IE42138B1 - Tetrahydropyridine carboxylic acid esters and salts thereof,and their use as insecticidal and acaricidal agents - Google Patents

Abstract

1468644 Tetrahydropyridinecarboxylic acid esters BAYER AG 23 Oct 1975 [14 Nov 1974] 43593/75 Heading C2C Novel tetrahydropyridinecarboxylic acid esters having the general formula wherein R is (C 2 -C 6 ) alkyl, cycloalkyl, (C 2 - C 6 ) alkenyl or (C 2 -C 6 ) alkynyl, or salts thereof, other than that wherein R is ethyl except in the form of a salt thereof, are prepared either by (i) reacting a compound of the formula with ROH; (ii) reacting a compound of the formula in the form of a hydrochloride, hydrobromide or hydrosulphate, with ROH and eliminating a molecule of water, (iii) reacting a compound of the formula wherein Z is an anion, with sodium borohydride, (iv) reacting a compound of the formula with a dehydroxylating agent; (v) reacting a compound of the formula with an organic or inorganic base; or (vi) reacting a compound of the formula with an organic or inorganic acid, wherein Hal is halogen, R1 is R or CH 3 and X is hydrochloride, hydrobromide or hydrosulphate. The novel compounds possess insecticidal properties.

Description

This invention relates to certain new tetrahydropyridinecarboxylic acid esters and salts thereof, to a process for their preparation and to their use as insecticides and acarieides.

Chemische Berichte (Volume 21, page 3404 (1888)) describes the extraction and fractionation of arecholine of the formula cooch5 oh5 and the preparation of salts thereof.

V.S. Patent No. 2,506,458 (1950) discloses preparation of arecholine of the above formula ethyl ester of the formula the and areoaidine Ό)~ΟΟΟθ2Η5 CH, making mention of the usefulness of these compounds in the veterinary field.

The above-mentibned arecholine is a naturally occurring alkaloid contained in the fruit of the betel nut, being known as a parasympathetic nerve affecting substance ih the field of medicine and also used as a vermicide for livestock. .

However, arecholine has never been used as an insecticidal agent and no effectiveness of it for use as an insecticidal agent is either stated or even suggested in any of the literature. ’! · · This invention is based on the surprising discovery that - 2 42138 tetrahydropyridinecarboxylic acid esters defined below have considerable insecticidal and acaricidal effects, much greater than that of arecholine which is a naturally occurring alkaloid.

In practise, the insecticidal agents which have actually been used have generally been such inorganic compounds as arsenical compounds or such organic synthetic insecticidal agents as certain organic phosphorus compounds, carbamate compounds and organic chlorine compounds.

However, many of the organic synthetic insecticidal agents of which widespread use has been made in recent years cause problems of acute toxicity, chronic toxicity and residual toxicity; for instance, some remain and build up in the soil, or migrate into the actual crop, and may pose toxicity problems in the food for humans and for livestock, or may pass into rivers and injure fish and shellfish, or cause fhe transmission of toxicity through the food chain to more remote consumers. Thus such compounds contribute to environmental pollution. Many such compounds have had to be restricted or entirely prohibited in use as in the case of lead arsenate, BHC and DDT.

The repeated use of the same type of chemicals in successive years gives rise to different problems, such as pests gaining resistance thereto, reducing the effectiveness of fhe pesticides.

On the one hand, natural insecticidal agents have a narrow insecticidal spectrum and a short residual effect, though quick in taking effect. They are often readily decomposed by the sunlight and air and are thus deprived cf insecticidal effect, so that they do not remain in the soil or crop and do little damage to the crop. - 3 42138 When they are actually used, it becomes necessary in order to make certain of their insecticidal effect either to use synergists concurrently with them or to increase the amount applied, there being many problems posed from the view-points of insecticidal effect and economy. Thus, there are not many of them that can compare favourably with synthetic agricultural chemicals.

Under these circumstances, the need for the advent of alternative agricultural chemicals with low toxicity Is rapidly more and more felt.' The present inventory repeatedly engaged themselves in the examination and study of the working characteristics of natural insecticidal agents, in which they took notice of the action and structure of arecholine which is a naturally occurring alkaloid and synthesized its derivatives,' finding as a result that tetfahydropyridinecarboxylic acid esters of the general formula (I) and their salts possess aii excellent insecticidal and acaricidal effect, having a peculiar selectivity in action and being free from phytotoxicity to the crop, and can therefore be used with safety.

