GB1596887A

GB1596887A - 2-pyridone derivatives and their use as plant growth regulators

Info

Publication number: GB1596887A
Application number: GB23085/78A
Authority: GB
Original assignee: Rohm and Haas Co
Current assignee: Rohm and Haas Co
Priority date: 1977-07-15
Filing date: 1978-05-26
Publication date: 1981-09-03
Also published as: AU521772B2; NL188695B; HU181943B; NL188695C; IL55133A; DK158350C; ES471780A1; CH635324A5; FR2397405B1; IT1108115B; DK318578A; FR2397405A1; SE7807006L; AR218070A1; SE436568B; NZ187735A; JPS5452084A; DE2830700A1; DE2830700C2; DK158350B

Abstract

Compounds corresponding to the formula <IMAGE> in which R<1> represents an alkyl group, R<2> represents a carboxyl group optionally in the form of a salt acceptable for agronomic use, or a carbalkoxy group, R<3> represents a hydrogen atom or an alkyl group, R<4> represents a hydrogen atom, an alkyl group or a halogen atom, and R<5> represents an optionally substituted aryl group. These compounds can be used for regulating the growth of plants.

Description

(54) NOVEL 2:-PYRIDONE DERIVATIVES AND THEIR US;E AS PLANT GROWTH REGULATORS (71) We, ROHM AND HAAS COMPANY,- a corporatio.n organised under the laWsof the State of Delaware, United States of America, of Independ;.ence MalJ.-.- wept, Philadelphia, Pennsylvania 19105, United States -of America, do hereby declare -e 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:- This invention concerns compounds which. show activity as plant growth regulators, particularly as chemical gametocides, to growth-regulant compositions*,whichQcom,p,rise these compounds, and to methods of regulating the growth of plants with these compounds and compositions. . - - A new class of compounds has now been found which can be used as plant growth regulators, and particularly as chemical gametocides in cereal-grains The compounds of the invention are 2-pyridones having the formulas

wherein Rl is an alkyl group, preferably having up to 4 carbon atoms; R2 is a carboxy group (-COOH) or an agronomically-acceptable salt thereof, or a carbalkoxy group (-COOR, wherein R is an alkyl group, preferably having up to 12 carbon atoms, most preferably up to 4 carbon atoms); R3 is a hydrogen atom or an alkyl group having up to 4 carbon atoms' R4 is a hydrogen atom, an alkyl group having up to 4 carbon atoms, or a halogen atom, preferably a bromine or a chlorine atom; and R5 is phenyl or naphthyl each substituted with one or two of the same or different substituents selected from halogen, (C1 -C4)alkyl, (C1 -C4)alkoxy, trifluoromethyl and nitro.

In a preferred embodiment of the invention, Rl is a methyl group, R2 is a carboxy group or a salt thereof, R3 is a hydrogen atom or a methyl group, R4 is a hydrogen atom or a halogen atom, and R5 is a substituted phenyl group.

When R2 is a salt of a carboxy group, an alkali metal, alkaline earth metal, or transition metal can provide the cation. The cation can also be ammonium or substituted ammonium.

Re resentative metal salt cations include alkali metal cations, such as sodium, potassium and lithium, alkaline earth metal cations, such as calcium, magnesium, barium and strontium, or heavy metal cations, such as zinc, manganese, cupric, cuprous, ferric, ferrous, titanium and aluminum. Among the ammonium salts are those in which the ammonium cation has the formula NZ1Z2Z5Z4, wherein each of Z1, Z2, Z3, and Z4 is individually a hydrogen atom, a hydroxy group, a (C1-C4)alkoxy group, a (C1-C20)alkyl group, a (C3- C8)alkenyl group, a (C3-C8)-alkynyl group, a (C2- C8)hydroxyalkyl group, a (C2-C8)alkoxy-alkyl group, a C2-C6)aminoalkyl group, a (C2-C6)haloalkyl group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted phenylalkyl group, having up to 4 carbon atoms in alkyl moiety, an amino or alkyl-substituted amino group, or any two of Z1, Z2, Z3, or Z4 can be taken together to form with the nitrogen atom a 5- or 6-membered heterocyclic ring, optionally having up to one additional hetero oxygen, nitrogen, or sulfur atom in the ring, and preferably saturated, such as a piperidine, morpholine, pyrrolidine, or piperazine ring, or any three of Z1, Z2, or Z4 can be taken together to form with the nitrogen atom a 5- or 6-membered aromatic heterocyclic ring, such as a pyrazole or pyridine ring. When the ammonium group contains a substituted alkyl, substituted phenyl or substitutedhenylalkyl group, the substituents will generally be selected from halogen atoms, (C1-C8)alkyl groups, (C1-C4)alkoxy groups, hydroxy groups, nitro groups, trifluoromethyl groups, cyano groups, amino groups and (CI-C4)al- kylthio groups. Such substituted phenyl groups preferably have up to two such substituents.

