US3647793A

US3647793A - 2-piperidino-3-phenylquinoxaline compounds

Info

Publication number: US3647793A
Application number: US871035A
Authority: US
Inventors: Quentin Francis Soper
Original assignee: Eli Lilly and Co
Current assignee: Eli Lilly and Co
Priority date: 1968-03-22
Filing date: 1969-11-05
Publication date: 1972-03-07
Anticipated expiration: 1989-03-07

Abstract

AND ITS ACID ADDITION SALTS, WHEREIN R, AS ABOVE, REPRESENTS HALO OR METHYL, SAID R BEING LOCATED ON THE 6 OR 7 POSITION, ONLY, AND N REPRESENTS AN INTEGER OF FROM 0 TO 1, BOTH INCLUSIVE.
THE PRESENT INVENTION IS CONCERNED WITH METHODS AND COMPOSITIONS USEFUL IN INHIBITING THE GROWTH OF PLANTS, AND IS PARTICULARLY DIRECTED TO METHOD EMPLOYING AND COMPOSITIONS COMPRISING AN ACTIVE AGENT WHICH IS A COMPOUND OF THE FORMULA

2-R'',3-PHENYL,(R)N-QUINOXALINE

OR ITS ACID ADDITION SALTS, WHEREIN R REPRESENTS HALO OR METHYL, SAID R BEING LOCATED ON THE 6 OR 7 POSITION, ONLY; R'' REPRESENTS HALO, HYDROXY, LOWERALKOXY, AMINO, N-LOWERALKYLAMINO, DI-N-LOWERALKYLAMINO, OR PIPERIDINO; AND N REPRESENTS AN INTEGER OF FROM 0 TO 1, BOTH INCLUSIVE. THE PRESENT INVENTION IS ALSO DIRECTED TO THE NOVEL COMPOUND OF THE FORMULA

2-PIPERIDINO,3-PHENYL,(R)N-QUINOXALINE

Description

United States Patent 3,647,793 2-PIPERIDINO-S-PHENYLQUINOXALINE COMPOUNDS Quentin Francis Soper, Indianapolis, Ind., assignor to Eli Lilly and Company, Indianapolis, Ind.

No Drawing. Original application Mar. 22, 1968, Ser. No. 715,144, now Patent No. 3,582,315. Divided and this application Nov. 5, 1969, Ser. No. 871,035

' Int. Cl. C07d 51/78 U.S. Cl. 260-250 R 2 Claims ABSTRACT OF THE DISCLOSURE The present invention is concerned with methods and compositions useful in inhibiting the growth of plants, and is particularly directed to methods employing and compositions comprising an active agent which is a compound of the formula i E-R' or its acid addition salts, wherein R represents halo or methyl, said R being located on the 6 or 7 position, only; R represents halo, hydroxy, loweralkoxy, amino, n-loweralkylamino, di-n-loweralkylamino, or piperidino; and n represents an integer of from 0 to 1, both inclusive.

The present invention is also directed to the novel compound of the formula and its acid addition salts, wherein R, as above, represents halo or methyl, said R being located on the 6 or 7 position, only, and n represents an integer of from 0 to 1, both inclusive.

CROSS REFERENCE TO RELATED APPLICATIONS This application is a divisional application of my 00- pending application Ser. No. 715,144, filed Mar. 22, 1968, now Pat. No. 3,582,315.

DETAILED DESCRIPTION OF THE INVENTION As above set forth, the present invention is concerned with methods employing and compositions comprising an active agent which is a compound of the formula 3,647,793 Patented Mar. 7, 1972 ICC or its acid addition salts, wherein R represents halo or methyl, said R being located on the 6 or 7 position, only; R represents halo, hydroxy, loweralkoxy, amino, n-loweralkylamino, di-n-loweralkylamino, or piperidino; and n represents an integer of from 0 to 1, both inclusive.

The present invention is also directed to the novel compound of the formula loweralkyl For the purposes of the present invention, either tautomeric form of such compounds can be utilized, or the compound can be employed as a mixture.

All of the compounds to be employed as active agent in accordance with the present invention are prepared by known procedures, and many of the compounds are commercially available.

