JPH0567625B2 - - Google Patents

Description

[Detailed description of the invention]

In the field of chemical hybridization agents, 1-aryl-
1,4-dihydro-4-oxo-6-alkylpyridazine-3-carboxylic acids are highly active pyridazine-type mother cell gamete killing agents. Although these compounds are highly effective as chemical hybridizing agents, they have the disadvantage of damaging plants and weakening seed quality when used in slight excess of their effective dosage. The 5-carboxypyridazines of this invention surprisingly do not have any deleterious effects on seed quality or plant damage rates even at dosages much higher than required to obtain maximum male sterility. First, it is a safer chemical hybridizing agent because it can produce hybrids at a higher rate. This invention is based on the general formula

[Formula] [In the formula, R ¹ is a substituted or unsubstituted phenyl group or naphthyl group; R ⁵ is a methoxycarbonyl group, a carboxyl group, or an alkali metal salt or acid addition salt thereof acceptable for crop cultivation; R ⁶ is ( _C1 − _C8 )
It represents an alkyl group or a substituted or unsubstituted phenyl group. ] Regarding the pyridazines shown. This type of pyridazines has the advantage of causing less damage to plants when making them male sterile, making them excellent plant growth regulators when used as crossbreeding agents for cereals. Among the above pyridazines, those with excellent effects are:
R ¹ is an unsubstituted phenyl group, or independently selected from halogen, nitro group, trifluoromethyl group, (C ₁ -C ₄ ) alkoxy group, (C ₁ -C ₄ ) alkyl group, and cyano group Substituted phenyl group having up to 3 substituents; R ⁶ is a (C ₁ -C ₈ ) alkyl group. As used in this specification and claims, the term "aryl" refers to phenyl or naphthyl groups, or halogen, nitro, trihalomethyl,
It means a phenyl or naphthyl group substituted with up to three substituents selected from the group consisting of ( _C1 - _C4 ) alkoxy, ( _C1 - _C4 ) alkyl, and cyano. As used in this specification and claims, the term "alkyl" refers to an alkyl group having up to 4 carbon atoms, which alkyl group may be straight-chain or branched. One of the preferred embodiments of this invention is that R ¹ is halogen, nitro, trihalomethyl, (C ₁ -C ₄ )
is an aryl group substituted with up to three substituents selected from the group consisting of alkoxy, (C ₁ -C ₄ ) alkyl, and cyano group, and R ⁶ is a (C ₁ -C ₄ ) alkyl group. Relating to a compound of a certain formula. In a more preferred embodiment of the present invention, R ⁵ is a carboxy group (COOH) or an alkali metal salt thereof,
or a carbalkoxy group (COOR) in which R is an alkyl group having up to 4 carbon atoms and an agriculturally acceptable acid addition salt thereof. The most preferred embodiment of this invention is that R ¹ is a phenyl group substituted with up to two substituents selected from the group consisting of halogen, nitro, trifluoromethyl, methoxy, methyl and cyano groups, and R ⁶ is It relates to compounds of the formula which are methyl or ethyl groups. Typical compounds included in this invention are listed below. 1-phenyl-1,4-dihydro-4-oxo-6-methylpyridazine-5-carboxylic acid, 1-
Phenyl-1,4-dihydro-4-oxo-6-
Ethylpyridazine-5-carboxylic acid, 1-phenyl-1,4-dihydro-4-oxo-6-propylpyridazine-5-carboxylic acid, 1-phenyl-1,4-dihydro-4-oxo-6-butylpyridazine -5-carboxylic acid, 1-
Phenyl-1,4-dihydro-4-oxo-6-
Phenylpyridazine-5-carboxylic acid, 1-(4-chlorophenyl)-1,4-dihydro-4-oxo-6-methylpyridazine-5-carboxylic acid, 1-(4-bromophenyl)-1,4-dihydro -4-oxo-6-ethylpyridazine-5-carboxylic acid, 1-(3,4-dichlorophenyl)-1,4-dihydro-4-oxo-6-propylpyridazine-
5-carboxylic acid, 1-(4-iodophenyl)-1,4-dihydro-4-oxo-6-butylpyridazine-5-carboxylic acid, 1-(4-chlorophenyl)-1,4-dihydro-4-oxo -6-phenylpyridazine-5-carboxylic acid, 1-(3-chlorophenyl)-1,4-dihydro-4-oxo-6-methylpyridazine-5-carboxylic acid, 1-(2-chlorophenyl)-1, 4-dihydro-4-oxo-6-ethylpyridazine-5-carboxylic acid, 1-(3-bromophenyl)-1,4-dihydro-4-oxo-6-propylpyridazine-5-carboxylic acid, 1-(2 -bromophenyl)-1,4-dihydro-4-oxo-6-butylpyridazine-5-carboxylic acid, 1-(2,4,6-trichlorophenyl)-1,