Further, there is an advantage in that the compounds of the invention, which have an altogether different working mechanism from the conventional chemicals, have a very high insecticidal and acaricidal effect against various types of pests which have gained resistance to chemicals as a result’of the same types of chemicals being used in successive years and in that,they are low in toxioity to warm-blooded animals, which make's it' possible to use with safety.

The invention provides compounds which are tetra- 4 42138 hydropyridinscarboxylic acid esters of the general formula: wherein R stands for an alkyl group having! 2- to 6 carbon.atoms, a cycloalkyl group, an alkenyl group having 2 to 6 oarbon atoms or an alkynyl group having to 6 carbon atoms, or salts thereof(excluding the compound in which R is- ethyl except when in the form of a salt).

Specific meanings of R include n- (or iso-) propyl, n- (iso-, sec- or tert.-) butyl and n- (sec-, neoor tert.-) pentyl, cyclopentyl, cyclohexyl, and cycloheptyl, vinyl, allyl, 1- (or 2-) methyl-2-propenyl and 2butenyl and 1- (or 2-) propynyl.

The invention also provides a process for the production 15 of a compound of formula (I) in which (a) a compound of the formula j/^j-COHal . ir ΰΆ$ is reacted with a compound of the (II) formula R CH or (b) a compound of the formula Q-COOH (IV) CH, (III) (whioh may be in the form of the hydrochloride, hydrobromide or hydrosulphate) is reacted with a compound of the formula H OH (III) with elimination of a molecule of water or (c) a-pyridinium compound of the general formula (V) (where Z is an anion, for example halide or methylsulphate) is reacted, with sodium borohydride , or (d) a oompound of the formula GOOR1 (VI) (which may be in the form of the hydrochloride, hydro15 bromide or hydrosulphate) is reacted with a compound of the formula R OH (III) or (e) a compound of the formula is reacted with a dehydroxylating agent, - 6 42138 or (f) a compound of the formula ig reacted with an inorganic or organic base, or (g) a compound of the formula COOK OIL· is reacted with an inorganic or organic acid.

In the above formula (II) - (VII), .

H has the name meaning aa in formula (3), Hal stands for halogen, for example chlorine or iodine, R has the same range of meanings as R or stands for CHj, and X stands for the hydrochloride, hydrobromide or hydrosulphate. dxamplesiof the pests which are effected by the present compounds as well as by arecaidine ethyl ester are coleopterous insects, for instance ditophilus zeamais. Agriotes fUBcioollls and Anomala rufocuprea. lepidopterous insectB, for instance lymantria dispar. Malacosoma neustria. Pieris rapae. Adoxophyes orana. Homona magnarinta and J3uprootis pseudooonspersa. hemipterous insects, for instance PBeudococcus oomstookl. Myzus persicae and Rhopalosiphum pseudobraaBloae. and aeari, for inatanna - 7 42138 Tetranvchus telarlus (Tetranychua urticae) and Panonychus citri .

The various methods of preparing the compounds of the invention are illustrated below.

Prooess variant (a) z 0001 ' CH, hci+hoch2ch=ck2 Qcooch2ch=ch2 .HCl+HCl CH, The ecylchlorJde to he used in variant (a) may, for instance, be 1-methyl-l,2,5,6-tetrahydronicotinic acid chloride hydrochloride* Examples of the alcohols of formula (III) to be used in this variant '(or in variants (b) and (d)) are n(or iso-) propyl, n- (iso-, see- or tert-) butyl, n- (sec-, neo- or tert-) pentyl, cyclopentyl, cyclohexyl, qyclobutyl-, 15 vinyl-, allyl-, 1- (or 2-) aethyl-2-propenyl, 2-butenyl-, and 1- (or 2-) propynyl-aicohol.

The foregoing reaction can be carried out in the presence of an aoid binder. Usable as suoh are hydroxides, carbonates, bicarbonates and alcoholates of alkali metals, of which use is generally made, and tertiary amines, examples of which include triethylamine·, diethylaniline and pyridine.

