Unsymmetrical Aminosulfinamide Derivatives of N-Phosphonomethylglycinonitrile, Herbicidal Compositions and Use

This invention relates to unsymmetrical aminosulfinamide derivatives of N-phosphonomethyl-glycinonitrile which are useful as herbicides. This invention further relates to herbicidal compositions containing such derivatives and to herbicidal methods employing such compounds and compositions.

U.S. Pat. No. 4,067,719 issued to Gerard A. Dutra on Jan. 10, 1978, discloses N-phosphono-methylglycinonitriles of the formula ##STR1## wherein (Aryl) is selected from phenyl, naphthyl or biphenyl, each x is a substituent on said Aryl selected from halogen, alkyl of 1 to 4 carbons, alkoxy and alkylthio of 1 to 3 carbons, alkoxycarbonyl of 2 to 3 carbon atoms, methylenedioxy, cyano, trifluoromethyl or nitro, Z is oxygen or sulfur, a is an integer from zero to 3, b is an integer from zero to 1, Y is a strong acid capable of forming a salt with the amino group, and x is zero or 2, provided that x must be zero when b is 1, as well as a process for producing such compounds. These N-phosphonomethylglycinonitriles are said to be useful as herbicides.

U.S. Pat. No. 4,008,296 issued to John Edward D. Barton on Feb. 15, 1977, describes ester derivatives of N-phosphonomethylglycinonitrile having the formula ##STR2## wherein Z.sub.1 and Z.sub.2 each represent an alkyl radical of from 1 to 6 carbon atoms; which are said to be useful as herbicides.

Japanese L.O.P. No. 142047/1977 discloses phenylcyanomethylaminomethylphosphonates of the formula ##STR3## wherein Z.sub.3 is hydrogen or phenyl and Z.sub.4 is phenyl. Japanese L.O.P. No. 93323/1974 describes the preparation of N-(diethylphosphonomethyl)aminoacetonitrile.

U.S. Pat. No. 4,407,764 issued to James A. Sikorski et al on Oct. 4, 1983, discloses compounds represented by the formula ##STR4## wherein R is phenyl, naphthyl or biphenyl; or phenyl, naphthyl or biphenyl substituted with from 1 to 3 substituents independently selected from the group consisting of lower alkyl, lower alkoxy, methylenedioxy; and R.sub.1 is phenyl or phenyl substituted with from 1 to 3 substituents independently selected from the group consisting of lower alkyl and lower alkoxy.

Japanese L.O.P. No. 56-1566295/1981 describes the preparation and herbicidal utility of symmetrical aminosulfinamide derivatives of the formula ##STR5## wherein Z.sub.5 is phenyl.

In accordance with the present invention there is provided novel aminosulfinamide derivatives of N-phosphonomethylglycinonitrile represented by the formula ##STR6## wherein R is selected from the group consisting of phenyl; or phenyl substituted with from 1 to 3 substituents independently selected from the group consisting of lower alkyl, lower alkoxy, trifluoromethyl, nitro, and halogen; and wherein R.sub.1 and R.sub.2 are independently selected from the group consisting of alkyl, cycloalkyl, alkenyl, alkynyl, aralkyl and R; or R.sub.1 and R.sub.2 are independently selected from the aforerecited groups and joined together through the nitrogen to form a cyclic structure having 4-8 carbon atoms. The above described compounds are herbicidally active.

These compounds are prepared by reacting a compound of the formula ##STR7## wherein R is as aforedefined with thionyl chloride in an aprotic solvent and in the presence of a hydrogen chloride acceptor to form a compound of the formula ##STR8## wherein R is as aforedefined.

The reaction temperature for the aforerecited reaction is in the range from about -50.degree. C. to about 100.degree. C., and is preferably from about -30.degree. C. to about +30.degree. C., although greater or lower temperatures may be employed if desired.

In preparing the compounds of formula (III), the ratio of reactants of formula (II) and thionyl chloride is not narrowly critical. For best results, however, for each mole of a compound of formula (II), one should employ one mole of thionyl chloride to produce one mole of a compound of formula (III).

The compound of formula (III) is reacted with a suitable secondary amine of the formula ##STR9## wherein R.sub.1 and R.sub.2 are as aforedefined in an aprotic solvent and in the presence of a hydrogen cloride acceptor to form a compound of formula (I).