Representative ammonium cations include ammonium, dimethylammonium, 2ethylhexylammonium, bis(2-hydroxyethyl)ammonium, tris(2-hydroxyethyl)ammonium, dicyclohexylammonium, t-octylammonium, 2-hydroxyethylammonium, morpholinium, piperidinium, 2-phenethylammonium, 2-methylbenzylammonium, n-hexylammonium, triethylammonium, trimethylammonium, tri(n-butyl)ammonium, methoxyethylammonium, diisopropylammonium, pyridinium, diallylammonium, pyrazoliurn, propargylammonium, dimethylhydrazinium, hydroxyammonium, methoxyammoniurn, dodecylammonium, oxtadecylammonium, 3 ,4-dichlorophenylammonium, 4-nitrobenzylammonium, benzyltrimethylammonium, 2-hydroxyethyldimethyloctadecylammonium, 2hydroxyethyldiethyloctylammonium, decyltrimethylammonium, hexyltriethylammonium, and 4-methylbenzyltrimethylammonium.

The most preferred substituents in R5 are halogen atoms, preferably with at least one in the 4-position, (C1 -C4)alkyl groups, preferably 4-methyl, (C1 -C4)alkoxy groups, preferably 4-methoxy, trifluoromethyl groups, preferably 4-trifluoromethyl, and nitro groups, preferably 4-nitro.

Typical compounds within the scope of this invention include: N-(4-chlornphenyl)-5-carboxy-4,6-dimethylpynd2one N-(3-chlorophenyl)-5-carboxy-4 ,6-dimethylpyrid-2-one N-(4-bromophenyl)-5-carboxy-4,6-dimethylpyrid-2-one N-(2-chlorophenyl)-5-carboxy-4,6-dimethylpyrid-2-one N-(4-iodophenyl)-5-carboxy-4,6-dimethylpyrid-2-one N-(2-fluorophenyl)-5-carboxy-4 ,6-dimethylpyrid-2-one N- (4-trifluoromethylphenyl) -5-carboxy-4,6-dimethylpyrid-2-one N-(4-methoxyphenyl)-5-carboxy-4,6-dimethylpyrid-2-one N-(3-nitrophenyl)-5-carboxy-4,6-dimethylpyrid-2-one N-(4-chlorophenyl)-5-carboxy-6-methylpyrid-2-one N-(4-nitrophenyl)-5-carboxy-6-methylpyrid-2-one N-(3-ethoxyphenyl)-5-carboxy-6-methylpyrid-2-one N-(4-methylphenyl)-5-carboxy-6-methylpyrid-2-one N-(3 ,4-dichlornphenyl)-5-carboxy-6-methylpynd-2one N-(4-methyl-3-chlorophenyl)-5-carboxy-6-methylpyrid-2-one N-(4-chlorophenyl)-5-carboxy-3 ,4,6-trimethylpyrid-2-one N-(4-bromophenyl)-5-carboxy-4,6-diethylpyrid-2-one N-(4-chlorophenyl)-5-carboxy-4,6-diethylpyrid-2-one N-(4-bromophenyl)-5-carboxy-4,6-dipropylpyrid-2-one N-(4-chlornphenyl)-5-carboxy-4-ethyl-6-methylpynd-2-one N-(4-trifluoromethylphenyl)-5-carboxy-6-ethyl-4-methylpyrid-2-one N-(4-chlorophenyl)-5-carboxy-6-ethylpyrid-2-one N-(4-bromophenyl)-5-carboxy-6-propylpyrid-2-one N-(4-chlorophenyl)-5-carboxy-3 ,6-dimethylpyrid-2-one N-(4-trifluoromethylphenyl)-5-carboxy-3 ,6-dimethylpyrid-2-one N-(4-bromophenyl)-5-carboxy-6-methylpyrid-2-one N-(3 ,4-dichlorophenyl)-5-carboxy-4,6-dimethylpyrid-2-one N-(2-chloro-4-methylphenyl)-5-carboxy-4,6-dimethylpyrid-2-one 3-bromo-N-(4-chlorophenyl)-5-carboxy-4,6-dimethylpyrid-2-one 3-bromo-N-(4-fluorophenyl)-5-carboxy-4 ,6-dimethylpyrid-2-one 3-chloro-N-(2,4-dichlorophenyl)-5-carboxy-4,6-dimethylpyrid-2-one 3-fluoro-N-(3-chlorophenyl)-5-carboxy-4,6-dimethylpyrid-2-one 3-bromo-N-(4-trifluoromethylphenyl)-5-carboxy-6-methylpyrid-2-one and agronomically-acceptable salts of the above acids, N-(4-chlorophenyl)-5-carbomethoxy-4,6-dimethylpyrid-2-one N-(4-fluorophenyl)-5-carbethoxy-4,6-dimethylpyrid-2-one N-(3-methylphenyl)-5-carbobutoxy-4,6-dimethylpyrid-2-one N-(3,4-dichlorophenyl)-5-carbethoxy-6-methylpyrid-2-one and N-phenyl-5-carbomethoxy-6-methylpyrid-2-one The compounds of the invention can be prepared by several convenient preparative routes. In the first method, an acid chloride of the formula

