Claims
- 1. A compound of the formula ##STR10## in which R is hydrogen or a lower alkyl group; and (a) the pyridinyl ring is attached at position 4; each X group is independently selected from halogen, (C.sub.1-4)alkyl, (C.sub.1-5)alkoxy, (C.sub.1-6)haloalkyl, (C.sub.1-2)alkoxycarbonyl, aminocarbonyl, (C.sub.1-4)alkylamino, di(C.sub.1-2)alkylamino, di(C.sub.1-2)alkylaminocarbonyl, di(C.sub.1-2)- alkylamino-N-oxide, (C.sub.1-2)alkylthio, (C.sub.1-2)alkylsulfonyl, pyridinyl, phenylthio, phenylsulfonyl, phenyl, or benzylamino in which the aromatic ring is in turn unsubstituted or substituted with 1 to 5 halogen atoms; each Y group is independently selected from halogen, (C.sub.1-2)alkyl, (C.sub.1-2)alkoxy, (C.sub.1-2)alkylthio, (C.sub.1-2)alkylsulfonyl, hydroxyl, or trihalomethyl; m is 0, 1 or 2; and n is 0 to 5; or
- (b) the pyridinyl ring is attached at position 3; X is chloro, methoxy, or an acetylmethylamino group; Y is halogen; m is 0 or 1; and n is 0 or 1.
- 2. A compound of claim 1 in which the pyridinyl ring is attached at position 4.
- 3. A compound of claim 1 in which Y is hydrogen.
- 4. A compound of claim 2 in which X is hydrogen, halogen, (C.sub.1-2)alkyl, or (C.sub.1-2)alkylthio.
- 5. A compound of claim 4 in which Y is hydrogen, halogen, (C.sub.1-2)alkyl of (C.sub.1-2)alkoxy; and n is 0, 1 or 2.
- 6. N-(3-chlorophenyl)-N'-(2-chloro-4-pyridinyl-N-oxide)urea, a compound of claim 5.
- 7. N-(3-chlorophenyl)-N'-(4-pyridinyl-N-oxide)urea, a compound of claim 5.
- 8. N-(2-chlorophenyl)-N'-(2-chloro-4-pyridinyl-N-oxide)urea, a compound of claim 5.
- 9. N'-(2-chloro-4-pyridnyl-N-oxide)-N-(2-methylphenyl)urea, a compound of claim 5.
- 10. N'-(2-chloro-4-pyridnyl-N-oxide)-N-(3,5-difluorophenyl)urea, a compound of claim 5.
- 11. N-(3,5-difluorophenyl)-N'-(4-pyridinyl-N-oxide)urea, a compound of claim 5.
- 12. N'-(2-iodo-4-pyridinyl-N-oxide)-N-phenylurea, a compound of claim 5.
- 13. N-phenyl-N'-(4-pyridinyl-N-oxide)urea, a compound of claim 5.
- 14. N'-(2-chloro-4-pyridinyl-N-oxide)-N-phenylurea, a compound of claim 5.
- 15. N'-(2-chloro-4-pyridinyl-N-oxide)-N-3-fluorophenyl)urea, a compound of claim 5.
- 16. N'-(2-methyl-4-pyridinyl-N-oxide)-N-phenylurea a compound of claim 5.
- 17. N'-(2-ethyl-4-pyridinyl-N-oxide)-N-phenylurea, a compound of claim 5.
- 18. N'-(2-ethylthio-4-pyridinyl-N-oxide)-N-phenylurea, a compound of claim 5.
- 19. [N-(2-chlorophenyl)-N'-(4-pyridinyl-N-oxide)]ethylurea, a compound of claim 5.
- 20. A plant growth regulator composition comprising a plant regulating amount of a compound of claim 1 in admixture with an agriculturally acceptable carrier or extender.
- 21. A method for retarding senescence in wheat or soybean plants which comprises applying to the plant a plant regulating amount of a compond of claim 1.
- 22. A method for improving leaf abscision of cotton for harvesting which comprises applying to cotton plants a defoliating amount of the compound of claim 1.