The above variant (a) can be practised over a relatively broad temperature range. Generally, a temperature between O°C and·the boiling point of the mixture, and preferably - 8 42138 between 30 and. 100°C, is used.

TheacyJchloride for use in the above reaction may be prepared as exemplified by the following formula scheme: ( s HCl+SOClg —> C00C1 .HCl+tJOg-filCl CH, Process variant (b) The carboxylic acid to be used in this process variant may, for example, be a salt (such as hydrochloride, sulphate or hydrobromide) of 1-methyl-1,2,5,b-tetrahydronicotinic acid.

If the above reaction is carried out in the presence of an esterifying agent, for instance, an alcoholate of en alkali metal or acid (for instance, hydrochloric acid, sulphuric acid, etc.), the product of the invention can be obtained in good yields.

The above variant (b) for the preparation of the compounds of this invention can be carried out over a - 9 15 43136 relatively broad temperature range. A temperature between 0°C and the boiling point of the mixture, and preferably between 20 and 120°C, is generally used.

Process variant (c) !00CH2CH=CHCH5 V z~ ch3 NaBS5 ---> COOGH2CH=OHCH3 CH5 Pyridinium salts to be used in this variant include, for instance, l-methyl-3-ethoxycarbonyl, l-methyl-3-n-(or iso-) propoxycarbonyl, l-methyl»3-n-(iso- or sec-) butoxycarbonyl, methyl-3-n-pentyloxycarbonyl, l-methyl-3-cyelopentyloxycarbonyl, l-methyl-3-cyclohexyloxycarbonyl, 1-methyl3-allyloxycarbonyl, l-methyl-3-(l'-(or 2')methyl-2'-propeayloxycarbonyl), l-methyl-3-(2,-butenyl0xycarbonyl), and 1methyl-3-(2’-propynyloxycarbonyl) salts, for instance, of chlorides, bromides, iodides and methyl sulphates, of pyridinium As the reducing agent to be used in the reaotion, there can be mentioned, for instance, sodium borohydride.

This variant for the preparation of the compounds of this invention can be practised over a relatively broad temperature range. Generally a temperature between -20 and 50°C, and preferaBy between -10 and 40°0, is used.

Process variant (d) ‘ · OH,· (^Γ C00CH3 + HOCHjCaOHg - H+ . . - 1048138 CH, cooch2c=ch2 +ch5oh ch3 Carboxylic acid esters to be used in this variant include, for instance, l-methyl-l,2,5,6-tetrahydropyridine-3-carboxylic acid methyl ester, l-methyl-l,2,5,6-tetrahydropyridine-35 carboxylic acid ethyl ester and their salts (for instance, hydrochlorides or sulphates).

In carrying out the above reaction the use of the esterifying agents indicated for process variant (b) will assist the obtaining of the products in good yields.

This variant can be practised over a relatively broad temperature range. Generally a temperature between 30°C and the boiling point of the mixture, and preferably between 50 and 100°C,is used.

Process variant (e) ί ητι .H01+30Cl2 >\-G00CHCH=CH2 k ι CH, OH, COOCHCH=CH2 .HCl+S02+2H01 As the 4-hydroxypiperidinium hydrochlorides to be used in the foregoing method for the preparation of the compounds of the invention, mention oan be made by way of specific examples, for instance, of l-methyl-3-ethoxyearbonyl, l-methyl-3-n-(or iso-) propoxycarbonyl, l-methyl-3-n-(lsoor sec-) butoxycarbonyl, l-raethyl-3-n-pentyloxycarbonyl, 1. ll 42138 methy1-3-oyclopentyloxycarbonyl, 1-methy1-3-cyclohexyloxycarbonyl, l-methyl-3-allyloxycarbonyl, l-methyl-3-[l'-(or 2,-)methyl-2'-propenyloxycarbonyl], l-methyl-2-(2'-butenyloxyoarbonyl), l-methyl-3-(2'-propynyloxycarbonyl) and 45 hydroxypiperidinium chloride.

Ae the dehydrating agent to he used in the reaction can be mentioned, for instance, thionyl chloride and phosphorus oxychloride.