wherein R6 is a hydrogen atom or an alkyl group, and R3 is as defined above, is condensed with an enamine of the formula

wherein R, R', and R5 are as defined above, to yield a dihydropyridone of the formula

wherein R, R1, R3, R5, and R6 are as defined above. This reaction is generally carried out in an inert solvent, such as ethyl ether, methylene chloride, benzene or toluene at a temperature of from 0 to 100"C. The dihydropyridone is then dehydrogenated in the presence of a dehydrogenating agent, such as 2,3-dichloro-5,6-dicyano-1,4-benzoquinone or similar quinone, palladium on charcoal, or N-bromosuccinimide, in an inert solvent, such as benzene, xylene or chlorobenzene generally at a temperature of from 50 C to 250 C to form a pyridone of the formula

wherein R, Rl, R3, RS,and R6 are as defined above. The ester can then be converted to the corresponding acid or salt by a conventional hydrolysis, such as sodium hydroxide, or potassium hydroxide at ambient or elevated temperature of up to about 100"C.

In a second preparative route to compounds of the invention, a pyrone of the formula

wherein R, R', and R3 are as defined above, is reacted with an amine of the formula NH2-R5 (VIII) wherein R5 is as defined above, in the presence of an acid catalyst, such as p-toluenesulfonic acid, methanesulfonic acid, hydrochloric acid or sulfuric acid, in an inert solvent such as chlorobenzene, toluene, xylene or cumene, or using 50% by volume aqueous acetic acid as the reaction medium, to form a pyridone of the formula

wherein R, R1, R3, and R5 are as defined above. This reaction is generally carried out at a temperature of from 50 C to 2500 C. The free acid and its salts can then be prepared by conventional techniques.

The compounds of the invention in which R4 is a halogen atom can be prepared by reacting the corresponding 2-pyridones in which R4 is a hydrogen atom with one equivalent of a halogenating agent such as bromine, chlorine, sulfuryl bromide, or sulfuryl chloride, in a suitable inert solvent such as ethylene dichloride, or methanol, generally at a temperature of from 0 to 1000C.

Illustrative compounds of Formula I which have been prepared are listed in Table I below which also contains melting points and elemental analyses. After Table I there appear illustrative examples showing preparations of some of the compounds in Table I and, in the examples, all temperatures are in degrees Celsius and parts and percentages are by weight unless otherwise indicated. Specific illustrative preparations of the compounds of Examples 1, 19, 25, and 28 are provided. Table I lists typical compounds of the invention and their melting points and elemental analyses.

