WO2002062768A1 - Herbicidal sulfonylureas - Google Patents

Abstract

Compounds of Formula I, and their agriculturally suitable salts, are disclosed which are useful for controlling undesired vegetation wherein R1 is C1-C3 alkyl, C1-C2 haloalkyl, C2-C3 alkenyl, cyclopropyl or NR?3R4;R2 is C¿1-C4 alkyl, C1-C3 haloalkyl, C2-C4 alkenyl, C2-C3 haloalkenyl, C2-C4 alkynyl, cyclopropyl, halocyclopropyl, C2-C3 alkoxyalkyl, C2-C4 alkylcarbonyl, C2-C4 alkoxycarbonyl, Cl or Br; or R2 is phenyl optionally substituted with 1 to 2 substituents independently selected from halogen, C¿1?-C3 alkyl and C1-C2 alkoxy;R?3¿ is H or C¿1?-C2 alkyl; and R?4 is C¿1-C3 alkyl or C1-C2 alkoxy;provided that when R1 is CF¿3? then R?2¿ is other than CH¿2?OCH3, when R?1¿ is N(CH¿3?)2 then R?2¿ is other than CH¿3?, and when R?1¿ is CH¿2?CH3 then R?2¿ is other than 2-fluorophenyl.Also disclosed are compositions containing the compounds of Formula I and a method for controlling undesired vegetation which involves contacting the vegetation or its environment with an effective amount of a compound of Formula I.

Description

HERBICIDAL SU FONY UREAS

FIELD OF THE INVENTION The present invention relates to a method of controlling the growth of undesired vegetation by applying certain sulfonylurea herbicides to the locus of undesired vegetation which is generally resistant to sulfonylurea herbicides, and to herbicidal mixtures and herbicidal compositions that control the growth of said vegetation.

BACKGROUND OF THE INVENTION

The control of undesired vegetation is extremely important in obtaining high agricultural efficiency. This can be achieved by the selective control of the growth of weeds in such useful crops as rice, soybean, sugar beet, corn, potato, wheat, barley, alfalfa, tomato and plantation crops such as citrus and sugarcane, among others. Unchecked weed growth in such useful crops can cause significant reduction in productivity and thereby result in increased costs to the consumer. The control of undesired vegetation in noncrop areas is also important.

Over the past two decades, the sulfonylureas and other herbicides inhibiting acetolactate synthase (ALS; EC 4.1.3.18) have become very important products for controlling weeds. However, there have also emerged weed biotypes that are resistant to these herbicides. When these resistant biotypes become prevalent, other herbicides are required to provide satisfactory control. Therefore new herbicides effective against resistant weed biotypes are needed. Surprisingly a novel subset of the sulfonylurea class of herbicides has now been discovered that is effective against resistant weeds, and furthermore this novel subset is safe to agronomically important crops.

U.S. Patents 4,515,624 and 4,878,938 generically embrace compounds of the present invention, but do not specifically name them or disclose their particular utilities for controlling resistant weeds in rice, wheat and barley crops.

SUMMARY OF THE INVENTION This invention is directed to compounds of Formula I including all isomers, agriculturally suitable salts thereof, agricultural compositions containing them and their use for controlling undesirable vegetation:

wherein R¹ is C_!-C₃ alkyl, -C₂ haloalkyl, C₂-C₃ alkenyl, cyclopropyl orNR³R⁴; R² is C_!-C₄ alkyl, C_!-C₃ haloalkyl, C₂-C₄ alkenyl, C₂-C₃ haloalkenyl, C₂-C₄ alkynyl, cyclopropyl, halocyclopropyl, C₂-C₃ alkoxyalkyl, C₂-C alkylcarbonyl C₂-C₄ alkoxycarbonyl, Cl or Br; or R² is phenyl optionally substituted with 1 to 2 substituents independently selected from halogen, C₁-C₃ alkyl and Cι-C₂ alkoxy; R³ is H or C_!-C₂ alkyl; and R⁴ is C_!-C₃ alkyl or Ci-C₂ alkoxy; provided that when R¹ is CF₃ then R² is other than CH₂OCH₃, when R¹ is N(CH₃)₂ then R² is other than CH₃, and when R¹ is CH₂CH₃ then R² is other than 2-fluorophenyl.

More particularly, this invention pertains to a compound of Formula I, or an agriculturally suitable salt thereof, or a composition comprising a herbicidally effective amount of said compound, which may be in the form of an agriculturally suitable salt, and at least one of the following: surfactant, solid or liquid diluent. The invention also pertains to a method for controlling undesired vegetation comprising applying to the locus of the vegetation a herbicidally effective amount of said compound, which may be in the form of an agriculturally suitable salt and may be formulated in a composition comprising at least one of the following: surfactant, solid or liquid diluent.

DETAILS OF THE INVENTION In the above recitations, the term "alkyl", used either alone or in derivative or compound words such as "alkoxy" or "haloalkyl" includes straight-chain or branched alkyl, such as, methyl, ethyl, n-propyl, z-propyl, or the different butyl isomers. "Alkenyl" includes straight-chain or branched alkenes such as ethenyl, 1-propenyl, 2-propenyl, and the different butenyl isomers. "Alkenyl" also includes polyenes such as 1,2-propadienyl and 1,3-butadienyl. "Alkynyl" includes straight-chain or branched alkynes such as ethynyl, 1-propynyl, 2-propynyl and the different butynyl isomers. "Alkoxy" includes, for example, methoxy, ethoxy, n-propyloxy, and isopropyloxy. "Alkoxyalkyl" denotes alkoxy substitution on alkyl. Examples of "alkoxyalkyl" include CH₃OCH₂, CH₃OCH₂CH₂ and CH₃CH₂OCH₂. The term "halogen", either alone or in compound words such as "haloalkyl", includes fluorine, chlorine, bromine or iodine. Further, when used in compound words such as "haloalkyl", said alkyl may be partially or fully substituted with halogen atoms which may be the same or different. Examples of "haloalkyl" include F₃C, C1CH₂, CF₃CH and CF₃CC1₂. The term "haloalkenyl" and the like, is defined analogously to the term "haloalkyl". Examples of "haloalkenyl" include (C1)₂C=CHCH₂ and H₂C=CHCF₂.

The total number of carbon atoms in a substituent group is indicated by the "Cj-C_j" prefix where i and j are numbers from 1 to 4. For example, C₂ alkoxyalkyl designates CH₃OCH₂; and C₃ alkoxyalkyl designates, for example, CH₃CH(OCH₃), CH₃OCH₂CH₂ or CH₃CH₂OCH₂. Examples of "alkylcarbonyl" include C(O)CH₃, C(O)CH₂CH₂CH₃ and C(O)CH(CH₃)₂. Examples of "alkoxycarbonyl" include CH₃OC(=O), CH₃CH₂OC(=O), CH₃CH₂CH₂OC(=O) and (CH₃)₂CHOC(=O).

Compounds of this invention can exist as one or more stereoisomers. The various stereoisomers include enantiomers, diastereomers, atropisomers and geometric isomers. One skilled in the art will appreciate that one stereoisomer may be more active and/or may exhibit beneficial effects when enriched relative to the other stereoisomer(s) or when separated from the other stereoisomer(s). Additionally, the skilled artisan knows how to separate, enrich, and/or to selectively prepare said stereoisomers. Accordingly, the present invention comprises compounds selected from Formula I and agriculturally suitable salts thereof. The compounds of the invention may be present as a mixture of stereoisomers, individual stereoisomers, or as an optically active form.

The agriculturally suitable salts of the compounds of the invention include those formed from alkali metals (e.g., lithium, sodium, potassium), alkaline earth metals (e.g., magnesium, calcium), ammonia, substituted amines (e.g., isopropylamine, dimethylamine, triethylamine, triethanolamine), quaternary ammonium (e.g., benzyltrimethylammonium, tetra-n-butylammonium), and ternary sulfides and derivatives (e.g., trimethylsulfonium (trimesium) and trimethylsulfoxonium).

A preferred embodiment of this invention comprises a method for controlling vegetation comprising at least one biotype resistant to herbicides inhibiting acetolactate synthase, the method comprising applying to the locus of the undesired vegetation a herbicidally effective amount of a compound of Formula I. A particularly preferred embodiment comprises the method wherein the undesired vegetation is a Scirpus species.

Another preferred embodiment of this invention comprises a method for selectively controlling undesired vegetation in a rice crop, particularly in paddy field cultivation, comprising applying to the locus of the rice crop a herbicidally effective amount of a compound of Formula I.

Yet another preferred embodiment of this invention comprises a method for selectively controlling undesired vegetation in a wheat or barley crop, comprising applying to the locus of the wheat or barley crop a herbicidally effective amount of a compound of Formula I.

For reasons including ease of synthesis and/or greater herbicidal efficacy, R¹ is preferably Cι~C₃ alkyl, cyclopropyl or dimethylamino, more preferably Cι~C₃ alkyl or cyclopropyl, even more preferably Cι~C₃ alkyl, still more preferably methyl or ethyl, and most preferably methyl. Preferably, R² is Cj-C alkyl, Cι-C₃ haloalkyl, C₂-C₄ alkenyl, C -C₃ haloalkenyl, C₂-C₄ alkynyl, cyclopropyl, C₂-C₄ alkylcarbonyl, C -C₄ alkoxycarbonyl or Cl; or R² is phenyl optionally substituted with 1 to 2 substituents selected from F, Cl or C_!-C₂ alkyl. More preferably, R² is C₁-C₃ alkyl, C_!-C₃ fluoroalkyl, cyclopropyl, C₂-C₄ alkoxycarbonyl, Cl or phenyl. Even more preferably, R² is Cι~C₃ alkyl, Cι~C₃ fluoroalkyl or C₂-C₃ alkoxycarbonyl. Still more preferably, R² is Cj fluoroalkyl. Most preferably, R² is CH₂F, or R² is CHF₂, or R² is CF₃.

Compounds of the invention illustrating groups preferred for reasons of better activity and/or ease of synthesis are: L A compound of Formula I provided that when R¹ is Cj-C₂ haloalkyl then R² is other than C₂-C₃ alkoxyalkyl, when R¹ is NR³R⁴ then R² is other than Cj- alkyl, and when R¹ is Cι-C₃ alkyl then R² is other than halophenyl.

2. A compound of Formula I wherein R² is Cι~C₄ alkyl, C_j-C₃ haloalkyl, C₂-C₄ alkenyl, C₂-C₃ haloalkenyl, C₂-C alkynyl, cyclopropyl, C₂-C₄ alkylcarbonyl, C₂-C₄ alkoxycarbonyl or Cl; or R² is phenyl optionally substituted with 1 to 2 substituents selected from F, Cl or Cι~C₂ alkyl.

3. A compound of Preferred 2 wherein R¹ is Cι~C₃ alkyl, cyclopropyl or dimethylamino.

4. A compound of Preferred 3 wherein R² is C_!-C₃ alkyl, C_!-C₃ fluoroalkyl, cyclopropyl, C₂-C₄ alkoxycarbonyl, Cl or phenyl.

5. A compound of Preferred 4 wherein R² is C_!~C₃ alkyl, C_!-C₃ fluoroalkyl or C₂-C₃ alkoxycarbonyl.

6. A compound of Preferred 5 wherein R¹ is Cι~C₃ alkyl or cyclopropyl; and R² is C_!-C₃ fluoroalkyl. 7. A compound of Preferred 6 wherein R² is Cγ fluoroalkyl.

8. A compound of Preferred 7 wherein R¹ is Cι~C₃ alkyl.

9. A compound of Preferred 8 wherein R¹ is methyl or ethyl.

10. A compound of Preferred 9 wherein R² is CH₂F.

11. A compound of Preferred 9 wherein R² is CHF₂. 12. A compound of Preferred 9 wherein R² is CF₃.

Specifically Preferred for reasons of greatest herbicidal efficacy and/or greatest crop safety is:

• the compound of Formula I wherein R¹ is methyl and R² is CHF₂ (2-(difluoromethyl)-N-[[(4,6-dimethoxy-2-pyrimidinyl)amino]- carbonyl] -6- [(methylsulfonyl)oxy]benzenesulfonamide).

The Formula I compounds can be prepared by one or more of the following methods. As the first method, the compounds of Formula I can be prepared by the procedure shown in Scheme 1. Scheme 1

wherein R¹ and R² are as previously defined.

The reaction of Scheme 1 can be carried out by contacting equimolar amounts of a sulfonamide of Formula 1 with a pyrimidinyl phenyl carbamate of Formula 2 in the presence of an equimolar amount of an organic base such as l,8-diazabicyclo[5.4.0]undec-7-ene (DBU) or an inorganic base such as lithium hydroxide by methods analogous to those described European Patent Publication EP-A-85,028. The phenyl carbamates of Formula 2 can be prepared by methods described in European Patent Publications EP-A-70,802 and EP-A-70,804.

Analogous to the first method, the compounds of Formula I can also be prepared by the procedure shown in Scheme 2.

Scheme 2

wherein R¹ and R² are as previously defined, and R⁵, R⁶ and R⁷ are independently Cj-C₄ alkyl.

The reaction of Scheme 2 can be carried out by contacting equimolar amounts of a silylsulfonamide of Formula 3 with a pyrimidinyl phenyl carbamate of Formula 2 in the presence of an equimolar amount of a fluoride source such as tetra-«-butylammonium fluoride by methods analogous to those described in U.S. Patent 5,090,993.

Silylsulfonamides of Formula 3 wherein R⁵ is tert-butyl and R⁶ and R⁷ are both methyl are particularly useful intermediates in this reaction.