4-dihydro-4-oxo-6-benzyl-pyridazine-5-carboxylic acid, 1-(4-methylphenyl)-1,4-dihydro-4-oxo-6-phenylpyridazine-5-carboxylic acid, 1- (4-trifluoromethylphenyl)-1,
4-dihydro-4-oxo-6-methylpyridazine-5-carboxylic acid, 1-(3-ethoxyphenyl)-1,4-dihydro-4-oxo-6-ethylpyridazine-5-carboxylic acid, 1- (3-cyanophenyl)-1,4-dihydro-4-oxo-6-butylpyridazine-5-carboxylic acid, 1-(2-chloro-4-methylphenyl)-1,
4-dihydro-4-oxo-6-benzylpyridazine-5-carboxylic acid, 1-(2-trifluoromethyl-4-chlorophenyl)-1,4-dihydro-4-oxo-6-
Methylpyridazine-5-carboxylic acid, 1-(2-trifluoromethyl-4-bromophenyl)-1,4-dihydro-4-oxo-6-
Ethylpyridazine-5-carboxylic acid, 1-(2-chloro-5-trifluoromethylphenyl)-1,4-dihydro-4-oxo-6-
Ethylpyridazine-5-carboxylic acid, 1-(2-naphthyl)-1,4-dihydro-4-
Oxo-6-butylpyridazine-5-carboxylic acid, and agriculturally acceptable alkali metal salts and acid addition salts thereof. Next, an example of the reaction process used to obtain the compounds of the present invention will be shown step by step.

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[ ^Chemical formula] ₍ wherein _, ( _C1 - _C4 ) is an alkyl group or a cyano group, n is 1, 2 or 3 and represents the number of substituents X, and x represents chlorine etc. forming a diazonium salt. It is unique in that it can generate expressions () and (). There are no reports in the literature about the direct synthesis of any of these types of compounds. In this reaction process, 3-oxoglutarate is first reacted with sodium hydride to replace the hydrogen atom of the active methylene group with a sodium atom, and then reacted with acetyl chloride to form an intermediate of formula (). . This intermediate is rearranged under acidic conditions to form a pyrone of formula (). However,
This pyrone is reacted with a diazonium salt to form a hydrazone of formula (). Finally, this hydrazone is rearranged in the presence of a base to obtain a dicarboxypyridazine derivative of formula (). This product is then decarboxylated under strongly acidic conditions and simultaneously converted (hydrolyzed) into an alkoxycarbonyl group at the 5-position to give 5-carboxypyridazine of formula (). Formula () is 5-carboxypyridazine, but if only decarboxylation at the 3-position is performed during conversion from formula () to formula (), the pyridazine corresponding to formula () is 5-methoxycarbonylpyridazine. becomes. Other compounds of general formula () can also be synthesized according to the same synthesis process as above, and if desired, alkali metal salts, acid addition salts, etc. can be further synthesized from 5-carboxypyridazine of formula () based on known techniques. Derivatives can be produced. Next, an example of a more preferable synthetic route for obtaining the compound of the present invention will be shown.

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[Formula] In the above method, 3-oxoglutarate is first reacted with a diazonium salt to form a hydrazone of formula (), then reacted with isopropylmagnesium chloride, and further reacted with acetyl chloride to form a hydrazone of formula (). A carboxypyridazine ester is formed and finally this pyridazine ester is hydrolyzed to the corresponding acid of formula (). Next, as described above, monocarboxypyridazine of formula () is produced by decarboxylation and hydrolysis under strongly acidic conditions. The above synthesis process is just an example, and for example, p-aryl chloride diazonium salt is used as the diazonium salt, but it is not limited to this, and the general formula ()
Diazonium salts having other substituents that R ¹ can take may also be used. Other derivatives can be produced as desired by applying known techniques. The following examples illustrate methods for making compounds of the invention. They do not limit the scope of the invention in any way. Method A: 6-Methyl-5-carbomethoxy- via dimethyl 2-acetyl-3-oxoglutarate
Synthesis of 4-Hydroxy-2-pyrone A three-necked round bottom flask was equipped with a dropping funnel, a paddle stirrer, and a thermometer. In a flask add 300 ml of dry toluene and sodium hydride (50 ml in mineral oil).