In a first method, suitable for preparation of those compounds wherein R"represents hydroxy, a phenylenediamine of the formula is reacted with benzoylformic acid;

HOJLL The reaction, conveniently conducted in an inert liquid reaction medium and at reflux temperatures, results in the preparation of the corresponding 2-hydroxy-3-pheny1- quinoxline. Such compounds can be converted to corresponding 2-halo compounds by the method of Shiho et al., (Chemical Abstracts, 56, 1453b [1962]) wherein, in the preparation-of 2-chloro-3-phenylquinoxaline, 2-hydroxy-3 phenylquinoxaline was refluxed with POCl For preparation of those compounds wherein R represents amino, loweralkylamino, diloweralkylamino, or piperidino, the corresponding 2-hal0-3-phenylquinoxaline is reacted with a suitable amine to obtain the corresponding Z-amino, loweralkylamino, diloweralkylamino, or piperidino compound. The reaction requires the presence of a hydrogen halide acceptor for good results.

In a representative example, 7.2 grams of 2-chloro-3- phenylquinoxaline (0.03 mole) is added to and mixed with sodium hydroxide (1.2 grams; 0.03 mole), piperidine (2.5 grams; 0.03 mole), and 25 milliliters of dimethylformamide. The mixture is refluxed for several hours, with stirring, and then permitted to cool and poured onto ice. The 2-piperidino-3-phenylquinoxaline typically separates as a yellow gum; it is separated, washed with water, dried,

and recrystallized from petroleum ether. In a representative operation, the product obtained melted at 824 C and its structure was confirmed by NMR analysis.

Also, the 2-halo, especially 2-chloro compounds, can be used as starting materials to prepare the corresponding 2- loweralkoxy compounds. Such Z-halo compound is reacted with an alkali metal loweralkoxide, preferably in the same loweralkanol as solvent. The tautomers can be separated in known chemical procedures. Thus, for example, the mixture can be subjected to hydrolysis whereupon the reacting 2-loweralkoxy tautomer will be converted to the corresponding Z-hydroxy compound which can, in turn, be separated from the non-reacting 1-loweralkyl-3-phenyl- 2(1H)-quinoxalone tautomer. Chromographic separation can also be employed, especially for small quantities.

Representative compounds to be employed in accordance with the present invention include:

2-chloro-3-phenylquinoxaline 2-bromo-3-phenylquinoxaline 2-iodo-3-phenylquinoxaline 2-amino-3-phenylquinoxaline 2-hydroxy-3-phenylquinoxaline 2-ethoxy-3-phenylquinoxaline 2-fluoro-3-phenylquinoxaline 2-methylamino-3-phenylquinoxaline 2-n-propylamino-3-phenylquinoxaline 2-dimethylamino-3-phenylquinoxaline 2-diethylamino-3-phenylquinoxaline 2,6-dichloro-3-phenylquinoxa.line 2-chloro-7-methyl-3-phenylquinoxaline 2-hydroxy-7-bromo-3-phenylquioxaline 2-amino-6-fluoro-3-phenylquinoxaline 2-methoxy-6-iodo-3-phenylquinoxaline 2-piperidino-6-chloro-3-phenylquinoxaline 2-piperidino-7-methyl-3-phenylquinoxaline 2-dimethylamino-6-chloro-3-phenylquinoxaline 2-piperidino-7-bromo-3-phenylquinoxaline 2-chloro-3-phenyliquinoxaline hydrochloride 2-hydroxy-3-phenylquinoxaline acetate Z-piperidino-3-phenylquinoxaline hydrochloride 1-rnethyl-3 -phenyl-2( 1H -quinoxalone 2-piperidino-6-methyl-3-phenylquinoxaline 2-sec-butoxy-S-phenylquinoxaline 2-piperidino-6-fiuoro-3-phenylquinoxaliue 1-ethyl-7-chloro-3-phenyl-2 1H) -quinoxalone 2-piperidino-7-iodo-3-phenylquinoxaline The compoundsserving as active agent in accordance 4 their selective'pa'ttern of"activity',' which'is' exhibited at lower rates, especially when employed in preemergent application. At such lower rates, defined more completely hereinbelow, the compounds are capable of eliminating from a crop area weed grass seeds and emerging seedlings as well as many broadleaf weed plants of varying ages, while leaving unharmed the crop. Crops from which weeds can be removed by this selective application of the present invention include cotton, corn, soybeans, and the like.

