GB1572357A - Insecticidal thiazines - Google Patents

Description

(54) INSECTICIDAL THIAZINES (71) We, SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ B.V., a company organised under the laws of the Netherlands, of 30 Carel van Bylandtlaan, The Hague, The Netherlands, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement:- The present invention concerns substituted thiazines and to methods for their preparation. Because the compounds possess insecticidal activity, the invention also concerns composition containing these compounds and to methods for combatting insects.

According to the invention there are provided, tetrahydro- 2 (nitromethylene) - 2H - 1,3 - thiazines being resonance hybrids, the principal forms contributing thereto being described by the formulae:

and nitro(tetrahydro - 2H - 1,3 - thiazin - 2 - ylidene)methyl aldehydes and ketones being resonance hybrids, the principal forms contributing thereto being described by the formulae:

wherein in formulae I and II; R is hydrogen, alkyl, alkenyl, alkoxyalkyl, cycloalkyalkyl, cyanoalkyl, haloalkenyl, aralkyl or alkoxy-carbonylvinyl, and R' is -CH2-NR2R3, wherein R2 is haloaryl and R3 is hydrogen, alkyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, alkenyl, aryl, haloaryl, or aralkyl; in formulae III, IV and V, R is hydrogen, halogen (particularly chlorine or bromine), or alkyl of from one to eight carbon atoms, and R' is alkoxycarbonylalkyl, Those compounds of formulae I and II, when R represents a hydrogen atom, may also exist in two tautomeric forms, one form being the resonance hybrid described above and the other being represented by the formula

This form, C, can be designated as a 2 - (R1 - nitromethyl) - 5,6 - dihydro - 4H 1,3 - thiazine. The left-hand form of the resonance hybrid (i.e., form A) can be designated as a 3 - R - tetrahydro - 2 - (nitromethylene) - 2H - 1,3 - thiazine, while the right-hand form of the hybrid (i.e., form B) can be designated as a 3 - R 2 - (aci - nitromethyl) - 5,6 - dihydro - 4H - 1,3 - thiazinium hydroxide inner salt.

The resonance hybrid may exist as either of two geometric (cis-trans) isomers, depending upon the spatial relationship of the moieties about the bond between the carbon atom of the nitromethylene moiety and the ring carbon atom to which it is joined.

In this specification, for the sake of simplicity, these compounds will be referred to generally as tetrahydro - 2 - (nitromethylene) - 2H - 1,3 - thiazines.

This terminology is intended to include all of the contributors to the resonance hybrid, the geometric isomers, and the tautomers, as well as mixtures thereof.

In all cases, each alkyl, cycloalkyl or alkenyl, moiety advantageously contains no more than eight and preferably no more than four carbon atoms and each may be of straight-chain or branched-chain configuration.

The preferred aryl moieties are optionally substituted phenyl. The preferred aralkyl moieties are optionally-substituted phenylmethyl.

Also, when R is hydrogen, the invention includes salts of that subclass of compounds-i.e., R is a cationic species. The contemplated salts are alkali metal salts, alkyl halide salts, ammonium salts and amine salts generally, and particularly salts of alkyl- and alkanolamines, and polyamines. Included are the salts of mono, di- and tri-alkyl, alkanol, alkenyl and mono- and poly-(alkoxy)alkyl-amines, and polyamines in which each alkyl, alkenyl, alkanol, or alkoxyalkyl moiety contains from one to twenty carbon atoms or more including, but not necessarily limited to, one or more of dimethylamine, diethanolamine, trimethylamine, oleyl propylenediamine, n-dodecylamine, n-tetradecylamine, n-hexadecylamine, noctadecylamine, heptylamine, triethanolamine, tert-C"~,4 and tert-C,8~24 primary amines, oleylamine, coco amine, hydrogenated tallow amine, tallow amine, soya amine, dicoco amine and di(hydrogenated tallow) amines, dimethyl hexadecylamine, dimethyl octadecylamine, dimethyl coco amine, dimethyl soya amine, N-coco propylenediamine, N-soya propylenediamine, N-tallow propylenediamine, and the like.

Of particular interest because of the activity of the members thereof is the subclass of this genus of compounds wherein R is hydrogen.