Many of the compounds of Formula I can be prepared by the procedure shown in

Scheme 3. Scheme 3

wherein R¹ and R² are as previously defined.

The reaction shown in Scheme 2 is carried out by contacting a phenyl carbamate of Formula 4 with an aminopyrimidine of Formula 5 in an inert organic solvent such as dioxane or tetrahydrofuran at temperatures of about 20-100 °C for a period of about one-half to twenty- four hours. The product can be isolated by evaporation of the reaction solvent and purified by the methods previously described.

Phenyl carbamates of Formula 4 are prepared from the corresponding sulfonamides of Formula 1 by the methods described, or modifications thereof known to those skilled in the art, in European Patent Publications EP-A-44,808 and EP-A-70,802.

As shown in Scheme 4, many of the compounds of Formula I can also be prepared by reacting a sulfonyl isocyanate of Formula 6 with an aminopyrimidine of Formula 5.

Scheme 4

wherein R¹ and R² are as previously defined.

The reaction is best carried out in an inert aprotic organic solvent such as dichloromethane, 1,2-dichloroethane, tetrahydrofuran or acetonitrile, at a temperature between 20 and 85 °C. The order of addition is not critical; however, it is often convenient to add the sulfonyl isocyanate or a solution of it in the reaction solvent to a stirred suspension of the amine.

In some cases, the desired product is insoluble in the reaction solvent at ambient temperature and crystallizes from it in pure form. Products soluble in the reaction solvent are isolated by evaporation of the solvent. Compounds of Formula I then are purified by trituration of the evaporation residue with solvents such as 1-chlorobutane or ethyl ether and filtration, by recrystallization from mixtures of solvents such as 1,2-dichloroethane, 1-chlorobutane and heptane, or by chromatography on silica gel. Sulfonyl isocyanates of Formula 6 are prepared from the corresponding sulfonamides of Formula 1 by one of the two following general methods.

In the first method, the sulfonamide 1 and an alkyl isocyanate (e.g., /j-butyl isocyanate) in xylene or other solvent boiling above 135 °C are mixed in the presence or absence of a catalytic amount of l,4-diazabicyclo[2.2.2]bicyclooctane (DABCO) and heated to 135-

140 °C. After 5-60 minutes phosgene is slowly added to the heated mixture at such a rate that the temperature remains between 133-135 °C. When the consumption of phosgene has ceased, the mixture is cooled and filtered to remove insoluble material. Finally, the solvent, alkyl isocyanate, and excess phosgene are evaporated, leaving the sulfonyl isocyanate 6. If desired, an alkyl isocyanate-sulfonamide adduct can be made and isolated before reaction with the phosgene. In this case, the sulfonamide 1, alkyl isocyanate, and anhydrous base (e.g., K₂CO₃) in a polar, aprotic solvent (e.g., acetone, butanone, or acetonitrile) are mixed and heated under reflux for 1 to 6 hours. The reaction mixture is then diluted with water, and the pH is adjusted to about 3 with acid (e.g., HCI, H SO₄). The adduct is filtered out and dried, and then reacted with phosgene as described above. This procedure modification is especially useful when sulfonamide 1 is high melting and has low solubility in the phosgenation solvent.

Sulfonyl isocyanates 6 can also be prepared by a second method which is shown in Scheme 5. Scheme 5

where R¹ and R² are as previously defined.

The sulfonamide 1 is heated at reflux in an excess of thionyl chloride. The reaction is continued until the sulfonamide protons are not longer detectable in the proton magnetic resonance spectrum. From 16 hours to 5 days is typically sufficient for complete conversion to the thionylamide 7. The thionyl chloride is evaporated and the residue is treated with an inert solvent (e.g., toluene) containing at least one equivalent (typically 2-3 equivalents) of phosgene. A catalytic amount of pyridine (typically 0.1 equivalent) is added, and the mixture is heated to about 60-140 °C, with 80-100 °C preferred. Conversion to the isocyanate 6 is usually substantially complete within 15 minutes to 3 hours. The mixture is then cooled and filtered, and the solvent is evaporated, leaving the sulfonyl isocyanate 6.

Sulfonamides of Formula 1 can be prepared from sulfonyl chloride counterparts of Formula 8 as shown in Scheme 6. Scheme 6

wherein R¹ and R² are as defined above.

This method involves treating a sulfonyl chloride of Formula 8 with at least two equivalents of ammonia. Typically the reaction is conducted in an inert solvent such as dichloromethane or tetrahydrofuran. As the reaction occurs rapidly and is exothermic, the ammonia is typically added to the reaction mixture at a temperature between -30 and -10 °C.

Sulfonamides of Formula 1 can also be prepared by treatment of the corresponding sulfonyl chlorides 8 with α-methylbenzylamine followed by removal of the α-methylbenzyl group by dissolution in trifluoroacetic acid. This alternative route is particularly useful when R¹ or R² is chiral, and separating the enantiomers of 1 is desired. Either (R)-(+)- α-methylbenzylamine or (S)-(-)-α-methylbenzylamine is used as the animating agent. The resulting diastereomeric N-α-methylbenzylsulfonamide intermediates have different physical properties, allowing them to be separated by such techniques as liquid chromatography and fractional crystallization.

Silylsulfonamides of Formula 3 can be prepared from the corresponding sulfonyl chlorides of Formula 8 by treatment with the respective aminosilanes R³R⁴R⁵SiΝH₂ according to the general methods of U.S. Patent 5,090,993.

Sulfonyl chlorides of Formula 8 can be prepared as shown in Scheme 7. Scheme 7

wherein R¹ and R² are as defined above.

This process involves diazotizing an aniline of Formula 9 and then coupling with sulfur dioxide and chloride ion in the presence of copper(II) according to the general procedure of H. Meerwein, G. Dittmar, R. Gollner, K. Hafher, F. Mensch, O. Steinfort, Chem. Ber. 1957, 90, 841-852 and variations known to those skilled in the art. Propanoic acid can be a particularly useful cosolvent for both the diazotization and coupling media. Anilines of Formula 9 can be prepared as shown in Scheme 8. Scheme 8

wherein R¹ and R² are as defined above.

The reduction of a nitrobenzene of Formula 10 to an aniline of Formula 9 can be achieved by one or more of a variety of standard methods. These methods include hydrogenation using a heterogeneous catalyst such as carbon-supported palladium (for general method, see

P. Rylander, Catalytic Hydrogenation in Organic Syntheses, Academic Press, New York,

1979, Chapter 7 and references cited therein) or platinum sulfide (for general method, see

F. S. Dovel and H. Greenfield, J. Am. Chem. Soc. 1965, 87, 2767-2768). Other reduction methods include treatment with iron in acetic acid as reviewed by C. A. Buehler and D. E.

Pearson, Survey of Organic Syntheses; Wiley-Interscience: New York, 1970, pp. 413-414, tin in acetic acid (M. Sheehan, D. J. Cram, J. Am. Chem. Soc. 1969, 91, 3544-3552), tin(II) chloride (F. D. Bellamy, K. Ou, Tetrahedron Lett. 1984, 25, 839-842), and titanium(III) chloride (M. Somei, K. Kato, S. Inous, Chem. Pharm. Bull. 1980, 28, 2515-2518). Particularly when R² is an electron-withdrawing group, such as alkylcarbonyl or alkoxycarbonyl, sulfonyl chlorides of Formula 8 can also be prepared from the corresponding nitrobenzenes of Formula 10 by nucleophilic displacement of the nitro group through treatment with a sodium or potassium alkylthiolate or benzylthiolate salt, and then oxidizing the derived thioether moiety with aqueous chlorine or hypochlorous acid to afford the sulfonyl chloride 8; for methods, see K. K. Andersen, "Sulfonic Acids and Their

Derivatives", Chapter 11.19 in Comprehensive Organic Chemistry, Pergamon Press: New

York, 1979, pp. 332-359, and the references cited therein.

Sulfonates 10 can be prepared as shown in Scheme 9.

Scheme 9

wherein R¹ and R² are as defined above.

This method involves contacting a phenol of Formula 11 with at least an equivalent of a sulfonyl chloride of Formula 12 in the presence of at least one equivalent of a base. The reaction is conveniently conducted using an inert solvent like dichloromethane and a tertiary amine base such as triethylamine. The sulfonyl chlorides of Formula 12 are commercially available or can be prepared by methods well known in the art.

Phenols of Formula 11 can be prepared as shown in Scheme 10.

Scheme 10

wherein R² is as defined above.

This method involves demethylating anisoles of Formula 13 by treatment with boron tribromide, conveniently in an inert solvent such as dichloromethane. This method for demethylating aromatic methyl ethers is described by J. F. W. McOmie, M. L. Watts, D. E. West, Tetrahedron 1968, 24, 2289-2292.

Sulfonamides of Formula 13a (Formula 13 wherein R² is CH₂F), Formula 13b (Formula 13 wherein R² is CHF₂) and Formula 13c (Formula 13 wherein R² is CF₃) can be prepared as shown in Scheme 11.

Scheme 11

The fluoroalkyl benzenes of Formulae 13a, 13b and 13c can be prepared from the corresponding alcohol, aldehyde and carboxylic acid of Formulae 14, 15 and 16 respectively by treatment with sulfur tetrafluoride using the procedures reviewed by G. A. Boswell, Jr., W. C. Ripka, R. M. Scribner, C. W. Turlock in Organic Reactions, Vol. 21, Chapter 1, Wiley: New York, 1974, pp. 1^06; C.-L. J. Wang, "Fluorination by Sulfur Tetrafluoride", Chapter 2 in Organic Reactions, Vol. 34, Wiley: New York, 1985, pp. 319-400; and M. R. C. Gerstenberger, A. Haas, Angew. Chem. Int. Ed. 1981, 20, 647-667. Conversion of the carboxylic acid of Formula 16 to the corresponding acyl chloride by treatment with thionyl chloride before treatment with sulfur tetrafluoride presents another method. A convenient alternative reagent to sulfur tetrafluoride for these conversions is (diethylamino)sulfur trifluoride (DAST) as described by W. J. Middleton, J. Org. Chem. 1975, 40, 574-578. Fluorination with DAST is reviewed by M. Hudlicky, "Fluorination with Diethylaminosulfur Trifluoride and Related Aminofluorosulfuranes", Chapter 3 in Organic Reactions, Vol. 35, Wiley: New York, 1988, pp. 513-637. The aldehyde of Formula 15 is commercially available (e.g., Aldrich Chemical

Company). The alcohol of Formula 14 and the carboxylic acid of Formula 16 can be prepared by general methods known in the art, including conversion from aldehyde 15. For example, the aldehyde 15 can be reduced to the alcohol 14 by reagents such as diborane in tetrahydrofuran (for general method, see H. C. Brown, B. C. S. Rao, J. Am. Chem. Soc. 1960, 82, 681-686) and lithium cyanoborohydride (for general method, see R. F. Borch, H. D. Durst, J. Am. Chem. Soc. 1969, 91, 3996-3997). The aldehyde 15 can be oxidized to the carboxylic acid 16 by reagents such as sodium chlorite (B. S. Bal, W. E. Childers, Jr., H. W. Pinnick, Tetrahedron 1981, 37, 2091-2094), sodium chlorite and hydrogen peroxide (E. Dalcanale, F. Montanari, J. Org. Chem. 1986, 51, 567-569), nickel peroxide (K. Nakagawa, S. Mineo, S. Kawamura, Chem. Pharm. Bull. 1978, 26, 299-302) and tetrabutylammonium permanganate (T. Sala, M. V. Sargent, J. Chem. Soc. Chem. Comm. 1978, 253-254). Alternatively, it may be convenient to chlorinate the aldehyde 15 (for general method see H. T. Clarke, E. R. Taylor in Organic Syntheses Coll. Vol. 1; Wiley: New York 1941, pp. 155-156) to the acyl chloride corresponding to carboxylic acid 16 and then directly treating with sulfur tetrafluoride to give the trifluoride of Formula 13c.

Compounds of Formula 13 wherein R² is a longer chain homolog of the fluoromethyl group of Formula 13a or the difluoromethyl group of Formula 13b can also be prepared in analogy to Scheme 11 by treatment of the corresponding longer chain alcohol or ketone, respectively, with sulfur tetrafluoride or DAST. Similarly, R² haloalkyl groups ∞ntaming halogens besides fluorine can be prepared from the corresponding alcohol, aldehyde, ketone and carboxylic acid groups by halogenation reagents well known in the art. Furthermore, R² alkoxyalkyl groups can be prepared by nucleophilic displacement of halogen from the corresponding chloro, bromo or iodoalkyl R² groups by methods well known in the art, for example, treatment with the appropriate alkali metal or quaternary ammonium alkoxide.

The carboxaldehyde of Formula 15 is particularly useful for condensation with nucleophilic reagents leading to R² substituents of the invention. For example, the carboxaldehyde 15 can be homologated to olefins by treatment with phosphonium ylids, such as Wittig reagents (for a review of the Wittig reaction, see A. Maercker, "The Wittig Reaction", Chapter 3 in Organic Reactions, Vol. 14, Wiley: New York, 1965, pp. 270-490). As shown in Scheme 12, treatment with the ylid 17 derived by deprotonation of methyltriphenylphosphonium bromide (R⁶ is H) or methoxymethyltriphenylphosphonium bromide (R⁶ is OCH₃) gives the corresponding styrene of Formula 18.

Scheme 12

where R⁶ is H or OCH₃.