TABLE 1

Compound No. X Y R MP C H N Halogen 1 4-Cl H H 35 & 9 60.55 4.36 5.06 12.77 60.85 4.42 4.99 13.07 2 4-Cl H Na > 300 56.10 3.70 4.67 11.83 55.29 3.78 4.73 11.65 3 4-CH3 H H 238-40 70.02 5.88 5.45 5 70.14 6.02 5.29 4 4-CH3 H Na > 300 64.51 5.05 5.02 63.45 5.18 5.09 5 3,4-diCI H H 276-7 53.87 3.55 4.49 22.72 54.02 3.54 4.32 22.68 6 3,4-diCl H Na 296-7 50.32 3.02 4.19 21.22 45.25 3.17 4.05 21.40 7 4-F H H 260-1 64.36 4.63 5.36 7.27 63.89 4.59 5.53 7.07 8 4-F H Na > 300 59.36 3.92 4.95 6.71 58.83 3.88 5.03 4.95 9 3-Cl H H 254-5 60.55 4.36 5.04 12.77 60.03 4.31 5.05 13.63 10 3-Cl H Na > 300 56.10 3.70 4.67 11.83 53.57 3.75 4.46 11.45 11 4-CHX,3-Cl H H 247-51 61.75 4.84 4.80 12.16 61.61 4.88 5.27 12.24 TABLE I (Cont'd) Compound No. X Y R MP C H N Halogen 12 4-CH3,3-Cl H Na > 300 54.29 4.56 4.22 10.66 54.88 4.23 4.39 11.05 13 4-OCH3 H H 219-21 65.92 5.53 5.13 65.52 5.39 5.18 14 4-OCH3 H Na 29580 - - - - 15 4-CF3 H H 230-2 57.88 3.89 4.50 18.31 58.31 3.93 4.66 18.04 16 4-CF3 H Na > 300 - - - 17 4-Br H H 244-6 52.19 3.76 4.35 24.81 52.67 3.85 4.60 24.84 18 4-Br H Na > 300 - - - 19 * H H 264-6 65.96 4.31 4.27 10.82 65.68 4.27 4.41 11.03 20 * H Na > 300 - - - 21 4-Cl Br H 243-6 47.14 3.11 3.93 47.65 3.13 4.29 22 4-Cl Br Na > 220 - - - - 23 4-Br Br H 248-50 41.92 2.77 3.49 39.85 42,06 2.72 3.91 40.33 24 4-Br Br Na 290 - - - - 25 4-Br H C2H5 129-30 54.87 4.61 4.00 22.82 54.97 4.69 3.98 23.33

26 4-Cl H H 271-73 59.21 3.82 5.31 13.45 59.17 3.76 5.71 13.49 * The N-substituent is 4-chloronaphthyl EXAMPLE 1 Preparation of N-(4-chlorophenyl)-5-carboxy-4, 6-dimethylpyrid-2-one (Compound I, Table I) (a) 4-Chloroaniline (48.4 g), p-toluene sulfonic acid (4.7 g) and ethyl isodehydacetate (65 g) are suspended in cumene (260 ml). The reaction mixture is brought to reflux, and water collected in a Dean-Stark trap. After 18 hours, the reaction mixture is cooled and washed with dilute hydrochloric acid to remove excess 4-chloroaniline. The cumene is then removed in vacuo, leaving the crude 5-carbethoxy-N-(4-chlorophenyl)-4,6-dimethylpyrid-2- one as a dark brown oil.

(b) The crude ester prepared in (a) above is suspended in a solution prepared by mixing methanol (500 ml), water (500 ml) and 50% aqueous sodium hydroxide (50 g). The suspension is refluxed for six hours. The solvent is then removed in vacuo and replaced with water (1000 ml). Insoluble material is filtered off and discarded. The clear aqueous layer is then acidified with hydrochloric acid and the resulting precipitate is filtered and dried, to yield (after recrystallization from acetone) 55 g of product, N-(4-chlorophenyl)-4,6dimethyl pyrid-2-one-5-carboxylic acid, having a melting point of 258-9 (decomposition).

EXAMPLE 2 Preparation of N-(4-bromophenyl)-5-carboxy-4, 6-dimethylpyrid-2-one (Compound 17, Table I) Ethyl dehydracetate (20 g 0.102 mole) and 4-bromoaniline (19.3 g, 0.112 mole are dissolved in 50% aqueous acetic acid (100 ml). The mixture is refluxed for 12 hours, the solvent removed, and the crude ester isolated as a brownish oil.

The crude ester isolated above is heated for 6 hours with 300 g 5% NaOH in 1:1 methanol/water. The mixture is cooled, diluted with water (100 ml) and filtered to remove insolubles. Some of the methanol is removed in vacuo, and an additional portion of water is added. The clear basic solution is then acidified and the resulting precipitate is filtered and dried. Recrystallization from acetonitrile provides pure N-(4-bromophenyl)-5-carboxy-4,6 dimethylpyrid-2-one (5.3 g, 16.1 % yield) having a melting point of 244-6 (dec).