However, those of the agents wherein R represents piperidino, which are taught and claimed herein as new compounds, exhibit a different pattern of activities. They exhibit, as the rest of the compounds to be employed in accordance with the present invention, selective activity in preemergent application. But they are active in postemergent application, although with little selectivity, at rates below those rates at which the rest of the compounds to be employed as active agent are elfective.

In its broadest sense, the present invention is directed to a method which comprises applying to a plant part, which can be a seed or other similar reproductive unit of a plant, a growth-inhibiting amount of the active agent of the present. invention. In a preferred embodiment, the present invention is directed to a method for inhibiting the growth of weeds in an area seeded or planted to a crop plant which comprises applying to the area an amount of active agent which inhibits the growth of weeds Without causing substantial harm to the crop plant.

It is not critical to the practice of the present invention that complete destruction of undesirable vegetation be obtained, it being adequate if the growth of the unwanted vegetation is merely inhibited. Especially in the practice of the present invention for obtaining selective action, inhibition falling short of actual killing is adequate, particularly when combined with naturally-occurring conditions, such as limited moisture and the like, which more adversely aifect the vegetation selectively inhibited than the crop plant.

The compounds serving as active agent in accordance with the present invention are suited to a wide variety of herbicidal applications. Thus, for example, at rates which evoke the selective action of the compounds, which rates are defined more completely hereinbelow, the compounds can be used as selective herbicides in crop plants, such as, for example, cotton, corn, sorghum, soybeans, and the like. In such use, application can be made preemergent to both crops and weeds, or, preferably by means of a directed spray application technique, postemergent to the crop plant but both preemer-gent and postemergent to the weeds. In another application, the compounds can be used to give broad herbicidal action on non-crop plant land, including intermittently non-crop strips of contour-farmed land. For such usage on socalled fallow land, application can be made in spring to suppress vegetative growth until a fall or following spring planting, or in the fall to suppress vegetative growth until a spring or following fall planting. Furthermore, in an other application, the present compounds can be utilized to control weeds in tree crop plantings, such as plantings of the various citrus trees. In these latter types of applications, the present compounds are particularly advantageous because of the relatively rapid disappearance of their herbicidal effect, thereby permitting subsequent crop plantings as in the instance of contour farming, and avoiding buildup in the soil.

Thus, in particular embodiments, the present invention is directed to a method for inhibiting the growth of weeds in an area seeded or planted to a crop plant which comprises applying to the area an amount of active agent which inhibits the growth of weeds without causing substantial harm to the crop plants, wherein the crop is (a) corn, (b) soybeans, or (c) sorghum.

In yet another particular embodiment, the present invention is directed to a method for controlling the growth of vegetation in fallow land which comprises applying to such land an effective amount of the active agent of the present invention.

The practice of the present invention in any of its numerous embodiments can in some instances be carried out with unmodified compound; however, for good results, it is generally necessary that the compound be employed in modified form, that is, as one component of a composition formulated to implement the plant growth inhibiting effects. Thus, for example, the active agent can be mixed with Water or other liquid or liquids, preferably aided by the usage of a surface active agent. The active agent can also be incorporated on a finely-divided solid, which can be a surface active substance, to yield a wettable powder, which can subsequently be dispersed in water or other liquid, or a dust which can be applied directly. Other methods of formulation are known in the art and can be employed in implementing the present invention.