When R⁶ is OCH₃ in Formula 18, the enol ether moiety can be hydrolyzed by aqueous acid to afford the corresponding aldehyde 19, which then can be converted to the difluoride 13d by treatment with sulfur tetrafluoride or DAST (analogous to the conversion of Formula 15 to Formula 13b in Scheme 11) as shown in Scheme 13.

Scheme 13

Furthermore, the aldehyde of Formula 19 can be reduced to the alcohol or oxidized to the carboxylic acid to give a compound of Formula 13 (R² is CH₂CH₂F) or (R² is CH₂CF₃), respectively, after treatment with a fluorinating reagent, analogous to the transformations shown in Scheme 11. Alternatively the alcohol obtained by reduction of aldehyde 19 can be converted to a bromide or iodide using reagents well known in the art, and then treated with an alkali metal methoxide to displace the halogen and give the compound of Formula 13 wherein R² is CH₂CH₂OCH₃. Also, the aldehyde of Formula 19 can be further homologated by reaction with a nucleophilic reagent such as a Wittig reagent and elaborated by methods well known in the art to give further R² groups of the invention.

When R⁶ is H in Formula 18, treatment with a carbene or carbenoid reagent gives the corresponding compound of Formula 13e, as illustrated by Scheme 14.

Scheme 14

wherein R⁷ and R⁸ are independently H or halogen.

Halocarbenes can be obtained from deprotonation of the corresponding halomethanes (e.g., tribromomethane or trichloromethane). Halocarbenes can also be generated by thermal decomposition of haloacetic acid salts, such as sodium trichloroacetate. For methods for making and using halocarbenes to prepare halocyclopropanes, see L. Skattebøl et al., Tetrahedron Lett. 1973, (16), 1367-1370; E. V. Dehmlow, Tetrahedron Lett. 1976, (2), 91- 94; W. E. Parham and E. E. Schweizer, "Halocyclopropanes from Halocarbenes", Chapter 2 in Organic Reactions, Vol. 13, Wiley: New York, 1963, pp. 55-90; and the references cited therein. (A particularly useful method for preparing difluorocyclopropanes of Formula 13e wherein R⁷ and R⁸ are F involves reaction of the styrene 18 (R⁶ is H) with the difluorocarbene liberated from sodium chlorodifluoroacetate in sulfolane at 185 °C.) One or both of the halogens at R⁷ and R⁸ can be reduced to H by use of a variety of reducing agents known in the art, such as tri-«-butyltin hydride (see N. I. Yakushkina et al., J. Org. Chem. USSR. 1980, 16, 1553-1557; L. A. Paquette et al., J. Am. Chem. Soc. 1979, 101, 4645- 4655; W. P. Neumann, Synthesis 1987, 665-683; and the references cited therein).

Schemes 11 through 14 and the accompanying explanation illustrate methods for preparing the key intermediate of Formula 13 suitable for a wide range of R² groups spanning the scope of the present invention. Alternatively, the sulfonamide intermediates of Formula 1 can be prepared from routes involving ortho lithiation of N-tert-butyl sulfonamides.

For example, sulfonamides of Formula 1 can be prepared by adding tert-butyl sulfonamides of Formula 19 to excess trifluoroacetic acid at room temperature, as shown in Scheme 15. Evaporation of the trifluoroacetic acid leaves the sulfonamides of Formula 1. Scheme 15

19 wherein R² is as defined above.

The sulfonates of Formula 19 can be prepared from the corresponding phenols of Formula 20 as depicted in Scheme 16, analogous to Scheme 9.

Scheme 16

wherein R¹ and R² are as defined above.

As shown in Scheme 17, the phenols of Formula 20 can be prepared by lithiation of the tert-butyl sulfonamide of Formula 21, reaction with trimethyl borate and oxidation. The lithiation can be carried out by treatment of the tert-butylsulfonamide 21 in tetrahydrofuran with at least two equivalents (typically 2.2 equivalents) of «-butyllithium at -40 °C and then warming to 0 °C before addition of the trimethyl borate. (For lithiation procedures, see M. A. Hanagan, U.S. Patent 4,604,131.) Oxidation to the phenol 20 can be carried out using hydrogen peroxide in acetic acid according to the general conditions of R. L. Kidwell et al. in Organic Syntheses, Vol. 49, Wiley: New York, 1969, pp. 90-93.

Scheme 17

wherein R¹ and R² are as defined above. When lithiation occurs more readily laterally on R² than at hydrogen at the other ortho position (such as when R² is CH₃ or CH₂CH₃), the method of Scheme 17 is modified. In this modification, after lateral lithiation the reaction mixture is treated with chlorotrimethyl- silane to give the trimethylsilyl derivative. The lithiation is then repeated. If the lithiation again occurs laterally on the substituent (as when starting R² is CH₃, which at this point has been silated to CH₂Si(CH₃)₃) treatment with chlorotrimethylsilane is repeated to give the bis-trimethylsilyl derivative. After the active hydrogens at lateral positions have been replaced by trimethylsilyl groups, lithiation then proceeds at the desired ortho position. After completion of the steps shown in Scheme 17, the trimethylsilyl groups can be removed using cesium fluoride in NN-dimethylformamide or tefra-n-butylammonium fluoride in tetrahydrofuran according to the general methods described by R. J. Mills et al., J. Org. Chem. 1989, 54, 4372-4385.

The tert-butyl sulfonamides of Formula 21 can be prepared by treatment of the corresponding sulfonyl chlorides with tert-butylamine, analogous to the process of Scheme 6. The sulfonyl chlorides can be prepared from the corresponding thiols or alkyl- or benzylthioethers by methods well known in the art such as chlorination in the presence of water; for methods see K. K. Andersen, "Sulfonic Acids and Their Derivatives", Chapter 11.19 in Comprehensive Organic Chemistry, Pergamon Press, ΝY, 1979, pp. 332-359, and the references cited therein. The synthetic strategy of Schemes 16-17 involves elaboration of R² groups mostly before adding a hydroxy function to phenyl ring through lithiation. However, as illustrated in Schemes 18-20, phenyl lithiation can also be used to introduce R² groups after the hydroxy group is already present in protected form. For example, as shown in Scheme 18, the sulfonamide intermediate of Formula 20 can be prepared by deprotection of the tert- butyldimethylsilyl ether 22 by treatment with a fluoride ion reagent, such as tetra-n- butylammonium fluoride in tetrahydrofuran as described by E. J. Corey and A. Venkateswarlu, J. Am. Chem. Soc. 1972, 94(11), 6190-6191 or an equimolar mixture of aqueous sodium fluoride and hydrogen fluoride solutions in tetrahydrofuran as described by P. M. Kendall et al., J. Org. Chem. 1979, 44(9), 1421-1424. Scheme 18

22 wherein R² is as defined above.

The intermediate of Formula 22 can be prepared with a wide variety of R² groups according to the processes diagrammed in Scheme 19. Scheme 19

wherein R² is as defined above, and X is Br or I.

The processes of Scheme 19 begin with lithiation of the tert-butyl sulfonamide of Formula 23 using at least two equivalents (typically 2.2 equivalents) of n-butyllithium according to the general method described for Scheme 17. The resulting lithiated intermediate 24 is useful in a wide variety of routes for preparing the tert-butylsulfonamides of Formula 22. As shown in branch (a), the lithiated intermediate 24 can be directly reacted with carbon-based electrophiles to give the R² groups of the invention directly or, instead, intermediate groups that can be converted to R² groups of the invention by subsequent chemical transformation. For example, reaction of 24 with an aliphatic aldehyde or ketone gives a 1-hydroxyalkyl substituent that can be dehydrated to give R² as an alkenyl group or oxidized to give R² as an alkylcarbonyl group, or the hydroxy function can be replaced by halogen to give R² as a haloalkyl group. A wide variety of methods for effecting these functional group interchanges are well known in the chemical art. As a further example, reaction of 24 with ethylene oxide gives a 2-hydroxyethyl intermediate that can be, for example, converted to R² being 2-fluoroethyl by treatment with DAST or alternatively converted to R² being 2-methoxyethyl by treatment with trimethyloxonium tetrafluoroborate and diisopropylethylamine. Furthermore, the lithiated intermediate 24 can be treated with a copper(I) salt to give the corresponding organocopper reagent, which can be reacted with alkyl, alkenyl and alkynyl halides to give R² as alkyl, alkenyl and alkynyl, respectively. Conjugate addition of cuprates to enones provides further entry to R² groups. Synthesis using organocopper reagents is extensively reviewed by B. H. Lipshutz and S. Sengupta, "Organocopper Reagents: Substitution, Conjugate Addition, Carbo/metallocupration, and Other Reactions", Chapter 2 in Organic Reactions, Wiley: New York, 1992, pp. 135-631.

As shown in branch (b) of Scheme 19, the lithiated intermediate 24 can also be treated with a halogen to give a phenyl halide of Formula 25. Phenyl halides of Formula 25 are also useful intermediates to prepare a wide variety of other R² groups. For example, the halogen can be replaced by a 1 -alkenyl group through mediation of a palladium catalyst in the Heck

Reaction (for reviews, see R. A. Abramovitch et al., Tetrahedron 1988, 44(U), 3039-3071;

W. Cabri and I. Candiani, Synthesis 1995, 25(1), 2-7; and R. F. Heck, "Palladium-catalyzed

Vinylation of Organic Halides", Chapter 2 in Organic Reactions, Vol. 27, Wiley: New York, 1982, pp. 345-390). The Heck Reaction is compatible with some haloalkenes, such as 3,3,3- trifluoropropene; see G. Meazza et al., Pestic. Sci. 1992, 35, 137-144. The 1 -alkenyl groups can be cyclopropanated as described for Scheme 14, reacted with halogen to give haloalkyl groups, or hydrogenated to give alkyl groups as R². Furthermore, phenyl halides of Formula

25 can be reacted with alkenyl-, alkynyl- and phenyl stannanes to afford alkenyl, alkynyl and phenyl groups, respectively, as R² by use of the Stille Reaction, as reviewed by V. Farina et al., "The Stille Reaction", Chapter 1 in Organic Reactions, Vol. 50, Wiley: New York, 1997, pp. 1-652.

As shown in branch (c) of Scheme 19, the lithiated intermediate 24 can also be reacted with tri-w-butyltin chloride to give the stannane of Formula 26. Stannane 26 can be coupled with alkenyl and phenyl bromides and iodides, also by use of the Stille Reaction, to provide alkenyl and phenyl groups, respectively, as R².

The tert-butylsulfonamide of Formula 23 is prepared according to the method diagrammed in Scheme 20.

Scheme 20

27 28 29

In this method the hydroxy group of the hydroxybenzenethiol 27 is protected as a tert- butyldimethylsilyl ether (28) by treatment with tert-butyldimethylsilyl chloride in the presence of a base such as a imidazole, which also functions as catalyst, and a solvent such as NN-dimethylformamide according to procedures known in the art, such as that reported by E. J. Corey and A. Venkateswarlu, J. Am. Chem. Soc. 1972, 94(11), 6190-6191 and P. M. Kendall et al., J. Org. Chem. 1979, 44(9), 1421-1424. Although the tert-butyldimethylsilyl reagent can silylate the thiol group, under equilibrating conditions silylation of the hydroxy group is thermodynamically preferred. The thiol 28 is then oxidatively chlorinated to the sulfonyl chloride of Formula 29 by treatment with more than two equivalents each of an inorganic nitrate and sulfuryl chloride in an aprotic solvent such as acetonitrile and NN-dimethylformamide according to the general procedure of Y. J. Park et al., Chemistry Letters 1992, 1483-1486. The sulfonyl chloride intermediate of Formula 29 thus prepared is converted to the sulfonamide of Formula 23 by treatment with at least two equivalents of tert-butylamine in an inert solvent such as dichloromethane.

Although tert-butyldimethylsilyl is used in Schemes 18-20, other protecting groups can also be useful, for example, 2-(trimethylsilyl)ethoxymethyl, as described by B. H. Lipshutz and J. J. Tegram, Tetrahedron Lett. 1980, 21, 3343-3346. It is recognized that some reagents and reaction conditions described in some of the schemes above for preparing compounds of Formula I may not be compatible with certain functionalities present in the intermediates. In these instances, the incorporation of protection/deprotection sequences or functional group interconversions into the synthesis will aid in obtaining the desired products. The use and choice of the protecting groups will be apparent to one skilled in chemical synthesis (see, for example, T. W. Greene; P. G. M. Wuts Protective Groups in Organic Synthesis, 2nd ed.; Wiley: New York, 1991). One skilled in the art will recognize that, in some cases, after the introduction of a given reagent as it is depicted in any individual scheme, it may be necessary to perform additional routine synthetic steps not described in detail to complete the synthesis of compounds of Formula I. One skilled in the art will also recognize that it may be necessary to perform a combination of the steps illustrated in the above schemes in an order other than that implied by the particular sequence presented to prepare the compounds of Formula I.

One skilled in the art will also recognize that compounds of Formula I and the intermediates described herein can be subjected to various electrophilic, nucleophilic, radical, organometallic, oxidation, and reduction reactions to add substituents or modify existing substituents.

Agriculturally suitable salts of the compounds of Formula I are also useful herbicides and can be prepared in a number of ways known in the art. For example, metal salts can be made by contacting a compound of Formula I with a solution of an alkali or alkaline earth metal salt having a sufficiently basic anion (e.g., hydroxide, alkoxide, carbonate or hydride). Quaternary amine salts can be made by similar techniques.

Salts of the compounds of Formula I can also be prepared by exchange of one cation for another. Cationic exchange can be effected by direct contact of an aqueous solution of a salt of a compound of Formula I (e.g., alkali or quaternary amine salt) with a solution containing the cation to be exchanged. This method is most effective when the desired salt containing the exchanged cation is insoluble in water and can be separated by filtration.