EXAMPLE 3 Preparation of N-(4-bromophenyl)-3-bromo-5-carboxy-4, 6-dimethylpyrid-2-one (Compound 23, Table I) Sodium N-(4-bromophenyl)-4,6-dimethylpyrid-2-one-5-carboxylate (285 g, 0.00828 mole) is dissolved in dry methanol (50 ml). Bromine (1.59 g, 0.00994 moles, 1.2 equivalents) is dissolved in methanol (50 ml) and slowly drop-added to the vigorously stirred salt solution over a period of 15 to 20 minutes. The solvent is then removed and the residue taken up in dilute base.

After filtering off the insoluble material, the clear basic aqueous solution is acidified with hydrochloric acid. The resulting precipitate is filtered and dried, and recrystallized from acetonitrile to yield N-(4-bromophenyl)-3-bromo-5-carboxy-4,6-dimethylpyrid-2-one (2.25 g, 67.8%) having a melting point of 248-250"C.

EXAMPLE 4 Preparation of N-(4-chlorophenyl) -5-carboxy-6-methylpyrid-2-one (Compound 26, Table I) (a) Ethyl -anilinocrotonate (23.9 g) is dissolved in dry benzene (200 ml) and placed in a flask under a nitrogen atmosphere. Acrylol chloride (10 g) is dissolved in additional dry benzene (200 ml) and drop-added via a sidearm additional funnel over the course of 11/2 hour. The reaction mixture is allowed to stand at about 25 for one hour. and then poured into water and extracted with methylene chloride. Evaporation of the solvent yields crude 5-carbethoxy-N-(4-chlorophenyl)-6-methyl-3 ,4-dihydropyrid-2-one (23.3 g) having a melt- ing point of 124-6 (from hexane/ether).

(b) The ester (15 g) preparecd in (a) above is dissolved in chlorobenzene (500 ml).

2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) (23.2 g) is added and the mixture refluxed for 3 hours. The reaction mixture is then cooled, filtered and diluted with an equal volume of methylene chloride and washed exhaustively with dilute aqueous sodium bicarbonate. The solvent is removed in vacuo and the residue of crude product is recrystallized from hexane-ether to yield pure 5-carbethoxy-N-(4-chlorophenyl)-6methylpyrid-2-one (8.3 g) having a melting point of 53-4 .

(c) The pyridone (7.0 g) prepared in (b) above is suspended in 5% aqueous sodium hydroxide (200 ml). The mixture is heated on a steambath for one hour, cooled and acidified with aqueous hydrochloric acid to yield N-(4-chlorophenyl)-5-carboxy-6methylpyrid-2-one (4.0 g) which, when recrystallized from acetonitrile has a melting point of 271-3 with decomposition.

The compounds of the invention are particularly useful as chemical gametocides in cereal crops, such as wheat, barley, corn (i.e. maize), rice, sorghum, millets, oats and rye. When used as chemical gametocides, the compounds effectively induce a high degree of sterility in the treated plants, without causing significant growth inhibition of the treated plants. The compounds of the invention also cause other plant growth regulatory responses, such as for example, inhibition of seed formation in undesirable monocot species for weed grass control, control of flowering, control of fruiting and inhibition of seed formation in non-cereal species, control of ripening, and other related growth regulatory responses.

When used as plant growth regulators, the compounds of the invention are applied in any amount which will be sufficient to effect the desired plant response without causing any undesirable or phytotoxic response. For example, when the compounds of the invention are used as chemical gametocides, they are generally applied to the plants to be treated as a rate of from 1/32 to 20 pounds per acre and preferably from 1/8 to 10 pounds per acre. The rate of application will vary depending on the plant species being treated, the compound being used for treatment, and related factors.

A preferred method of applying a compound of the invention as a plant growth regulator is by foliar application. When this method is employed, gametocidal activity is most effectively induced when the compound is applied prior to meiosis, and preferably after flow initiation. The compounds of the inventions may also be applied as a seed treatment by soaking the seed in a liquid formulation containing the active compound or by coating the seed with the compound. In seed treatment applications, the compounds of the invention will generally be applied at a rate of from 1/4 to 10 pounds per hundred weight of seed. The compounds of the invention can also be applied to the soil or, in rice crops, to the water surface.