In carrying out the novel method of the present invention, the exact amount of the active agent employed is not critical and will vary, depending upon the type of growth-inhibiting effect desired, the identity of the plants concerned, the particular active agent used, weather conditions, and the like. In general, a broad growth-inhibiting effect is obtained with rates of from 0.5 to 20 pounds or more of active agent per acre, and preferably with rates of from to pounds or more, and such rates are suitable and effective for control of vegetative growth on fallow land. When it is desired to obtain a selective growth-inhibiting effect on weeds in areas containing crop plants such as corn, soybeans, and cotton, rates of from 0.5 to 10 pounds generally give good results. The Z-piperidino compounds disclosed and claimed herein as new compounds generally give selective growth inhibition, in preemergent application, at rates of from 5 pounds, and preferably at rates of from 7.5 pounds and higher per acre; postemergent activity with these compounds is exhibited at rates as low as 1 pound and lower, with some selectivity. When in the typical mode of operation, the active agent is employed as a composition comprising the agent, the exact concentration of active agent in the composition is not critical, except that the concentration and total amount of formulation employed be adequate to supply the appropriate amount of active agent on a per acre basis. In general, good results are obtained when employing formulations containing the active agent in a concentration of from 0.5 to 10 percent or higher, in the instance of a liquid formulation; and in a concentration of from 1.0 to 5.0 percent or higher, in the instance of a dust, powder, granule, or the like. More concentrated formulations can be prepared and are often preferred in that they can serve, depending upon the particular application contemplated and the particular concentration, both as a concentrated formulation for purposes of shipment, storage, and the like, and as an ultimate treating composition. A preferred composition comprises a surface active agent, an inert finely-divided solid and the present active agent, the active agent being present in an amount of from 0.5 to 99.5 percent, by weight.

The expression surface active dispersing agent, as herein employed, is intended to include all agents which are capable of acting at the interfacial surface between the active agent and water or other liquid medium, facilitating thereby the dispersion of the agent in the medium. The term is inclusive of solid emulsifying agents such as finely-divided bentom'te, pyrophyllite, fullers earth, attapulgite, silica, other clays, and mineral carriers as well as liquid wetting and dispersing agents.

The term inert finely-divided solid, as herein employed, refers to materials whose primary function is not as dispersant of the active agent in a liquid medium but as carrier for dust compositions. Representative such materials are chalk, talc, gypsum, powdered walnut shells, etc.

Liquid compositions containing the desired amount of active agent are prepared by dissolving the substance in an organic liquid or by dispersing the substance in water with or without the aid of a suitable surface active dispersing agent such as an ionic or non-ionic emulsifying agent. Such compositions can also contain modifying substances which serve as a spreader and sticker on plant foliage. Suitable organic liquid carriers include the agricultural spray'oils and the petroleum distillates such as diesel fuel, kerosene, fuel oil naphthas and Stoddard solvent. Among such liquids the petroleum distillates are generally preferred. The aqueous compositions can contain one or more water immiscible solvents for the toxicant compound. In such compositions, the carrier comprises an aqueous emulsion, e.g., a mixture of water, emulsifying agent and water immiscible solvent. The choice of dispersing and emulsifying agent and the amount thereof employed is dictated by the nature of the composition and by the ability of the agent to facilitate the dispersion of the active agent in the carrier to produce the desired composition. Dispersing and emulsifying agents which can be employed in the compositions include the condensation products of alkylene oxides with phenols and organic acids, alkyl aryl sulfonates, polyoxyalkylene derivatives or sorbitan esters, complex ether alcohols and the like. For a review of known surface active agents which are suitably employed in implementing the present invention, attention is directed to U.S. 3,095,299, second column, lines 25-36, and references there cited.

In the preparation of dust compositions, the active ingredient is intimately dispersed in and on a finely-divided solid such as talc, chalk, gypsum, and the like. In one method of achieving such dispersion, the finely-divided carrier is mechanically mixed or ground with the active agent.

Similarly, dust compositions containing the toxicant compounds can be prepared with various of the solid surface active dispersing agents, such as bentonits, fullers earth, attapulgite, and other clays. Depending upon the proportions of ingredients, these dust compositions can be employed as concentrates and subsequently diluted with additional solid surface active dispersing agents or with chalk, talc, or gypsum and the like to obtain the desired amount of active ingredient in a composition adapted to be employed for the suppression of the growth of the plants. Also, such dust compositions can be dispersed in water, with or without the aid of a dispersing agent, to form spray mixtures.