This variant of the process for the preparation of the 10 compounds of the invention can be practised over a relatively bread temperature range > Generally a temperature between 10°0 and the boiling point of the mixture, and preferably between 30 and 50°C, ie used.

The tetrahydropyridinium halides which can be obtained 15 by the variants (a), (b), (d) and (e). as described above may be admixed with the same classes of inorganic and. organic bases as mentioned for variant (a) to alkalise the solutions upon which various corresponding 1-methyl-l,2,5,6-tetrapyridine-3-oarboxylie acid esters oan be synthesised, As the acid fo be used for the preparation of the salt from the carboxylic acid ester, there may be used an organic or inorganic aoid such as HCl, HBr, HI, HgSO^, H^PO^, HPO^, HN°3, HO14, HSOjHNg, CH-COOH, C^CCOOH, citric acid, lactic acid, formie acid, oxalic aoid, benzoic acid, oleic acid, 2,3,6-trichlorobenzoic acid, dodecylbenzenesulphonic acid, salicyclic acid or OHjOClgCOOH, The above-mentioned, process variants can be carried out in the presence of a solvent or diluent.For this purpose any suitable inert chemical or diluent can be used.

Examples of such solvents or diluents include water; aliphatic, cycloaliphatic and aromatic hydrocarbons (which may bo chlorinated), such as hexane, cyclohexane, petroleum ether, ligroin, benzene, toluene, xylene, methylene chloride, chloroform, earbon tetrachloride, ethylene chloride, trichloroethylene and chlorobenzene; ethers, such as diethyl ether, methyl ethyl ether, di-iso-propyl ether, dibutyl ether, propylene oxide, dioxan and tetrahydrofuran; ketones, such as acetone, methyl ethyl ketone, methyl-iao-propyl ketone and methyl-iso-butyl ketone; nitriles, such as acetonitrile, propionitrile and acrylonitrile; alcohols, such as methanol, ethanol, iso-propanol, butanol and ethylene glycol; esters, such as ethyl acetate and amyl acetate; acid amides, such as dimethyl formamide and dimethyl acetamide; sulphones and sulphoxides, such as dimethyl sulphoxide and sulpholane; and bases, such as pyridine.

The reaction is preferably carried out under atmospheric pressure, but it is also possible to operate under an elevated or reduced pressure.

The active compounds according to the present invention can be converted into the usual formulations, such as solutions, emulsions, suspensions, powders, pastes and granulates. These may be produced in known manner, for example by mixing the active compounds with extenders,, that is, liquid or solid or liquefied gaseous diluents or carriers, optionally with the use of surface-active agente, that is, emulsifying agents and/or dispersing agents, and/or foamforming agents. In the case of the use of water as an extender, organic solvents can, for example, also be used as auxiliary solvents.

As liquid diluents or carriers, there are preferably used aromatic hydrocarbons, such as xylenes, toluene, benzene or alkyl naphthalenes, chlorinated aromatic or aliphatic - 13 42138 hydrocarbons, such as chlorobenzenes, chloroethylenes or methylene chloride, aliphatic hydrocarbons, such as cyclohexane or paraffins, for example mineral oil fractions, alcohols, suoh as butanol or glycol as well as their ethers and esters, ketones, such as acetone, methyl ethyl ketone, methyl isobutyl ketone or cyclohexanone, or strongly polar solvents, slich as dimethyl formamide, dimethyl sulphoxide or acetonitrile, as well as water.

By liquefied gaseous diluents or carriers are meant . liquids' which Would be gaseous at normal temperatures and pressures, e.g. aerosol propellants, suoh as halogenated hydrocarbons, e.g. Freon. Freon is a Registered Trade Mark.

As solid diluents or carriers, there are preferably usea ground natural minerals, such as kaolins, clays, talc, chalk, quartz, attapulgite, montmorillonite or diatomaoeous earth, or ground synthetic minerals, such as highly-dispersed silicic acid, alumina or silicates.

Preferred examples of emulsifying and foam-forming agents, include non-ionic, and anionic emulsifiers,., such as polyoxyethylene-fatty acid esters, polyoxyethylene-fatty alcohol ethers, for example alkylarylpolyglycol. ethers,, alkyl sulphoates, alkyl sulphates and aryl sulphonates as well as albumin hydrolyzation products; and preferred examples of dispersing agents include lignin, sulphite waste liquors and .25 methyl cellulose.