In those compounds of formulae III, IV and V, the left hand form of one resonance hybrid (Form A') can be designated as a nitro(tetrahydro - 2H - 1,3 thiazin - 2 - ylidene)methyl aldehyde or ketone. The central form (Form B') can be designated as a 2 - (R1 - carbonyl - aci - nitromethyl) - 5,6 - dihydro - 4H 1,3 - thiazinium hydroxide inner salt. The right-hand form (Form C1) can be designated as a 2 - ((R' - hydroxymethylene)nitromethyl) - 5,6 - dihydro - 4H 1,3 - thiazinium hydroxide inner salt.

When R is hydrogen, these compounds may also exist in the corresponding tautomeric enol form which can be described by the formula:

This form (Form D) can be designated as a 2 - nitro - 2 - (5,6 - dihydro 2H - 1,3 - thiazin - 2 - yl) derivative of the unsaturated alcohol, CH2=C(OHR1.

The resonance hybrid may exist as either of two geometric (cis-trans) isomers, depending upon the spatial relationship of the moieties about the bond between the carbon atom of the nitromethylene moiety and the ring carbon atom to which it is joined.

In this specification, for the sake of simplicity, these compounds will be referred to generally as nitro(tetrahydro - 2H - 1,3 - thiazin - 2 - ylidene)methyl aldehydes and ketones. This terminology is intended to include all of the contributors to the resonance hybrid, the geometric isomers, and the enol forms, as well as mixtures thereof.

Desirably, the moiety represented by R contains no more than four carbon atoms, while the moiety represented by R1 contains no more than ten carbon atoms, and when R is alkyl it may be of straight-chain or branched-chain configuration.

The most interesting insecticidal properties appear to be associated with the compounds of the class wherein R is hydrogen or middle halogen, so that these subclasses are preferred.

Compounds of this invention of formulae I and II can be prepared by several general procedures: Method A: treating a nitroketene dimethyl mercaptole (NKDM) (R. Gompper & H.

Schaefer, Berichte, 100, 591 (1967)) with a 3 - amino - 1 - propanethiol (S.D.

Turk, et al., J. Org. Chem., 27, 2846 (1962)), including suitably substituted 3 amino - 1 - propanethiols, referring to the definitions of R and R'.

Method B: treating 5,6 - dihydro - 2 - (methylthio) - 4H - 1,3 - thiazine (A. F. McKay et al., J. Am. Chem. Soc. 80, 3339 (1958)) with an alkyl nitroacetate (S. Zen, et al., Kogyo Kagaku Zasshi, 74, 70 (1971)) in the presence of a catalytic amount of zinc ion (e.g., zinc chloride) to form the alkyl nitro(tetrahydro - 2H - 1,3 - thiazine 2 - ylidene)acetate, which is hydrolyzed with a base and decarboxylated by acidification to give the desired product.

Method C: substituting a moiety, R, on the ring nitrogen atom by treating tetrahydro - 2 (nitromethylene)- 2H - 1,3 - thiazine, which can be prepared by either of Methods A or B with a strong alkali. metal base in a liquid mixture of tetrahydrofuran and hexamethylphosphoramide, or with an alkali metal derivative of the appropriate alcohol in an alcohol as solvent, then treating the resulting intermediate with the appropriate R-sulfate, iodide, chloride, bromide or tosylate.

Method D: compounds of this invention wherein R is halogen can be prepared by direct halogenation, by elemental halogen or by a halogenated compound containing positive halogen, of the appropriate R=H precursor.

Method E: involves a Mannich Reaction, wherein tetrahydro - 2 - (nitromethylene) - 2H - 1,3 - thiazine is treated with a dihaloaniline with the resulting mixture being treated with formaldehyde to form the substituted aminomethyl nitromethylenethiazine.

Method F: Compounds of the invention wherein R' is -CH2-NR2R3 can be prepared by treating 2 - nitro - 2 - (tetrahydro - 2H - 1,3 - thiazin - 2 - ylidene)ethanol (R1=-CH2OH) with the appropriate amine, H-NR2R3.

Method A is carried out by mixing the reactants in a liquid medium such as an alkanol of from 1 to 10 carbon atoms. The reaction can in some cases be carried out at essentially room temperature while in other cases gentle to moderate heating (up to 1000C) may be required. Generally, it will be found best to employ a slight to moderate excess (5-25%) of the thiol over that theoretically required to react with the mercaptole. For best results, oxygen should be excluded from the reaction zone by conducting the reaction in a nitrogen atmosphere. The product can be recovered by removing the solvent, digesting the residue with water and then extracting the desired product from the aqueous phase by means of a solvent such as methylene chloride.