Formulations containing the present active agent are often advantageously further modified by incorporation therein of an effective amount of a surfactant which facilitates the dispersion and spreading of the formulation on the plant leaf surfaces and the incorporation of the formulation by the plant.

In accordance with the present invention, the active agent can be dispersed in soil or other growth media in any convenient fashion. Applications can be carried out by simply mixing with the media, by applying to the surface of soil and thereafter dragging or discing into the soil to the desired depth, or by employing a liquid carrier to accomplish the pentration and impregnation. The application of spray and dust compositions to the surface of soil, or to plant parts or the above ground surfaces of plants can be carried out by conventional methods, e.g., powder dusters, boom and hand sprayers and spray dusters, whether surface or air-borne.

In a further method, the distribution of the active agent in soil can be accomplished by introducing the agent in the water employed to irrigate the soil. In such procedures, the amount of water is varied with the porosity and water holding capacity of the soil to obtain a desired depth of distribution of the agent.

In addition, the present method also comprehends the employment of an aerosol composition containing one or more of the present active agents as an active compound.

- 7 Such a composition is prepared according to conventional methods wherein the agent is dispersed in a solvent, and the resultant dispersion mixed with a propellant in liquid state. Such variables as the particular agent to be used and the nature of the vegetation which is to be treated will 5 determine the desirability of the solvent and concentration of the agent therein. Examples of suitable solvents are water, acetone, isopropanol, and Z-ethoxyethanoL- Satisfactory results are obtained when the active agent of the present invention, or a composition comprising such active agent, is combined with other agricultural materials intended to be applied to plants, plant parts, or their habitats. Such materials include fertilizers, fungicides, insecticides, other herbicides, soil conditioning agents, and the like. 15

Where the present compounds are to be employed for selective weed control in corn, a particularly preferred formulation is one which comprises the present active agent in a solution of nitrogen, with, optionally, other adjuvants also present. The nitrogen solution serves as a fertilizer for the corn crop, but also is initially effective as a contact herbicide. Inasmuch as the contact herbicidal action is not selective, such a nitrogen solution is applied as a directed spray to avoid or limit crop damage. Typically, such nitrogen solutions contain from about 26 to about 32 percent nitrogen as ammonium nitrate, ammonium sulfate, urea, and other nitrogen-containing compounds, and are applied at such rates as to provide 90 pounds of nitrogen per acre.

While the compounds to be employed as active agent in accordance with the present invention give good herbicidal results when employed alone, there are circumstances where it is desirable to employ one or more of the present compounds in combination with one or more other known, herbicides. For example, a combination of one of the present compounds with a known herbicide may yield a herbicidal product which is less expensive, as for largescale herbicidal purposes, than sole use of the present compound would be-with the combination being equally effective. In addition, there are circumstances where the herbicidal activity of a compound of the present invention complements that activity of a known herbicide, making a combination of the two substances particularly desirable 45 from the standpoint of the herbicidal results obtained.

The identity of the known herbicide with which one or more of the present compounds is combined is not critical. Representative known herbicides with which a compound of the present invention can be combined include, for example, those known herbicides listed in the Herbicide Handbook of the Weed Society of America (W. F. Humphrey Press, Inc., Geneva, N.Y., 1967); however, others can also be used.

Moreover, while the particular known herbicides with which a present compound or compounds is combined is not critical, a particularly preferred combination is that of 1) One or more of the compounds to be employed as active agent in accordance with the present invention; and

(2) A phenoxy or substituted phenoxyalkanoic acid of the formula:

agfiwat a,

Preferred phenoxy or substituted phenoxyalkanoic acids are 2,4-dichlorophenoxyacetic acid: YY i and its salts and estersiand 2-methyl-4-chlorophenoxyacetic acid: Y

and its salts and esters.