% dispersion, 82.8 g, 1.72 mol). Add dimethyl 3-oxoglutarate (acetone) to the dropping funnel.
Dimethyl ester of 1,3-dicarboxylic acid, 300
g, 1.72 mol) was added. The flask was cooled to 5°C in an ice-water bath. The diester was added dropwise to the sodium hydride slurry. At this time, the reaction temperature is 10
I made sure not to exceed ℃. It took 3 hours to complete the dropping. The resulting mixture was stirred at 5°C for 30 minutes. Next, aticel chloride (135g, 1.72mol)
was added dropwise from a dropping funnel. At this time, care was taken to maintain the temperature of the pot at 5-10°C.
After the addition was complete, the resulting slurry was stirred for an additional 30 minutes and then slowly poured into 500 ml of water saturated with ammonium chloride. The pH of the resulting mixture was 6. The layers were separated. The aqueous phase was dissolved in methylene chloride (3×
100ml). The organic layers were combined and dried under reduced pressure, leaving a yellow oil. Vacuum distillation (0.5 mmHg) of this oil yielded a fraction with a boiling point of 50-120°C. Main fraction of bp85-110℃ (97g)
contains the desired acetylated diester;
Judging from NMR, a small amount of raw material was also observed. The crude acetylated diester thus obtained (97 g) was dissolved in 300 ml of dry xylene together with p-toluenesulfonic acid (100 mg). The mixture was refluxed into a Dean-Stark trap for 12 hours. The resulting dark solution was cooled in an ice-water bath. The desired pyrone crystallized as fine needles (28.1 g, 10% yield based on dimethyl 3-oxoglutarate).
Analytical samples were crystallized from ethyl acetate.
NMR ( _CDCl3 ): 5.6 (S, 1H); 4.1 (S, 3H); 2.7
(S,3H)ppm. IR ( _CH2Cl2 ): 5.75 _, 5.95,
6.90, 9.10μ. mp: 104−106℃. Elemental analysis Calculated value: C: 52.18; H: 4.38 Actual value: C: 52.30; H: 4.44. Synthesis of 1-(p-chlorophenyl)-1,4-dihydro-4-oxo-3-carboxy-5-carbomethoxy-6-methylpyridazine A 250 ml three-necked round-bottomed flask was equipped with a dropping funnel, a paddle stirrer, and I installed a thermometer. In a flask, add 50 ml of methanol, sodium acetate (16.0 g,
0.198 mol) and 6-methyl-5-carbomethoxy-4-hydroxy-2-pyrone (8.0 g,
0.043mol) was added. Furthermore, a solution of sodium nitrite (3.3 g, 0.047 mol) dissolved in 10 ml of water,
p-chloroaniline (5.6 g, 0.043 mol) in aqueous hydrochloric acid solution [12HN NCl 16.5 ml (0.198 mol) + water 10 ml]
p-chlorobenzenediazonium chloride was prepared by dropping it into the cooled (5° C.) slurry contained in the solution. 6 diazonium chloride solution
-Methyl-5-carbomethoxy-4-hydroxy-2-pyrone was added dropwise to the solution containing it.
Although this dropping was carried out for 10 minutes, no significant heat generation was observed. After the dropwise addition was completed, the resulting orange slurry was stirred at room temperature for 40 minutes. Filtration gave an orange percolate which was washed repeatedly with water and then suction dried for 2 hours. The thus obtained supercake was put back into the three-necked flask used earlier. Methanol (200ml) was added to form a slurry. Morpholine (10.0g,
0.115 mol) was added all at once. A mildly exothermic reaction occurred and a dark homogeneous solution was obtained.