The insecticidal and acaricidal compositions of this invention can contain the above-mentioned active ingredients including arecaidine.ethyl eater in an amount of 0,1. to 95$ by weight, preferably 0.5 to 90$ by weight. They may be diluted for actual application. Por application, the amount of the active compound in the above various preparations and ready-to-use preparations ia gawa-rany c. in the range from 0.0001 to 20?» by weight, preferably from 0.005 to 10% by weight.

The 'amount of the active ingredients can bo suitably varied according to the formulation and to the method, purpose, time and locus of application as well as to the condition of the pests.

The compounds of the invention, may be used mixed with other agricultural chemicals, for instance other insecticides or fungicides, acaricides, nematocides, anti-virus chemicals, weeding agents, plant growth regulators and attractants (for instance, organic phosphoric acid ester type compounds, carbamate type compounds, dithio(or thiol) carbamate type compounds, organic chlorine type compounds, dinitro type compounds, organic sulphur or metallic compounds, antibiotics, substituted diphenyl ethor compounds, urea compounds, triazine compounds) or/and with fertilizers. If they aro mixed with cholineosterase inhibitors, such as organic phosphorus containing insecticides (for example Dipterex, Baycid). and carbamate containing insecticides (for example Suncide, Bassa),they exhibit an excellent synergistic effect.Dipterexis a Registered Trade Mark.

The compounds or formulations may be applied by any of the methods of application generally employed, such as scattering (for example liquid scattering (spraying), misting, atomizing, dusting, granules scattering, water surface application, pouring); fumigation; soil application (for instance mixing, sprinkling), vaporising, (irrigation); surface application (for example coating,banding, powder coating, covering); immersion; or as bait. They can be applied also by means of the ultra-low-volume method; in this method formulations are used containing up to 95% or even 100?» of the - 15 42138 active compound.

The active compounds are geneally applied to areas of crop cultivation in an amount of 3 to 1,000 grams, preferably 30 to 800 grams, of active ingredient per 10 ares. But for special reasons it is possible and may even be necessary for them to be applied in an amouit greater or smaller than this.

The invention therefore provides an insecticidal or acaricidal composition containing as active ingredient a compound according to the invention including arecaidine ethyl ' ester in admixture with a solid or liquefied gaseous diluent or carrier or in admixture with a liquid, diluent or carrier containing a surface-active agent.

The invention also provides a method of combating insect or acarid pests which comprises applying to the pests or a habitat thereof a compound according to the invention including arecaidine ethyl ester alone or in the form of a composition containing as active ingredient a compound according to the invention in admixture with a diluent or carrier.

The invention also provides crops protected from damage by insects or aearids-by being grown in areas in which, immediately prior to and/or during the time of the •growing, a compound according to the invention was applied alone or in admixture with a diluent or carrier. It will be seen that the usual methods of providing a harvested crop may be improved by-the present invention.

The compounds according to the invention, and the preparation and use of the compounds according to the invention, are illustrated by the following Examples. Examples (i) to (vii) exemplify formulations of suoh compounds, Examples A-B exemplify the compounds and their insecticidal and acaricidal properties, and Examples 1-18 exemplify the compounds and their preparation. In Examples (i) to (vii) and A-B the compounds . .-36-. of the invention are identified by number corresponding to those of the preparative ixamples 1-18, Parts-and percentages are by weight.

Example (i) (Wettable Powder) parts of compound 2, 80 parts of a mixture of diatomaceous earth with kaolin (1:5) and 5 parts of the ( i emulsifier itunox (trade name of the product made by Toho Chemical Co.) (polyoxyethylene alkyl aryl ether) were pulverised and mixed to form a wettable powder. It was diluted with water to a concentration of 0.05?j and used to treat pests and/or their habitat.