The compounds of the invention can be used as plant growth regulators either individually or in mixtures. For example, they can be used in combination with other plant growth regulators, such as auxins, gibberellins, morphactins, ethylene-releasing agents such as ethephon, pyridones, cytokinins, maleic hydrazide, succinic acid 2,2-dimethylhydrazide, choline and its salts, (2-chloroethyl) trimethylammonium chloride, triiodobenzoic acid tributyl-2,4-dichlorobenzylphosphonium chloride, polymeric N-vinyl-2-oxazolidones, tri (dimethylaminoethyl) phosphate and its salts, and N-dimethylamino-1,2,3,6tetrahydrophthalamic acid and its salts, 2,3-dichloroisobutyric acid and its salts and 3-(4-chlorophenyl)-6-methoxy-s-triazine-2,4-(lH,3H)-dione, and under some conditions may be used advantageously with other agricultural chemicals such as herbicides, fungicides, insecticides, and plant bastericides.

A compound of the invention can be applied to the growth medium or to plants to be treated either by itself or, as is generally done, as a component in a growth regulant composition or formulation which also comprises an agronomically acceptable carrier. By "agronomically acceptable carrier" is meant any substance which can be used to dissolve, disperse, or diffuse a compound in the composition without impairing the effectiveness of the compound and which by itself has no significant detrimental effect on the soil, equipment, crops, or agronomic environment. Mixtures of compounds of the invention may also be used in any of these formulations. Compositons of the invention can be either solid or liquid formulations or solutions. For example, the compounds can be formulated as wettable powders, emulsifiable concentrates, dusts, granular formulations, aerosols, or flowable emulsion concentrates. In such formulations, the compounds are extended with a liquid or solid carrier and, when desired suitable surfactants are incorporated.

It is usually desirable, particularly in foliar applications, to include adjuvants, such as wetting agents, spreading agents, dispersing agents, stickers and adhesives, in accordance with agricultural practices. Examples of adjuvants which are commonly used in the art can be found in the John W. McCutcheon, Inc. publication "Detergents and Emulsifiers Annual".

The compounds of the invention can be dissolved in any appropriate solvent. Examples of solvents which are useful in the practice of this invention include water, alcohols, ketones, aromatic hydrocarbons, halogenated hydrocarbons, dimethylformamide, dioxane and dimethyl sulfoxide. Mixtures of these solvents can also be used. The concentration of the solution can vary from 2% to 98% by weight with a preferred range being from 20% to 75%.

For the preparation of emulsifiable concentrates, the compound can be dissolved in organic solvents, such as benzene, toluene, xylene, methylated naphthalene, corn oil, pine oil, o-dichlorobenzene, isophorone, cyclohexanone, and methyl oleate or in mixtures of these solvents, together with an emulsifying agent or surfactant which permits dispersion in water. Suitable emulsifiers include, for example, the ethylene oxide derivatives of alkylphenols or long-chain alcohols, mercaptans, carboxylic acids, and reactive amines and partially esterified polyhydric alcohols. Solvent-soluble sulfates or sulfonates, such as the alkaline earth salts or amine salts of alkylbenzenesulfonates and the fatty alcohol sodium sulfates, having surface-active properties can be used as emulsifiers either alone or in conjunction with an ethylene oxide reaction product. Flowable emulsion concentrates are formulated similarly to the emulsifiable concentrates and include, in addition to the above components, water and a stabilizing agent such as a water-soluble cellulose derivative or a water-soluble salt of a polyacrylic acid. The concentration of the active ingredient in emulsifiable concentrates is usually from 10% to 60% by weight and in flowable emulsion concentrates this can be as high as 75%.

Wettable powders suitable for spraying can be prepared by admixing the compound with a finely divided solid, such as clays, inorganic silicates and carbonates, and silicas and incorporating wetting agents, sticking agents, and/or dispersing agents in such mixtures.

The concentration of active ingredients in such formulations is usually in the range of from 20% to 98% by weight, preferably from 40% to 75%. A dispersing agent may generally consititute from 0.5% to 3% by weight of the composition, and a wetting agent may generally constitute from 0.1% to 5% by weight of the composition.

Dusts can be prepared by mixing the compounds of the invention with finely divided inert solids which may be organic or inorganic in nature. Materials useful for this purpose include, for example, botanical flours, silicas, silicates, carbonates and clays. One convenient method of preparing a dust is to dilute a wettable powder with a finely divided carrier. Dust concentrates containing from 20% to 80% by weight of the active ingredient are commonly made and are subsequently diluted to from 1% to 10% by weight use concentration.

Granular formulations can be preparecd by imgrenating a solid such as granular fuller's earth, vermiculite, ground corn cobs, seed hulls, including bran or other grain hulls, or similar material. A solution of one or more of the compounds in a volatile organic solvent can be sprayed or mixed with the granular solid and the solvent then removed by evaporation. The granular material can have any suitable size, with a preferable size range of 16 to 20 mesh. (U.S. Standard Screen Series). The active compound will usually comprise from 2 to 15% by weight of the granular formulation.

Salts of the compounds of the invention can be formulated and applied as aqueous solutions. The salt will typically comprise from 0.05 to 50% by weight, preferably from 0.1% to 10%, of the solution. These compositions can also be further diluted with water if desired prior to actual application. In some applications, the activity of these compositions can be enhanced by incorporating into the composition an adjuvant such as glycerin, methylethylcellulose, hydroxyethylcellulose, polyoxyethylenesorbitan monooleate, polypropylene glycol, polyacrylic acid, polyethylene sodium malate or polyethylene oxide. The adjuvant will generally comprise from 0.1 to 5% by weight, preferably from 0.5 to 2%, of the composition. Such compositions can also optionally include an agronomicallyacceptable surfactant.

The compounds of the invention can be applied as sprays by methods commonly employed, such as conventional hydraulic sprays, aerial sprays, and dusts. For low-volume applications a solution of the compound is usually used. The dilution and volume of application will usually depend upon such factors as the type of equipment employed, the method of application, the area to be treated and the type and stage of development of the crop being treated.

The data in Table II below show male gametocidal activity of typical compounds of Formula I and these data were obtained by the following procedure.

An awned variety (Fielder) and an awnless variety (Mayo-64) of spring wheat (both varieties have male and female fertility) are planted at the rate of 6 to 8 seeds per 6" pot containing a sterile medium of 3 parts soil and 1 part humus. The plants are grown under short-day (9 hour) conditions for the first 4 weeks to obtain good vegetative growth before flow initiation. The plants are then moved to long-day (16 hour) conditions which are provided by high intensity lights in the greenhouse. The plants are fertilized at 2, 4, and 8 weeks after planing with a water soluble fertilizer (N16%, P25%, K16% by weight) at the rate of 1 tsp/gal of water, and are frequently sprayed with isotox for aphid control and dusted with sulfur for powdery mildew control.

Test compounds are foliarly applied to the awned male/female plants when these plants reach the flag leaf emergence stage (stage 8 on Feekes' scale). All compounds are applied in a carrier volume of 50 U.S. gal/A containing a surfactant, (such as Triton X-100, Triton being a registered trade mark) at the rate of 2 oz/50 U.S. gal.

After spike emergence but before anthesis, of the treated plants, 4 to 6 spikes per pot are bagged to prevent outcrossing. At the first signs of flower opening, two spikes per pot are cross pollinated, using the approach method, with the awnless male/female parent. As soon as the seeds become plainly visible, spike length (uncrossed) is measured and seeds per spikelet counted in both bagged and crossed spikes. Male sterility is then calculated as percent inhibition of seed set in bagged (uncrossed) spikes of treated plants. After maturity the seed on crossed spikes can be planted for determination of percent hybridization.

Percent sterility is calculated from the following formula: % Sterility = Sc - St x 100 Sc Sc = secds/spikelet in bagged spikes of control plants St = seeds/spikelet in bagged spikes of treated plants Table II summarizes typical results obtained in the evaluation of compounds of the invention. A dash indicates that no test at the indicated rate was made.