The identity of the salt or ester, when such derivative form is employed, is not critical. In general, the salt or ester moiety is selected to confer higher water solubility or other desirable properties on the substance. Representative and suitable salts and estersinclude the alkali metal, ammonium, trimethylammonium alkylamine, which can be monoalkylamine, dialkylamine, or trialkylamine, alkanolamine which can be monoalkanolamine, dialkanolamine, or trialkanolamine, salts, and the alkyl, alkoxyalkyl, and alkenyl esters. Others, of course, can be used. \Preferred alkylamine or alkanolamines are those containing less than about 25 carbon atoms. Representative such amines include methylamine, ethylamine, diethylamine, trimethylamine, rnonoethanolamine, triethanolamine, isopropanolamine, n-hexylamine, morpholine, dimethylamine, N-allyl- 1,3-propylenediamine. Preferred esters are those in which the ester moiety contains not more than about 25 carbon atoms; and yet more preferred are those containingnot more than about 10 carbon atoms.

Representative phenoxy and substituted phenoxyalkanoic acid compounds to be employed in such combinations include the following: 1 Y

2,4-dichlorophenoxyacetic acid isooctyl 2,4-dichlorophenoxyacetate morpholine salt of 2,4-dichlorophenoxyacetic acid 2,4,S-trichlorophenoxyacetic acid isooctyl 2,4,5-trichlorophenoxyacetate methyl 4-chlorophenoxyacetate n-butoxy-n-propyl 2,4-dichlorophenoxyacetate trimethylamine salt of 2,4-dichlorophenoxyacetic acid n-butyl 4-(4-chlorophenoxy)butyrate ethyl 2-(4-chlorophenoxy)propionate 2,4-dichlorophenoxyacetic acid, sodium salt 2,4,S-trichlorophenoxyacetic acid, potassium salt triethanolamine salt of 2,4-dichl0rophenoxyacetic acid 2-methyl-4-chlorophenoxyacetic acid allyl2-methyl-4-chlorophenoxyacetate 2 (2,4,5-trichlorophenoxy)acetic acid N-allyl-1,3-propylenediamine salt of 2,4-dichlorophenoxyacetic acid Y isooctyl 2- (2,4,5 -trichlorophenoxy) propionate 2-(2,4-dichlorophenoxy)propionic acid isooctyl 2- 2,4-dichlorophenoxy) propionate n-hexylamine salt of Z-methyl-4-chlorophenoxyacetic acid 4-(2,4-dichlorophenoxy)butyric acid n-hexyl 4-(2,4-dichlorophenoxy)butyrate 4- (2-methyl-4-chlorophenoxy) butyric acid n-hexyl 4-(2,4,5-trichlorophenoxy)butyrate 4- (2-methyl-4-chlorophenoxy butyric acid n-hexyl 4- (2,4,5-trichlorophenoxy)butyrate 2,4-dichlorophenoxyacetic acid, ammonium salt trimethylamine salt of 2-methyl-4-chlorophenoxy acetic acid. Y

Such phenoxy or substituted phenoxyalkanoic acids can also be employed as the corresponding anilide. Thus, for example, the compounds of the present invention can also be employed jointly with compounds such as 2-(2- methyl-,4-chlorophenoxy)-- m .(trifluoromethyDacetanilide and 2 -(2 methyl 4 chlorophenoxy)-o-chloroacetanilide. In addition, theactive agent of the present invention is advantageously" combined with substituted benzoic. acid and benzonitrile. herbicides, such as, for example, 3-amino-2,5-dichlorobenzoic acid, 2,5-dichloro- 3 nitrobenzoic acid, Z-m'ethoxy-3,6-dichlorobenzoic acid, 2-rnethoxy-3,5,6- -trichlor0benzoic acid, and 2,6-dic'hlorobenzonitrile. Furthermore, the active agent of the present inventioncanbecombinedwith-yet other known herbicides, such as, for example, 4-aminc-3,5,6-trichlorpicolinic acid or its salts or other derivatives.

The following examples illustrate the present invention.