Method B can be conducted by gradually treating the thiazine with a slight to moderate (5-20%) excess of the alkyl nitroacetate at a moderately elevated temperature, e.g. 80--1300C, in the presence of a catalytic amount of zinc ion which conveniently is supplied as zinc chloride, to form the thiazine acetate intermediate. While a solvent may be used, in some cases at least, one will not be required. The product can be worked up by conventional extraction and crystallization techniques. The acetate then is decarboxylated by treatment (hydrolysis) with excess base, followed by neutralization of the mixture and recovery of the product. The hydrolysis can be effected at room temperature or at slight to moderately elevated temperatures. Product work-up again can be effected by conventional filtration, extraction, crystallization and elution (chromatographic) techniques.

In method C the thiazine is substituted on the ring nitrogen atom by treating the thiazine with about an equimolar amount of a strong alkali metal base in a liquid reaction medium at room temperature or at a slight to moderately elevated temperature, then treating the resulting mixture with about the theoretical amount of the sulfate, iodide, bromide, chloride or tosylate of the moiety, R, to be substituted on the nitrogen atom of the thiazine ring. This latter treatment preferably is conducted at temperatures below room temperature, for example, at 0--15"C. The base used may be, for example, sodium, potassium or lithium hydrides, their hydroxides, or alkyls or alkoxides of from 1 to 10 carbon atoms. An example of a liquid reaction medium for use with the metal hydride, alkyl or hydroxide thereof is tetrahydrofuran/hexamethyl - phosphoramide mixture.

Where an alkoxide is used, it preferably is tertiary-butoxide and the solvent is tertiary butyl alcohol. In many cases, at least, it will not be necessary to isolate the intermediate product-the crude reaction mixture containing it may be treated with the R-sulfate, -iodide, -bromide, -chloride or -tosylate.

As has been indicated, most of the reactions should be conducted in a nitrogen atmosphere, and the techniques for recovery and purification of the intermediate and final products from the crude reaction mixtures are conventional and are illustrated in the examples indicated hereinafter.

In Method D, the thiazine compound (R=H), optionally dissolved in a solvent, optionally in the presence of a hydrogen halide acceptor, is treated with an equimolar quantity of a halogen or of a positive halogenating agent. Suitable positive halogenating agents are any of the conventional halogenating agents in which the halogen has a positive character, such as N-chloro- and Nbromosuccinimide. Water is ordinarily suitable and convenient as the solvent when chlorine or bromine is used as the halogenating agent. When a positive halogenating agent is used, the haloalkanes of from I to 10 carbon atoms are suitable solvents. The reaction ordinarily can be effected under mild conditions, e.g., OOC to about 45"C. To avoid di-halogenation, it is usually desirable to employ a temperature of the range of 5--10"C and add the halogen slowly with vigorous stirring to avoid local excess of the halogen.

In Method E, the thiazine reactant preferably is mixed with a small amount of an alkanol of from 1 to 10 carbon atoms and the reactions are conducted at about room temperature. In some cases it may be necessary to heat the mixture to a moderately elevated temperature-e.g. about 50"C, to effect the reaction at a reasonable rate.

In Method F, the treatment is carried as described for Method E. Preparation of the precursor alcohol is described in Example 3.

In some cases, the product is non-basic in character so that it will not form a salt with the by-product hydrogen halide even when no acid acceptor is present. In such cases, the desired product can be recovered by extracting the reaction mixture with a non-water soluble solvent, then evaporating the solvent. Suitable solvents are the halogenated alkanes such as methylene chloride. Where the product forms the salt, the product can be recovered by treating the reaction mixture with a base such as sodium bicarbonate to spring the product, then recovering it by solvent extraction of the aqueous mixture with a halogenated alkane.

Compounds of the invention of formulae III, IV and V can be prepared by several general procedures. In some cases, they can be prepared directly as by heating together at a moderately elevated temperature (5l 500 C) 5,6 - dihydro 2 - (methylthio) - 4H - 1,3 - thiazine (A. F. McKay et al., J. Am. Chem. Soc., 80, 8339 (1958)) and the appropriate nitromethyl ketone in the presence of a catalytic amount of zinc ion.

In many cases it will be found that the most facile procedure will be the acylation of the nitromethylene thiazines, which thiazines can be prepared by the method A or B described above.