Example (ii) (Emulsifiable Concentrate) parts of compound 17, 30 parts of xylene, 30 parts of Kawakasol (trade name of the product of Kawasaki Chemical Co.) and 10 parts of Solpol (trade name of the product of Toho Chemical Oo.) (polyoxyethylene alkyl phenyl ether) were mixed and stirred together to form an emulsifiable concentrate. It was diluted with water to a concentration of 0.05?ί and sprayed to treat pests and/or their habitat.

Example (iii) (Dust) parts of the compouifi 15 and 98 parts of a mixture of talc and clay (1:3) were pulverised and mixed together to form dusts. They were applied to pests and/or their habitat. Example (iv) (Dust) 1.5 parts of compound 4, 0.5 part of isopropyl hydrogen phosphate (PAP) and 98 parts of a mixture of talc and clay (1:3) were pulverised and mixed together to make dusts and applied to peets and/or their habitat.

Example (v) (Granules) A mixture consisting of 10 parts of compound 1, 10 parts of bentonite, 78 parts of a mixture of talc and clay - 17 42X38 • (1:3) and. 2 parts of lignin sulphonate was admixed with 25 parts of water, intimately blended, cut to small piecee by means of an extrusion type granulation machine and made into granules of 20 to 40 mesh in size and dried at 40 to 50°C to prepare granules. They were applied to pests and/or their habitat.

Examole (vi) (Granules) parts of particles of Olay having a particle size distribution of 0.2 to 2 mm were placed in a rotary mixer and sprayed, while this was in operation, with 5 parts of compound 18 dissolved in an organic solvent and uniformly moistened, followed by drying at 40 to 50°G to prepare granules. They were applied to pests and/or their habitat·..

Example (vii) (Oil) 0.5 part of compound 3, 20 parts of Bercicol AR-50 (trade name of the product of Bercicol Co.) (high boiling point aromatic compound) and .9.5 parts of kerosene were mixed, and stirred together to form an oil. ,It was applied to treat pests and/or their habitat.

Example A Test on Effect against Smaller Tea Tortrix and Tea Tussock Moth (Preparation of the Test Solution) Solvent: xylol 3·parts by weight Emulsifier: polyoxyethylene alkyl phenyl ether l.part by weight In order to make a preparation of the active compound, part by weight of the active compound was mixed with tiie above-given amount of the solvent containing the above-mentioned emulsifier, and the mixture so obtained Was diluted with water to a prescribed concentration. - 18 42138 Tea leaves were immersed in a solution of the active compound diluted with water to a predetermined concentration and the solution was aerated, following which the leaves were each placed in a Petri dish of 9 centimeters diameter, in each of which 10 of the insects (incubated larvae of smaller tea tortrix and 3-age stage larvae of tea tussock moth) were left, and the number of insects killed after 24 hours was counted to calculate the killing ratio as a percentage.

The results of the test are given in Table A.

Results of test on Smaller Tea Tortrix and Tea Tussock Moth o •H «Ρ s £ o S Λ1 ϋ o ra ra EH iti Φ EH Concentration of active ingredient 100 ppm O - o · o o o o 6 A O O KS o o O O O O ο ο ο ο σ Q Η Η rt rt rt rt [lOOO ppm Ο Ο O Q Ο O O O O O O O A rt rt rt rt rt 1 Smaller Tea Tnartrix . *P fc A 0 Φ O ci •rl fi &§ si 81 o aj a & o V £8888888888888 Η Η Η Η Η H t & o 8 8 § oo 8 8 8 8 8 8 8 8 8 8 i-j f-ι p-j HrMHHHHHHHri I λ g g g 8 8 8 88888888.8 rt rt rt rt rt rt rt rt rt rt rt rt rt rt -ft rt CMtn < ΙΑ Ό t“ Ο Ο O r-j Oj tq § O tn o tn r-i H Table A (continued) LA ? 21 42138 Example Β Test on Effect against Tetranvchus cinabarinus -A kidney bean Beedling planted in a vinyl resin pot of 6 centimeters diameter was inoculated with 50 to 100 Tetranvchus cinabarinus larvae who had already gained resistance to organic phosphoric acid type acaricides, and one day after the inoculation the compound of the invention which was diluted to a predetermined concentration was applied by means of a spray gun in ail amount of 50 cubic centimeters per three pots and the pots were left at room temperature. After three days the number of insects killed was counted to estimate insecticidal index in accordanoe with the following', scale. - 0% of the larvae survive 2 - 5% of the larvae survive - 5 to 50% of the larvae survive 0 -more than 50% of the.larvae survive.

The results of the test are shown in Table B.

Table B Results of tests on Tetranvchus Cinabarinus Compound Insecticidal indices Concentration of active ingredient 5000 ppm 1000 ppm 300 ppm - 1 ' 3 ' 3 2 3 3 3 1 4 3 3 2 5 3 3 1 9- 3 3 1 17 3 3 2 18 .3 3 3 Arecholine (Control) 3 '1 0 - 22 42138 Table B (continued) Compound Insecticidal indices Concentration of active ingredient 3000 ppm 1000 ppm 300 ppm Nicotine sulphate (Control, com mercially available) 2 1 0 Phenkaptone (Control) (Commercially available)2 0 0 In Tables A and BiNicotine sulphate: X-l-methyl-2-3'-pyridinylpyrrolidine sulphate Phenkaptone: 0,0-diethyl-S-(2,5-dlehlorcphenylthiomethyl) phosphorothiorothionate Example 1 cooch2ch=ch3 0¾ .HOI To 2 grams of l-methyl-l,2,5,6-tetrahydronicotinic acid hydrochloride were added 16.38 grams of thionyl chloride, and the mixture was stirred at a reaotion temperature of 70°C over a period of 10 minutes.

Excess thionyl chloride, was removed by means of distillation under reduced pressure to leave l-methyl-l,2,5,6tetrahydroniootinic acid hydrochloride.

To the product obtained above was added 3.4 grams of - 23 42138 allyl alcohol and the mixture waa left at 27°C for a period of 5 hours, followed by stirring at 90 to 100 °0 over 2 hours to distil off the unreacted allyl alcohol and recrystallising the residue from a mixture of chlbroform and ether to yield 1.86 gram of the intended product of 1-methyl-3-allyloxycirb onyl-1,2,5,6-tetrahydropyridinium chloride. m. p. 120-125°C. Examnle 2 grams of 1-methyl-l,2,5,6-tetrahydropyridine-310 carboxylic acid hydrochloride were suspended in 6.64 grams of cyclopentanol and dry hydrochloric acid gas was blown into the mixture till the reaetion liquid became transparent while stirring of the mixture was being carried out at a reaouion temperature of 100°C. : 15 After the completion of the reaction, the excess hydrochloric acid and cyclopentanol were distilled off under reduced pressure, and to the residue was added a 10# aqueous solution of sodium carbonate to reader it alkaline, and it was extracted with ether.

The resulting product was dried with anhydrous sodium sulphate and ether was removed by evaporation, and the residue was distilled under reduced pressure to yield l.Jl gram of the intended product of 1-methyl-l,2,5,6-tetrahydropyridine-3carboxylic acid cyclopentyl ester. b.p. 102 - 103°C/0.3 mm Hg ' 4° 1.4942. - 24 42138 Example 3 .cooch2ch=chch5 grams of l-methyl-3-2'-butenyloxycarbonylpyridinium iodide were added to 75 milliliters of methanol and 1.44 gram of sodium borohydride was added little by little to the mixture at a reaction temperature of O°C with stirring. The reaction was continued for 40 minutes after the addition.

After the completion of the reaction, methanol was distilled off and 30 milliliters of water were added to the reaction product which was then extracted with ether.

By following the same subsequent procedures as described in Bxample 2 there were obtained 1.88 gram of the intended product of 1-methy1-1,2,5,6-tetrahydropyridine-3carboxylic acid-2*-butenyl ester. b.p. 96 - 97°C/0.4 mm Hg njj° 1.4890.

Examples 4 - 18 By the procedures similar to those of Exemples 1-3 the following compounds were prepared.

The compounds were of formula (i) in which R had the meanings given below. (Where A is Shown, this is a salt radioal.) - 25 42138 it.

Table '« - 26 43138 Table 5 (continued) in We hereby disclaim the compound of the formula (1) below in which R is ethyl except in the form of a salt thereof.

Subject to this disclaimer,

Claims (20)

1. CLAIMS:1. Compounds which are tetrahydropyridinecarboxylio acid esters of the general formula: (I) wherein R stands for an alkyl group having 2 fo 6 carbon atoms, a cycloalkyl groups an alkenyl group

2. Compounds according to claim 1 in which R is any cf the following radicals: n-(or iso-) propyl, n-(iso-,

3. Compounds according to claim 1 which are hereinbefore 2o identified in any of Examples 1 to 18.

4. A process for the production of a compound according any of claims 1 to 3 in which (a) a compound of the formula j^-COHal (II) 25 is reacted with a compound of the fornula ' ROH (Hi) or (b) a compound of the foimula - 2842138 O COOH (IV) I Cttj (which may be in the form of the hydrochloride, hydrobromide, or hydrosulphate) is reacted with a compound of the formula ft OH (III) with elmination of a molecule of water or (c) a pyridinium compound of the general formula CH, y (where Z is an anion) is reacted with sodium borohydride, or (a) a compound of the formula □1 ,-COOR (VI) (which may be in the form of or hydrosulphate) is reacted with a compound of the hydrochloride, hydrobromide the formula R OH (III) or (e) a compound of the formula OH 0-COOR (ra > I CH 5 is reacted with a dehydroxylating agent, - 29 20 or (f) a oompound of the formula . φ.ΟΟ°Η L ch 5 J is reacted with an inorganic or organic base, or (g) a compound of the formula is reacted with an inorganic or organic acid, in which R has the meaning given in claim 1, Hal stands for halogen, R· 1 · has the same range of meanings of R or stands for 011^, and X stands for hydrochloride, hydrobromide or hydrosulphate.

5. A process according to claim 4(a) in which the reaction is carried out at a temperature between 30 and 100°C.

6. A process according to claim 4(b) in which the reaction is carried out at a temperature between 20 and 120°C,

7. A process according to claim 4(c) in which the reaction is earned out at a temperature between -10 and 40°C.

8. A process according to claim 4(d) in whieh the reaotion is carried out at a temperature between 50 ani 100°C.

9. A process according to claim 4(e) in which the 421 3 8 reaction is carried out at a temperature between 30 and 50°0.

10. A process according to any of claims 4 to 9 in which the reaction is carried out in the presmce of a solvent or diluent. 10 having 2 to 6 carbon atoms or an alkynyl group having 2 to 6 carbon atoms, or Salts thereof.

11. A process for the production of a compound according to claim 1 substantially as hereinbefore described in any of Examples 1 to 18.

12. Oompounds according to claim 1 whenever prepared by a process according to any of claims 4 to 11.

13. An insecticidal or acaricidal composition containing as active ingredient a compound us defined in any of el aims 1-3 or 12 in admixture with a solid or liquefied gaseous diluent or carrier or in admixture with a liquid diluent or carrier containing a surface-active agent.

14. A composition according to claim 13 containing from 0.1 to 95% of the active compound by weight.

15. A method of combating insect or acarid pests which comprises applying t o the pests or a habitat thereof a compound as defined in any of claims 1-3 or 12 alone or in the form of a composition containing as active ingredient a compound according to any of claims 1-3 or 12 in admixture with a diluent or carrier. 15 seo- or tert.-) butyl and n- (sec-, neo- or tert.-) pentyl, cyclopentyl, cyclohexyl, and cycloheptyl, vinyl, allyl, 1(or 2-) methyl-2-propeiyl and 2-butenyl and 1- (or 2-) propynyl.

16. A method according to claim 15 in which a composition is used containing from 0.0001 to 20% of the active compound, by weight.

17. A method according to claim 16 in Whieh the active compound is applied to an area of crop cultivation in an amount of 3 to 1000 g per 10 ares.

18. Harvested crops protected from damage by insects or acarids by being grown in areas in which, immediately prior to and/or during the time of the growing, a compound as defined any.of claims 1-3 or 12 was applied alone |Or in admixture with, a diluent or carrier. (

19. A composition containing as active ingredient arecaidine 5 ethyl ester in admixture with a diluent or carrier. ί'

20. A method of combating insect or acarid pests whioh comprises applying, to the pests or a habitat thereof arecaidine ethyl ester in admixture with a diluent or a carrier.