After stirring for 10 minutes, the solution was poured into 300 ml of water. Extracted with methylene chloride (3x100ml). The organic extracts were combined and extracted multiple times with a dilute aqueous solution of sodium hydroxide (PH8). The alkaline aqueous solutions were combined and acidified with 6N hydrochloric acid. Cool and
A solid crystallized out of solution when the container walls were scraped. Filtration gave an ocher powder (8.2 g, 6-methyl-5-carbomethoxy-4-hydroxy-2-
60% yield based on pyrone). NMR ( _CDCl3 ): 7.5 (multiplet, 4H); 4.0 (S,
3H); 2.3 (S, H) ppm. IR( _CH2Cl2 ): _5.75 ,
6.22, 6.90μ. mp: 203-204℃ (decomposed). Analytical samples were recrystallized from methanol. Elemental analysis Calculated value: C: 52.10; H: 3.44; N: 8.68 Actual value: C: 52.06; H: 3.43; N: 8.89. Synthesis of 1-(p-chlorophenyl)-1,4-dihydro-4-oxo-5-carboxy-6-methylpyridazine 1-(p-chlorophenyl)-1,4-dihydro-4-oxo-3-carboxy- 5-Carbomethoxy-6-methylpyridazine (2.0g, 6.2mmol)
was dissolved in 10 ml of concentrated sulfuric acid under a dry nitrogen gas atmosphere. The solution was immediately heated to 200°C and held at that temperature for 40 minutes. The resulting dark solution was cooled and then poured into cold water (50ml). A brown precipitate formed immediately. Aspirate and wash with water to obtain the desired acid (1.0 g, pure by NMR).
A yield of 63% was obtained. NMR ( _CDCl3 ): 8.5 (S, 1H); 7.6 (AB quartet,
4H); 2.8 (S, 3H) ppm. IR [Nujol]: 5.81μ. mp: 207-208℃ (decomposed). Analytical samples were recrystallized from methanol. Elemental analysis Calculated value: C: 54.45; H: 3.43; N: 10.59 Actual value: C: 54.45; H: 3.52; N: 10.16. Method B: Dimethyl 2,3-dioxyglutarate, 2-p
-Synthesis of chlorophenylhydrazone Ten wide-mouthed polyethylene containers were equipped with a stirring paddle and an addition funnel. Add dimethyl 3-oxoglutarate (1Kg, 5.7mol), methanol (1.5) and sodium acetate (1Kg, 12.19mol) to this container.
I put it in. Separately, p-chloroaniline (7 x 104
g, 5.75mol), hydrochloric acid (7 x 314ml 12N,
26 mol), water (7 x 200 ml) and sodium nitrite (7 x 100 ml of water 65.6 g, 6.66 mol) to give p
-Chlorobenzenediazonium chloride was prepared in equal amounts in seven separate batches. The diazonium salt was quickly added dropwise to the reaction vessel. The PH was monitored periodically and maintained at 5 by adding sodium acetate with a spatula during the reaction. At the end of this investigation, an additional 800 g of sodium acetate was added. The resulting mixture was left overnight, then filtered by suction,
The filter cake was thoroughly washed with water. Air-dry brick-red overcake to yield desired yield () 1.4Kg
(yield 80%). NMR ( _CDCl3 ): 7.5 (S,
4H); 3.9 (S, 6H); 3.7 (S, 2H) ppm. This compound is a known compound described in the literature.
Bulow and Hofner, Berichte (Bulow and
Hopfner, Berichte) 34, 71 (1901);
See 2835 (1911). Synthesis of dimethyl 1-(p-chlorophenyl)-1,4-dihydro-4-oxo-pyridazine-3,5-dicarboxylate A dry four-necked round-bottomed flask was equipped with a stirrer, a thermometer, and a nitrogen inlet. and a rubber bulkhead was installed. In a flask, add dimethyl 2,3-dioxoglutarate, 2-p-chlorophenylhydrazone (50
g, 0.16 mol) of dry tetrahydrofuran (170
ml) solution was added. This solution was kept under a dry nitrogen gas atmosphere while being cooled to 5°C. Isopropylmagnesium chloride (72ml, 2.25N ethyl ether solution, 0.16mol) was added to the pot at a temperature of 5-10°C.
