grain beetle) The invention i8 illustrated by the following examples.

5 Parts by weight of 0,0-dimethyl 2-diethylaminopyrimidin-4-yl phosphorothionate were thoroughly mixed in a suitable mixer with 95 parts by weight of talc. There was thus obtained a dusting powder.

10 Parts by weight of 0,0-dimethyl 2-diethylaminopyrimidin-4-yl phosphorothionate 10 parts of an ethylene oxide-octylphenol condensate ~ . .

("Lissapol" NX; "Lissapol" is a Trade Mark) and 80 parts by weight of diacetone alcohol were thoroughly mixed. There was thus obtained a concentrate which, in mixing with water, gave an aqueous dispersion suitable for application as a spray in the control of insect pests.

A granular composition was prepared by dissolving the active ingredient in a solvent, spraying the solution obtained on to the granules of pumice and allowing the solvent to evaporate.
% wt.
0,0-dimethyl 2-diethylaminopyrimidin-4-yl 5 phosphorothionate Pumice Granules 95 100%

An aqueous dispersion formulation was prepared by mixing and grinding the ingredients recited below in the proportions stated.
% wt.
0,0-dimethyl 2-diethylaminopyrimidin-4-yl 40 phosphorothionate Calcium lignosulphonate 10 Water 5 100%

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~o47~97 The activity of 0,0-dimethyl 2-diethylaminopyrimidin-4-yl phosphorothionate was tested against a variety of insect and other invertebrate pests. The compound was used in the form of a liquid preparation containing 0.1% by weight of the compound except in the test with Aedes aegypti where the preparations contained 0.01% by weight Or the compound. The preparations 1~ were made by dissolving the compound in a mixture of solvents consisting of 4 parts by volume of acetone and 1 part~by volume of diacetone alcohol.
The solutions were then diluted with water containing 0.01% by weight of a wetting agent sold under the trade name "LISSAPOL" NX until the liquid preparations contained the required concentration of the compound. "Lissapol" is a Trade Mark.
The test procedure adopted with regard to each pests was basically the same and comprised supporting a number of the pests on a medium which was usually a host plant or a foodstuff on which the pests feed, and treating either or both the pests and the medium with the preparations.
The mortality of the pests was then assessed at periods usually varying from one to three days after th-e t~eatment.
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The results of the tests are given below in Table 2. In this table the first column indicates the name of the pest species. Each of the subsequent columns indicates the host plant or medium on which it was supported, the number of days which were allowed to elapse after the treatment before assessing the mortality of the pests, and the results obtained for the compound.
The assessment is expressed in integers which range from 0-3.

0 represents less t han 30% kill 1 represents 30-49% kill 2 represents 50-90% kill

3 represents over 90% kill In Table 2 "contact test" indicates that both the pests and the medium were treated, "residual test" indicates that the medium was treated before infestation with the pests, and "systemic test"
indicates that the leaves of the host plant were infested after the roots of the plant had been treated with the aqueous preparation.

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1~)47497 ! Pest Species, Support No of Grading Medium Days ~ - ! --Tetranychus telarius I French 3 3 red spider mites, adults I Bean fabae 1 Broad 2 3 aph1ds) Bean Megoura viceae ~ Broad 2 3 (aphids) I Bean Dysdercus fasciatus Grain 2 3 (capsids) .
Aedes ae~Y~ti Water 1 3 T~squito larvae) Aedes aegypti Plywood 1 3 (mosquito adults) Musca domestica Milk/ 2 3 (hou~eflies - contact test) Sugar Musca domestica Plywood 2 3 (houseflies - residual test) Blattella germanica _ 2 3 chroaches) ~
Pieris brassicae Cabbage 2 3 (cabbage white, larvae -systemic test) . .
Pieris brassicae Cabbage 2 3 (cabbage white, larvae -contact test) . .
Plutella maculipenni~ Mustard 2 2 (diamond back, ~arvae -systemic test) Plutella maculipennis Mustard 2 3 (diamond back, larvae -residual test) Phaedon cochleariae Mustard 2 3 (mustard beetles - systemic . test) . .

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- ~, TABLE 2 (continued) _____ . _., ., . ._ , ., .. .. __ Pest Species Support No of Grading Medium Days t ~ _ ._ ___ Phaedon cochleariae Mustard 2 3 (mustard beetles -residual test) Calandra granaria Grain 2 3 (grain beetles~

Tribolium confusum Grain 2 3 (flour beetles) Meloidogyne incognita Tomato 14 3 nemat ode s .

This example illustrates the prepàration of 0,0-dimethyl 2-diethylaminopyrimidin-4-yl phosphorothionate.
To a solution of 2-diethylamino-4-hydroxypyrimidine (3.0 ~) in dry acetone (50 ml.) was added anhydrous potassium carbonate (4.96 g.) and dimethylphosphorochlorido-thionate (3.03 g.). The mixture was stirred at the ambient temperature for 24 hours and then filtered to remove the insoluble material. The filtrate was evaporated under reduced pressure at 35C, and the residual oil dissolved in methylene chloride (50 ml.) The solution was washed successively with aqueous sodium hydroxide solution (1%, 2 x 15 ml.), water (2 x 15 ml.) and brine (20 ml.), and dried over anhydrous magnesium sulphate. After filtration and evaporation of the solvent - : . -,' .
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, ~047497 the residual oil was purified by preparative thin layer chromatography to yield 0,0-dimethyl 2-diethylaminopyrimidin-4-yl phosphorothionate, pale yellow oil, ~4 1.5340. The structure of the product was confirmed by infra-red and nuclear magnetic spectroscopy.

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Claims (2)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-

1. O,O-dimethyl 2-diethylaminopyrimidin-4-yl phosphorothionate.

2. A method of combating insect pests at a locus which comprises applying to the locus an insecticidally effective amount of O,O-dimethyl 2-diethylaminopyrimidin-4-yl phosphorothionate in association with a dilent or carrier.