A thiazine may be substituted on the ring nitrogen atom by treating the thiazine with about an equimolar amount of a strong alkali metal base in a liquid reaction medium at room temperature or at a slight to moderately elevated temperature, then treating the resulting mixture with about the theoretical amount of the sulfate, iodide, bromide, chloride or tosylate of the moiety, R, to be substituted on the nitrogen atom of the thiazine ring. This latter treatment preferably is conducted at temperatures below room temperature, for example, at 0--15"C. The base used may be, for example, sodium, potassium, or lithium hydrides, their hydroxides or alkyls or alkoxides of from 1 to 10 carbon atoms. An example of a liquid reaction medium for use with the metal alkyl or hydride thereof is tetrahydrofuran/hexamethylmethylphosphoramide mixture; where an alkoxide is used, it preferably is the tertiary-butoxide and the solvent is tertiary butyl alcohol.

In many cases, at least, it will not be necessary to isolate the intermediate product-the crude reaction mixture containing it may be treated with the Rsulfate, -iodide, -bromide or -tosylate.

As has been indicated, most of the reactions are best conducted in a nitrogen atmosphere, and the techniques for recovery and purification of the intermediate and final products from the crude reaction mixtures are conventional and are illustrated in the examples indicated hereinafter.

Acylation of the nitromethylene thiazine is readily accomplished by heating together at a moderately elevated temperature-for example, 60--150"CC-the thiazine and the appropriate acid anhydride, using a solvent if necessary. In some cases, an excess of the anhydride can be used as the solvent. In other cases, another inert solvent can be used-halogenated alkanes such as methylene chloride and I ,2-dichloroethane are suitable. Recovery of the product is readily effected by conventional techniques such as distillation, extraction, filtration, recrystallization, elution and the like, as illustrated in the examples hereinafter.

Compounds of the invention wherein R is halogen can be prepared by treating the unsubstituted precursor (R=H) with about a 10% molar excess of a halogen or a halogenated compound containing positive halogen at about room temperature, employing a halogenated alkane as solvent. Examples of halogenating agents are chlorine, bromine, N-chloro- and N-bromosuccinimide. Recovery of the product is conveniently effected by filtering the mixture, evaporating the solvent and recrystallizing the product. Other conventional techniques such as distillation, extraction and elution can be used as appropriate.

In some cases, the acylation is conveniently effected by treating the appropriate thiazine with a 1 - (R' - carbonyl) - 3 - methylimidazolium chloride by the method described by E. Guibe-Jampel, et al., Bull. Soc. Chim. Fr. 1973 (3) (Pt. 2), pp. 1021-7. According to this method the imidazolium chloride is prepared by treating 1 - methylimidazole with the appropriate acid chloride, R'--C(O))-CI, preferably in a solvent and at a low temperature, for example, about 0 C. A suitable general method for conducting this procedure comprises adding a solution of the acid chloride in tetrahydrofuran or monoglyme slowly (e.g., dropwise) to a cold (e.g., OOC) solution of the N - methylimidazole in the same solvent, stirring the cold mixture for a period of from about 15 minutes to one hour to ensure complete reaction, then adding to that stirred cold mixture a solution of the thiazine, then warming the stirred mixture to a temperature of from about room temperature to the reflux temperature, and stirring the warm mixture for a time to ensure complete reaction.

The desired product can be isolated from the crude reaction mixture and purified by conventional methods, such as filtration, extraction, crystallization and elution (chromatography).

The invention will be further understood from the following in which Example 1 relates to an intermediate and Examples 2 to 4 relate to compounds of the invention. In all cases, the identity of the product and the identity of any intermediate used was confirmed by appropriate analyses.

EXAMPLE 1 Tetrahydro-2-(nitromethylene)-2H-l ,3-thiazine (1) Ethyl nitro (tetrahydro-2H- 1 ,3-thiazin-2-ylidene)-acetate (1 A) To a mixture of 235 g of 5,6 - dihydro - 2 - (methylthio) - 4H - 1,3 - thiazine and 2 g of zinc chloride at approximately 1150C in a nitrogen atmosphere, 263 g of ethyl nitroacetate was added dropwise over a 1.5 hour period. The mixture was held at 1 10--120"C. When evolution of methyl mercaptan ceased after 45 minutes further stirring of the heated mixture, 1 g of zinc chloride was added and the mixture was stirred at about 115 C for 1.25 hours. An additional 1 g of zinc chloride then was added and stirring of the mixture at about 115"C was continued for 1.5 hours. The mixture then was poured into a cooled solution of 2/1 wt.

ether/isopropyl alcohol mixture. The crystallized product was collected, washed with ether and dried under reduced pressure to leave a tan solid, m.p. 101020C, which on recrystallization from methanol gave IA as a pale yellow solid, m.p. 105 106"C.

2.3 g of IA was added to 10 ml of 20% wt. aqueous sodium hydroxide and the mixture was stirred at room temperature for 12 hours. The resulting solution was treated dropwise with 3.5 g of acetic acid. The addition was accompanied by vigorous gas evolution. The resulting mixture was extracted with methylene chloride and the extract was dried (magnesium sulfate) and concentrated under reduced pressure to give I as a pale yellow solid, m.p. 76--780C.

EXAMPLE 2 3,4-dichloro-N-(2-nitro-2-(tetrahydro-2H- 1,3- thiazine-2-ylidene)ethylbenzeneamine (2) Method E 18 g of 25 /n wt. aqueous 3,4 - dichloroaniline was added to a slurry of 4 grams of I in 12 ml of ethanol. Then, with external cooling, 2.3 g of 37 /n wt. aqueous formaldehyde was added at 24--270C. The mixture then was stirred for 2 hours at 25"C, then was diluted with water and extracted with methylene chloride. The extract was dried and concentrated under reduced pressure to leave a yellow solid.

This solid was washed with ether and air dried to give 2 as a bright yellow solid, m.p.: 132--1330C.

EXAMPLE 3 2,4-dichloro-N-(2-nitro-2-(tetrahydro-2H- 1,3 thiazin-2-ylidene) ethylbenzene amine (3) 2-nitro-2-(tetrahydro-2H- 1,3 thiazin-2-ylidene)ethanol (3A) 36.8 ml of 370, wt. formaldehyde in water was added dropwise over a 30minute period to a slurry of 32 g of 1 in 120 ml of ethanol and 2 g of triethylamine (as catalyst), at 5--10"C. 30 ml of ethanol and 20 ml of water were added to facilitate stirring and the mixture was stirred overnight. The solid which formed was separated by filtration and was washed with ethanol and ether, then was dried in a vacuum oven to give 3A, as a light yellow solid, m.p.: 132-1330C (with decomposition).

3.9 g of 2,4-dichloroaniline was added, in several parts, to a solution of 3.7 g of 3A in 25 ml of ethanol at 10"C. The mixture was stirred for 2 hours, being allowed to warm to room temperature. It then was stirred and heated gently, to 500C for 1.5 hours. It then was allowed to stir overnight at room temperature. The solid product was separated by filtration. It was washed with isopropyl alcohol, then with ether and air-dried. The residue was stirred in methylene chloride for 15 minutes. The mixture was filtered, the filtrate was washed with 5% wt. sodium hydroxide solution, then was dried and the solvent was evaporated to give 3, as a light yellow solid, m.p.: 122--1240C.

EXAMPLE 4 2-nitro- 1 - [2-(methoxycarbonyl)ethyl] -2-(tetrahydro- 2H-1,3-thiazine-2-ylidene)ethanone (4) A solution/suspension of 16.7 g of 2-methoxycarbonyl propionyl chloride in 25 ml of monoglyme was added dropwise at 5--100C to a solution of 9.09 g of N methylimidazole in 75 ml of monoglyme and the mixture was stirred for an additional 30 minutes at 5-100C after which was added dropwise (same temperature) a solution/suspension of 16.0 g of tetrahydro - 2 - (nitromethylene) 2H - 1,3 - thiazine in 25 ml of monoglyme, after which the stirred mixture was allowed to warm to room temperature and stirred for 96 hours. The mixture then was taken up in methylene chloride, washed with water and saturated sodium chloride solution, dried (Na2SO4) and the solvent evaporated under reduced pressure to give an oil which was chromatographed on florosil (Registered Trade Mark) using methylene chloride as eluent to give a gum, which was washed with ether to give 4, as a pale green solid, m.p.: 87-87.50C.