TABLE II

% Sterility at the Stated Application Rate (1b/A) X Y R7 (8) (4) (2) (1) () (1/4) (1/8) 4-Cl H H 100 100 100 96 - - 4-Cl H Na 100 100 100 100 92 52 4-CH3 H H 21 0 0 14 13 12 2 4-CH3 H Na 0 0 0 14 11 2 3 3,4-diCl H H 98 93 80 12 20 16 12 3,4-diCl H Na 96 91 33 22 25 21 4 4-F H H 0 0 0 9 0 24 13 4-F H Na 0 0 0 2 7 18 15 3-Cl H H 4 0 0 0 3 3 2 3-Cl H Na 0 2 0 - - - - 4-CH3,3-Cl H H 6 4 0 19 0 - 4-CH3,3-Cl H Na 0 2 1 0 1 6 4-OCH3 H H 56 18 2 9 - - 4-OCH3 H Na 54 31 0 3 - - 4-CF3 H H 15 3 - - - - 4-CF3 H Na 0 3 0 0 1 - 4-Br H H 100 100 100 - - - - 4-Br H Na 100 100 100 100 100 100 100 TABLE II (Cont...) X Y R7 (8) (4) (2) (1) (1/2) (1/4) (1/8) * H H 2 - - - - - * H Na 14 4 0 0 - - 4-Cl Br H 9 7 9 16 13 - 4-Cl Br Na 15 13 13 20 13 - 4-Br Br H - - - - - - - 4-Br Br Na 100 99 89 43 25 - 4-Br H C2H5 100 - 100 - 100 - 100

4-Cl H H 100 88 49 19 - 4-Cl H Na 100 100 90 39 - - *The N-substituent is 4-chloronaphthyl.

WHAT WE CLAIM IS:- 1. A compound of the formula

wherein R1 is alkyl; R2 is a carboxy group (or an agronomically acceptable salt thereof) of a carbalkoxy group; R is a hydrogen atom or a (C1-C4)alkyl group; R4 is a hydrogen atom, a (C1-C4)alkyl group, or a halogen atom; and

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

Claims

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

TABLE II (Cont...) X Y R7 (8) (4) (2) (1) (1/2) (1/4) (1/8) * H H 2 - - - - - * H Na 14 4 0 0 - - 4-Cl Br H 9 7 9 16 13 - 4-Cl Br Na 15 13 13 20 13 - 4-Br Br H - - - - - - - 4-Br Br Na 100 99 89 43 25 - 4-Br H C2H5 100 - 100 - 100 - 100

4-Cl H H 100 88 49 19 - 4-Cl H Na 100 100 90 39 - - *The N-substituent is 4-chloronaphthyl.

WHAT WE CLAIM IS:- 1. A compound of the formula

wherein R1 is alkyl; R2 is a carboxy group (or an agronomically acceptable salt thereof) of a carbalkoxy group; R is a hydrogen atom or a (C1-C4)alkyl group; R4 is a hydrogen atom, a (C1-C4)alkyl group, or a halogen atom; and

R5 is a phenyl or naphthyl group each substituted with one or two of the same or different substituents selected from halogen, (C1-C4)alkyl, (C1-C4)alkoxy, trifluoromethyl and nitro.
2. A compound according to Claim 1, wherein R1 is (C1-C4)alkyl; R2 is carboxy (or an agronomically acceptable salt thereof) or carb(C1-C4)alkoxy; R3 is hydrogen or (C1-C4)alkyl; R4 is hydrogen, (C1-C4)alkyl or halogen and R5 is phenyl substituted with one or two halogen atoms.
3. A compound according to Claim 2, wherein R2 is carboxy or an agronomically acceptable salt thereof.
4. A compound according to Claim 3, wherein R1 is methyl and R4 is hydrogen.
5. A compound according to Claim 4, wherein R3 is methyl.
6. A compound according to Claim 5, wherein R5 is phenyl substituted with halogen.
7. A compound according to Claim 6, wherein R5 is 4-halophenyl.
8. A compound according to Claim 4, wherein R3 is hydrogen.
9. A compound according to Claim 3, wherein R1 is a methyl group and R4 is halogen.
10. A compound according to Claim 9, wherein R3 is methyl.
11. A compound according to Claim 10, wherein R4 is bromine.
12. A plant growth regulant composition which comprises a compound according to any one of the preceding claims and an agronomically acceptable carrier.
13. A method of regulating plant growth which comprises applying to the plant, the plant seeds, or the plant habitat an effective amount of a compound according to any one of Claims 1-11.
14. A method of Claim 13, wherein the plant is a cereal having both male and female fertility.
15. The method of Claim 14, wherein the compound is applied to the plant prior to meiosis in an amount effective to produce male sterility in the plant.
16. A compound according to Claim 1 being any one of those individual compounds identified in the foregoing description.
17. A method of preparing a compound according to Claim 1, the method being, as appropriate, any of those generally described in the foregoing descriptive portion of the specification.
18. A compound according to Claim 1 when prepared substantially as hereinbefore described with reference to any one of the foregoing Examples 1-4.