Exchange may also be effected by passing an aqueous solution of a salt of a compound of Formula I (e.g., an alkali metal or quaternary amine salt) through a column packed with a cation-exchange resin containing the cation to be exchanged for that of the original salt and the desired product is eluted from the column. This method is particularly useful when the desired salt is water soluble (e.g., a potassium, sodium or calcium salt).

Without further elaboration, it is believed that one skilled in the art using the preceding description can utilize the present invention to its fullest extent. The following Synthesis Example is, therefore, to be construed as merely illustrative, and not limiting of the disclosure in any way whatsoever. Percentages are by weight except for chromatographic solvent mixtures or where otherwise indicated. Parts and percentages for chromatographic solvent mixtures are by volume unless otherwise indicated. *H NMR spectra are reported in ppm downfield from tetramethylsilane; s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet, dd = doublet of doublets, dt = doublet of triplets, br s = broad singlet.

Synthesis Example 1 - Preparation of 2-(difluoromethyl)-N-[[(4,6-dimethoxy- 2-pyrinιiidinyl)amino] carbonyl] -6- [(methylsulfonyl)oxy]benzenesulfonamide

Step A - Preparation of l-(difluoromethyl)-3-methoxy-2-nitrobenzene A solution of 3-methoxy-2-nitrobenzaldehyde (15.0 g, 82.8 mmol) in dichloromethane

(100 mL) was added to a stirred solution of (diemylamino)sulfur trifluoride (DAST, 13.1 mL, 100 mmol) in dichloromethane (100 mL) under nitrogen atmosphere. The reaction mixture was stirred at room temperature for 2 hours and then poured into ice water (200 mL). The layers were separated, and the organic layer was washed with an aqueous 1:1 bicarbonate-carbonate buffer solution and then dried (MgSO ). The solvent was removed by rotary evaporation, the residue was taken up in trichloromethane and again rotary evaporated to leave the title compound as a reddish oil (18.76 g). ^lH ΝMR: 5 3.92 (s, OCH₃), 6.80 (t, J=56 Ηz, CHF₂), 7.3 (m, 2Η, aryl H), 7.59 (t, 1H, aryl H). Step B - Preparation of 3-(difluoromethyl)-2-nitrophenol

A stirred solution of l-(difluoromethyl)-3-methoxy-2-nitrobenzene (8.27 g, 41 mmol) in dichloromethane (50 mL) under nitrogen atmosphere was cooled to below -40 °C. To this chilled dichloromethane solution was added a solution of boron tribromide (1.0 M, 43 mL, 43 mmol), and the reaction mixture was allowed to warm to room temperature. After 30 minutes the reaction mixture was poured into a mixture of ice and water (120 mL), using more dichloromethane for rinsing. The layers were separated, and the aqueous layer was extracted twice with dichloromethane. The combined organic extracts were washed with portions of aqueous bicarbonate solution and water. The bicarbonate and water washes were acidified with hydrochloric acid (6 Ν) and back extracted with two portions of ethyl acetate. The combined dichloromethane and ethyl acetate organic phases were dried (Νa₂SO₄) and rotary evaporated to leave the title product as an oil (9.0 g). ^!H NMR (90 MHz, CDCl₃-(CD₃)₂SO): δ 6.85 (t, J=57 Hz, CHF₂), 7.2 (m, 3H, aromatic H), 10.2 (OH). Some residual ethyl acetate was evident as an impurity. The crude product was used directly in the next step.

Step C - Preparation of 3-(difluoromethyl)-2-nitrophenol methanesulfonate A stirred solution of 3-(difluoromethyl)-2-nitrophenol (9.0 g, 47.6 mmol) in dichloromethane (95 mL) was chilled using an ice/water bath and then methanesulfonyl chloride (3.8 mL, 48.6 mmol) was added. Then a solution of triethylamine (7.3 mL, 52 mmol) in dichloromethane (30 mL) was slowly added at such a rate as to keep the temperature of the stirred reaction mixture below 10 °C. The reaction mixture was then allowed to warm to room temperature. After 1 hour the reaction mixture was washed once each with portions of water and hydrochloric acid (1 N) and then dried (MgSO₄). The solvent was removed by rotary evaporation to leave crude product (10.6 g). This was eluted through a column of silica gel to remove highly polar impurities, leaving the title product after rotary evaporation as an amber brown oil (9.6 g). ^!Η NMR: δ 3.29 (CH₃S(O)₂O-), 6.90 (t, J=56 Ηz, CHF₂), 7.75 (m, 3Η, aromatic H). IR: 1170, 1360 cm-¹ (-OSO₂-).

Step D - Preparation of 2-amino-3-(difluoromethyl)phenol methanesulfonate

Palladium on carbon catalyst (10%, 1.0 g) was added to a solution of 3-(difluoromethyl)-2-nitrophenol methanesulfonate (9.5 g, 38 mmol) in acetic acid (130 mL) under a nitrogen atmosphere. Over 5.5 hours the reaction mixture was shaken with hydrogen gas at a pressure of 47 to 36.5 psi (324 to 252 kPa). The reaction mixture was then filtered through Celite® diatomaceous filter aid under a blanket of nitrogen gas, and the diatomaceous filter aid was rinsed thoroughly with acetic acid. The acetic acid was removed from the filtrate by rotary evaporation, and the residue was taken up in ether (250 mL) to give a slurry. The slurry was treated with an aqueous 1:1 bicarbonate-carbonate buffer solution (100 mL). The aqueous layer was separated and found to have a pH > 8. The aqueous layer was then extracted twice with ether. The combined ether extracts were washed once with aqueous bicarbonate solution, once with brine, and then dried (K₂CO₃). The ether was removed by rotary evaporation to leave the title product as an oil. ^!H NMR (CDC1₃): δ 3.19 (CH₃S(O)₂O-), 4.45 (NH₂), 6.76 (t, J=56 Ηz, CHF₂), 6.75 (t, aromatic Η), 7.2 (d, aromatic Η), 7.3 (d, aromatic Η). IR: 3400, 3500 cm-¹ (NΗ₂). A little residual ether was evident in the NMR spectrum as the only impurity. The crude product was used directly in the next step. Step E - Preparation of 2-(difluoromethyl)-6-[(methylsulfonyl)oxy]benzenesulfonyl chloride

A stirred solution of 2-amino-3-(difluoromethyl)phenol methanesulfonate (8.1 g, 34 mmol) in propanoic acid (80 mL), hydrochloric acid (6 N, 30 mL) and water (30 mL) was cooled to 0 °C using an ice bath. A solution of sodium nitrite (2.72 g, 40 mmol) in water (20 mL) was then added to the stirred reaction mixture over about 20 minutes at such a rate as to keep the temperature of the reaction mixture below 5 °C. This diazotized reaction mixture was stirred for 10 minutes more at 0 °C.

Meanwhile in another reaction flask with a dry ice condenser, a stirred solution of copper(II) chloride (l.lg, 8 mmol) in propanoic acid (100 mL), acetic acid (25 mL) and concentrated hydrochloric acid (10 mL) was cooled to 0 °C. Condensed sulfur dioxide (17 mL, 400 mmol) was added via a vacuum-jacketed addition funnel. To this stirred Meerwein coupling reaction mixture was added dropwise the previously described diazotized reaction mixture via an addition funnel chilled using an ice-filled jacket. The diazotized reaction mixture was added at such a rate as to maintain temperature of the Meerwein coupling reaction mixture between 5 and 12 °C (close to 10 °C). The reaction mixture was stirred an additional hour at ~10 °C, and was then allowed to warm to room temperature and stirred for 2.5 hours more. The reaction mixture was then cooled using an ice/water bath and diluted with excess water, causing a suspension of solids to form. The mixture was stirred for 30 minutes, and then filtered and rinsed with water. The filtered peach-colored solid was dried in a desiccator to provide the title product melting at 100-123 °C. ¹H NMR: δ 3.44 (CH₃S(O)₂O-), 7.55 (t, J=56 Ηz, CHF₂), 7.90 (m, 3Η, aromatic H).

Step F - Preparation of 2-(difluoromethyl)-6-[(methylsulfonyl)oxy]benzenesulfonamide

A stirred solution of 2-(difluoromethyl)-6-[(methylsulfonyl)oxy]benzenesulfonyl chloride (3 g, 9.36 mmol) in tetrahydrofuran (40 mL) was cooled to < -30 °C in a flask with a dry ice condenser. Condensed ammonia (0.7 mL, 28.1 mmol) was added, resulting in a temperature increase. The reaction mixture was allowed to warm to 0 °C, and then sufficient 2% hydrochloric acid was added to lower the pH to below 2. The reaction mixture was extracted twice with ethyl acetate. The combined ethyl acetate extracts were washed with brine and dried (MgSO₄). Rotary evaporation left a residue that crystallized on standing. The solid was recrystallized from a mixture of dichloromethane and 1-chlorobutane, and collected using 1-chlorobutane for rinsing to provide the title product melting at 110-112 °C. The yield from a similar run at the same scale was 2.38 g.

1H NMR (CDC1₃): δ 3.38 (s, 3H, CH₃S(O)₂O-), 5.44 (br s, NH₂), 7.62 (t, J=56 Ηz, CHF₂), 7.75 (m, 2Η, aromatic H), 7.88 (m, 1H, aromatic H). IR: 3280 sh, 3320, 3450 cm^"1 (NH₂). Step G - Preparation of 2-(difluoromemyl)-N-[[(4,6-dimemoxy-2-pyrimidmyl)amino]- carbonyl]-6-[(methylsulfonyl)oxy]benzenesulfonamide

To a stirred solution of 2-(difluoromethyl)-6-[(methylsulfonyl)oxy]benzene- sulfonamide (0.62 g, 2.06 mmol) in dry acetonitrile (9 mL) was added phenyl (4,6- dimethoxy-2-pyrimidinyl)carbamate (0.69 g, 2.75 mmol) to give a cream-colored slurry. To this stirred slurry was added l,8-diazabicyclo[5.4.0]undec-7-ene (DBU, 0.37 mL, 2.75 mmol) to immediately give a dark golden solution. The reaction mixture was stirred 30 minutes at room temperature. Then water (60 mL) and hydrochloric acid (1 Ν, 3 mL) were sequentially added, causing gummy solids to precipitate. The mixture was stirred well for 30 minutes, while the gummy solids were scratched to promote crystallization. The white solid was then filtered off, rinsed well with water, and dried in a vacuum oven to provide the title product (0.88 g), a compound of the invention, melting at 199-201 °C with apparent decomposition. The ΝMR spectrum was similar to that of an earlier run: ^l ΝMR: δ 3.57 (s, CH₃S(O)₂O-), 3.90 (s, 6Η, OCH₃), 6.02 (s, pyrimidinyl Η), 7.83 (t, J=55 Ηz, CHF₂), 7.9-8 (m, 3Η, aromatic H), 10.8 (ΝH), 13.1 (ΝH).

By the procedures described herein together with methods known in the art, the following compounds of Table A can be prepared. In this table, "Ph" means phenyl.

Table A Structures of Illustrative Formula I Compounds

o

U XJ

4^

0 π 0 0 π 0 a 0 0 0 π 0 0 0 0 0 0 Q 0 a 1 J a a U aJ a UJ U aJ a a u a> a> U aJ U aJ U aJ U aJ a u a> U aJ

CH₂0-Ph

0-5-CH₃-Ph

Formulation/Utility

The compounds of Formula I are generally used in formulation with an agriculturally suitable carrier comprising a liquid or solid diluent and/or a surfactant wherein the formulation is consistent with the physical properties of the active ingredients, mode of application and environmental factors such as soil type, moisture and temperature. Useful formulations include liquids such as solutions (including emulsifiable concentrates), suspensions, emulsions (including microemulsions and/or suspoemulsions) and the like which optionally can be thickened into gels. Useful formulations further include solids such as dusts, powders, granules, pellets, tablets, films, and the like which can be water- dispersible ("wettable") or water-soluble. Active ingredients can be (micro)encapsulated and further formed into a suspension or solid formulation; alternatively the entire formulation of active ingredient can be encapsulated (or "overcoated"). Encapsulation can control or delay release of the active ingredients. Sprayable formulations can be extended in suitable media and used at spray volumes from about one to several hundred liters per hectare. High-strength compositions are primarily used as intermediates for further formulation.

The formulations will typically contain effective amounts of active ingredients, diluent and surfactant within the following approximate ranges which add up to 100 percent by weight.

Weight Percent

Active Ingredient Diluent Surfactant

Water-Dispersible and Water-soluble 5-90 0-94 1-15 Granules, Tablets and Powders.

Suspensions, Emulsions, Solutions 5-50 40-95 0-15 (including Emulsifiable Concentrates)

Dusts 1-25 70-99 0-5

Granules and Pellets 0.01-99 5-99.99 0-15

High Strength Compositions 90-99 0-10 0-2

Typical solid diluents are described in Watkins, et al., Handbook of Insecticide Dust Diluents and Carriers, 2nd Ed., Dorland Books, Caldwell, New Jersey. Typical liquid diluents are described in Marsden, Solvents Guide, 2nd Ed., Interscience, New York, 1950. McCutcheon 's Detergents and Emulsifiers Annual, Allured Publ. Corp., Ridgewood, New Jersey, as well as Sisely and Wood, Encyclopedia of Surface Active Agents, Chemical Publ. Co., Inc., New York, 1964, list surfactants and recommended uses. All formulations can contain minor amounts of additives to reduce foam, caking, corrosion, microbiological growth and the like, or thickeners to increase viscosity.

Surfactants include, for example, polyethoxylated alcohols, polyethoxylated alkylphenols, polyethoxylated sorbitan fatty acid esters, dialkyl sulfosuccinates, alkyl sulfates, alkylbenzene sulfonates, organosilicones, NN-dialkyltaurates, lignin sulfonates, naphthalene sulfonate formaldehyde condensates, polycarboxylates, and polyoxy- ethylene/polyoxypropylene block copolymers. Solid diluents include, for example, clays such as bentonite, montmorillinite, attapulgite and kaolin, starch, sugar, silica, talc, diatomaceous earth, urea, calcium carbonate, sodium carbonate and bicarbonate, and sodium sulfate. Liquid diluents include, for example, water, NN-dimethylformamide, dimethyl sulfoxide, N-alkylpyrrolidone, ethylene glycol, polypropylene glycol, paraffins, alkylbenzenes, alkylnaphthalenes, oils of olive, castor, linseed, tung, sesame, corn, peanut, cotton-seed, soybean, rape-seed and coconut, fatty acid esters, ketones such as cyclohexanone, 2-heptanone, isophorone and 4-hydroxy-4-methyl-2-pentanone, and alcohols such as methanol, cyclohexanol, decanol, benzyl and tefrahydrofurfuryl alcohol.

Solutions, including emulsifiable concentrates, can be prepared by simply mixing the ingredients. Chemically stabilized aqueous sulfonylurea or agriculturally suitable sulfonylurea salt dispersions are taught in U.S.4,936,900. Solution formulations of sulfonylureas with improved chemical stability are taught in U.S. 4,599,412. Dusts and powders can be prepared by blending and, usually, grinding as in a hammer mill or fluid- energy mill. Suspensions are usually prepared by wet-milling; see, for example, U.S. 3,060,084. Granules and pellets can be prepared by spraying the active material upon preformed granular carriers or by agglomeration techniques. See Browning, "Agglomeration", Chemical Engineering, December 4, 1967, pp 147-48, Perry's Chemical Engineer's Handbook, 4th Ed., McGraw-Hill, New York, 1963, pages 8-57 and following, and WO 91/13546. Pellets can be prepared as described in U.S. 4,172,714. Water-dispersible and water-soluble granules can be prepared as taught in U.S. 4,144,050, U.S. 3,920,442 and DE 3,246,493. Tablets can be prepared as taught in U.S. 5,180,587, U.S. 5,232,701 and U.S. 5,208,030. Films can be prepared as taught in GB 2,095,558 and U.S. 3,299,566.

For further information regarding the art of formulation, see T. S. Woods, "The Formulator's Toolbox - Product Forms for Modern Agriculture" in Pesticide Chemistry and Bioscience, The Food-Environment Challenge, T. Brooks and T. R. Roberts, Eds., Proceedings of the 9th International Congress on Pesticide Chemistry, The Royal Society of Chemistry, Cambridge, 1999, pp. 120-133. See also U.S. 3,235,361, Col. 6, line 16 through Col. 7, line 19 and Examples 1 1; U.S. 3,309,192, Col. 5, line 43 through Col. 7, line 62 and Examples 8, 12, 15, 39, 41, 52, 53, 58, 132, 138-140, 162-164, 166, 167 and 169-182; U.S. 2,891,855, Col. 3, line 66 through Col. 5, line 17 and Examples \-4; Klingman, Weed Control as a Science; Wiley: New York, 1961, pp. 81-96; and Hance et al., Weed Control Handbook, 8th Ed.; Blackwell Scientific Publications: Oxford, 1989.

Mixtures of the compounds of Formula I with other herbicides, including those inhibiting acetolactate synthase, as well as insecticides and fungicides, can be formulated in a number of ways:

(a) the Formula I compounds and other herbicides, insecticides and fungicides can be formulated separately and applied separately or applied simultaneously in an appropriate weight ratio, e.g., as a tank mix; or (b) the Formula I compounds and other herbicides, insecticides and fungicides can be formulated together in the proper weight ratio. In the following Examples, all percentages are by weight and all formulations are prepared in conventional ways.

Example A High Strength Concentrate

2-(difluoromethyl)-N- [ [(4,6-dimemoxy-2-pyrimidmyl)amino] - carbonyl]-6-[(methylsulfonyl)oxy]benzenesulfonamide 98.5% silica aerogel 0.5% synthetic amorphous fine silica 1.0%. Example B

Wettable Powder

2-(difluoromethyl)-N-[[(4,6-dimethoxy-2-pyrimidinyl)amino]- carbonyl] -6- [(methylsulfonyl)oxy]benzenesulfonamide 65.0% dodecylphenol polyethylene glycol ether 2.0% sodium ligninsulfonate 4.0% sodium silicoaluminate 6.0% montmorillonite (calcined) 23.0%.

Example C Granule 2-(difluoromethyl)-N-[[(4,6-dimethoxy-2-pyrimidinyl)amino]- carbonyl]-6-[(methylsulfonyl)oxy]benzenesulfonamide 10.0% attapulgite granules (low volatile matter,

0.71/0.30 mm; U.S.S. No. 25-50 sieves) 90.0%. Example D Aqueous Suspension

2-(difluoromethyl)-N- [ [(4,6-dimethoxy-2-pyrimidinyl)amino] - carbonyl] -6- [(methylsulfonyl)oxy]benzenesulfonamide 25.0% hydrated attapulgite 3.0% crude calcium ligninsulfonate 10.0% sodium dihydrogen phosphate 0.5% water 61.5%.

Example E Extruded Pellet

2-(difluoromethyl)-N-[[(4,6-dimethoxy-2-pyrimidinyl)amino]- carbonyl]-6-[(methylsulfonyl)oxy]benzenesulfonamide 25.0% anhydrous sodium sulfate 10.0% crude calcium ligninsulfonate 5.0% sodium alkylnaphthalenesulfonate 1.0% calcium/magnesium bentonite 59.0%.

Utility

The sulfonylurea compounds of Formula I have been discovered to have excellent herbicidal activity on many weeds that are commercially troublesome in agronomic crops. Furthermore, these compounds have been discovered to have considerable safety to certain agronomic crops, particularly rice and cool season cereals such as wheat and barley. Remarkably, these compounds have been found to control many very important weeds in rice crops with safety to the rice plants, and also agronomically important weeds in wheat and barley with safety to these crops. Even more remarkably and surprisingly, these compounds have been discovered to effectively control weed species biotypes that are resistant to sulfonylurea herbicides and other acetolactate synthase-inhibiting herbicides, including those now commercially employed in rice, wheat and barley cultivation, such as bensulfuron-methyl, pyrazosulfuron-ethyl, metsulfuron-methyl, thifensulfuron-methyl, triasulfuron, tribenuron-methyl and chlorsulfuron. As the mode of resistance of many of these biotypes is believed to be mutation of the acetolactate synthase enzyme (ALS; EC 4.1.3.18) to reduce inhibition by acetolactate synthase-inhibiting herbicides, the effectiveness of the particular sulfonylurea compounds of this invention is very remarkable and surprising.

In rice cultivation, sulfonylurea herbicides are primarily used to control broadleaf weeds and sedges, although they can also have useful effect against some grass weeds, such as barnyardgrass. They are particularly valued for sedge control, because few other rice-safe herbicides are effective against sedges such as Cyperus and Scirpus species. As the particular sulfonylurea compounds of the present invention are effective for controlling sedges, including biotypes that have shown resistance to existing sulfonylurea herbicides, they hold considerable value for maintaining commercially acceptable control of sedges as well as other weeds in rice cultivation. The control of Scirpus species by the compounds of the invention is especially valuable. Furthermore, although herbicides with other modes of action can now be used to control biotypes of some weeds that have shown resistance to sulfonylurea herbicides, biotypes may evolve with resistance to these other herbicides as well. Therefore the broad efficacy of the particular sulfonylurea compounds of the present invention against a wide range of weeds, including biotypes both susceptible or resistant to acetolactate synthase-inhibiting herbicides in general, makes these compounds especially valuable for cultivation of agronomic crops, particularly rice.

In wheat and barley cultivation, the sulfonylurea herbicides of the invention are primarily useful for controlling broadleaf weeds, although they also have significant effect against certain grass weeds as well.

The rice, wheat and barley tolerance of the compounds of Formula I is believed to result from metabolism, and thus these compounds can be used for selective weed control with rice, wheat and barley varieties either containing or not containing forms of acetolactate synthase resistant to inhibition by acetolactate synthase-inhibiting herbicides. Many of the compounds of Formula I exhibit good safety to even sensitive japonica varieties of rice, and indica varieties typically demonstrate even better tolerance. The compounds of Formula I can advantageously be used alone or in combination with other acetolactate synthase-inhibiting herbicides to control resistant biotypes of weeds. Alternatively, the compounds of Formula I can be used as part of a management program to suppress the development of weed biotypes resistant to acetolactate synthase-inhibiting herbicides. The compounds of Formula I can be applied postemergence or preemergence to the crop or weeds. As the compounds of the invention have both preemergent and postemergent herbicidal activity, to control undesired vegetation by killing or injuring the vegetation or reducing its growth, the compounds can be usefully applied by a variety of methods involving contacting a herbicidally effective amount of a compound of the invention, or a composition comprising said compound and at least one of a surfactant, a solid diluent or a liquid diluent, to the foliage or other part of the undesired vegetation or to the environment of the undesired vegetation such as the soil or water in which the undesired vegetation is growing or which surrounds the seed or other propagule of the undesired vegetation (i.e. locus of the undesired vegetation). A herbicidally effective amount of the compounds of this invention is determined by a number of factors. These factors include: formulation selected, method of application, amount and type of vegetation present, growing conditions, etc. In general, a herbicidally effective amount of the subject compounds is applied at rates from 0.001 to 20 kg/ha with a preferred rate range of about 5 to 200 g/ha. The specifically preferred compound of Formula I wherein R¹ is methyl and R² is CHF₂ (2-(difluoromethyl)-N-[[(4,6-dimethoxy- 2-pyrimidinyl)amino]carbonyl]-6-[(methylsulfonyl)oxy]benzenesulfonamide) is generally applied at an application rate in the range of about 10 to 250 g/ha, with 20 to 80 g/ha preferred for most uses in rice crops, and 16 to 250 g/ha preferred for most uses in wheat and barley crops. The lower rates in these ranges are particularly useful in combinations with other herbicides, while the higher rates in these ranges may be needed to give complete weed control of some resistant biotypes. One skilled in the art can easily determine application rates necessary for the desired level of weed control. The compounds of Formula I can additionally be used in combination with other commercial herbicides, insecticides or fungicides. For resistance management of acetolactate synthase-inhibiting herbicides used in rice crops, the compounds of Formula I are useful with such commercial herbicides as azimsulfuron, bensulfuron-methyl, bispyribac-sodium, chlorimuron-ethyl, cinosulfuron, cyclosulfamuron, ethoxysulfuron, imazosulfuron, halosulfuron-methyl, metsulfuron-methyl, nicosulfiiron, pyrazosulfuron-ethyl and pyriminobac. For resistance management of acetolactate synthase-inhibiting herbicides used in wheat and barley crops, the compounds of Formula I are useful with such commercial herbicides as amidosulfuron, chlorsulfuron, florasulam, flucarbazone and its salts such as sodium, flupyrsulfuron-methyl and its salts such as sodium, imazamethabenz-methyl, iodosulfuron-methyl, mesosulfuron, metosulam, metsulfuron- methyl, penoxsulam, propoxycarbazone, prosulfuron, sulfosulfuron, thifensulfuron-methyl, triasulfuron, tribenuron-methyl and tritosulfuron.

Also, the following herbicides which are safe to rice and do not inhibit acetolactate synthase are particularly useful as mixture partners for the Formula I compounds: anilofos, benfuresate, butachlor, cafensfrole, fenfrazamid, carfenfrazone-ethyl, cyhalofop-butyl, daimuron, dimepiperate, etobenzanid, indanofan, mefenacet, molinate, oxaziclomefone, pentoxazone, pretilachlor, propanil, pyributicarb, quinclorac, thenylchlor and thiobencarb. Besides broadening weed control spectrum, some of these herbicides, for example daimuron and thiobencarb, can safen the Formula I compounds on rice. The following herbicides which are safe to wheat and barley and do not inhibit acetolactate synthase are particularly useful as mixture partners for the Formula I compounds: bentazone, bifenox, bromoxynil and its esters such as octanoate, carfentrazone- ethyl, cinidon-ethyl, chlortoluron, clopyralid, clodinafop and its esters such as propargyl, 2,4-D and its esters such as butotyl, butyl, isoctyl and isopropyl and its salts such as sodium, potassium, dimethylammonium, diolamine and trolamine, diallate, dicamba and its salts such as dimethylammonium, potassium and sodium, diclofop and its esters such as methyl, difenzoquat salts such as metilsulfate, diflufenican, fenoxaprop and fenoxaprop-P and their esters such as ethyl, flamprop and flamprop-M and their esters such as methyl and isopropyl, fluroxypyr, fluroglycophen and its esters such as ethyl, flurtamone, ixoxaben, ioxynil and its esters such as octanoate and its salts such as sodium, isoproturon, linuron, MCPA and its salts such as dimethylammonium, potassium and sodium and its esters such as isoctyl, mecoprop and mecoprop-P and their salts such as potassium, isobutyl and dimethylammonium, methabenzthiazuron, neburon, pendimethalin, picolinafen, prosulfocarb, terbutryn, tralkoxydim, tri-allate and trifluralin.