EXAMPLE 1 Various of the compounds to be employed as active agent in accordance with the present invention were evaluated for pre-emergent application to various species of plants. In this evaluation, a soil was prepared consisting of one part masonry sand and one part shredded top soil blended together in a cement mixer. One gallon of this soil was placed in a 25 x 35 cm. galvanized flat and was patted down with a bench'brush until level. A three-row marker was used to make 2 /2 cm. deep furrows in approximately two-fifths of the flat. Crop seeds consisting of four kernels of corn, five cottonseeds and five soybean seeds were placed in these furrowsfA four-row template was then placed on the remaining soil and the indicated amounts of each of the ,followingseeds were planted, one species to each section: foxtail (millet), 100 mg.; broad-leaf mustard, 50-75 mg.; rough pigweed, 30-50 mg.; and large crabgrass, 350-400 mg.

Sufficient soil was added to cover the entire flat. Thus, theweed seeds were covered to a'depth of about 6 mm. and the crop plant seeds weref'coveredto a depth of about 3 'r',

In assaying the effect of the. composition as preemergent herbicides, a flat prepared as above, taken either on the day of planting or on the next day, was placed in a chamber equipped with a turntable and an air. exhaust. The herbicidal composition, either a spray-type emulsion or a wettable powder, was applied to the flat with a modified De Vilbiss atomizer hooked to an air source. Twelve and one-half ml. of the composition under test were applied to each flat either on the day of planting or the succeeding day. Injury ratings and observations as to type of injury were made eleven to twelve days after treatment. The injury rating scale used was as follows:

0no injury 1-slight injury 2-moderate injury 3-severe injury 4death When more than one determination was carried out, an average value was calculated for the injury rating. Each compound evaluated was formulated as a spray by one of the following procedures. In one method, the particular compound was Wetted by grinding in a mortar with one part of polyoxyethylene sorbitan monolaurate. Five hundred parts of water were added slowly to the resultant creamy paste to give an aqueous dispersion with a surfactant concentration of 0.2 percent. This dispersion was entirely satisfactory for spray application. In a second procedure the compound was dissolved in one volume of acetone, and the acetone solution was diluted with nineteen volumes of water containing 0.1 percent of polyoxyethylene sorbitan monolaurate.

In the following table setting forth the results of the evaluation, column 1 gives the name of the compound under test; column 2, the rate in pounds per acre at which the compound was applied to the test flat; and the remaining columns, the injury to the particular plant seeds or seedlings as measured by the foregoing scale.

JTABLE I.-IN.TURY RATING ON PREEMERGENT TREATMENT LbsJ Soy- Crab- Mus- Pig- Foxtail Velvet Compound acre Corn Cotton beans grass tard weed millet leaf Z-hydroxY-Ii-phenylquinoxaline 8 0 0 0 2 3 4 2 2-chlor0-3-phenylquinoxaline 8 0 0 0 3 4 4 3 2 4 0 0 0 3 3 4 3 1 2 0 0 0 2 2 4 2 0 1 0 0 0 1 1 3 1 0 2(dipropylamino)-3-phenylquinoxaline 8 0 1 1 4 4 3 4 0 1 1 4 3 2 2 0 0 0 4 3 1 2-ethoxy-3-phenylquinoxaline 8 0 0 0 4 4 3 4 0 0 0 4 2 1 2-hydroxy-7-methyl-3-pheny1quinoxa1ine 8 0 0 0 4 3 3 2-hydroxy-fi-methylfl-phenylquinoxaline 8 0 0 0 4 3 3 6-0hloro-2-hydroxy-3-phenylquinoxaline 8 0 0 0 4 3 3 7-cl1loro-2-h drox -3- hen l uinoxaline 8 0 0 0 4 3 3 y y p y q 2 0 0 0 4 2 1 l-meth 1-3- hen 1-2- 1H uinoxalone 8 1 0 0 4 4 3 y p y q 4 0 1 0 4 4 3 2 0 0 0 4 4 3 2-methox -3- hen l uinoxaline 8 1 0 (l y p yq 4 0 0 0 3 l 1 0 l-nro l-3- hen l-2-1H uinoxalone 8 0 0 0 2 4 4 0 p Dy p y q 4 0 0 1 3 1 4 3 1 2 0 0 1 2 0 2 2 1 211- ro 0x -3- hen l uinoxaline 8 0 0 0 2 4 4 1 p p y p y q 4 0 0 1 3 1 4 3 1 2 0 0 0 2 0 2 2 1 2-umino-3-phenylquinoxaline 8 0 0 0 4 4 3 4 0 0 0 4 2 2 2 0 0 0 4 1 0 2-piperidino-3-phenylquinoxaline 8 0 0 1 4 2 0 EXAMPLE 2 Representative compounds of the present invention WEED CONTROL RATING were evaluated for post-emergent application to plants. Injury rating The evaluation was carried out 1n accordance w1th the Grasses Pigweed Crops (an PH) procedures of Example 1 except that the test solutions Lb I PH SS P I were applied about 9-12 days after the preparation and am P Sorghum Swbeans seeding of the flats. The results are as set forth in the fol- 8 7-0 9.0 10.0 10.0 4 v o 0 4 6.0 9.5 9.0 10.0 0 0 0 lowing table.