The compounds of this invention exhibit useful insecticidal activity, being of particular interest for control of the larvae "caterpillar" or "worm" forms of insects of the genus Heliothis, such as H. zea (corn earworm), cotton bollworm, tomato fruitworm), H. virescens (tobacco budworm); the genus Agrotis, such as A.

ipsilon (black cutwork); the genus Trichoplusia, such as T. ni (cabbage looper), and the genus Spodoptera, such as S. littoralis (Egyptian cotton leafworm). Some are also of interest for controlling aphids whiteflies and houseflies. In tests that have been conducted they have exhibited low, or no, toxicity to other insects such as the 2-spotted spider mite and mosquito larva. Some act very rapidly, providing "quick knock-down" of insects, in some cases even though the compound is not very toxic to the insects.

Activity of compounds of this invention with respect to insects was determined by using standardized test methods to establish the LC50 dosage (in milligrams of test compound per 100 millilitres of solvent or liquid carrier required in the solution of suspension of test compound used) that was required to kill 50% of the test insects. The test insects were the housefly, corn earworm, pea aphid and 2-spotted spider mite, and in some cases the black cutworm. Activity with respect to mosquito larvae was determined by placing the larvae in water containing the test compound.

Compounds 2 and 3 were found to be inactive or but slightly active with respect to the mites and mosquito larvae. With respect to the corn earworm compounds 2 and 3 were found to be active.

Compound 4 was found to be active with respect to the housefly, with respect to the pea aphid. Compound 4 acted very quickly upon corn earworms.

The invention includes within its scope insecticidal compositions comprising an adjuvant-that is, a carrier, optionally a surface-active agent-and, as active ingredient, at least one insecticide of this invention. Likewise the invention includes also a method of combating insect pests at a locus which comprises applying to the locus an effective amount of at least one insecticide of the invention.

The term "carrier" as used herein means a material, which may be inorganic or organic and of synthetic or natural origin with which the active compound is mixed or formulated to facilitate its application to the plant, seed, soil and other object to be treated, or its storage, transport or handling. The carrier may be a solid or a liquid.

Examples of solid carriers are natural and synthetic clavs and silicates, for example, natural silicas such as dlatomacec,us earths. magnesium silicates, for example, talcs; magnesium aluminum silicates, for example, attapulgites and vermiculites; aluminum silicates, for example, kaolinites, montmorillonites and micas; calcium carbonate; calcium sulfate; synthetic hydrated silicon oxides and synthetic calcium or aluminum silicates; elements such as for example, carbon and sulfur; natural and synthetic resins such as, for example, coumarone resins, polyvinyl chloride and styrene polymers and copolymers; solid polychlorophenols; bitumen, waxes such as beeswax, paraffin wax, and chlorinated mineral waxes; degradable organic solids, such as ground corn cobs and walnut shells; and solid fertilizers, for example, superphosphates.

Liquid carriers may be solvents for the compounds of this invention or liquids in which the toxicant is insoluble or only slightly soluble.

Examples of such solvents and liquid carriers generally are water, alcohols, for example, isopropyl alcohol, ketones, such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ethers; aromatic hydrocarbons such as benzene, toluene and xylene; petroleum fractions, such as kerosene, light mineral oils, chlorinated hydrocarbons, such as carbon tetrachloride, perchlorethylene, trichloroethane, including liquefied normally vaporous gaseous compounds.

Mixtures of different liquids are often suitable.

If used, the surface-active agent may be an emulsifying agent or a dispersing agent or a wetting agent. It may be nonionic or ionic. Surface-active agents usually applied in formulating pesticides may be used. Examples of such surface-active agents are the sodium or calcium salts of polyacrylic acids and lignin sulfonic acids; the condensation products of fatty acids or aliphatic amines or amides containing at least 12 carbon atoms in the molecule with ethylene oxide and/or propylene oxide; fatty acid esters of glycerol, sorbitan, sucrose or pentaerythritol; fatty acid salts of low molecular weight, mono-, di- and trialkylamines; condensates of these with ethylene oxide and/or propylene oxide; condensation products of fatty alcohols or alkyl phenols, for example, p-octylphenol or p-octylcresol, with ethylene oxide and/or propylene oxide; sulfates or sulfonates of these condensation products; alkali or alkaline earth metal salts, preferably sodium salts, of sulfuric or sulfonic acids esters containing at least 10 carbon atoms in the molecule, for example, sodium lauryl sulfate, sodium secondary alkyl sulfates, sodium salts of sulfonated caster oil, and sodium alkaryl sulfonates such as sodium

These compositions are applied in sufficient amount to supply the effective dosage of toxicant at the locus to be protected. This dosage is dependent upon many factors, including the carrier employed, the method and conditions of application, whether the formulation is present at the locus in the form of an aerosol, or as a film, or as discrete particles, the thickness of film or size of particles and the insect species to be controlled, proper consideration and resolution of these factors to provide the necessary dosage of active material at the locus being within the skill of those versed in the art. In general, however, the effective dosage of toxicants of this invention at the locus to be protected-i.e. the dosage to which the insect contacts-is of the order of 0.001% to 0.5% based on the total weight of the formulation, though under some circumstances the effective concentration will be as little as 0.0001% or as much as 2%, on the same basis.