Parent Case Info
This application is a continuation-in-part of U.S. Ser. No. 586,574, filed Mar. 6, 1984, now abandoned, which is a continuation-in-part of U.S. Ser. No. 480,055, filed Mar. 29, 1983, now abandoned.
The present invention relates to N-phenyl-N'-(pyridinyl-N-oxide)ureas as plant regulators for agricultural crops such as wheat, corn, cotton, soybean and the like, to novel compositions thereof, and to a method for regulating growth and development of agricultural crops.
Substantial research efforts have been devoted to finding new chemical compounds which exhibit cytokinin-like hormonal activity in agricultural crops. Such activity can beneficially affect the course of plant development in many ways. For example it can accelerate plant growth, modify plant growth or development in such a way as to increase yield, ensure flowering or fruiting at a desired period in time, prevent or promote abscission, i.e., the falling of fruit or flowers from plants, increase the weight of leaves or stalks, retard senescence of the plant, and/or exhibit various other properties desirable in the growth and development of various plants. Compounds which perform such functions are commonly known as "plant regulators" and are hereinafter referred to by that term.
Typical compounds which have exhibited plant regulator activity include 6-benzyladenine, kinetin, and 4-pyridylphenylurea. U.S. Pat. No. 4,193,788 discloses the use of certain N-(2-chloro-4-pyridyl)ureas as plant regulators. Likewise U.S. Pat. Nos. 4,279,639 and 4,308,054 disclose various other N-(2- and/or 6-substituted-4-pyridyl)-N'-(optionally substituted phenyl)ureas as plant regulators.
While the foregoing patents describe only pyridylureas in which the pyridyl group is attached at the 4-position, certain other pyridylureas in which the pyridyl group is attached at the 2- and 3-position also exhibit some cytokinin-like activity. See, for example, Bruce, M. I. and Zwar, J. A., "Cytokinin Activity of Some Substituted Ureas and Thioureas", Proc. Roy. Soc. (London) 1966, pp. 245-265. The prior art does not teach or suggest the use of pyridinyl N-oxides as plant regulators.
The N-oxides of this invention exhibit improved anti-senescence performance over the unoxidized analogs. For some compounds this improvement is manifested by a greater than 100% increase in chlorophyll retention. Alternatively, the N-oxides may be used at significantly lower concentrations than the unoxidized compounds to achieve equivalent chlorophyll retention.
As used throughout the following description and claims the terms "halogen" and "halo" mean halogen atoms selected from bromine, chlorine, fluorine and iodine, preferably bromine, chlorine and fluorine. The term "lower alkyl" means methyl, ethyl, or propyl.
In accordance with the foregoing, the present invention comprises plant regulators of the formula ##STR2## in which R is hydrogen or a lower alkyl group, and (a) the pyridinyl ring is attached at position 4; each X group is independently selected from halogen, (C.sub.1-6)haloalkyl, (C.sub.1-4)alkyl (C.sub.1-5)alkoxy, (C.sub.1-2)alkoxycarbonyl, aminocarbonyl, (C.sub.1-4)alkylamino, di(C.sub.1-2)alkylamino, di(C.sub.1-2)alkylaminocarbonyl, di(C.sub.1-2)alkylamino-N-oxide, (C.sub.1-2)alkylthio, (C.sub.1-2)alkylsulfonyl, pyridinyl, phenylthio, phenylsulfonyl, phenyl, or benzylamino in which the aromatic ring is in turn unsubstituted or substituted with 1 to 5 halogen atoms; each Y group is independently selected from halogen, (C.sub.1-2)alkyl, (C.sub.1-2)alkoxy, (C.sub.1-2)alkylthio, (C.sub.1-2)alkylsulfonyl, hydroxyl, or trihalomethyl; m is 0, 1 or 2; and n is 0 to 5; or
The composition aspect of the present invention provides a composition containing a plant regulating amount of the compounds described herein in admixture with an agriculturally acceptable carrier, diluent, extender or adjuvant.