The following herbicides are also useful as mixture partners for the Formula I compounds: acetochlor, acifluorfen and its salts such as sodium, acrolein (2-propenal), alachlor, ametryn, amitrole, ammonium sulfamate, asulam, atrazine, benazolin and its esters such as ethyl, benfluralin, bensulide, bromacil and its salts such as lithium, butralin, butylate, carbetamide, chlomethoxyfen, chloramben, chlorbromuron, chloridazon, chlornitrofen, 2-[4- chloro-5-(cyclopentyloxy)-2-fluorophenyl]-4,5,6,7-tetrahydro- lH-indene- 1 ,3(2H)-dione, 3-[4-chloro-2-fluoro-5-(l-methyl-2-propynyloxy)phenyl]-5-(l-methylethylidene]- 2,4-oxaxolidinedione, chlorpropham, chlorthal-dimethyl, cinmethylin, clethodim, clomazone, clopyralid, clopyralid-olamine, cloransulam-methyl, cyanazine, cycloate, cycloxydim, dalapon and its salts such as sodium, dazomet, 2,4-DB and its salts such as dimethylammonium, potassium and sodium, desmedipham, desmetryn, dichlobenil, 3-[2,4- dichloro-5-(2-propynyloxy)phenyl]-5-( 1 , 1 -dimethylethyl)- 1 ,3 ,4-oxadiazol-2(3H)-one, dichlo rop, diclosulam, dimefuron, 6-[[6,7-dihydro-6,6-dimethyl-3H,5H-pyrrolo[2,l-c]- [l,2,4]thiadiazol-3-ylidine]amino]-7-fluoro-4-(2-propynyl)-2H-l,4-benzoxazin-3(4H)-one, dimethylarsinic acid and its salts such as sodium, dinitramine, diphenamid, diquat salts such as dibromide, dithiopyr, diuron, DNOC, endothal, EPTC, esprocarb, ethalfluralin, ethametsulfuron-methyl, ethofumesate, ethyl [2-chloro-5-[4-chloro-5-(difluoromethoxy)-l- methyl- lH-pyrazol-3-yl]-4-fluorophenoxy]acetate, ethyl α,2-dichloro-5-[4-(difluoromethyl)- 4,5-dihydro-3-methyl-5-oxo- 1H- 1 ,2,4-triazol- 1 -yl]-4-fluorobenzenepropanoate, fenuron, fenuron-TCA, flazasulfuron, fluazifop and fluazifop-P and their esters such as butyl, fluchloralin, flumetsulam, flumiclorac and its esters such as pentyl, flumioxazin, fluometuron, fluoroglycofen-ethyl, flupoxam, fluridone, flurochloridone, fluthiacet-methyl, fomesafen, fosamine-ammonium, glufosinate and its salts such as ammonium, glyphosate and its salts such as isopropylammonium, sesquisodium and trimesium, haloxyfop and its esters such as methyl and etotyl, hexazinone, imazapyr, imazaquin, imazethapyr, isouron, lactofen, lenacil, maleic hydrazide, mefluidide, metam and its salts such as sodium, metazachlor, methylarsonic acid and its salts such as calcium, monoammonium, monosodium and disodium, methyl [[[l-[5-[2-chloro-4-(trifluoromethyl)phenoxy]-2- nitrophenyl]-2-methoxyethylidene]amino]oxy]acetate (AKΗ-7088), methyl 5-[[[[(4,6- dimethyl-2-pyrimidinyl)amino] carbonyl] amino] sulfonyl] - 1 -(2-pyridinyl)- lH-pyrazole-4- carboxylate, N-(4-fluorophenyl)-N-(l-memylethyl)-2-[[5-(trifluoromethyl)-l,3,4-thiadiazol- 2-yl]oxy]acetamide, metobenzuron, metolachlor, metosulam, metoxuron, metribuzin, monolinuron, napropamide, naptalam, norflurazon, oryzalin, oxadiargyl, oxadiazon, oxasulfuron, oxyfluorfen, paraquat dichloride, pebulate, perfluidone, phenmedipham, picloram and its salts such as potassium, primisulfuron-methyl, prometon, prometryn, propachlor, propaquizafop, propazine, propham, propyzamide, pyrazolynate, pyridate, pyrithiobac and its salts such as sodium, quinmerac, quizalofop and quizalofop-P and their esters such as ethyl and tefuryl, rimsulfuron, sethoxydim, siduron, simazine, sulfentrazone, sulfometuron-methyl, TCA and its salts such as sodium, tebutam, tebuthiuron, terbacil, terbuthylazine, tribenuron-methyl, triclopyr and its esters such as butotyl and its salts such as triethylammonium, tridiphane, trifloxysulfuron, triflusulfuron-methyl and vernolate.

A composition of the invention comprising the above herbicide mixture partners may contain any number of said mixture partners. Mixture partners that have acidic or basic centers may be in the form of salts. Also, mixture partners that are in the form of esters or salts may be in the form of a single ester or salt or a mixture of more than one ester or salt.

In the following tests the test compounds are as identified in Index Table A.

Index Table A Formula I Compounds

Compound El B2 Melting Point ( ⁰O

1 CH₃ CHF₂ 199-201 (d)

2 CH₂CH₃ CHF₂ 133-138

3 (CH₂)₂CH₃ CHF₂ 148-150

4 cyclopropyl CHF₂ 168-180

5 N(CH₃)₂ CHF₂ 168-174

6 CH₃ 2,2-di-F-cyclopropyl 178-184 (d)

7 CF₃ CH₃ 145-147

8 CH₃ C0₂CH₃ 114-116

9 CH₃ CH₃ 130-136

10 CH₃ CH(CH₃)₂ 175-177 (d)

11 CH₂CH₃ 2,2-di-F-cycloproρyl 98-108

12 CH₃ CH₂CHF₂ 176-179

13 CH₃ C0₂CH₂CH₃ 166-170

14 CF₃ CHF₂ 155-160

15 CH(CH₃)₂ CHF₂ 132-135 Test 1 Protocol

The compounds evaluated in this test were formulated in a non-phytotoxic solvent mixture which included a surfactant and were applied to the soil surface before plant seedlings emerged (preemergence application), and to plants that were in the one-to-four leaf stage (postemergence application). A sandy loam soil was used for the preemergence and postemergence tests.

Plant species in the preemergence and postemergence tests consisted of winter barley (Hordeum vulgare), barnyardgrass (Echinochloa crus-galli), blackgrass (Alopecurus myosuroides), d ckweed (Stellaria media), cocklebur (Xanthium strumarium), corn (Zea mays), cotton (Gossypium hirsutum), crabgrass (Digitaria sanguinalis), downy brome (Bromus tectorum), giant foxtail (Setaria faberii), johnsongrass (Sorghum halpense), lambsquarters (Chenopodium album), morningglory (Ipomoea hederacea), rice (Oryza sativa), rape (Brassica napus), soybean (Glycine max), sugar beet (Beta vulgaris), velvetleaf (Abutilon theophrasti), spring wheat (Triticum aestivum), wild buckwheat (Polygonum convolvulus), and wild oats (Avena fatua). All plant species were planted one day before application of the compound for the preemergence portion of this test. Plantings of these species were adjusted to produce plants of appropriate size for the postemergence portion of the test. All plant species were grown using normal greenhouse practices. Visual evaluations of injury expressed on treated plants, when compared to untreated controls, were recorded approximately fourteen to twenty one days after application of the test compound. Plant response to the test compound is summarized in Table 1, recorded on a 0 to 100 scale where 0 is no effect and 100 is complete control. A dash (-) response means no test result.

TABLE 1 Compound TABLE 1 Compound

Rate 250 g/ha 8 Rate 250 g/ha 8 9

Postemergence Preemergence

Barley, winter 100 Barley, winter 60 70

Barnyardgrass 100 Barnyardgrass 100 100

Blackgrass 100 Blackgrass 90 80

Buckwheat, Wild 100 Buckwheat, Wild 90 90

Chickweed 100 Chickweed 95 100

Corn 100 Corn 80 100

Cotton 100 Cotton 90 100

Cocklebur 100 Cocklebur 90 100

Crabgrass 100 Crabgrass 100 100

Downy brome 100 Downy brome 90 40

Foxtail, giant 100 Foxtail, giant 80 100

Johnsongrass 100 Johnsongrass 90 100 Lambsquarter 100 Lambsquarter 100 100

Morningglory 100 Morningglory 80 100

Rape 100 Rape 95 100

Rice 100 Rice 90 80

Soybean 100 Soybean 90 100

Sugarbeets 100 Sugarbeets 90 100

Velvetleaf 100 Velvetleaf 90 100

Wheat, Spring 90 Wheat Spring 60 0

Wild oats 100 Wild oats 30 50

TABLE 1 Compound

Rate 62 g ha 1 6 8 9 10 11 12 13

Postemergence

Barley, winter 0 40 90 0 70 55 20 40

Barnyardgrass 100 100 100 100 100 90 100 100

Blackgrass 50 70 100 90 80 70 60 100

Buckwheat, Wild 100 90 100 90 90 90 100 100

Chickweed 100 80 100 100 90 40 60 100

Corn 90 100 100 100 100 100 90 100

Cotton 100 100 100 100 100 100 80 100

Cocklebur 100 100 100 100 100 100 100 100

Crabgrass 0 80 100 90 90 0 60 60

Downy brome 0 50 90 30 90 70 60 50

Foxtail, giant 50 70 100 100 80 40 45 70

Johnsongrass 30 100 100 100 70 40 60 100

Lambsquarter 100 - 100 100 - - - 100

Morningglory 100 100 100 100 100 100 100 100

Rape 100 100 100 100 100 100 100 100

Rice 0 70 100 70 50 70 50 100

Soybean 100 100 90 100 90 100 100 100

Sugarbeets 100 100 100 40 100 100 100 100

Velvetleaf 100 100 100 100 100 100 100 100

Wheat, Spring 20 40 90 40 30 10 0 80

Wild oats 0 40 90 20 60 0 0 90

TABLE 1 Compound

Rate 62 g/ha 1 6 8 9 10 11 12 13

Preemergence

Barley, winter 20 0 60 50 40 70 50 0 Barnyardgrass 40 100 100 100 80 50 95 90

Blackgrass 70 100 90 50 60 50 70 90

Buckwheat, Wild 80 80 80 90 70 80 70 90

Chickweed 80 100 90 90 90 70 60 100

Corn 30 35 70 80 0 50 80 60

Cotton 40 50 90 70 30 30 20 70

Cocklebur 70 100 90 90 - 60 90 100

Crabgrass 70 100 100 90 90 70 80 100

Downy brome 0 80 80 40 70 50 70 60

Foxtail, giant 70 20 70 100 40 40 40 80

Johnsongrass 30 90 90 100 70 50 30 90

Lambsquarter 100 - 100 100 100 - - 100

Morningglory 90 100 80 100 80 40 80

Rape 100 100 90 100 100 100 100 100

Rice 40 100 80 60 70 90 70 90

Soybean 40 60 80 90 20 20 70 80

Sugarbeets 90 100 90 100 100 80 100 100

Velvetleaf 90 100 90 100 70 100 100 100

Wheat, Spring 0 20 30 0 0 40 30 0

Wild oats 0 0 30 20 0 40 50 0

TABLE 1 Compound

Rate 16 g ha 1 6 8 9 10 11 12 13 Postemergence

Barley, winter 0 20 80 0 60 50 20 0

Barnyardgrass 100 100 100 100 90 70 90 100

Blackgrass 0 60 100 90 80 60 40 100

Buckwheat, Wild 100 80 90 90 80 70 95 100

Chickweed 90 70 90 100 80 30 50 90

Corn 70 70 100 100 90 90 80 100

Cotton 100 90 90 100 90 100 40 100

Cocklebur 100 100 90 100 100 100 100 100

Crabgrass 0 60 40 70 80 0 50 50

Downy brome 0 40 80 20 90 40 50 40

Foxtail, giant 30 60 100 100 60 40 30 50

Johnsongrass 30 90 100 60 60 - 50 55

Lambsquarter 100 - 30 70 - - - 100

Morningglory 100 100 100 100 100 100 100 100 Rape 100100100100100100100 100

Rice 0 50 90 50 40 60 50 90

Soybean 100100 90100 80 - 100 100

Sugarbeets 100100100100100100 100 100

Velvetleaf 100100100100100 70 100 100

Wheat, Spring 0 30 80 0 30 0 0 70

Wild oats 0 30 80 10 30 0 0 40

TABLE 1 Compound Rate 16 g/ha 1 6 8 9 10 11 12 13 Preemergence Barley, winter 0 0 20 20 0 40 30 0 Barnyardgrass 30 70 70100 30 20 20 50 Blackgrass 30 40 50 50 30 40 40 60 Buckwheat, Wild 70 80 70 80 0 40 70 0 Chickweed 60100 90 80 80 50 60 95 Corn 0 30 20 10 0 20 20 0 Cotton 30 30 80 60 0 20 20 40 Cocklebur 70100 90 90 - 40 70 70 Crabgrass 70 95100 75 30 50 80 70 Downy brome 0 40 70 30 30 40 50 0 Foxtail, giant 30 0 50 70 20 20 30 40 Johnsongrass 30 30 90 90 30 20 30 70 Lambsquarter 90 - 90100 90 100 Morningglory 70 40 80 20 80 20 60 Rape 100100 80100 70 80 100 80 Rice 30 50 60 40 30 40 50 0 Soybean 20 30 60 40 20 0 40 30 Sugarbeets 70100 90100 90 80 90 80 Velvetleaf 70100 80 95 60 30 40 90 Wheat, Spring 0 0 0 0 0 20 20 0 Wild oats 0 0 0 20 0 20 40 0