In reacting a compound of formula (III) with a compound of formula (IV), the temperature is in the range from about -50.degree. C. to about 100.degree. C. and is preferably from about -30.degree. C. to about +30.degree. C. although greater or lower temperatures may be employed if desired.

The ratio of compounds of formula (III) to compound of formula (IV) is not critical. For best results, however, one should employ for each mole of a compound of formula (III) a mole of a compound of formula (IV).

Typical compounds which may be employed as a compound of formula (IV) include symmetrical secondary amines such as dimethylamine; diethylamine, diisopropylamine, diallylamine, dibutylamine, dioctylamine, diphenylamine, dicyclohexylamine, dibenzylamine, dipropargylamine, piperidine, homopiperidine, or morpholine and the like or unsymmetrical secondary amines such as N-methylaniline, N-methylbenzylamine, N-methylcyclohexylamine, N-methylbutylamine, N-methylpropargylamine and the like.

It is preferred that R is phenyl, R.sub.1 and R.sub.2 are preferably alkyl such as methyl, benzyl, phenyl or cyclic such as morpholino. These compounds appear to be most active herbicidally.

Illustrative of the substituted phenyl groups which R, R.sub.1, R.sub.2 independently represent are mono-substituted phenyl wherein the substituent is in the ortho, meta or para position, for example, methylphenyl, butylphenyl, methoxyphenyl, butoxyphenyl, fluorophenyl, chlorophenyl, bromophenyl, iodophenyl, trifluoromethylphenyl, nitrophenyl and the like, and the di- and tri-substituted phenyl groups wherein the substituents are the same or different and are located in the 2, 3, 4, 5, or 6 positions of the phenyl ring, for example, dichlorophenyl, dimethylphenyl, methylchlorophenyl, ethylfluorophenyl, dibutoxyphenyl, butylnitrophenyl, trimethylphenyl, trichlorophenyl, tributylphenyl, ethyldichlorophenyl and the like.

The term "alkyl" is employed throughout the claims and description to mean a substituted or unsubstituted monovalent radical in a straight or branched chain of the formula C.sub.n H.sub.2n+1 -derived from an aliphatic hydrocarbon by removal of one hydrogen therefrom wherein n is an integer from 1 to 10.

As employed herein, the term "lower alkyl" designates alkyl radicals which have from 1 to 4 carbon atoms in a straight or branched chain, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, and t-butyl.

The term "halo" or "halogen" as employed herein means chlorine, bromine, iodine, and fluorine.

The term "lower alkoxy" includes groups representative of the term "lower alkyl" in combination with oxygen and includes methoxy, ethoxy, propoxy, butoxy, mixtures thereof and the like.

Typical groups representative of the term "alkenyl" includes groups representative of the term "alkyl" which also contains a carbon-carbon double bond and includes allyl, propenyl, butenyl and the like.

Typical groups representative of the term "alkyl" includes groups representative of the term "lower alkyl" as well as groups such as n-pentyl, n-hexyl, n-heptyl, n-octyl, isopentyl, neopentyl, isohexyl, 2-methylpentyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl and the like.

The term "aralkyl" includes groups representative of the term "alkyl" in combination with phenyl or substituted phenyl groups and includes benzyl, phenethyl, phenylbutyl, and the like.

The term "cycloalkyl" is employed throughout the claims and description to mean carbon and hydrogen atoms arranged in a cyclic or ring arrangement having 3 to 8 carbon atoms therein. Typical groups representative of the term "cycloalkyl" include cyclopentyl, cyclohexyl, cyclopropyl, cyclooctyl and the like.

Typical groups representative of the embodiment wherein R.sub.1 and R.sub.2 are joined together to form a cyclic arrangement include morpholino, piperidino, thiomorpholino, azepano and the like.

Typical groups representative of the term "alkynyl" include groups representative of the term "alkyl" which also contain a carbon-carbon triple bond and include propargyl and butynyl and the like.

The hydrogen chloride acceptor is typically an amine, preferably a tertiary amine which will not react with the reactants employed or products formed. Examples of suitable tertiary amine hydrogen chloride acceptors include trimethylamine, triethylamine, tributylamine, trihexylamine, 1,5-diazabicyclo-[5.4.0]-undec-5-ene, pyridine, quinoline, mixtures thereof and the like.