TABLE IL-INJ'URY RATING ON POST-EMERGENT TREATMENT Lbs./ Soy- Crab- Mus- Pig- Foxtail Compound acre Corn Cotton beans grass tard weed millet 2-chloro-3-phenylquinoxaline 8 1 2 1 3 4 4 2 2-amino-3-phenylquinoxaline 8 0 0 2 3 3 1 2 4 0 1 2 2 1 1 1 2-piperidino-3-phenylquinoxaline 8 2 2 2 2 4 2 2 4 2 2 2 3 4 3 4 2 1 1 1 2 4 3 2 1 1 0 1 2 4 2 2 EXAMPLE 3 I claim:

2-chloro-3-phenylquinoxaline was evaluated under field conditions. In this evaluation, field plots were prepared in routine fashion and a number of the plots divided into two portions. One portion of each plot was seeded with foxtail and crabgrass (grasses); the other portion was seeded with pigweed. Other plots were seeded with corn, sorghum, and soybeans, and yet other plots were set aside as control plots. In the instance of the plots seeded with grasses and pigweed, treatment was by way of incorporation in the soil immediately preceding the seeding in the instance of one-half of each portion of such plot; in the instance of the other half, treatment was by means of a surface spray application immediately after seeding. In the instance of the plots seeded to crop plants, application was exclusively by means of pre-plant incorporation. All plots were then held under good growing conditions for a period of several weeks, at which time readings were made of the degree of control.

The results of the evaluation are set forth in the following table, where herbicidal activity is rated from 0-10, 0 indicating no herbicidal elfect, and 10 indicating a killing of the vegetaton in question. PPI is used to indicate application by pre-plant soil incorporation, and SS to indi- 1. The compound ofthe formula 1 I References Cited UNITED STATES PATENTS 3,453,365 7/1969 nae et a1 260-250R NICHOLAS S. RIZZO, 7 Primary Examiner P0-1050 UNITED STATEs PATENT hmhh CERTIFICATE OF CORREUHGN Patent No. 5,6 WJ95 Dated March 7, 1972- InventoI-(B) Quentin Francis Soper It is certified that error appears in the above-identified patent I and that said Letters Patent are hereby corrected as shown below:

an In column 1, lines about 58-65, that portion of the formula.

reading should be Rn v n .[n column '2, lines 26-55, that portion of the right-hand formula reading loweralkyl loweralkyl N v 0 should be T o also in column 2, line 61, the first word unit, "quinoxline",

should be --quinoxaline--.

In column 5, line 56, "2chloro-5-phenyliquinoxaline hydrochloride" should be -2-chloro-5phenylquinoxaline hydrochloride-- In column 6, line 58, "bent onitsl' should be -bentonite--; also, in column 6, line 61, "pentration" should be -penetration-- .[n column 7, line 56, "herbicides" should be -herbicide-.

In column 8, line 2 1-, "trimethylammonium" should be followed by a comma.

in column 9, line 12, "trichlorpicolinic" should be -trichloropicolinic.

(5/69) UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 5; +T,795 Dated March 7; 97

lnventoz-(s) Quentin Francis Sope'r It is certified that: error appears it the above-identified patent and that said Letters Patent are hereby corrected as shown below:

At column 12, lines about 27-51, that portion of the formula reading T Y] should be Signed and sealed this 7th day of November 1972,

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents