USRE31550E - N-(2-Chloro-4-pyridyl) ureas - Google Patents

N-(2-Chloro-4-pyridyl) ureas Download PDF

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Publication number
USRE31550E
USRE31550E US06/305,768 US30576881A USRE31550E US RE31550 E USRE31550 E US RE31550E US 30576881 A US30576881 A US 30576881A US RE31550 E USRE31550 E US RE31550E
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Prior art keywords
pyridyl
chloro
urea
inclusive
carbon atoms
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US06/305,768
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Koichi Shudo
Toshihiko Okamoto
Yo Isogai
Soshiro Takahashi
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OKAMOTO TOSHIHIKI
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OKAMOTO TOSHIHIKI
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Priority claimed from JP12128577A external-priority patent/JPS5481275A/en
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Assigned to OKAMOTO, TOSHIHIKI, SATO, SUSUMU, SHUDO, KOICHI, ISOGAI, YO reassignment OKAMOTO, TOSHIHIKI ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: OKAMOTO, TOSHIHIKO, SHUDO, KOICHI, TAKAHASHI, SOSHIRO, ISOGAI, YO
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    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07DHETEROCYCLIC COMPOUNDS
    • C07D213/00Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
    • C07D213/02Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
    • C07D213/04Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
    • C07D213/60Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
    • C07D213/72Nitrogen atoms
    • C07D213/75Amino or imino radicals, acylated by carboxylic or carbonic acids, or by sulfur or nitrogen analogues thereof, e.g. carbamates
    • AHUMAN NECESSITIES
    • A01AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01NPRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
    • A01N47/00Biocides, pest repellants or attractants, or plant growth regulators containing organic compounds containing a carbon atom not being member of a ring and having no bond to a carbon or hydrogen atom, e.g. derivatives of carbonic acid
    • A01N47/08Biocides, pest repellants or attractants, or plant growth regulators containing organic compounds containing a carbon atom not being member of a ring and having no bond to a carbon or hydrogen atom, e.g. derivatives of carbonic acid the carbon atom having one or more single bonds to nitrogen atoms
    • A01N47/28Ureas or thioureas containing the groups >N—CO—N< or >N—CS—N<
    • A01N47/36Ureas or thioureas containing the groups >N—CO—N< or >N—CS—N< containing the group >N—CO—N< directly attached to at least one heterocyclic ring; Thio analogues thereof

Definitions

  • the invention relates to novel N-(2-chloro-4-pyridyl)ureas and thioureas represented by the formula(I) indicated hereinafter, agricultural compositions thereof, and a method of treating plants with them.
  • British Pat. No. 1,122,662 discloses that some derivatives of urea can be used for preservation of plant materials. Further, Proc. Roy. Soc., vol. B165, page 245, London (1966) reports that some ureas produce a desirable effect for developing the plantbud, while others show a mold effect as initiators of cell division.
  • This invention relates to novel N-(2-chloro-4-pyridyl)ureas and thioureas of formula(I) and acid addition salts thereof; a process for their preparation; a method of using the compounds and compositions for agricultural purposes, especially as plant growth regulators, and a process for the preparation of such compositions.
  • novel compounds of formula(I) have valuable agricultural properties, especially growth-regulating effects as further elucidated hereinafter, which makes them useful as plant growth regulators.
  • This invention relates to novel N-(2-chloro-4-pyridyl)ureas and thioureas, a process for their preparation, agricultural compositions which are useful as plant growth regulators containing one of the said compounds as an effective component thereof, and a method of treating plants therewith.
  • Regulation of plant growth means acceleration or suppression of plant growth with a very small quantity of a chemical to regulate and control the state of plant growth as desired. Consequently, it does not indicate merely an increase or decrease in the height of a plant, but also the ability to have flowers or fruits when desired, or to obtain fruits without seeds, or to make the seeds dormant or conversely take them out of dormancy.
  • One object of this invention is to provide plant growth regulators which have advantages over such known useful substances. Other advantages will become apparent hereinafter.
  • the active compounds provided by this invention comprise N-(2-chloro-4-pyridyl)ureas and thioureas having the following formula(I): ##STR2## wherein R 1 represents hydrogen or alkyl of 1 to 3 carbon atoms, inclusive, such as methyl, ethyl, propyl and isopropyl; R 2 represents an aromatic group, preferably phenyl, pyridyl, naphthyl or biphenyl, which may be substituted by alkyl of 1 to 3 carbon atoms, inclusive, alkoxy of 1 to 3 carbon atoms, inclusive, hydroxyl, or halogen, especially one or two bromine, chlorine, or fluorine atoms; and X is oxygen or sulfur; and acid addition salts thereof.
  • halogen-substituted phenyl is preferably chlorine and fluorine, more preferably chlorine.
  • the compounds represented by formula(I), wherein X represents oxygen can be prepared by conventional methods.
  • R 1 is a hydrogen atom and R 2 is unsubstituted phenyl.
  • R 1 is a hydrogen atom
  • R 2 is unsubstituted phenyl.
  • 2-chloro-4-aminopyridine is reacted with phenyl isocyanate
  • 2-chloro-4-pyridyl isocyanate is reacted with aniline
  • 2-chloro-isonicotinoylacide is reacted with aniline.
  • reaction it is preferred to use a slight excess of one of the reactants, although approximately equivalent amounts of reactants may also be used in the usual suitable solvents.
  • Some solvents for the reaction are benzene, toluene, xylene, actone, methyl ethyl ketone, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, chloroform, dichloromethane, tetrachloromethane, pyridine, and triethyl amine.
  • An excess of aniline, when a reactant is particularly useful as solvent.
  • the reaction is favorably conducted in the range of -5° to 150° C., including room temperature, although it is most preferred to effect the reaction at the reflux temperature of the reaction mixture. A reaction time between five-tenths and five hours is sufficient to produce a good yield of desired product.
  • the compounds represented by the formula(I), wherein X represents sulfur can be also prepared by conventional methods illustrated in (a) and (b) by using the corresponding starting materials and under similar reaction conditions.
  • the reaction temperature should generally be in the range of 20° to 150° C.
  • N-(2-Chloro-4-pyridyl)-N'-phenylurea N-(2-chloro-4-pyridyl)-N'-(2-chlorophenyl)urea, N-(2-chloro-4-pyridyl)-N'-(3-chlorophenyl)urea, N-(2-chloro-4-pyridyl)-N'-(4-chlorophenyl)urea, N-(2-chloro-4-pyridyl)-N'-(2-methylphenyl)urea, N-(2-chloro-4-pyridyl)-N'-(3-methylphenyl)urea, N-(2-chloro-4-pyridyl)-N'-(4-methylphenyl)urea, N-(2-chloro-4-pyridyl)-N'-(2,5-dichlorophenyl)urea, N-(2-chloro-4-pyrid
  • N-(2-chloro-4-pyridyl)ureas and thioureas of this invention possess accelerating action on cell mitosis, cell enlargement, and cell differentiation, and are effective in the acceleration of fruiting, prevention of fruit and flower from falling, growth acceleration, and growth suppression.
  • concentration of the chemical employed By adjusting the concentration of the chemical employed, a marked suppression of growth(herbicidal) can be caused to occur at a high concentration of the chemical.
  • Table A The action, field of application, use, and plants to which these chemicals are applicable, are listed in the following table (Table A).
  • Table A The most prominent effective use of these chemicals is found in the increased number of fruits in pepos such as melon and watermelon, inhibition of flower shedding, accelerated growth of green vegetables, extension of tobacco leaf area, and herbicidal effect (when desired).
  • the urea derivatives of this invention show the same activity in concentrations only a fraction of that required with 6-(N-benzyl)adenine and kinetin, which have hitherto been considered the most potent plant growth regulating substances available. Even in comparison with N-(4-pyridyl)-N'-phenylurea of similar structure, they show a 100-fold or greater increase in activity. This increased activity is unexpectedly observed only when a chlorine atom is present at the 2-position of the pyridine ring.
  • the optimal concentration to give maximum yield of callus is 0.01 ppm for 6-(N-benzyl)adenine and 0.1 ppm for N-(4-pyridyl)-N'-phenylurea, whereas that of the potent N-(2-chloro-4-pyridyl)ureas of this invention is only 0.0005 to 0.001 ppm.
  • substitution on the phenyl ring decreases the activity in the tobacco test for the acceleration of cell differentiation, the optimal concentration of 6-benzyladenine being 10 ppm, but less than 1 ppm of N-(2-chloro-4-pyridyl)ureas gives formation of numerous shoots.
  • N-(2-Chloro-4-pyridyl)ureas of this invention show the effect of increasing weight, not only in callus cells but also on pith tissue, leaf tissue, and on plants during growth.
  • the plant growth regulators of this invention can be applied to plants and crops in general, but are especially effective when applied to a member of the leguminosae, solanaceae, unbelliferae, popes vitaceal, cucurbitaceae and vitaceae families.
  • the amount of a compound of this invention to be used by spraying the plant directly is generally 100 to 1000 liters per Ha as a solution of a concentration of 0.0001 to 10,000 ppm, preferably 0.01 to 10,000 ppm. When used in soil, an amount 5- to 100-fold of that given above is required. It goes without saying that the amount to be applied will differ according to the object of the control and the plant to which applied. For example, 100 to 1000 liters of a solution of the following concentration should be used per Ha.
  • the compounds of this invention can be used alone or in admixture with other substances or compositions having effective components, such as other plant regulators, herbicides, insecticides, fungicides, and acericides, usually in the form of solutions, emulsions, wettable powders, granules, fine granules, or powders.
  • compositions may be carried out in known manner, as by mixing, for example, 0.1 to 50%, preferably 0.1 to 10%, of a compound of this invention with a bulking agent, such as a liquid or solid diluent or carrier and, if necessary, using an emulsifying agent or dispersing agent.
  • a bulking agent such as a liquid or solid diluent or carrier
  • an emulsifying agent or dispersing agent emulsifying agent or dispersing agent.
  • a liquid diluent or a carrier may be cited water, aromatic hydrocarbons such as xylene, benzene, and methylnaphthalene, chlorinated aromatic hydrocarbons such as chlorobenzene, mineral oil fractions such as paraffin, alcohols such as methanol and propanol, and polar solvents such as dimethylformamide and acetone.
  • the substances preferably as a solid diluent or carrier are, for example, talc, clay, kaolin, white carbon, wood powder and sand.
  • a emulsifying agent may be used polyoxyethylene-fatty acid esters or polyoxyethylene-fatty acid alcohol ethers.
  • Dispersing agents include alkyl sulfonates, alkyl aryl sulfonates, alkali metal salts, alkaline earth metal salts, ammonium salt of lignin-sulfonic acid, and methylcellulose.
  • These compounds or preparations thereof per se may be added to a medium or applied directly to the plant or onto the surface of leaves or stalks thereof, or sprayed on the soil, but are usually applied in the form of the usual preparations thereof. Further, the plant growth controlling agents of this invention may be added together with fertilizers and/or extenders.
  • These compounds can also be used in the form of an inorganic or organic salt such as the hydrochloride, phosphate, or sulfate thereof.
  • Tobacco callus was cultured in Murashige-Skoog medium containing 0.0001 to 0.1 ppm of N-(2-chloro-4-pyridyl)-N'-phenylurea and 2 ppm of indoleacetic acid as auxin, for 30 days at a temperature of about 26° C. Final weight of fresh callus is shown in Table I.
  • the control was a tabacco callus cultured in the Murashige-Skoog medium containing only auxin, under the same condition. For the sake of comparison, values obtained in a medium containing optimal amount 6-(N-benzyl)adenine are also given in Table I. Values are all an average of six individuals.
  • Tobacco callus was cultured in the same way as in Example 1 and the results shown in the following Table II were obtained.
  • Section(s) of tobacco pith tissue were inoculated in Murashige-Skoog medium containing 0.01 to 10 ppm of N-(2-chloro-4-pyridyl)-N'-phenylurea. This was cultured at a temperature of about 26° C. for 30 days, and the number of pith sections forming shoots was counted. For comparison, benzyladenine was tested in a similar way. Results are shown in Table III.
  • Tobacco callus was inoculated in Murashige-Skoog medium containing 0.01 to 10 ppm of N-(2-chloro-4-pyridyl)-N'-phenylurea. This was cultured at room temperature for 30 days, and the number of callus with shoot formation was counted. For comparison, benzyladenine was tested in a similar way. Results are shown in Table IV.
  • Solutions containing 10, 1, and 0.1 ppm of N-(2-chloro-4-pyridyl)-N'-phenylurea in water were prepared.
  • 10 pieces of the leaf of Brassica repa var. pervidis which were round leaves of a 10 mm. diameter and cut out with a corkborer, were floated on the surface of the solution, one group being in contact with the solution with the back of the leaf and the other group being in contact with the surface of the solution with the surface of the leaf.
  • the dishes were allowed to stand at room temperature for 8 days, and diameter and weight of each leaf pieces determined. The control leaves were left in water.
  • Watermelon (variety ⁇ Yamato ⁇ ) raised outdoors was used as test plant. Artificial pollination was made at the peak of flowering, and a solution of the selected chemical in desired concentration was pinted or sprayed on the gynophore. Fruit-bearing rate was examined two weeks after the treatment.
  • Seedlings of tobacco were transplanted in unglazed pots of about 13 cm. in diameter and the pots were left in a greenhouse. Solutions of the selected chemical of desired concentration were sprayed with a sprayer, 15 ml. for each pot, homogeneously on leaves and stalk at the time when 6 to 8 leaves were out. One section of the pots was sprayed once and the other section three times at 13-day intervals. Examination of the result was made when middle leaves started to become yellow (35 days after the initial spraying of the chemical), and height of the plant, fresh weight of stalk and leaves, and average area of five lower leaves were measured, and ratio of these values to those of the non-treated plants was calculated. Experimental section was three pots per area and their average was taken. Results are listed in the following Table VIII.
  • Grapevine (variety Delaware) raised in plastic house covering was used for the examination. N-(2-Chloro-4-pyridyl)-N'-phenylurea or benzyladenine (200 or 100 ppm) was dded to 100 ppm of gibberelline solution, and recemose flowers were dipped in each solution (April 14). Ten days after full bloom (May 4), all the fruit clusters were again soaked and treated with 100 ppm solution of gebberelline. The grapevines were then left to usual cultivation conditions until harvest. Grapes were harvested on June 29, and weight of each cluster, length of cluster, density of berries, number of berries on each cluster, and berry diameter were measured. These values were compared with those found with grapes with gebberelline treatment alone. Experimental area contained two new brances, three repetition, and average value of fifteen fruit clusters was calculated.
  • Soil containing the subterranean stems of narrowleaf waterplantain (Alisma canaliculatum) and bulrush (Scirpus juncoides) homogeneously was filled in ceramic pots of 30 cm in diameter. Seeds of barnyard grass (Echinochloa crus-balli), umbrella plant (Cyperus diformis) were each sown in pots, fifty seeds to each pot. Then paddy rice seedlings (Variety Kinmaze) at the two-leaf stage was planted, five seedlings per pot, and the pots were filled with water so as to have a water layer of three cm. above the soil.
  • Datura Sunguinea sp. (average height of 8 cm.) were transplanted outdoors. Solutions of the chemically desired concentration were sprayed with a sprayer, 15 ml. each plant, on the leaves and stalk of the plant at the time when the average height of the plant was 20 cm. Three weeks later, the plants were harvested and the height of the plant and the total weight of fresh leaves and stalks on the new brances were measured. Average values of five plants are listed in Table XI.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Agronomy & Crop Science (AREA)
  • Pest Control & Pesticides (AREA)
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Abstract

N-(2-Chloro-4-pyridyl)ureas represented by the formula (I): ##STR1## wherein R1 represents hydrogen or alkyl, R2 represents an aromatic group, especially phenyl, which may be substituted by alkyl, alkoxyl, hydroxyl or halogen, and X is oxygen or sulfur, and acid addition salts thereof, useful as plant growth regulators, are disclosed. Method of making and using same and agricultural compositions thereof are also disclosed.

Description

BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to novel N-(2-chloro-4-pyridyl)ureas and thioureas represented by the formula(I) indicated hereinafter, agricultural compositions thereof, and a method of treating plants with them.
2. Brief Description of the Prior Art
British Pat. No. 1,122,662 discloses that some derivatives of urea can be used for preservation of plant materials. Further, Proc. Roy. Soc., vol. B165, page 245, London (1966) reports that some ureas produce a desirable effect for developing the plantbud, while others show a mold effect as initiators of cell division.
SUMMARY OF THE INVENTION
This invention relates to novel N-(2-chloro-4-pyridyl)ureas and thioureas of formula(I) and acid addition salts thereof; a process for their preparation; a method of using the compounds and compositions for agricultural purposes, especially as plant growth regulators, and a process for the preparation of such compositions.
The novel compounds of formula(I) have valuable agricultural properties, especially growth-regulating effects as further elucidated hereinafter, which makes them useful as plant growth regulators.
DETAILED DESCRIPTION OF THE INVENTION
This invention relates to novel N-(2-chloro-4-pyridyl)ureas and thioureas, a process for their preparation, agricultural compositions which are useful as plant growth regulators containing one of the said compounds as an effective component thereof, and a method of treating plants therewith. Regulation of plant growth means acceleration or suppression of plant growth with a very small quantity of a chemical to regulate and control the state of plant growth as desired. Consequently, it does not indicate merely an increase or decrease in the height of a plant, but also the ability to have flowers or fruits when desired, or to obtain fruits without seeds, or to make the seeds dormant or conversely take them out of dormancy.
Control of plant growth with plant hormones is becoming an important technique in the agricultural and horticultural fields. Among the best and best-known plant growth regulators are cytokinine 6-(N-benzyl)adenine and kinetine.
One object of this invention is to provide plant growth regulators which have advantages over such known useful substances. Other advantages will become apparent hereinafter.
It has now been found that 4-pyridylureas and thioureas, which contain a chlorine atom in the 2-position of the pyridine ring, possess an extremely potent activity of the said type and have the ability to regulate plant growth over a wide range.
The active compounds provided by this invention comprise N-(2-chloro-4-pyridyl)ureas and thioureas having the following formula(I): ##STR2## wherein R1 represents hydrogen or alkyl of 1 to 3 carbon atoms, inclusive, such as methyl, ethyl, propyl and isopropyl; R2 represents an aromatic group, preferably phenyl, pyridyl, naphthyl or biphenyl, which may be substituted by alkyl of 1 to 3 carbon atoms, inclusive, alkoxy of 1 to 3 carbon atoms, inclusive, hydroxyl, or halogen, especially one or two bromine, chlorine, or fluorine atoms; and X is oxygen or sulfur; and acid addition salts thereof.
Of these substituents, hydrogen and methyl for R1, unsubstituted or methyl-substituted phenyl for R2 and oxygen for X are preferred. The most preferred are hydrogen for R1, unsubstituted phenyl for R2 and oxygen for X. In the case of the halogen-substituted phenyl for R2, the halogen is preferably chlorine and fluorine, more preferably chlorine.
The compounds represented by formula(I), wherein X represents oxygen, can be prepared by conventional methods. For brevity, reference is specifically made to the compound represented by formula(I), wherein R1 is a hydrogen atom and R2 is unsubstituted phenyl. Following conventional preparations, either (a) 2-chloro-4-aminopyridine is reacted with phenyl isocyanate, or (b) 2-chloro-4-pyridyl isocyanate is reacted with aniline, or (c) 2-chloro-isonicotinoylacide is reacted with aniline.
In carrying out this reaction, it is preferred to use a slight excess of one of the reactants, although approximately equivalent amounts of reactants may also be used in the usual suitable solvents. Some solvents for the reaction are benzene, toluene, xylene, actone, methyl ethyl ketone, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, chloroform, dichloromethane, tetrachloromethane, pyridine, and triethyl amine. An excess of aniline, when a reactant, is particularly useful as solvent. The reaction is favorably conducted in the range of -5° to 150° C., including room temperature, although it is most preferred to effect the reaction at the reflux temperature of the reaction mixture. A reaction time between five-tenths and five hours is sufficient to produce a good yield of desired product.
The compounds represented by the formula(I), wherein X represents sulfur can be also prepared by conventional methods illustrated in (a) and (b) by using the corresponding starting materials and under similar reaction conditions. However, as the reactivity and speed of the reaction for preparing thioureas is not as great when compared with the urea compounds, the reaction temperature should generally be in the range of 20° to 150° C.
The above-mentioned preparations (a), (b) and (c) can be represented by the following chemical reaction schemes: ##STR3## wherein R1 and X have the same meanings as in formula(I) and R3 represents lower alkyl, lower alkoxyl, hydroxyl, or halogen, especially bromine, chlorine or fluorine.
Some of the compounds of this invention are listed in the following:
N-(2-Chloro-4-pyridyl)-N'-phenylurea, N-(2-chloro-4-pyridyl)-N'-(2-chlorophenyl)urea, N-(2-chloro-4-pyridyl)-N'-(3-chlorophenyl)urea, N-(2-chloro-4-pyridyl)-N'-(4-chlorophenyl)urea, N-(2-chloro-4-pyridyl)-N'-(2-methylphenyl)urea, N-(2-chloro-4-pyridyl)-N'-(3-methylphenyl)urea, N-(2-chloro-4-pyridyl)-N'-(4-methylphenyl)urea, N-(2-chloro-4-pyridyl)-N'-(2,5-dichlorophenyl)urea, N-(2-chloro-4-pyridyl)-N'-(2-fluorophenyl)urea, N-(2-chloro-4-pyridyl)-N'-(4-n-propylphenyl)urea, N-(2-chloro-4-pyridyl)-N'-(2-ethoxyphenyl)urea, N-(2-chloro-4-pyridyl)-N'-phenylthiourea, N-(3-bromo-4-pyridyl)-N'-phenylurea, etc.
The N-(2-chloro-4-pyridyl)ureas and thioureas of this invention possess accelerating action on cell mitosis, cell enlargement, and cell differentiation, and are effective in the acceleration of fruiting, prevention of fruit and flower from falling, growth acceleration, and growth suppression. By adjusting the concentration of the chemical employed, a marked suppression of growth(herbicidal) can be caused to occur at a high concentration of the chemical.
The action, field of application, use, and plants to which these chemicals are applicable, are listed in the following table (Table A). The most prominent effective use of these chemicals is found in the increased number of fruits in pepos such as melon and watermelon, inhibition of flower shedding, accelerated growth of green vegetables, extension of tobacco leaf area, and herbicidal effect (when desired).
              TABLE A                                                     
______________________________________                                    
Action    Application, Use                                                
                         Plants to be applied                             
______________________________________                                    
1. Acceleration                                                           
          Increased fruits                                                
                         pepos, tomato, eggplant,                         
of fruit bearing                                                          
          (flowers)(fruit)                                                
                         apple, Japanese pear,                            
                         citrus, apricot, soybean                         
Prevention of                                                             
          Inhibition of  grape                                            
fruit falling                                                             
          flower shedding                                                 
2. Acceleration                                                           
          Picking fruits citrus, plum, peach,                             
of fruit falling                                                          
          (picking excess                                                 
                         apple, tomato, pineapple                         
and defoliation                                                           
          fruits to                                                       
          increase fruit                                                  
          yield and to                                                    
          make fruit size                                                 
          uniform)                                                        
          Picking flowers                                                 
                         apricot, Japanese pear,                          
          (excess flowers                                                 
                         plum, peach                                      
          picked to                                                       
          increase fruit                                                  
          yield and to                                                    
          make fruit size                                                 
          uniform)                                                        
          Defoliation    cotton, soybean                                  
          (to remove leaves                                               
          for easier                                                      
          harvesting of                                                   
          cotton and soybeans)                                            
3. Growth Acceleration of                                                 
                         cuttage                                          
acceleration                                                              
          root growth and                                                 
          taking root                                                     
          Growth accelera-                                                
                         vegetables                                       
          tion(stalk, leaves,                                             
          roots)                                                          
          Increased size of                                               
                         citrus, apple, apricot                           
          fruit(increase in                                               
          commercial value                                                
          by larger size of                                               
          fruit)                                                          
          Increased tiller-                                               
                         soybean, pineapple                               
          ing, accelerated                                                
          bud formation                                                   
          Accelerated    flowering plants                                 
          flowering                                                       
4. Growth Suppression of trees, grass, flowering                          
suppression                                                               
          height         plants                                           
          Suppression of paddy rice, wheat                                
          lodging                                                         
          Suppression of potato, onion                                    
          budding                                                         
          Suppression of soybean                                          
          tillering                                                       
          (prevention of                                                  
          excess growth)                                                  
5. Organ  Renewal of new rose, fruit tree                                 
Formation branches(buds) seedlings                                        
6. Others Herbicidal effect                                               
          Desiccation    cotton                                           
          Increased sugar                                                 
                         sugar cane, sugar beet                           
          content                                                         
______________________________________                                    
The urea derivatives of this invention show the same activity in concentrations only a fraction of that required with 6-(N-benzyl)adenine and kinetin, which have hitherto been considered the most potent plant growth regulating substances available. Even in comparison with N-(4-pyridyl)-N'-phenylurea of similar structure, they show a 100-fold or greater increase in activity. This increased activity is unexpectedly observed only when a chlorine atom is present at the 2-position of the pyridine ring.
To explain in more concrete terms, in the test for tobacco callus growth, the optimal concentration to give maximum yield of callus is 0.01 ppm for 6-(N-benzyl)adenine and 0.1 ppm for N-(4-pyridyl)-N'-phenylurea, whereas that of the potent N-(2-chloro-4-pyridyl)ureas of this invention is only 0.0005 to 0.001 ppm. Generally, substitution on the phenyl ring decreases the activity in the tobacco test for the acceleration of cell differentiation, the optimal concentration of 6-benzyladenine being 10 ppm, but less than 1 ppm of N-(2-chloro-4-pyridyl)ureas gives formation of numerous shoots.
N-(2-Chloro-4-pyridyl)ureas of this invention show the effect of increasing weight, not only in callus cells but also on pith tissue, leaf tissue, and on plants during growth.
The plant growth regulators of this invention can be applied to plants and crops in general, but are especially effective when applied to a member of the leguminosae, solanaceae, unbelliferae, popes vitaceal, cucurbitaceae and vitaceae families.
The amount of a compound of this invention to be used by spraying the plant directly is generally 100 to 1000 liters per Ha as a solution of a concentration of 0.0001 to 10,000 ppm, preferably 0.01 to 10,000 ppm. When used in soil, an amount 5- to 100-fold of that given above is required. It goes without saying that the amount to be applied will differ according to the object of the control and the plant to which applied. For example, 100 to 1000 liters of a solution of the following concentration should be used per Ha.
______________________________________                                    
For growth acceleration and                                               
                        0.01-1,000 ppm                                    
increased fruiting                                                        
For growth acceleration of callus                                         
                        0.0001-100 ppm                                    
For acceleration of fruit                                                 
                        0.1-10,000 ppm                                    
falling and defoliation                                                   
For growth suppression and herbicidal                                     
                        10-more than                                      
                        10,000 ppm                                        
______________________________________                                    
The compounds of this invention can be used alone or in admixture with other substances or compositions having effective components, such as other plant regulators, herbicides, insecticides, fungicides, and acericides, usually in the form of solutions, emulsions, wettable powders, granules, fine granules, or powders.
The preparation of suitable compositions may be carried out in known manner, as by mixing, for example, 0.1 to 50%, preferably 0.1 to 10%, of a compound of this invention with a bulking agent, such as a liquid or solid diluent or carrier and, if necessary, using an emulsifying agent or dispersing agent. As substances preferably as a liquid diluent or a carrier may be cited water, aromatic hydrocarbons such as xylene, benzene, and methylnaphthalene, chlorinated aromatic hydrocarbons such as chlorobenzene, mineral oil fractions such as paraffin, alcohols such as methanol and propanol, and polar solvents such as dimethylformamide and acetone. Among the substances preferably as a solid diluent or carrier are, for example, talc, clay, kaolin, white carbon, wood powder and sand. As an emulsifying agent may be used polyoxyethylene-fatty acid esters or polyoxyethylene-fatty acid alcohol ethers. Dispersing agents include alkyl sulfonates, alkyl aryl sulfonates, alkali metal salts, alkaline earth metal salts, ammonium salt of lignin-sulfonic acid, and methylcellulose.
These compounds or preparations thereof per se may be added to a medium or applied directly to the plant or onto the surface of leaves or stalks thereof, or sprayed on the soil, but are usually applied in the form of the usual preparations thereof. Further, the plant growth controlling agents of this invention may be added together with fertilizers and/or extenders.
These compounds can also be used in the form of an inorganic or organic salt such as the hydrochloride, phosphate, or sulfate thereof.
The following examples and preparations are given by way of illustration only, and are not to be construed as limiting.
Some representative examples of preparative forms will be given below.
______________________________________                                    
Preparation 1.                                                            
           Wettable powder                                                
           N--(2-Chloro-4-pyridyl)-N'--                                   
                               1%                                         
           phenylurea                                                     
           Sodium β-naphthalenesulfonate-                            
                               2%                                         
           formaldehyde condensate                                        
           Polyoxyethylene alkyl aryl ether                               
                               2%                                         
           Clay                95%                                        
______________________________________                                    
These ingredients are ground, mixed and diluted with water.
______________________________________                                    
Preparation 2.                                                            
          Emulsion                                                        
          N--(2-Chloro-4-pyridyl)-N'--                                    
                               1%                                         
          (3-chlorophenyl)urea                                            
          Xylene              74%                                         
          Polyoxyethylene alkyl aryl ether                                
                              4.5%                                        
          Alkyl aryl sulfonate                                            
                              0.5%                                        
          Isophorone          20%                                         
______________________________________                                    
The above ingredients are mixed to dissolve and the resulting solution is emulsified in water.
______________________________________                                    
Preparation 3.                                                            
          Liquid                                                          
          N--(2-Chloro-4-pyridyl)-N'--                                    
                               1%                                         
          (2-chlorophenyl)urea                                            
          Dimethylformamide   94%                                         
          Polyoxyethylenesorbitan                                         
                               5%                                         
          monolaurate                                                     
                              Parts                                       
Preparation 4.                                                            
          Granule             by Weight                                   
          N--(2-Chloro-4-pyridyl)-N'--                                    
                               5%                                         
          (3-methylphenyl)urea                                            
          Bentonite           15                                          
          Talc                47.5                                        
          Clay                30                                          
          Sodium dodecylbenzene sulfonate                                 
                               0.5                                        
          Sodium ligninsulfonate                                          
                               2                                          
Preparation 5.                                                            
          Emulsion                                                        
          N--(2-Chloro-4-pyridyl)-N'--                                    
                               5%                                         
          (3-methylphenyl)urea                                            
          Xylene              70%                                         
          Polyoxyethylene alkyl aryl ether                                
                              4.5%                                        
          Alkyl aryl sulfonate                                            
                              0.5%                                        
          Isophorone          20%                                         
______________________________________                                    
These ingredients are mixed, ground, mixed with 25 parts of water, and made into granules using an extrusion-granulation apparatus. The granules are then dried and sieved. These granules are sprayed per se.
______________________________________                                    
Preparation 6.                                                            
           Wettable powder                                                
           N--(2-Chloro-4-pyridyl-N'--                                    
                                5%                                        
           (3-methylphenyl)urea                                           
           Sodium -naphthalenesulfonate-                                  
                                3%                                        
           formaldehyde condensate                                        
           Polyoxyethylene alkyl aryl ether                               
                                3%                                        
           Clay                 89%                                       
Preparation 7.                                                            
           Solution                                                       
           N--(2-Chloro-4-pyridyl)-N'--                                   
                                100 ppm                                   
           (3-chlorophenyl)urea                                           
           Acetone              20%                                       
           Water                80%                                       
______________________________________                                    
SYNTHESIS 1 Manufacture of N-(2-chloro-4-pyridyl)-N'-phenylurea
(1) To a solution of 257 mg. (2 mmol) of 2-chloro-4-aminopyridine dissolved in ten ml. of dry acetone, 238 mg. (2 mmol) of phenyl isocyanate is added and the mixture is stirred at room temperature for 8 hrs. The solvent is evaporated under a reduced pressure, the residue is chromatographed over alumina, and the column is developed with chloroform. Eluates containing the objective substance are collected, and the solvent is evaporated under a reduced pressure. The residue is recrystallized from acetone-ether mixture and 364 mg. of N-(2-chloro-4-pyridyl)-N'-phenylurea is obtained. Yield, 73.5%, mp 173°-174° C.
______________________________________                                    
Analysis for C.sub.12 H.sub.10 CIN.sub.3 O                                
       C            H      N                                              
______________________________________                                    
Calcd.   58.19          4.07   19.69                                      
Found    58.27          4.15   16.93                                      
______________________________________                                    
(2) To a solution of 365 mg. (2 mmol) of 2-chloroisonicotinoyl azide dissolved in 10 ml. of dry benzene, 186 mg. (2 mmol) of aniline is added and the mixture is refluxed for 3 hrs. When cooled, the solvent is evaporated under a reduced pressure and the residue is chromatographed over alumina. The column is developed with chloroform and eluates containing the objective substance are collected. The solvent is evaporated under a reduced pressure and the residue is recrystallized from acetone-ether mixture to 453 mg. of N-(2-chloro-4-pyridyl)-N'-phenylurea, mp 183°-184° C. Yield, 91.4%.
The following compounds were also prepared in the same manner.
______________________________________                                    
Compound                    mp (°C.)                               
______________________________________                                    
N--(2-Chloro-4-pyridyl)-N'--(2-chlorophenyl)urea                          
                            183                                           
N--(2-Chloro-4-pyridyl)-N'--(3-chlorophenyl)urea                          
                            198-199                                       
N--(2-Chloro-4-pyridyl)-N'--(4-chlorophenyl)urea                          
                            201-201.5                                     
N--(2-Chloro-4-pyridyl)-N'--(2-methylphenyl)urea                          
                            184-185                                       
N--(2-Chloro-4-pyridyl)-N'--(3-methylphenyl)urea                          
                            93-95                                         
N--(2-Chloro-4-pyridyl)-N'--(4-methylphenyl)urea                          
                            188.5-190                                     
N--(2-Chloro-4-pyridyl)-N'--(2,5-dichlorophenyl)urea                      
                            215-216                                       
N--(2-Chloro-4-pyridyl)-N'--(2-fluorophenyl)urea                          
                            186-187                                       
N--(2-Chloro-4-pyridyl)-N'--(4-n-propylphenyl)urea                        
                            156-157                                       
N--(2-Chloro-4-pyridyl)-N'--(2-ethoxyphenyl)urea                          
                            96-99                                         
N--(2-Chloro-4-pyridyl)-N'--phenylthiourea                                
                            141-142                                       
______________________________________                                    
EXAMPLE 1 Test on Growth Effect of N-(2-chloro-4-pyridyl)-N'-phenylurea on Tobacco Callus Cells
Tobacco callus was cultured in Murashige-Skoog medium containing 0.0001 to 0.1 ppm of N-(2-chloro-4-pyridyl)-N'-phenylurea and 2 ppm of indoleacetic acid as auxin, for 30 days at a temperature of about 26° C. Final weight of fresh callus is shown in Table I. The control was a tabacco callus cultured in the Murashige-Skoog medium containing only auxin, under the same condition. For the sake of comparison, values obtained in a medium containing optimal amount 6-(N-benzyl)adenine are also given in Table I. Values are all an average of six individuals.
              TABLE I                                                     
______________________________________                                    
                 Concentration                                            
                             Weight                                       
                 (ppm)       (mg)                                         
______________________________________                                    
N--(2-Chloro-4-pyridyl)-N'--urea                                          
                   0.0001        782                                      
"                  0.001         4,991                                    
"                  0.01          1,235                                    
"                  0.1           519                                      
Benzyladenine      0.01          5,150                                    
Control                          153                                      
______________________________________                                    
EXAMPLE 2 Test on Growth Effect of N-(2-Chloro-4-pyridyl)-N'-(3-methylphenyl)urea on Tobacco Callus
Tobacco callus was cultured in the same way as in Example 1 and the results shown in the following Table II were obtained.
              TABLE II                                                    
______________________________________                                    
                            Weight                                        
               Concentration(ppm)                                         
                            (g.)                                          
______________________________________                                    
N--(2-Chloro-4-pyridyl)-N'--                                              
                 0.001          1,784                                     
(3-methylphenyl)urea                                                      
N--(2-Chloro-4-pyridyl)-N'--                                              
                 0.01           6,760                                     
(3-methylphenyl)urea                                                      
N--(2-Chloro-4-pyridyl)-N'--                                              
                 0.1            4,945                                     
(3-methylphenyl)urea                                                      
N--(2-Chloro-4-pyridyl-N'--                                               
                 1              1,508                                     
(3-methylphenyl)urea                                                      
Control                         153                                       
______________________________________                                    
The use of N-(2-chloro-4-pyridyl)-N'-(3-chlorophenyl)urea gave a similar result.
EXAMPLE 3 Test on Shoot Formation Effect on N-(2-Chloro-4-pyridyl)-N'-phenylurea from Pith Tissue:
Section(s) of tobacco pith tissue were inoculated in Murashige-Skoog medium containing 0.01 to 10 ppm of N-(2-chloro-4-pyridyl)-N'-phenylurea. This was cultured at a temperature of about 26° C. for 30 days, and the number of pith sections forming shoots was counted. For comparison, benzyladenine was tested in a similar way. Results are shown in Table III.
              TABLE III                                                   
______________________________________                                    
Shoot Formation from Pith Sections                                        
Shoot Formation*                                                          
Conc.    6-(N--Benzyl)-                                                   
                     N--(2-Chloro-4-pyridyl)-                             
(ppm)    adenine     N'--phenylurea                                       
______________________________________                                    
10       1/24        10/24                                                
1        12/24       13/24                                                
0.1      2/24        10/24                                                
0.01     0/24         0/24                                                
______________________________________                                    
 *Number of pith sections with shoots/number of pith sections planted. One
 to six shoots are formed from one pith section.                          
EXAMPLE 4 Test on Shoot Formation from Callus Cells by N-(2-Chloro-4-pyridyl)-N'-(2-methylphenyl)urea
Tobacco callus was inoculated in Murashige-Skoog medium containing 0.01 to 10 ppm of N-(2-chloro-4-pyridyl)-N'-phenylurea. This was cultured at room temperature for 30 days, and the number of callus with shoot formation was counted. For comparison, benzyladenine was tested in a similar way. Results are shown in Table IV.
              TABLE IV                                                    
______________________________________                                    
Shoot Formation from Tobacco Callus                                       
Shoot Formation Rate*                                                     
Concn.               N--(2-Chloro-4-pyridyl)-                             
(ppm)    Benzyladenine                                                    
                     N'--(2-methylphenyl)urea                             
______________________________________                                    
10       12/12.sup.a 10/12.sup.a                                          
1        12/12.sup.a 9/12.sup.a                                           
0.1       2/12.sup.b 1/12.sup.b                                           
0.01     0/12        0/12                                                 
______________________________________                                    
 *Number of callus forming shoots/number of callus inoculated             
 .sup.a Number of shoots. 50-70(size of individual shoots. 1-3 cm.)       
 .sup.b Number of shoots. 1-10(size of individual shoots. 0.5-1 cm.)      
EXAMPLE 5 Test on Shoot Formation from Callus by N-(2-Chloro-4-pyridyl)-N'-phenylurea
Medium solutions containing 0.0001 to 1 ppm of N-(2-chloro-4-pyridyl)-N'-phenylurea were prepared and tobacco callus culture was carried out as in Example 4. The results obtained are shown in Table V.
              TABLE V                                                     
______________________________________                                    
Shoot Formation from Tobacco Callus                                       
Shoot Formation Rate*                                                     
Concn.                N--(2-Chloro-4-pyridyl)-                            
(ppm)     Benzyladenine                                                   
                      N'--phenylurea                                      
______________________________________                                    
10        12/12.sup.a --                                                  
1         12/12.sup.a 12/12.sup.a                                         
0.1        2/12.sup.b 12/12.sup.a                                         
0.01      0/12        12/12.sup.a                                         
0.001     --           2/12.sup.b                                         
0.0001    --          0/12                                                
______________________________________                                    
 *Number of callus section forming shoots/number of callus sections       
 inoculated                                                               
 .sup.a Number of shoots. 50-70(size of individual shoots. 1-3 cm.)       
 .sup.b Number of shoots. 1-10(size of individual shoots. 0.5-1 cm.)      
EXAMPLE 6 Test on Increase in Size of Leaves of Green Vegetable by N-(2-Chloro-4-pyridyl)-N'-phenylurea
Solutions containing 10, 1, and 0.1 ppm of N-(2-chloro-4-pyridyl)-N'-phenylurea in water were prepared. To 50 ml. of each solution placed in a petrie dish, 10 pieces of the leaf of Brassica repa var. pervidis which were round leaves of a 10 mm. diameter and cut out with a corkborer, were floated on the surface of the solution, one group being in contact with the solution with the back of the leaf and the other group being in contact with the surface of the solution with the surface of the leaf. The dishes were allowed to stand at room temperature for 8 days, and diameter and weight of each leaf pieces determined. The control leaves were left in water. These results are shown in Table VI.
              TABLE VI                                                    
______________________________________                                    
With Back of the Leaf                                                     
                 With Surface of the Leaf                                 
in Contact with Water                                                     
                 in Contact with Water                                    
Concn. Diameter  Weight  Concn.  Diameter                                 
                                        Weight                            
(ppm)  (mm)      (mg)    (ppm)   (mm)   (mg)                              
______________________________________                                    
10     13.7      30.5    10      13.2   26.8                              
1      13.5      32.1    1       14.2   31.1                              
0.1    14.2      33.3    0.1     13.9   28.1                              
Control                                                                   
       12.1      21.7    Control 11.9   21.0                              
______________________________________                                    
EXAMPLE 7 Test on Acceleration of Fruit Bearing in Pepos
Watermelon (variety `Yamato`) raised outdoors was used as test plant. Artificial pollination was made at the peak of flowering, and a solution of the selected chemical in desired concentration was pinted or sprayed on the gynophore. Fruit-bearing rate was examined two weeks after the treatment.
              TABLE VII                                                   
______________________________________                                    
                         Concen-                                          
                         tration  Fruit-bearing                           
Treatment                                                                 
        Chemical         (ppm)    rate (%)                                
______________________________________                                    
Painting                                                                  
        N--(2-Chloro-4-pyridyl)-                                          
                         1,000    100                                     
        N'--phenylurea                                                    
        BA (liquid)*     1,000    65                                      
        "                10,000   100                                     
        None                      43                                      
Spraying                                                                  
        N--(2-Chloro-4-pyridyl)-                                          
                         1,000    90                                      
        N'--phenylurea                                                    
        "                  500    87                                      
        "                  100    82                                      
        BA(liquid)*      10,000   83                                      
        None                      35                                      
______________________________________                                    
 *BA(liquid) is a liquid containing 3% benzyladenine[i.e.,                
 6(N--benzyl)aminopurine]: same as hereafter                              
EXAMPLE 8 Test on Suppression of Height and Extension of Leaf Area in Tobacco Plant
Seedlings of tobacco (variety, Bright Yellow) were transplanted in unglazed pots of about 13 cm. in diameter and the pots were left in a greenhouse. Solutions of the selected chemical of desired concentration were sprayed with a sprayer, 15 ml. for each pot, homogeneously on leaves and stalk at the time when 6 to 8 leaves were out. One section of the pots was sprayed once and the other section three times at 13-day intervals. Examination of the result was made when middle leaves started to become yellow (35 days after the initial spraying of the chemical), and height of the plant, fresh weight of stalk and leaves, and average area of five lower leaves were measured, and ratio of these values to those of the non-treated plants was calculated. Experimental section was three pots per area and their average was taken. Results are listed in the following Table VIII.
              TABLE VIII                                                  
______________________________________                                    
             No. of                                                       
                   Percent to Non-treated Area                            
Compound   Concn.  spray-        Fresh  Leaf                              
tested     (ppm)   ings    Height                                         
                                 Weight Area                              
______________________________________                                    
N--(2-Chloro-4-                                                           
           500     1       74    171    158                               
pyridyl)-N'--                                                             
phenylurea                                                                
                   3       42    169    145                               
5% WP*     100     1       78    188    175                               
                   3       72    206    185                               
            20     1       102   178    172                               
                   3       98    160    152                               
BA(liquid) 500     1       99    151    118                               
                   3       85    138    111                               
           100     1       98    118    141                               
                   3       90    115    124                               
            20     1       106   109    120                               
                   3       98    113    121                               
None(%)                    100   100    100                               
"                          (74.6 (126.6 (278                              
                           cm)   g/stock)                                 
                                        cm.sup.2 /leaf                    
______________________________________                                    
 *5% WP: Wettable powder containing 5%                                    
 N--(2chloro-4-pyridyl)-N'--phenylurea                                    
EXAMPLE 9 Inhibition of Flower Shedding and Acceleration of Fruit Bearing in Grape
Grapevine (variety Delaware) raised in plastic house covering was used for the examination. N-(2-Chloro-4-pyridyl)-N'-phenylurea or benzyladenine (200 or 100 ppm) was dded to 100 ppm of gibberelline solution, and recemose flowers were dipped in each solution (April 14). Ten days after full bloom (May 4), all the fruit clusters were again soaked and treated with 100 ppm solution of gebberelline. The grapevines were then left to usual cultivation conditions until harvest. Grapes were harvested on June 29, and weight of each cluster, length of cluster, density of berries, number of berries on each cluster, and berry diameter were measured. These values were compared with those found with grapes with gebberelline treatment alone. Experimental area contained two new brances, three repetition, and average value of fifteen fruit clusters was calculated.
Results are shown in Table IX.
                                  TABLE IX                                
__________________________________________________________________________
Effect on Inhibition of Flower Shedding of Delaware-Grape (Average of 15  
Clusters)                                                                 
Items                                                                     
Examined                No. of                                            
Compound  Weight                                                          
               Length                                                     
                   Density                                                
                        Berries                                           
                            Seed-                                         
                                Diameter                                  
                                      Weight                              
                                            Hardness                      
added to  of Berry                                                        
               of One                                                     
                   of   per less                                          
                                of    of    of                            
GA (100                                                                   
      concn.                                                              
          Cluster                                                         
               Cluster                                                    
                   Berries                                                
                        Cluster                                           
                            Berries                                       
                                Gynophore                                 
                                      Gynophore                           
                                            Gynophore                     
ppm)Soln.                                                                 
      (ppm)                                                               
          (g)  (cm)                                                       
                   (No./cm)                                               
                        (No.)                                             
                            (%) (mm)  (g)   (feel)                        
__________________________________________________________________________
N--(2-                                                                    
      200 195.6                                                           
               13.7                                                       
                   14.3 136.6                                             
                            100 5.08  5.96  Hard                          
Chloro-   (190)                                                           
               (91)                                                       
                   (210)                                                  
                        (194)   (213) (248)                               
4-pyridyl)-                                                               
N'--phenyl-                                                               
urea                                                                      
      100 196.3                                                           
               14.5                                                       
                   13.5 136.3                                             
                            100 5.60  5.47  slightly                      
          (109)                                                           
               (97)                                                       
                   (199)                                                  
                        (194)   (192) (228) hard to hard                  
       50 189.8                                                           
               14.4                                                       
                   13.5 129.6                                             
                            100 4.62  4.71  slightly                      
          (184)                                                           
               (94)                                                       
                   (199)                                                  
                        (184)   (193) (196) hard to hard                  
       25 180.8                                                           
               15.0                                                       
                   13.5 129.6                                             
                            100 3.82  4.71  slightly                      
          (175)                                                           
               (100)                                                      
                   (178)                                                  
                        (202)   (160) (196) hard to hard                  
BA    200 136.8                                                           
               14.8                                                       
                    9.2  93.3                                             
                            100 3.82  2.75  Ordinary                      
3% Soln.  (132)                                                           
               (99)                                                       
                   (135)                                                  
                        (133)   (139) (115)                               
      100 125.3                                                           
               15.5                                                       
                    8.1  73.9                                             
                            100 3.02  2.46  slightly soft                 
          (122)                                                           
               (103)                                                      
                   (119)                                                  
                        (105)   (126) (103) to ordinary                   
GA alone                                                                  
      (100)                                                               
          103.1                                                           
               15.0                                                       
                    6.8  70.3                                             
                            100 2.39  2.40  slightly                      
          (100)                                                           
               (100)                                                      
                   (100)                                                  
                        (100)   (100) (100) soft                          
__________________________________________________________________________
 BA = 6(N--benzyl)aminopurine.                                            
 GA = Gibberellin                                                         
 Values in parentheses denote percentage to the values obtained with the  
 use of GA alone.                                                         
EXAMPLE 10 Test on Herbicidal Effect
Soil containing the subterranean stems of narrowleaf waterplantain (Alisma canaliculatum) and bulrush (Scirpus juncoides) homogeneously was filled in ceramic pots of 30 cm in diameter. Seeds of barnyard grass (Echinochloa crus-balli), umbrella plant (Cyperus diformis) were each sown in pots, fifty seeds to each pot. Then paddy rice seedlings (Variety Kinmaze) at the two-leaf stage was planted, five seedlings per pot, and the pots were filled with water so as to have a water layer of three cm. above the soil. When the barnyard grass reached the one-leaf stage, the desired quantity of the solution of the selected test chemical(s), prepared according to Preparation 1, was sprayed uniformly over the surface of the water. Herbicidal effect was examined fourteen days after the chemical treatment. Result of this test was expressed by the following index (Table X):
                                  TABLE X                                 
__________________________________________________________________________
                              Narrow                                      
                                   Effect                                 
             Control of Weeds leaf on                                     
        Amount                                                            
             Barnyard                                                     
                  Unbrella                                                
                       Mono-                                              
                           Bul-                                           
                              water                                       
                                   paddy                                  
Compound                                                                  
        (kg/Ha)                                                           
             grass                                                        
                  plant                                                   
                       choria                                             
                           rush                                           
                              plantain                                    
                                   rice                                   
__________________________________________________________________________
N--(2-Chloro-                                                             
        1    5    5    5   4  5    0                                      
4-pyridyl)-                                                               
N'--phenylurea                                                            
        0.5  4    4    4.5 3  4.5  0                                      
__________________________________________________________________________
 5: Complete control of weeds                                             
 4: Over 80% control of weeds                                             
 3: Over 60% control of weeds                                             
 2: Over 40% control of weeds                                             
 1: Over 20% control of weeds                                             
 0: No effect                                                             
EXAMPLE 11 Test on Increase of Leaf and New Brances in Datura Sunguinea
Datura Sunguinea sp. (average height of 8 cm.) were transplanted outdoors. Solutions of the chemically desired concentration were sprayed with a sprayer, 15 ml. each plant, on the leaves and stalk of the plant at the time when the average height of the plant was 20 cm. Three weeks later, the plants were harvested and the height of the plant and the total weight of fresh leaves and stalks on the new brances were measured. Average values of five plants are listed in Table XI.
              TABLE XI                                                    
______________________________________                                    
          Concn.  Height  Total Weight                                    
                                   New Branches                           
Compound  (ppm)   (cm)    (g)      (g)                                    
______________________________________                                    
N--(2-Chloro-                                                             
           20     80      450      80                                     
4-pyridyl)-                                                               
N'--phenyl-                                                               
urea                                                                      
N--(2-Chloro-                                                             
          100     75      500      100                                    
4-pyridyl)-                                                               
N'--phenyl                                                                
urea                                                                      
BA(liquid)                                                                
          500     90      402      70                                     
Control           103     348      40                                     
______________________________________                                    
EXAMPLE 12 Test on Increase of Leaf and New Branches in Datura Sunguina
Datura Sunguina sp. (average height of 8 cm.) were transplanted outdoors and test using N-(2-chloro-4-pyridyl)-N'-(3-bromophenyl)urea were conducted as in Example 11. The results shown in Table XII were obtained.
              TABLE XII                                                   
______________________________________                                    
          Concn.  Height  Total Weight                                    
                                   New Branches                           
Compound  (ppm)   (cm)    (g)      (g)                                    
______________________________________                                    
N--(2-chloro-                                                             
           60     81      450      78                                     
4-pyridyl)-                                                               
N'--(3-bromo-                                                             
phenyl)urea                                                               
N--(2-chloro-                                                             
          300     74      490      98                                     
4-pyridyl)-                                                               
N'--(3-bromo-                                                             
phenyl)urea                                                               
BA(liquid)                                                                
          500     91      391      68                                     
Control           102     352      41                                     
______________________________________                                    
Various modifications and equivalents will be apparent to one skilled in the art and may be made in the compounds, compositions and methods of the present invention without departing from the spirit or scope thereof, and it is therefore to be understood that the invention is not to be limited to the specific examples and embodiments disclosed herein.

Claims (17)

What is claimed is:
1. A compound selected from the group consisting of N-(2-chloro-4-pyridyl)ureas of the following formula ##STR4## wherein R1 represents hydrogen or alkyl of from 1 to 3 carbon atoms, inclusive; R2 represents aryl selected from the group consisting of phenyl, which may be substituted by alkyl of from 1 to 3carbon atoms, inclusive; alkoxy; of from 1 to 3 carbon atoms, inclusive; or halogen; and X stands for oxygen or sulfur; and acid addition salts thereof.
2. An N-(2-chloro-4-pyridyl)urea as claimed in claim 1 wherein X is an oxygen atom.
3. An N-(2-chloro-4-pyridyl)urea as claimed in claim 1 wherein R1 is hydrogen.
4. A compound of claim 1 which is selected from the group consisting of N-(2-chloro-4-pyridyl)-N'-phenylurea and an acid addition salt thereof.
5. An agricultural composition useful as a plant growth regulator comprising as active ingredient a compound selected from the group consisting of an N-(2-chloro-4-pyridyl)urea of claim 1, of the formula: ##STR5## wherein R1 represents hydrogen or alkyl of from 1 to 3 carbon atoms, inclusive; R2 represents aryl selected from the group consisting of phenyl, .[.pyridyl, naphthyl, and biphenyl,.]. which may be substituted by alkyl of from 1 to 3 carbon atoms, inclusive; alkoxy of from 1 to 3 carbon atoms, inclusive; hydroxyl or halogen; and X is oxygen or sulfur; and an acid addition salt thereof, in an effective plant-growth regulating amount, together with an inert carrier or diluent.
6. The agricultural composition of claim 5 which further contains an emulsifying or dispersing agent.
7. The agricultural composition of claim 5 wherein said N-(2-chloro-4-pyridyl)urea is present in a herbicidally-effective amount.
8. A method of controlling plant growth which comprises contacting a plant or part thereof with a compound selected from the group consisting of an N-(2-chloro-4-pyridyl)urea of claim 1, of the formula: ##STR6## wherein R1 represents hydrogen or alkyl of from 1 to 3 carbon atoms, inclusive; R2 represents aryl selected from the group consisting of phenyl, .[.pyridyl, naphthyl, and biphenyl,.]. which may be substituted by alkyl of from 1 to 3 carbon atoms, inclusive; alkoxy of from 1 to 3 carbon atoms, inclusive; hydroxyl or halogen; and X is oxygen or sulfur; and acid addition salt thereof, in an amount effective for regulation of the growth of the plant involved.
9. The method of claim 8, wherein the compound is in admixture with an inert carrier or diluent.
10. The method of claim 8, wherein the compound is contacted with the plant in a herbicidally-effective amount thereof.
11. The composition according to claim 5, wherein X is oxygen and R2 is phenyl.
12. The composition according to claim 11, wherein R1 is hydrogen.
13. The method of controlling plant growth according to claim 8, wherein X is oxygen and R2 is phenyl.
14. The method of controlling plant growth according to claim 13, wherein R1 is hydrogen.
15. A compound of claim 1, wherein X is sulfur. .[.16. A compound of claim
1, wherein R2 is pyridyl..]. 17. A composition of claim 5, wherein X is sulfur. .[.18. A composition of claim 5, wherein R2 is pyridyl..].
9. A method of claim 8, wherein X is sulfur. .[.20. A method of claim 8, wherein R2 is pyridyl..].
US06/305,768 1977-10-08 1981-09-25 N-(2-Chloro-4-pyridyl) ureas Expired - Lifetime USRE31550E (en)

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JP12128577A JPS5481275A (en) 1977-10-08 1977-10-08 Nn*22chlorr44pyridyl*ureas*manufacture and vegetable growth regulating agent
KR1019780003042A KR830000128B1 (en) 1977-10-08 1978-10-05 Preparation of N- (2-chloro-4-pyridyl) urea
US06/305,768 USRE31550E (en) 1977-10-08 1981-09-25 N-(2-Chloro-4-pyridyl) ureas

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WO2012087980A1 (en) 2010-12-21 2012-06-28 Agraquest, Inc. Sandpaper mutants of bacillus and methods of their use to enhance plant growth, promote plant health and control diseases and pests
WO2013039937A1 (en) 2011-09-12 2013-03-21 Agraquest, Inc. Methods of enhancing health and/or promoting growth of a plant and/or of improving fruit ripening

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Publication number Priority date Publication date Assignee Title
WO2012087980A1 (en) 2010-12-21 2012-06-28 Agraquest, Inc. Sandpaper mutants of bacillus and methods of their use to enhance plant growth, promote plant health and control diseases and pests
WO2013039937A1 (en) 2011-09-12 2013-03-21 Agraquest, Inc. Methods of enhancing health and/or promoting growth of a plant and/or of improving fruit ripening

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