Due to the reactive nature of the various reaction intermediates and reactants, the process of the present invention should be conducted in an aprotic solvent under essentially anhydrous conditions. Illustrative of the aprotic solvents employed in the process of this invention include benzene, toluene, methylene chloride, tetrahydrofuran, cyclohexane, methylcyclohexane, hexane, octane, dioxane, ethyl ether, mixtures thereof and the like, although a solvent is not required.

The following illustrative, non-limiting examples will serve to further demonstrate to those skilled in the art the process of this invention wherein specific compounds within the scope of this invention can be prepared. In the examples, all parts are parts by weight unless otherwise expressly stated.

A methylene chloride solution of this reagent was generated according to the procedure described in Japanese L.O.P. 57-120595/1982 as follows:

To a flame-dried 250 ml flask, cooled under nitrogen, was added 2.40 ml (3.9 g, 0.033 mol) of thionyl chloride and 75 ml of methylene chloride. The resulting solution was cooled to -30.degree. C. and then a solution of 10.0 g (0.033 mol) of diphenyl-N-phosphonomethylglycinonitrile and triethylamine (3.3 g, 0.033 mol) in 75 ml of CH.sub.2 Cl.sub.2 was added under nitrogen via double-ended needle at such a rate that the temperature did not exceed -30.degree. C. After 15 minutes at -30.degree. C., .sup.31 P NMR indicated that a clean, quantitative conversion to the aminosulfinyl chloride had occured (.delta.9.4 ppm) and the resulting heterogeneous mixture was subsequently used immediately without further purification.

To a flame-dried 500 ml flask, cooled under nitrogen, was added 100 ml of CH.sub.2 Cl.sub.2, 4.6 ml of triethylamine (3.3 g, 0.033 mol) and 0.033 mol of the appropriate secondary amine. The resulting solution was cooled to -30.degree. C. and then a methylene chloride solution containing phosphonic acid [[[(cyanomethyl)-N-chlorosulfinyl]amino]methyl]-, diphenyl ester (0.033 mol) generated as described above was added slowly under nitrogen via double-ended needle at such a rate that the temperature did not exceed -30.degree. C. When the addition was complete, the reaction mixture was allowed to come to room temperature, concentrated at 20.degree. C. to approximately one-half the volume using a rotovap, and then washed successively twice with an equal volume of 5% NaOH and twice with cold brine solution; dried over MgSO.sub.4, filtered and concentrated to give crude products. The crude products were purified either by crystallization from 50:50 ethyl acetate/cyclohexane or by preparative thin-layer chromatography on silica gel eluting with 50:50 ethyl acetate/cyclohexane to give the desired aminosulfinamide derivatives of N-phosphonomethylglycinonitrile. 'H and .sup.31 P NMR, TLC, and elemental analysis were all consistent with pure products.

Phosphonic acid, [[(cyanomethyl) (4-morpholinosulfinyl)amino]methyl]-, diphenyl ester, corresponding to a compound of formula I wherein R is phenyl and R.sub.1 and R.sub.2 are joined together to form the cyclic structure morpholine, was prepared via the above procedure as a white solid having a melting point of 82.5.degree.-83.5.degree. C.

Anal. Calc'd. for C.sub.19 H.sub.22 N.sub.3 O.sub.5 P.sub.1 S.sub.1 : C, 52.41; H, 5.09; N, 9.65; S, 7.36. Found: C, 52.58; H, 5.15; N, 9.44; S, 7.25.

Phosphonic acid, [[(cyanomethyl) (diallyl-aminosulfinyl)amino]methyl]-, diphenyl ester, corresponding to a compound of formula I wherein R is phenyl and R.sub.1 and R.sub.2 are each allyl was prepared via the above procedure as a yellow oil having a refractive index n.sup.21.5 =1.5481.

Anal. Calc'd. for C.sub.21 H.sub.24 N.sub.3 O.sub.4 P.sub.1 S.sub.1 : C, 56.62; H, 5.43; N, 9.43; S, 7.20. Found: C, 56.78; H, 5.59; N, 9.26; S, 7.39.