WHAT WE CLAIM IS: 1. Tetrahydro - 2 - (nitromethylene) - 2H - 1,3 - thiazines being resonance hybrids, the principal forms contributing thereto being described by the formulae:

and nitro(tetrahydro - 211 - 1,3 - thiazin - 2 - ylidene)methyl aldehydes and ketones being resonance hybrids, the principal forms contributing thereto being described by the formulae:

wherein in formulae I and II; R is hydrogen, alkyl, alkenyl, alkoxyalkyl, cycloalkylalkyl, cyanoalkyl, haloalkenyl, aralkyl or alkoxycarbonylvinyl, and R1 is -CH2-NR2R3, wherein R2 is haloaryl andR3 is hydrogen, alkyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, alkenyl, aryl, haloaryl, or aralkyl; and in formulae III, IV and V, R is hydrogen, halogen, or alkyl of from one to eight carbon atoms, and R1 is alkoxycarbonylalkyl; tautomeric forms thereof and salts of the thiazines.

2. Tetrahydro - 2 - (nitromethylene) - 2H - 1,3 - thiazines being resonance

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. These compositions are applied in sufficient amount to supply the effective dosage of toxicant at the locus to be protected. This dosage is dependent upon many factors, including the carrier employed, the method and conditions of application, whether the formulation is present at the locus in the form of an aerosol, or as a film, or as discrete particles, the thickness of film or size of particles and the insect species to be controlled, proper consideration and resolution of these factors to provide the necessary dosage of active material at the locus being within the skill of those versed in the art. In general, however, the effective dosage of toxicants of this invention at the locus to be protected-i.e. the dosage to which the insect contacts-is of the order of 0.001% to 0.5% based on the total weight of the formulation, though under some circumstances the effective concentration will be as little as 0.0001% or as much as 2%, on the same basis. WHAT WE CLAIM IS:

1. Tetrahydro - 2 - (nitromethylene) - 2H - 1,3 - thiazines being resonance hybrids, the principal forms contributing thereto being described by the formulae:

and nitro(tetrahydro - 211 - 1,3 - thiazin - 2 - ylidene)methyl aldehydes and ketones being resonance hybrids, the principal forms contributing thereto being described by the formulae:

wherein in formulae I and II; R is hydrogen, alkyl, alkenyl, alkoxyalkyl, cycloalkylalkyl, cyanoalkyl, haloalkenyl, aralkyl or alkoxycarbonylvinyl, and R1 is -CH2-NR2R3, wherein R2 is haloaryl andR3 is hydrogen, alkyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, alkenyl, aryl, haloaryl, or aralkyl; and in formulae III, IV and V, R is hydrogen, halogen, or alkyl of from one to eight carbon atoms, and R1 is alkoxycarbonylalkyl; tautomeric forms thereof and salts of the thiazines.

2. Tetrahydro - 2 - (nitromethylene) - 2H - 1,3 - thiazines being resonance

hybrids, the principal forms contributing thereto being described by formulae I and II as defined in Claim 1.

3. Nitro(tetrahydro - 2H - 1,3 - thiazin - 2 - ylidene)methyl aldehydes and ketones being resonance hybrids, the principal forms contributing thereto being described by formulae III, IV and V as defined in Claim 1.

4. Insecticidal compositions comprising a compound as claimed in Claim 1, 2 or 3, together with an adjuvant therefor.

5. Method for combatting insects using a compound as claimed in Claim 1, 2 or 3, or a composition as claimed in Claim 4.

6. A compound as claimed in Claim I and as hereinbefore described with particular reference to any one of Examples 2 to 4.

7. A process for preparing a compound as claimed in Claim 1 as hereinbefore described with particular reference to any one of Examples 2 to 4.

8. Composition as claimed in Claim 4 and as hereinbefore described.