TABLE 1 Compound Rate 4 g/ha 1 6 8 9 10 11 12 13 Postemergence Barley, winter 0 0 50 0 60 0 0 0 Barnyardgrass 60 70 90 60 80 10 60 90 Blackgrass 0 50 80 50 40 20 20 80 Buckwheat, Wild 80 60 80 85 70 50 80 90

Chickweed 60 30 90 100 50 0 40 60

Corn 50 60 40 90 80 10 40 100

Cotton 90 60 40 90 70 40 0 100

Cocklebur 100 100 30 100 90 100 100 70

Crabgrass 0 40 0 40 60 0 45 40

Downy brome 0 30 70 0 60 0 0 30

Foxtail, giant 0 50 40 100 20 20 0 20

Johnsongrass 0 60 80 50 60 - 30 55

Lambsquarter 80 - 0 60 - - - 80

Morningglory 90 100 30 100 100 100 100 100

Rape 100 90 100 100 100 100 100 100

Rice 0 30 90 40 30 55 20 70

Soybean 85 100 90 100 80 100 100 100

Sugarbeets 100 100 100 100 100 100 90 100

Velvetleaf 100 100 80 90 100 70 100 100

Wheat, Spring 0 0 50 0 0 0 0 50

Wild oats 0 0 30 0 30 0 0 20

TABLE 1 Compound

Rate 4 g/ha 1 6 8 9 10 11 12 13

Preemergence

Barley, winter 0 - 0 0 0 20 20 0

Barnyardgrass 0 30 30 60 0 0 0 30

Blackgrass 0 30 30 30 0 0 20 30

Buckwheat, Wild 50 - 60 70 0 0 70 0

Chickweed 50 90 80 70 80 30 40 90

Corn 0 0 0 0 0 0 30 0

Cotton 0 0 0 30 0 0 0 0

Cocklebur 70 100 - - 0 0 60 50

Crabgrass 60 40 60 70 0 0 30 70

Downy brome 0 30 0 0 0 0 40 0

Foxtail, giant 0 0 0 30 0 0 0 0

Johnsongrass 0 0 60 60 0 0 0 40

Lambsquarter 70 - 80 60 60 0 - 100

Morningglory 60 0 40 0 50 0 0 -

Rape 80 90 60 70 50 50 80 0

Rice 0 0 0 10 0 20 20 0 Soybean 0 0 30 30 0 0 20 20

Sugarbeets 70 60 70 100 70 0 70 40

Velvetleaf 70 80 0 70 0 0 20 50

Wheat, Spring 0 0 0 0 0 0 10 0

Wild oats 0 0 0 0 0 0 30 0

TABLE 1 Compound

Rate 1 g/ha 1 6 9 10 11 12 13

Postemergence

Barley, winter 0 0 0 20 0 0 0

Barnyardgrass 50 40 50 70 0 30 80

Blackgrass 0 0 40 0 0 0 50

Buckwheat, Wild 60 50 60 50 0 50 40

Chickweed 30 0 50 30 0 0 30

Corn 0 0 50 70 0 30 0

Cotton 40 40 70 60 - 0 60

Cocklebur 80 100 70 50 50 60 70

Crabgrass 0 30 30 30 0 40 30

Downy brome 0 30 0 30 0 0 0

Foxtail, giant 0 40 50 0 0 0 0

Johnsongrass 0 40 50 50 0 0 50

Lambsquarter 70 - 60 - - - 50

Morningglory 30 80 50 100 70 80 100

Rape 100 80 100 80 100 100 80

Rice 0 0 30 0 0 0 0

Soybean 80 100 100 80 100 60 100

Sugarbeets 100 70 100 95 40 - 100

Velvetleaf 80 80 80 80 40 50 60

Wheat, Spring 0 0 0 0 0 0 30

Wild oats 0 0 0 0 0 0 0

TABLE 1 Compound I

Rate 1 g ha 1 6 10 11 12 13

Preemergence

Barley, winter 0 0 0 0 20 0

Barnyardgrass 0 0 0 0 0 0

Blackgrass 0 0 0 0 0 0

Buckwheat, Wild 30 0 0 0 50 0

Chickweed 30 70 50 30 40 60 Com 0 0 0 0 0 0

Cotton 0 0 0 0 0 0

Cocklebur 30 0 - - 30 30

Crabgrass 50 20 0 0 20 50

Downy brome 0 20 0 0 20 0

Foxtail, giant 0 0 0 0 0 0

Johnsongrass 0 0 0 0 0 0

Lambsquarter 0 - 30 - - 100

Morningglory 0 0 50 0 0 -

Rape 70 50 30 50 60 0

Rice 0 0 0 0 0 0

Soybean 0 0 0 0 0 0

Sugarbeets 60 50 40 0 50 30

Velvedeaf 50 - 0 0 0 0

Wheat, Spring 0 0 0 0 0 0

Wild oats 0 0 0 0 30 0

Test 2 Protocol

The compound evaluated in this test was formulated in a non-phytotoxic solvent mixture which included an organic solvent, a surfactant and water. This mixture, at appropriate concentrations was applied to water standing on the soil surface of a pot containing the test species. Plant species in this flood test consisted of rice (Oryza sativa), smallflower flatsedge (Cyperus difformis), ducksalad (Heteranthera limosa) and barnyardgrass (Echinochloa crus-galli) grown to the 2-leaf stage for testing. Treated plants and controls were maintained in a greenhouse for twelve to sixteen days, after which all species were compared to controls and visually evaluated. Plant response ratings, summarized in Table 2, are based on a scale of 0 to 10 where 0 is no effect and 10 is complete control.

TABLE 2 Co mpound TABLE 2 Compound

Rate 500 g/ha 1 Rate 250 g/ha 1

Flooded Paddy Test Flooded Paddy Test

Rice 20 Rice 5

Barnyardgrass 100 Barnyardgrass 100

Smallflower Flatsedge 100 Smallflower Flatsedge 95

Ducksalad 100 Ducksalad 95 TABLE 2 Compound TABLE 2 Compound

Rate 125 g/ha 1 Rate 62 g/ha 1

Flooded Paddy Test Flooded Paddy Test

Rice 5 Rice 5

Barnyardgrass 100 Barnyardgrass 100

Smallflower Flatsedge 90 Smallflower Flatsedge 90

Ducksalad 95 Ducksalad 95

TABLE 2 Compound

Rate 31 g/ha 1

Flooded Paddy Test

Rice 0

Barnyardgrass 90

Smallflower Flatsedge 80

Ducksalad 80

Test 3 Protocol

Compounds evaluated in this test were formulated in a non-phytotoxic solvent mixture which included a surfactant and applied to plants that were in the 1- to 4-leaf stage

(postemergence application). A mixture of sandy loam soil and greenhouse potting mix in a 60:40 ratio was used for the postemergence test. A preemergence planting was prepared immediately before chemical application using a sandy loam soil.

Plantings of these crops and weed species were adjusted to produce plants of appropriate size for the postemergence test. All plant species were grown using normal greenhouse practices. Crop and weed species include annual bluegrass (Poa annua), blackgrass (Alopecurus myosuroides), black nightshade (Solanum nigra), cheatgrass (Bromus secalinus), chickweed (Stellaria media), downy brome (Bromus tectorum), field pennycress (Thlaspi arvense), field violet (Viola arvensis), bedstraw (Galium aparine), green foxtail (Setaria viridis), Italian ryegrass (Lolium multiflorum), jointed goatgrass (Aegilops cylindrica), kochia (Kochia scoparia), lambsquarters (Chenopodium album), rapeseed (Brassica napus), Russian thistle (Salsola kali), scentless chamomile (Matricaria inodora), spring barley (Hordeum vulgare), sugar beet (Beta vulgaris), birdseye speedwell (Veronica persica), ivyleaf speedwell (Veronica hederaefolia), spring wheat (Triticum aestivum), winter wheat (Triticum aestivum), wild buckwheat (Polygonum convolvulus), wild oat (Avena fatua), and winter barley (Hordeum vulgare). Treated plants and untreated controls were maintained in a greenhouse for approximately 21 to 28 days, after which all treated plants were compared to untreated controls and visually evaluated. Plant response ratings, summarized in Table 3, are based upon a 0 to 100 scale where 0 is no effect and 100 is complete control. A dash re spons means no test result.