It was added dropwise using a syringe. After the addition was complete, the mixture was stirred in the cold for 15 minutes and then acetyl chloride (12 ml, 13.0 g, 0.16 mol) was immediately added dropwise while keeping the temperature of the reaction mixture below 10°C. The resulting dark solution was warmed to room temperature and held for 2 hours. Water (200ml) was added. This mixture was stirred for 30 minutes. Next, it was extracted with ethyl acetate. The extract was dried with _MgSO4 , then filtered and
The volume was reduced under vacuum. The resulting dark oil was dissolved in ethyl ether and cooled in an ice bath. The desired diester crystallizes out as a yellow powder.
22.1 g (yield 42%) was obtained. mp153−154℃.
NMR ( _CDCl3 ): 7.6 (multiplet, 4H); 4.0 (S,
6H); 2.3 (S, 3H) ppm. IR( _CH2Cl2 ): _5.75 ,
6.12, 9.15μ. The table below shows the structure, melting point, and elemental analysis of other representative compounds included in the present invention prepared by the methods described above.

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[Table] The compounds of the present invention are particularly useful as chemical hybridizing agents for cereal crops, such as comb, barley, maize, Poaceae, sorghum, millet, oat, lime, triticale, and feed crops. When used as chemical hybridizing agents, the compounds of the present invention induce selective male sterility at high rates without significantly inducing female sterility in the treated plants. Moreover, the growth inhibition of treated plants does not occur to a certain extent. As used herein, the term "male sterility" refers to actual male sterility, recognized by the absence of stamens or by sterile pollen, and stamens incapable of pollinating. This includes functional male sterility. The compounds of the invention also have other plant growth regulating responses, such as flowering regulation, fruit regulation and inhibition of seed formation in non-shell species, and other relevant growth regulating responses. When used as plant growth regulators, the compounds of the present invention are used in any amount sufficient to produce the desired plant response without producing undesirable or phytotoxic reactions. For example, when the compounds of the present invention are used as chemical hybridizing agents, they are typically used at a rate of about 1/32 to about 20 pounds per acre (about 0.035 to 22.4 Kg per hectare) of the crop being treated, preferably about 1/32 to about 20 pounds per acre (about 0.035 to 22.4 kg per hectare); 8 to about 10 pounds (about 0.14 per hectare)
~11.2Kg). The rate used will vary depending on the crop being treated, the compounds used in the treatment and other relevant factors. To obtain hybrid seeds, the following methods are usually adopted. Plant the parents of the two hybrid species in separate locations. The female parents are treated with a compound of the invention. When the male sterile female parent produced in this way is pollinated with pollen from another male fertile male parent, the seeds produced from the female parent become hybrid seeds, which are then harvested by conventional methods. can do. A preferred method of using the compound of the present invention as a chemical hybridization agent is to use it on leaves. When employing this method, selective male sterility is most effectively obtained when the compound is used between flowering and meiosis. The compounds of the invention may also be applied for seed treatment by soaking the seeds in a formulation containing the active compound or by applying the compounds to the seeds. In carrying out seed treatments, the compounds of the present invention are typically used in amounts ranging from about 1/4 to about 100 pounds per 100 pounds of seed.
It is used at a rate of 10 pounds (approximately 2.5 to 100 grams per kilogram of seeds). The compounds of the present invention are effective on soil and, in rice crops, on water surfaces. The compounds of the present invention can be used alone or as a mixture as a plant growth regulator.
For example, these compounds include auxins, gibberellins and ethephon, pyridone, cytokinins, maleic hydrazide, 2,2-dimethyl succinic hydrazide, choline and its salts, (2-chloromethyl)trimethylammonium chloride, triiodobenzoin, acid, tributyl-
2,4-dichlorobenzylphosphonium chloride, N-vinyl-2-oxazolidinone polymer, tri(dimethylaminoethyl)phosphate and its salts, and N-dimethylamino-1,
Can be used in combination with other plant growth regulators such as ethylene releasing agents such as 2,3,6-tetrahydrophthalamic acid and its salts, and in some cases herbicides, fungicides and insecticides. and other agricultural chemicals such as plant fungicides. The compounds of the present invention can be used alone or as a component of growth regulator compositions or preparations containing agriculturally acceptable carriers in the growth medium or plants to be treated, as is conventionally practiced. "Agriculturally acceptable carrier" means any substance that can be used to dissolve, disperse, or diffuse a compound into a composition without impairing the effectiveness of the compound;
As such, it means a substance that has no harmful effects on soil, equipment, crops or the agricultural environment.