In the composition aspect of this invention, the plant regulator compounds of this invention, like most agricultural chemicals, are generally not applied full strength, but are formulated with agriculturally acceptable carriers normally employed for facilitating the dispersion of active ingredients, various additives, and optionally with other active ingredients, recognizing that the formulation and mode of application of the active component may affect the activity of the material. The present compounds may be applied, for example, as powders or liquids, the choice of application varying with the plant species and environmental factors present at the particular locus of application. Thus, the compounds may be formulated as emulsifiable concentrates, as wettable powders, as flowable formulations, as solutions, as dispersions, as suspensions and the like.
The plant regulators of this invention are suitably employed in a number of broad-leafed and grain crops, for example, soybean, lima bean, wheat, rice, corn, sorghum, and cotton, and turf grasses to name a few. In soybean, the compounds of the invention retard senescence and increase yields. In wheat, they retard senescence and exert an antilodging effect. In cotton, the compounds of the invention improve leaf abcission. In turf grasses, the compounds retard growth rate.
A typical formulation may vary widely in concentration of the active ingredient depending on the particular agent used, the additives and carriers used, other active ingredients, and the desired mode of application. With due consideration of these factors, the active ingredient of a typical formulation may, for example, be suitably present at a concentration of from about 0.5% up to about 99.5% by weight of the formulation. Substantially inactive ingredients such as adjuvants, diluents, and carriers may comprise from about 99.5% by weight to as low as about 0.5% by weight of the formulation. Surface active agents, if employed in the formulation, may be present at various concentrations, suitably in the range of 1 to 30% by weight. Provided below is a general description of exemplary types of formulations which may be employed for dispersion of the plant regulators of the present invention.
Emulsifiable concentrates (EC's) are homogeneous liquid compositions, usually containing the active ingredient dissolved in a liquid carrier. Commonly used liquid carriers include xylene, heavy aromatic naphthas, isophorone, and other nonvolatile or slightly volatile organic solvents. For application, these concentrates are dispersed in water, or other liquid vehicle, forming an emulsion, and are normally applied as a spray to the area to be treated. The concentration of the essential active ingredient in EC's may vary according to the manner in which the composition is to be applied, but, in general, is in the range of 0.5 to 95%, frequently 10 to 80%, by weight of active ingredient, with the remaining 99.5% to 5% being surfactant and liquid carrier.
The following are specific examples of emulsifiable concentrate formulations suitable for use in the present invention:
Wettable powders, also useful formulations for plant regulators, are in the form of finely divided particles which disperse readily in water or other liquid vehicles. The wettable powder is ultimately applied to the plant as a dry dust or a dispersion in water or other liquid. Typical carriers for wettable powders include fuller's earth, kaolin clays, silicas, and other highly absorbent or adsorbent inorganic diluents. The concentration of active ingredient in wettable powders is dependent upon physical properties of the active ingredient and the absorbency characteristics of the carrier. Liquids and low melting solids (mp<100.degree. C.) are suitably formulated in the concentration range of 5 to 50% by weight, usually from 10 to 30%; high melting solids (mp>100.degree. C.) being formulated in the range of 5 to 95% by weight, usually 50 to 85%. An agriculturally acceptable carrier or diluent, frequently including a small amount of a surfactant to facilitate wetting dispersion and suspension, accounts for the balance of the formulation.
The following are specific examples of wettable powder formulations suitable for use in the present invention:______________________________________Component: % by Wt.______________________________________Active ingredient 40.00Sodium ligninsulfonate 20.00Attapulgite clay 40.00Total 100.00Active ingredient 90.00Dioctyl sodium sulfosuccinate 0.10Synthetic fine silica 9.90Total 100.00Active ingredient 20.00Sodium alkylnaphthalenesulfonate 4.00Sodium ligninsulfonate 4.00Low viscosity methyl cellulose 3.00Attapulgite clay 69.00Total 100.00Active ingredient 25.00Base: 75.0096% hydrated aluminum magnesium silicate2% powdered sodium lignosulfonate2% powdered anionic sodium alkyl-naphthalenesulfonateTotal 100.00______________________________________
Flowable formulations are similar to EC's except that the active ingredient is suspended in a liquid carrier, generally water. Flowables, like EC's, may include a small amount of a surfactant, and contain active ingredient in the range of 0.5 to 95%, frequently from 10 to 50%, by weight of the composition. For application, flowables may be diluted in water or other liquid vehicle, and are normally applied as a spray to the area to be treated.