Phosphonic acid, [[[(cyanomethyl) (N-methyl-N-phenyl)aminosulfinyl]amino]methyl]-, diphenyl ester, corresponding to a compound of formula I wherein R is phenyl, R.sub.1 is methyl and R.sub.2 is phenyl, was prepared via the above procedure as a white solid having a melting point of 79.degree. C.

Anal. Calc'd. for C.sub.22 H.sub.22 N.sub.3 O.sub.4 P.sub.1 S.sub.1 : C, 58.01; H, 4.87; N, 9.23; S, 7.04. Found: C, 58.08; H, 4.98; N, 9.23; S, 6.99.

Phosphonic acid, [[(cyanomethyl) (dicyclohexylaminosulfinyl)animo]methyl]-, diphenyl ester, corresponding to a compound of formula I above wherein R is phenyl and R.sub.1 and R.sub.2 are each cyclohexyl; was prepared via the above procedure as a white solid, m.p. 132.degree.-133.degree. C.

Anal. Calc'd. for C.sub.27 H.sub.36 N.sub.3 O.sub.4 P.sub.1 S.sub.1 : C, 61.23; H, 6.85; N, 7.93; S, 6.05. Found: C, 61.20; H, 6.88; N, 7.87; S, 6.16.

Phosphonic acid, [[[(cyanomethyl) (N-methyl-N-benzyl)aminosulfinyl]amino]methyl]-, diphenyl ester, corresponding to a compound of the formula I wherein R is phenyl, R.sub.1 is methyl, and R.sub.2 is benzyl; was prepared via the above procedure as a white solid, m.p. 92.degree.-93.5.degree. C.

Anal. Calc'd. for C.sub.23 H.sub.24 N.sub.3 O.sub.4 P.sub.1 S.sub.1 : C, 58.84; H, 5.15; N, 8.95; S, 6.83. Found: C, 58.47; H, 5.43; N, 8.67; S, 6.73.

Phosphonic acid, [[(cyanomethyl) (di-n-octylaminosulfinyl)amino]methyl]-, diphenyl ester, corresponding to a compound of formula I wherein R is phenyl and R.sub.1 and R.sub.2 are each n-octyl; was prepared via the above procedure as a yellow oil having a refractive index of n.sup.21.5 =1.5077.

Anal. Calc'd. for C.sub.31 H.sub.48 N.sub.3 O.sub.4 P.sub.1 S.sub.1 : C, 63.13; H, 8.20; N, 7.12; S, 5.44. Found: C, 63.06; H, 8.43; N, 6.83; S, 5.05.

Other compounds which may be prepared by this procedure include but are not limited to the following:

(a) Phosphonic acid, [[(cyanomethyl) (dimethylaminosulfinyl)amino]methyl],-diphenyl ester

(b) Phosphonic acid, [[(cyanomethyl) (1-piperidinylsulfinyl)amino]methyl],-bis(4-chloro-3-methylphenyl) ester

(c) Phosphonic acid, [[(cyanomethyl) (N-methyl-p-chlorophenylaminosulfinyl)amino]methyl],-bis(p-methoxyphenyl)e ster

(d) Phosphonic acid, [[(cyanomethyl) (N-methylpropargylaminosulfinyl)amino]methyl],- diphenyl ester

(e) Phosphonic acid, [[(cyanomethyl) (N-methyl-o-nitrophenylaminosulfinyl)amino]methyl],- diphenyl ester