Mixtures of the compounds of the invention may also be used in any of these preparations. The compositions of the invention may be either solid or liquid preparations or solutions. For example, the compounds can be formulated as wettable powders, emulsion concentrates, powders, granules, aerosols, or flowable emulsion concentrates. In such formulations, the compound is extended with a liquid or solid carrier and, if desired, a suitable surfactant is added. In accordance with agricultural practice, it is usually desirable to include adjuvants such as wetting agents, spreading agents, dispersing agents, fixing agents, adhesives, etc., especially when used on leaves. Examples of adjuvants commonly used in this technical field are
John W.Mc Cutcheon.
Listed in the ``Detergents and Emulsifiers Annual'' published by Inc. The compounds of the invention can be dissolved in a suitable solvent. Examples of solvents useful in the practice of this invention include water, alcohols, ketones, aromatic hydrocarbons, halogenated hydrocarbons, dimethylformamide, dioxane, dimethyl sulfoxide, and the like. Mixtures of these solvents can also be used. Solution concentration can vary from about 2% to about 98%, with a preferred range of about 2% to about 75%. For the preparation of concentrated emulsions, the compounds can be mixed with benzene, toluene, xylene, methylated naphthalene,
Dissolved in an organic solvent such as corn oil, pine oil, 0-dichlorobenzene, isophorone, cyclohexanone, methyl oleate, etc., or in a mixture of these solvents, together with an emulsifier or surfactant that can be dispersed in water. be able to. Suitable emulsifiers include, for example, ethylene oxide derivatives of alkylphenols or long-chain alcohols, mercaptans, carboxylic acids, and reactive amines as well as partially esterified polyhydric alcohols. Sulfates or sulfonates soluble in surface-active solvents, such as alkaline earth metal salts or amine salts of alkylbenzene sulfonates and fatty alcohol sodium sulfates as emulsifiers alone or together with ethylene oxide reaction products. Can be used.
Flowable concentrated emulsions are formulated similarly to concentrated emulsions and contain, in addition to the above ingredients, water and stabilizers such as water-soluble cellulose derivatives or water-soluble polyacrylates. The concentration of active ingredient in concentrated emulsions is usually about 10% to 60% by weight, and in flowable concentrated emulsions,
The concentration can be approximately 75%. Powdered wettable powders suitable for spraying mix the compound with finely divided solids, such as clays, inorganic silicates and carbonates, and silicic acid, and contain wetting agents, fixing agents and/or
Or it can be prepared by adding a dispersant into the mixture. The concentration of active ingredient in such hydrating agents is usually about 20-98% by weight, preferably 40-75%.
Weight%. Dispersants generally account for about 0.5 to
Comprising about 3% by weight, the wetting agent generally accounts for about 3% by weight of the composition.
It constitutes 0.1 to about 5% by weight. Powders can be prepared by mixing the compound of the invention with an inert organic or inorganic finely divided solid. Substances used for this purpose include, for example, vegetable powders, silicic acid, silicates, carbonates and clays. One convenient method of preparing powders is to dilute a powdered wettable powder with a finely divided carrier. Usually, a concentrated powder containing about 20 to 80% by weight of the active ingredient is made, which is then diluted to about 1% by weight.
Use at a concentration of ~10% by weight. Granules can be prepared by saturating solids of granular clay, vermiculite, ground corn ears, seed husks including bran and other cereal husks, and other similar materials. A solution of one or more compounds in a volatile organic solvent can be sprayed onto or mixed with the particulate solid, or the solvent can then be removed by evaporation. The granular material can be of any size, but is preferably between 16 and 60 mesh. The active compound is usually present in the granules in an amount of about 2-15% by weight. Salts of the compounds of this invention can be formulated and used as aqueous solutions. The salt is typically in solution at about
It accounts for 0.05 to about 50% by weight, preferably about 0.1 to about 10% by weight. These compositions can also be further diluted with water if desired prior to actual use. Depending on the application, the activity of these compositions may vary depending on the composition, such as glycerin, methyl ethyl cellulose, hydroxyethyl cellulose, polyoxyethylene sorbitan monooleate, polypropylene glycol, polyacrylic acid, polyethylene sodium maleate, polyethylene oxide, etc. This can be enhanced by including such adjuvants. Adjuvants generally represent from about 0.1% to about 5% by weight of the composition, preferably from about 0.5% to about 2%. Such compositions may optionally contain a commercially acceptable surfactant. The compounds of the invention can be used as sprays in the manner conventionally employed, such as conventional hydraulic sprays, air sprays and dust powders. When used in small amounts, a solution of the compound is usually used. The degree of dilution and the amount used will usually vary depending on the type of equipment employed, the method of use, the area to be treated and the type and stage of development of the crop being treated. The following examples further illustrate the growth regulating action of the compounds of the invention, but they are not intended to limit the invention in any way. Example 18 Chemical Hybridization Effect The following procedure is used to evaluate the effect of compounds of the invention on causing male sterility in shellfish. Fielder and non-awn varieties of spring-sown wheat (May-64) were grown in 6-inch pots containing sterile medium consisting of 3 parts soil and 1 part direct soil. Plant at a rate of ~8 species. Plants are grown for the first 4 weeks under short day (9 hours) conditions to ensure good growth before flowering.
The plants are then subjected to long day (16 hour) conditions and exposed to high intensity light at room temperature. Plants should be fed with water-soluble fertilizer (16-25-16) 2, 4 and 8 weeks after sowing.
at a rate of 18.66 cm ³ per liter of water, sometimes sprayed with isotox to control aphids and sprinkled with sulfur to prevent powdery mildew. When these plants reach the stage of flag leaf emergence (stage 8 on the Feekes scale), the sample compound is applied to the leaves of the awn female plants. All compounds are used in a ^{carrier containing} a ^surfactant such as ^Triton.RTM . 4 per pot after spike appearance and before flowering.
~6 spikes are placed in a bag to prevent outcrossing.
At the time of first flowering, two spikes per pot are cross-pollinated by the awnless stamina using the approach method. As soon as the seeds are clearly visible, measure the length of the spikes and count the number of seeds per spikelet for bagged spikes and hybrid spikes. Here, male sterility can be calculated as the percentage inhibition of seeds that set in the bagged spikes of treated plants, and female fertility in hybrid spikes can be calculated as the percentage of control seeds that set in the bagged spikes of treated plants. can. After maturity, seeds of hybrid spikes are planted to determine the hybridization rate. The sterility rate, fertility rate, and growth (height) inhibition rate are calculated using the following formulas. a Sterility rate (%) = (Sc - St / Sc) × 100 S = number of seeds / spikelets in the bag panicles of control plants St = number of seeds / spikelets in the bag panicles of treated plants Panicle b Fertility rate (%) = (Ft/Fc) x 100 Ft = Number of seeds/spikes in approach hybrid spikes of treated plants Fc = Number of seeds/spikes in unbagged spikes of control plants c Growth (height) inhibition rate (%) = (Hc - Ht/Hc)
×100 Hc = Height of control plants Ht = Height of treated plants The table summarizes the results obtained in the evaluation of the compounds of the invention.

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[Table] The 5-carboxypyridazinones of the present invention are 3-
Compared to carboxypyridazones, it maintains high activity and has improved safety. 1-aryl-1,4-dihydro-4 of the present invention
- Greenhouse data for oxo-6-alkylpyridazine-5-carboxylic acid sodium salt, which is a known compound, 1-(p-chlorophenyl)-1,4-
Dihydro-4-oxo-6-methylpyridazone-
A comparison with 3-carboxylic acid is shown in the table.

[Table] Known 1-(p-chlorophenyl)-1,4-dihydro-4-oxo-6-methylpyridazine-3
- The improved safety profile of 5-carboxypyridazinones compared to carboxylic acids also makes them useful as a breeding tool for shellfish when used directly on female parent seeds before planting. It is something. It is to be understood that changes and modifications to the subject matter of this invention may be made without departing from the spirit of the invention as set forth in the appended claims.

Claims (1)

[Claims] 1 Formula [Formula] [In the formula, R ¹ is a substituted or unsubstituted phenyl group or a naphthyl group; R ⁵ is a methoxycarbonyl group, a carboxyl group, or an alkali metal salt thereof acceptable for crop cultivation, or Acid addition salt; R ⁶ is (C ₁ −C ₈ )
It represents an alkyl group or a substituted or unsubstituted phenyl group. ] A compound represented by: 2 R ₁ is independently selected from unsubstituted phenyl group, halogen, nitro group, trifluoromethyl group, (C ₁ -C ₄ ) alkoxy group, (C ₁ -C ₄ ) alkyl group and cyano group; A substituted phenyl group having up to three substituents; ^R6 is a ( _C1 - _C8 ) alkyl group. 3. The compound according to claim 2, wherein R ⁶ is a methyl group or an ethyl group. Claim 3, wherein R ¹ is a substituted phenyl group having up to two substituents independently selected from halogen, nitro group, trifluoromethyl group, methoxy group, methyl group, and cyano group. Compounds described. 5. A compound according to claim 4, wherein R ¹ is a substituted phenyl group having substituents with up to two halogen atoms. 6. A method for making a cereal plant male sterile, which comprises treating the shell plant with a compound represented by the following formula in an amount effective to make the shell plant male sterile before meiosis. Formula [Formula] [In the formula, R ¹ is a substituted or unsubstituted phenyl group or naphthyl group; R ⁵ is a methoxycarbonyl group, a carboxyl group, or an alkali metal salt or acid addition salt thereof acceptable for crop cultivation; R ⁶ is ( _C1 − _C8 )
Indicates an alkyl group, substituted or unsubstituted phenyl group. ] 7 A composition for inducing male sterility for cereal plants, comprising an effective amount of a compound represented by the following formula and a carrier acceptable for crop cultivation. Formula [Formula] [In the formula, R ¹ is a substituted or unsubstituted phenyl group or naphthyl group; R ⁵ is a methoxycarbonyl group, a carboxyl group, or an alkali metal salt or acid addition salt thereof acceptable for crop cultivation; R ⁶ is ( _C1 − _C8 )
Indicates an alkyl group, substituted or unsubstituted phenyl group. ] 8 A composition for inducing male sterility for non-cereal plants, comprising an effective amount of a compound represented by the following formula and a carrier acceptable for crop cultivation. Formula [Formula] [In the formula, R ¹ is a substituted or unsubstituted phenyl group or naphthyl group; R ⁵ is a methoxycarbonyl group, a carboxyl group, or an alkali metal salt or acid addition salt thereof acceptable for crop cultivation; R ⁶ is ( _C1 − _C8 )
Indicates an alkyl group, substituted or unsubstituted phenyl group. ]9 Reaction of 1 mole of dimethyl 3-oxoglutarate with about 1 mole of sodium hydride in an inert solvent at a temperature of about 0°C to about 10°C, followed by reaction under acidic conditions after reaction with acetyl chloride. 4-hydroxy-2-pyrone is formed, and the pyrone is then heated with about 1 mole of a diazonium salt from about 0°C to about 50°C.
℃ to obtain a 3,5-dicarpoxypyridazine derivative in the presence of a base, which is then reacted with an excess of aqueous sulfuric acid under an inert atmosphere at temperatures from around room temperature to about 250℃. A method for producing a compound represented by the following formula. Formula [Formula] [In the formula, R ¹ is a substituted or unsubstituted phenyl group or naphthyl group; R ⁵ is a methoxycarbonyl group, a carboxyl group, or an alkali metal salt or acid addition salt thereof acceptable for crop cultivation; R ⁶ is ( _C1 − _C8 )
It represents an alkyl group or a substituted or unsubstituted phenyl group. ] 10 Reacting 1 mole of dimethyl 3-oxoglutarate with 1 molar equivalent of diazonium salt in an inert solvent to give a hydrazone, which is then reacted with isopropylmagnesium chloride and an acid chloride in an inert solvent to give 3 , 5-dicarboxypyridazine ester, this pyridazine ester is hydrolyzed to form the corresponding pyridazine-3
- A method of producing a compound represented by the following formula by reacting a carboxylic acid with excess concentrated sulfuric acid at a temperature from around room temperature to about 250°C. Formula [Formula] [In the formula, R ¹ is a substituted or unsubstituted phenyl group or naphthyl group; R ⁵ is a methoxycarbonyl group, a carboxyl group, or an alkali metal salt or acid addition salt thereof acceptable for crop cultivation; R ⁶ is ( _C1 − _C8 )
It represents an alkyl group or a substituted or unsubstituted phenyl group.