The following are specific examples of flowable formulations suitable for use in the present invention:______________________________________Component: % by Wt.______________________________________Active ingredient 46.00Colloidal magnesium aluminum silicate 0.40Sodium alkylnaphthalenesulfonate 2.00Paraformaldehyde 0.10Water 41.42Propylene glycol 7.50Acetylinic alcohols 2.50Xanthan gum 0.08Total 100.00Active ingredient 45.00Water 48.50Purified smectite clay 2.00Xanthan gum 0.50Sodium alkylnaphthalenesulfonate 1.00Acetylinic alcohols 3.00Total 100.00______________________________________
Typical wetting, dispersing or emulsifying agents used in agricultural formulations include, but are not limited to, the alkyl and alkylaryl sulfonates and sulfates and their sodium salts; alkylaryl polyether alcohols; sulfated higher alcohols; polyethylene oxides; sulfonated animal and vegetable oils; sulfonated petroleum oils; fatty acid esters of polyhydric alcohols and the ethylene oxide addition products of such esters; and the addition product of long-chain mercaptans and ethylene oxide. Many other types of useful surface-active agents are available in commerce. The surface-active agent, when used, normally comprises from 1 to 15% by weight of the composition.
Other useful formulations include simple solutions or suspensions of the active ingredient in a relatively non-volatile solvent such as water, corn oil, kerosene, propylene glycol, or other suitable solvents. This type of formulation is particularly useful for ultra low volume application.
The following illustrate specific suspensions which are suitable for use in the present invention:______________________________________Oil Suspension: % by Wt.______________________________________Active ingredient 25.00polyoxyethylene sorbitol hexaoleate 5.00Highly aliphatic hydrocarbon oil 70.00Total 100.00Aqueous Suspension:Active ingredient 40.00Polyacrylic acid thickener 0.30Dodecylphenol polyethylene 0.50glycol etherDisodium phosphate 1.00Monosodium phosphate 0.50Polyvinyl alcohol 1.00Water 56.70Total 100.00______________________________________
The concentration of the compound in use dilution is normally in the range of about 2% to about 0.1%. Many variations of spraying and dusting compositions in the art may be used by substituting or adding a compound of this invention into compositions known or apparent to the art.
The compositions may be formulated and applied with other suitable active ingredients, including nematicides, insecticides, acaricides, fungicides, other plant regulators, herbicides, fertilizers, etc.
In applying the foregoing chemicals, an effective growth regulating amount of the active ingredient must be applied. While the application rate will vary widely depending on the choice of compound, the formulation and mode of application, the plant species being treated and the planting density, a suitable use rate may be in the range of 0.01 to 10 kg/hectare, preferably 0.05 to about 5 kg/hectare.
The compounds of this invention may be prepared by heating an aminopyridine and a substituted phenyl isocyanate in a solvent such as 2-butanone, toluene, or methylene chloride to produce the corresponding N-pyridinylurea. The N-pyridinylurea is then treated with a suitable oxidizing agent, for example metachloroperoxybenzoic acid (MCPBA) in a solvent such as ethanol or ethyl acetate to produce the corresponding (pyridinyl-N-oxide)urea.
The following examples illustrate preparation of the compounds of this invention.
US Referenced Citations (6)
Foreign Referenced Citations (1)
| Number |
Date |
Country |
| 1147438 |
Apr 1969 |
GBX |
Non-Patent Literature Citations (2)
| Entry |
| Katritzky, J. Chem. Soc., 191-197 (1957). |
| Isogai, Chemical Regulation in Plants, 17, 27-43, 1982. |
Continuation in Parts (2)
|
Number |
Date |
Country |
| Parent |
586574 |
Mar 1984 |
|
| Parent |
480055 |
Mar 1983 |
|
Patent Grant
4787931