The post-emergence herbicidal activity of some of the various compounds of this invention was demonstrated by greenhouse testing in the following manner. A good grade of top soil is placed in aluminum pans having holes in the bottom and compacted to a depth of 0.95 to 1.27 cm. from the top of the pan. A predetermined number of seeds of each of several dicotyledonous and monocotyledonous annual plant species and/or vegetative propagules for the perennial plant species are placed on the soil and pressed into the soil surface. The seeds and/or vegetative propagules are covered with soil and leveled. The pans are then placed on a sand bench in the greenhouse and watered from below as needed. After the plants reach the desired age (two to three weeks), each pan, except for the control pans, is removed individually to a spraying chamber and sprayed by means of an atomizer operating at a positive air pressure of approximately 1.46 kg/cm.sup.2 absolute. The atomizer contains 6 ml of a solution or suspension of the chemical. In that 6 ml is an amount of a cyclohexanone emulsifying agent mixture to give a spray solution or suspension which contains about 0.4% by weight of the emulsifier. The spray solution or suspension contains a sufficient amount of the candidate chemical in order to give application rates corresponding to those set forth in the tables. The spray solution is prepared by taking an aliquot of a 1.0% by weight stock solution or suspension of the candidate chemical in an organic solvent such as acetone or tetrahydrofuran or in water. The emulsifying agent employed is a mixture comprising 35 weight percent butylamine dodecylbenzene sulfonate and 65 weight percent of a tall oil ethylene oxide condensate having about 11 moles of ethylene oxide per mole of tall oil. The pans are returned to the greenhouse and watered as before and the injury to the plants as compared to the control is observed at approximately two weeks and the results recorded. The test results are reported in Tables I and II below.

The post-emergence herbicidal activity index used in Table I is as follows:

The plant species utilized in these tests are identified by letter in accordance with the following legend.

From the test results presented in Table I, it can be seen that the postemergent herbicidal activity of the compounds of this invention is, for the most part, general in nature. In certain specific instances, however, some selectivity is demonstrated. In this regard it should be recognized that each individual species selected from the above tests is representative member of a recognized family of plant species.

The herbicidal compositions, including concentrates which require dilution prior to application to the plants of this invention contain from 5 to 95 parts by weight of at least one compound of this invention and from 5 to 95 parts by weight of an adjuvant in liquid or solid form, for example, from about 0.25 to 25 parts by weight of wetting agent, from about 0.25 t 25 parts by weight of a dispersant and from 4.5 to about 94.5 parts by weight of inert liquid extender, e.g., water, acetone, tetrahydrofuran, all parts being by weight of the total composition. Preferably, the compositions of this invention contain from 5 to 75 parts by weight of at least one compound of this invention, together with the adjuvants. Where required, from about 0.1 to 2.0 parts by weight of the inert liquid extender can be replaced by a corrosion inhibitor such as ethanol mercaptan, sodium thiosulfate, dodecylmono or dimercaptan or antifoaming agent such as a dimethylpolysiloxane, or both. The compositions are prepared by admixing the active ingredient with an adjuvant including diluents, extenders, carriers and conditioning agents to provide compositions in the form of finelydivided particulate solids, pellets, solutions, dispersions or emulsions. Thus, the active ingredient can be used with an adjuvant such as a finelydivided solid, a liquid of organic origin, water, a wetting agent, a dispersing agent, an emulsifying agent or any suitable combination of these.

The herbicidal compositions of this invention, particularly liquids and soluble powders, preferably contain as a conditioning agent one or more surfaceactive agents in amounts sufficient to render a given composition readily dispersible in water or in oil. The incorporation of a surfaceactive agent into the compositions greatly enhances their efficacy By the term "surfaceactive agent", it is understood that wetting agents, dispersing agents, suspending agents and emulsifying agents are included therein. Anionic, cationic and nonionic agents can be used with equal facility.

Preferred wetting agents are alkyl benzene and alkyl naphthalene sulfonates, sulfated fatty alcohols, amines or acid amides, long chain acid esters of sodium isothionate, esters of sodium sulfosuccinate, sulfated or sulfonated fatty acid esters petroleum sulfonates, sulfonated vegetable oils, polyoxyethylene derivatives of phenols and alkylphenols (particularly isooctylphenol and nonylphenol) and polyoxyethylene derivatives of the monohigher fatty acid esters of nexitol and anhydrides (e.g., sorbitan). Preferred dispersants are methyl cellulose, polyvinyl alcohol, sodium lignin, sulfonates, polymeric alkyl napthalene sulfonates sodium napthalene sulfonate, polymethylene bisnaphthalenesulfonate and sodium Nmethyl-N-(long chain acid) taurates.

When operating in accordance with the present invention, effective amounts of the compounds or compositions of this invention are applied to the plants, or are incorporated into aquatic media in any convenient fashion. The application of liquid and particulate solid compositions to plants or soil can be carried out by conventional methods, e.g., power dusters, boo and hand sprayers and spray dusters. The compositions can also be applied from airplanes as a dust or a spray because of their effectiveness at low dosages. The application of herbicidal compositions to aquatic plants is usually carried out by adding the compositions to the aquatic media in th area where control of the aquatic plants is desired.

The application of an effective amount of the compounds or compositions of this invention to the plant is essential and critical for the practice of the present invention. The exact amount of active ingredient to be employed is dependent upon the response desired in the plant as well as such other factors as the plant species and stage of development thereof, and the amount of rainfall as well as the specific glycine employed. In foliar treatment for the control of vegetative growth, the active ingredients are applied in amounts from about 11.2 to about 56.0 or more kilograms per hectare. In applications for the control of aquatic plants, the active ingredients are applied in amounts of from about 100 parts per million to about 1000 parts per million, based on the aquatic medium. An effective amount for phytotoxic or herbicidal control is that amount necessary for overall or selective control, i.e., a phytotoxic or herbicidal amount. It is believed that one skilled in the art can readily determine from the teachings of this specification, including examples, the approximate application rate.

There are several possible methods for applying liquid compositions of thi invention to emerged plants. Such methods include the use of wiper system whereby the plant to be treated is contacted with an absorbent material containing the particular liquid composition, a portion of which is thereby released onto the plant upon contact therewith. Such wiper system typically comprise a reservoir of the liquid composition into which a portion of the absorbent material is placed and is fed therethrough. Generally, substances employable as absorbent material include substances of any shape or form capable of absorbing the liquid composition and releasing a portion of the same upon contact with the plant. Typical absorbent materials include felt, foam rubber, cellulose, nylon, sponges, hemp, cotton, burlap, polyester over acrylic, combinations thereof and th like. Forms of absorbent material include rope, twine, string, cloths, carpets, combinations thereof and the like. These forms may be assembled in any manner desired including a pipe rope wick, a wedge rope wick, a multirope wick and the like.

In another possible application method, liquid compositions may be selectively applied to weeds by the use of recirculating sprayer systems wherein the recirculating spray unit is mounted on a tractor or high clearance mobile equipment and the spray is directed horizontally onto th weeds growing over a crop. Spray not intercepted by the weeds is collecte in a recovery chamber before contacting the crop and is reused. Roller applications may also be employed to apply liquid compositions to weeds growing over a crop.

In yet another possible application method, shielded applicators may be employed to direct the liquid composition in the form of a spray onto the weeds while effectively shielding the crops from the spray.

These and other possible application methods for selectively applying liquid compositions to weeds are discussed in detail in Innovative Method of PostEmergence Weed Control, McWhorter C. G., Southern Weed Science Society, 33rd Annual Meeting Proceedings, Jan. 15-17, 1980; Auburn University Printing Service, Auburn, Ala., U.S.A., the teachings of which are incorporated herein by reference in their entirety.

Another possible method of applying liquid compositions of this invention to plants includes controlled droplet application which is also known as the ultra lowvolume chemical application. Controlled droplet application involves the production of uniform or nearly uniform spray drops of a predetermined size and the conveyance of these drops with negligible evaporation to a spray target. In particular, this method comprises feeding spray solutions to a rotary atomizer comprising a small disk with serrated edges that disperses liquid into droplets as the disk spins. Different droplet sizes are produced by changing solution flow rates to the spinning disk or changing the speed of rotation of the disk.

Those of skill in the art will recognize that the physical and chemical characteristics of the compound or composition employed will determine to a large extent the particular application method selected therewith.

The aforementioned and other methods for applying liquid compositions to plants are discussed in detail in "Rope Wick Applicator--Tool With A Future", Dale, James E., pp. 3-4, "The Recirculating Sprayer and Roundup.RTM. Herbicide", Derting, Claude W., pp. 5-7, and "C.D.A. Herbicide Application", McGarvey, Frank X., Weeds Today, Volume 11, Numbe 2, pp. 8-9, Late Spring, 1980, 309 W. Clark St., Champaign, Ill., the teaching of which are incorporated herein by reference in their entirety.

Although this invention has been described with respect to specific modifications, the details thereof are not to be construed as limitations for it will be apparent that various equivalents, changes, and modifications may be resorted to without departing from the spirit and scope thereof and it is understood that such equivalent embodiments are intended to be included herein.