TABLE 3 Compound TABLE 3 Compound

Rate 125 g/ha 6 9 13 Rate 125 g/ha 6 9 13

Postemergence Preemergence

Wheat, Spring 60 10 80 Wheat, Spring 10 0 60

Wheat, Winter 30 10 70 Wheat, Winter 20 10 50

Barley, Spring 70 10 70 Barley, Spring 30 10 10

Barley, Winter 90 10 90 Barley, Winter 60 20 80

Sugarbeet 100 100 100 Sugarbeet 100 100 100

Rapeseed 100 100 100 Rapeseed 100 100 100

Wild oat 40 10 60 Wild oat 20 10 30

Downy brome 70 40 60 Downy brome 50 10 20

Cheatgrass 90 60 100 Cheatgrass 90 70 90

Blackgrass 100 90 100 Blackgrass 90 70 90

Bluegrass, annual 100 20 100 Bluegrass, annual 70 30 90

Foxtail, green 20 70 100 Foxtail, green 70 70 70

Ryegrass, Italian 60 30 80 Ryegrass, Italian 20 30 30

Goatgrass, jointed 80 0 90 Goatgrass, jointed 20 10 40

Chamomile, scentless 100 100 100 Chamomile, scentless 100 100 100

Bedstraw 100 100 100 Bedstraw 100 90 100

Russian thistle 100 100 100 Russian thistle 60 40 90

Lambsquarter 70 70 30 Lambsquarter 100 90 90

Kochia 60 90 70 Kochia 60 90 90

Nightshade, Black 100 80 90 Nightshade, Black 80 70 90

Speedwell, birdseye 100 30 0 Speedwell, birdseye 100 70 90

Speedwell, ivyleaf 100 80 100 Speedwell, ivyleaf 100 80 90

Buckwheat, wild 100 100 90 Buckwheat, wild 80 60 100

Violet, field 100 70 90 Violet, field 100 100 100

Pennycress 100 100 100 Pennycress 100 100 90

TABLE 3 Compound TABLE 3 Compound

Rate 64 g/ha 6 9 13 Rate 64 g ha 6 9 13

Postemergence Preemergence

Wheat, Spring 0 0 80 Wheat, Spring 10 0 20

Wheat, Winter 0 0 60 Wheat, Winter 10 0 20

Barley, Spring 30 10 70 Barley, Spring 20 10 0

Barley, Winter 70 20 80

Barley, Winter 60 10 60 Sugarbeet 100 100 100 Sugarbeet 100 100 100

Rapeseed 100 100 100 Rapeseed 100 100 100

Wild oat 10 0 40 Wild oat 10 0 10

Downy brome 30 10 30 Downy brome 40 10 0

Cheatgrass 90 60 90 Cheatgrass 80 50 80

Blackgrass 90 80 100 Blackgrass 90 70 60

Bluegrass, annual 80 20 100 Bluegrass, annual 60 30 80

Foxtail, green 70 70 80 Foxtail, green 60 70 70

Ryegrass, Italian 20 10 70 Ryegrass, Italian 10 30 10

Goatgrass, jointed 20 0 90 Goatgrass, jointed 10 10 10

Chamomile, scentless 100 100 100 Chamomile, scentless 90 100 90

Bedstraw 80 100 100 Bedstraw 80 90 100

Russian thistle 50 100 100 Russian thistle 40 - 80

Lambsquarter 90 50 10 Lambsquarter 100 90 80

Kochia 50 90 50 Kochia 30 80 90

Nightshade, Black 90 50 80 Nightshade, Black 70 50 90

Speedwell, birdseye 80 10 0 Speedwell, birdseye 80 70 90

Speedwell, ivyleaf 80 70 90 Speedwell, ivyleaf 100 80 90

Buckwheat, wild 90 90 90 Buckwheat, wild 70 60 100

Violet, field 100 50 70 Violet, field 100 100 100

Pennycress 90 100 100 Pennycress 100 90 90

TABLE 3 Compound TABLE 3 Compound

Rate 32 g ha 6 9 13 Rate 32 g/ha 6 9 13

Postemergence Preemergence

Wheat, Spring 0 0 70 Wheat, Spring 0 0 0

Wheat, Winter 0 0 60 Wheat, Winter 0 0 10

Barley, Spring 20 0 60 Barley, Spring 10 10 0

Barley, Winter 60 0 80 Barley, Winter 50 0 40

Sugarbeet 100 100 100 Sugarbeet 100 90 100

Rapeseed 100 100 100 Rapeseed 100 100 100

Wild oat 10 0 40 Wild oat 10 0 0

Downy brome 20 0 20 Downy brome 20 0 0

Cheatgrass 80 20 90 Cheatgrass 80 20 70

Blackgrass 90 50 90 Blackgrass 70 50 30

Bluegrass, annual 60 0 90 Bluegrass, annual 30 10 70

Foxtail, green 50 50 80 Foxtail, green 10 60 30

Ryegrass, Italian 20 0 40

Ryegrass, Italian 0 10 0 Goatgrass, jointed 10 0 90 Goatgrass, jointed 0 0 0

Chamomile, scentless 100 90 100 Chamomile, scentless 90 100 90

Bedstraw 30 100 80 Bedstraw 80 70 70

Russian thistle 20 100 100 Russian thistle 10 10 80

Lambsquarter 80 50 0 Lambsquarter 90 80 80

Kochia 50 90 50 Kochia 10 80 70

Nightshade, Black 70 50 80 Nightshade, Black 50 50 90

Speedwell, birdseye 60 0 0 Speedwell, birdseye 80 50 80

Speedwell, ivyleaf 80 40 90 Speedwell, ivyleaf 100 80 80

Buckwheat, wild 60 80 80 Buckwheat, wild 50 60 70

Violet, field 90 50 70 Violet, field 100 90 90

Pennycress 80 100 80 Pennycress 100 90 80

TABLE 3 Compound TABLE 3 Compound

Rate 16 g/ha 6 9 13 Rate 16 g/ha 6 9 13

Postemergence Preemergence

Wheat, Spring 40 0 70 Wheat, Spring 0 0 0

Wheat, Winter 20 0 40 Wheat, Winter 0 0 0

Barley, Spring 40 0 60 Barley, Spring 10 0 0

Barley, Winter 40 0 60 Barley, Winter 20 0 20

Sugarbeet 100 100 100 Sugarbeet 100 80 100

Rapeseed 100 100 100 Rapeseed 100 70 90

Wild oat 0 0 30 Wild oat 0 0 0

Downy brome 20 0 10 Downy brome 0 0 0

Cheatgrass 80 10 80 Cheatgrass 70 0 40

Blackgrass 60 50 90 Blackgrass 40 10 10

Bluegrass, annual 40 0 70 Bluegrass, annual 10 0 50

Foxtail, green 0 50 70 Foxtail, green 0 30 10

Ryegrass, Italian 10 0 30 Ryegrass, Italian 0 10 0

Goatgrass, jointed 40 0 80 Goatgrass, jointed 0 0 0

Chamomile, scentless 90 90 100 Chamomile, scentless 70 90 80

Bedstraw 100 100 80 Bedstraw 70 20 10

Russian thistle 100 100 80 Russian thistle 0 0 50

Lambsquarter 40 10 0 Lambsquarter 70 80 70

Kochia 20 80 40 Kochia 0 60 40

Nightshade, Black 70 50 80 Nightshade, Black 50 40 80

Speedwell, birdseye 70 0 0 Speedwell, birdseye 50 50 70

Speedwell, ivyleaf 100 40 40

Speedwell, ivyleaf 90 40 60 Buckwheat, wild 70 80 80 Buckwheat, wild 20 40 60

Violet, field 50 30 40 Violet, field 100 90 80

Pennycress 70 100 70 Pennycress 100 90 70

TABLE 3 Compound TABLE 3 Compound

Rate 8 g/ha 6 9 13 Rate 8 g/ha 6 9 13

Postemergence Preemergence

Wheat, Spring 40 0 60 Wheat, Spring 0 0 0

Wheat, Winter 10 0 30 Wheat, Winter 0 0 0

Barley, Spring 40 0 50 Barley, Spring 0 0 0

Barley, Winter 20 0 50 Barley, Winter 10 0 0

Sugarbeet 100 100 100 Sugarbeet 90 80 100

Rapeseed 100 100 100 Rapeseed 80 50 100

Wild oat 0 0 10 Wild oat 0 0 0

Downy brome 10 0 0 Downy brome 0 0 0

Cheatgrass 80 0 70 Cheatgrass 40 0 20

Blackgrass 40 30 80 Blackgrass 20 0 0

Bluegrass, annual 20 0 40 Bluegrass, annual 0 0 20

Foxtail, green 0 50 50 Foxtail, green 0 20 0

Ryegrass, Italian 0 0 10 Ryegrass, Italian 0 0 0

Goatgrass, jointed 20 0 80 Goatgrass, jointed 0 0 0

Chamomile, scentless 70 90 90 Chamomile, scentless 40 90 60

Bedstraw 70 60 40 Bedstraw 20 20 0

Russian thistle 100 100 70 Russian thistle 0 0 0

Lambsquarter 20 0 0 Lambsquarter 30 70 30

Kochia 10 80 40 Kochia 0 50 20

Nightshade, Black 60 40 50 Nightshade, Black 20 20 60

Speedwell, birdseye 60 0 0 Speedwell, birdseye 30 20 60

Speedwell, ivyleaf 90 20 10 Speedwell, ivyleaf 70 20 0

Buckwheat, wild 60 80 70 Buckwheat, wild 0 20 20

Violet, field 30 10 20 Violet, field 100 80 60

Pennycress 40 100 50 Pennycress 100 - 40

TABLE 3 Compound TABLE 3 Compound

Rate 4 g ha 6 9 Rate 4 g/ha 6 9

Postemergence Preemergence

Wheat, Spring 30 0 Wheat, Spring 0 0

Wheat, Winter 0 0

Wheat, Winter 0 0

In following tests, Compound 1 was tested in flooded application. Some of these tests include for comparison bensulfuron-methyl, azimsulfuron and pyrazosulfuron-ethyl, which are sulfonylurea active ingredients in commercial herbicides for growing rice.

Tests 4, 5 and 6 include rice as well as important rice weeds. The rice varieties 'Nipponbare' and 'M202' used in these tests are both japonica types, which are known to be more susceptible to injury by sulfonylurea herbicides than are indica rice types. In commercial cultivation rice seedlings are typically transplanted at depths of at least 2 cm, but lesser depths were also used in the following tests to make assessment of any phytotoxicity easier. Comparison with pyrazosulfuron-ethyl was used to verify acceptable crop safety, as pyrazosulfuron-ethyl is commercially used as a single active ingredient herbicide for weed control in japonica rice. Test 4 Protocol

Plastic pots (11 cm diameter) were partially filled with non-sterilized Tama silt loam soil containing a 35:50:15 ratio of sand, silt and clay and 2.6% organic matter. Seeds of one ordinary susceptible biotype (Hl-S) from the U.S. of Heteranthera limosa (ducksalad), one ordinary biotype (Ec-S) of Echinochloa crus-galli (barnyardgrass) from the U.S., one sulfonylurea herbicide-resistant biotype from the U.S. (Cd-Rl) of Cyperus difformis (smallflower umbrella sedge) and one stand of four rice seedlings (Oryza sativa cv. 'M202') were planted into a single 11 cm pot for each rate. To obtain this planting, C. difformis and H. limosa seeds were mixed separately in soil and applied as a 1-cm deep, seed-containing soil layer at particular locations within the pot. Water levels were brought to a puddled condition above the soil surface directly after planting. E. crus-galli and rice seeds were planted in cavity trays in the silt loam soil and transplanted at the 1.5 and 2.0 leaf stage, respectively. E. crus-galli and rice plants were transplanted at about 2 cm depth. Plantings were sequential so that these plant species all reached the 2.0-2.5 leaf stage in the 11 cm pot at time of treatment. Plants were grown in a greenhouse with day/night temperatures of about 29.5/26.7 °C, and supplemental balanced lighting was provided to maintain a 16 hour photoperiod.

At treatment time, test pots were flooded to 3 cm above the soil surface and maintained at that water depth for the duration of the test. Chemical treatments were formulated in acetone and applied directly to the paddy water. Test pots were maintained in the greenhouse. Treated weeds were compared to controls after 13 days and visually evaluated. Plant response ratings are reported on a 0 to 100 scale where 0 is no effect and 100 is complete control and are listed in Table 4.

TABLE 4 - Greenhouse Test of Compound 1 on Rice and Three Weeds

Test 4 demonstrated good control of the important rice weeds including a biotype of Cyperus difformis that is resistant to commercial sulfonylurea herbicides like bensulfuron-methyl.

Test 5 Protocol

Containers having 200 cm² area were partially filled with non-sterilized clay loam soil containing a 36:44:20 ratio of sand, silt and clay and 1.2% organic matter. The soil was then flooded with water and puddled, and rice seedlings (Oryza sativa cv. 'Nipponbare', 2.2 leaf stage) were planted at depths of 0 and 2 cm. Seeds of one susceptible biotype of Scirpus juncoides (Sj-S), two resistant biotypes from Japan (Sj-Rl, Sj-R2) of Scirpus juncoides and one resistant biotype from Italy (Sm-Rl) of Scirpus mucronatus were planted separately in the soil. The containers were maintained outdoors for the duration of the test. At treatment time (5 days after transplanting for rice, 1.5-2 leaf stage for Scirpus), the water level was raised to 3 cm above the soil surface. Chemical treatments were formulated in acetone and applied directly to the paddy water. Rice and weeds were compared to controls after 14 and 34 days, respectively, and visually evaluated. (Rice injury was measured early, as the rice plants later recover.) Plant response ratings are reported on a 0 to 100 scale where 0 is no effect and 100 is complete control and are listed in Table 5.

TABLE 5 - Outdoor Comparison of Compound 1 to Bensulfuron-methyl for Controlling Scirpus Biotypes in Rice

In Test 5, Compound 1 provided as good or better control than bensulfuron-methyl of an ordinary Scirpus juncoides biotype. Its control of three resistant biotypes was similarly good, while bensulfuron-methyl had little effect.

Test 6 Protocol

Concrete pots (50 cm x 50 cm) were partially filled with non-sterilized clay loam soil containing a 36:44:20 ratio of sand, silt and clay and 1.2% organic matter. The soil was then flooded with water. The same soil mixed with seeds of ordinary susceptible biotypes Monochoria vaginalis (Mv-S), Cyperus difformis (Cd-S), Rotala indica (Ri-S), Lindernia procumbens (Lp-S) and Scirpus juncoides (Sj-S), was spread on the paddy soil and then it was puddled. Also, two resistant biotypes from Japan (Sj-R2, Sj-R3) of Scirpus juncoides, one resistant biotype from Italy (Sm-R2) of Scirpus mucronatus, one resistant biotype from Japan (Ld-Rl) of Lindernia dubia and one resistant biotype from Spain (Cd-R2) of Cyperus difformis were sown onto the soil surface in specific areas divided by a 10 cm-diameter plastic tube which was removed two days before chemical treatment. Rice seedlings (Oryza sativa cv. 'Nipponbare', 2.2 leaf stage) were planted at depths of 0, 1 and 2 cm. For 0 and 1 cm planting, rice seedlings were supported by plastic ties. Tubers of ordinary susceptible biotypes of Sagittaria pygmaea (Sp-S), Cyperus serotinus (Cs-S) and Eleocharis kuroguwai (Ek-S) were also planted in the soil. The pots were maintained outdoors for the duration of the test.

At treatment time of 5 days after rice transplanting (5 DAT), the water level was raised to 4 cm above the soil surface. Chemical treatments were formulated in acetone and applied directly to the paddy water. Paddy water in each concrete pot was leached out of the soil at the hole on the bottom edge at the rate of 7.5 liters per 24 hours for 2 days immediately after the treatments. The water level was raised to 4 cm after the first 24 hours leaching and was raised to 3 cm when the leaching was finished. The test pots were maintained at that water level for the duration of the test. Treated rice and weed species were compared to controls at 14 days after treatment and visually evaluated. Plant response ratings are reported on a 0 to 100 scale where 0 is no effect and 100 is complete control, and are listed in Tables 6A and 6B.

TABLE 6A - Outdoor Concrete Pot Test

In Test 6, Compound 1 gave control of ordinary weed biotypes comparable to bensulfuron- methyl and pyrazosulfuron-ethyl. At application rates giving comparable weed control, Compound 1 caused less rice injury than did the commercial herbicide pyrazosulfuron-ethyl, confirming that the rice phytotoxicity of Compound 1 is commercially acceptable. On resistant weeds, Compound 1 also gave excellent control, while bensulfuron-methyl and pyrazosulfuron-ethyl had little or no effect.

Test 7 Protocol

Plastic pots having 100 cm² area were partially filled with non-sterilized clay loam soil containing a 36:44:20 ratio of sand, silt and clay and 1.2% organic matter. The soil was then flooded with water and puddled. Tubers of ordinary susceptible biotypes of Sagittaria pygmaea, Cyperus serotinus, Sagittaria trifolia and Eleocharis kuroguwai were planted in the soil. The pots were maintained in a greenhouse for the duration of the test. The weeds were treated when S. pygmaea reached the three-leaf stage and the other weed species attained 10 cm height. At the time of treatment, test pots were flooded to 3 cm above the soil surface and maintained at that water depth for the remainder of the test. Chemical treatments were formulated in acetone and applied directly to the paddy water. Treated weeds were compared to controls 28 days after treatment and visually evaluated. Plant response ratings are reported on a 0 to 100 scale where 0 is no effect and 100 is complete control, and are listed in Table 7. TABLE 7 - Comparison of Compound 1 to Bensulfuron-methyl and Azimsulfuron for Controlling Perennial Weeds

In Test 7, Compound 1 gave control of four important perennial rice weeds as good or better than bensulfuron-methyl and azimsulfuron.

Test 8 Protocol

Containers having 200 cm² area were partially filled with non-sterilized clay loam soil containing a 36:44:20 ratio of sand, silt and clay and 1.2% organic matter. The soil was then flooded with water and puddled. Seeds of ordinary susceptible biotypes of Echinochloa oryzicola, Lindernia procumbens and Scirpus juncoides were sown on the soil surface. The pots were maintained in a greenhouse for the duration of the test. The seedlings were treated when E. oryzicola reached the 3.1 leaf stage, at which time S. juncoides was at the 2.5 leaf stage and L. procumbens was at the 1 leaf stage. At the time of treatment, test pots were flooded to 4 cm above the soil surface.

The chemical treatments were formulated in acetone and applied directly to the paddy water. Paddy water in each container was leached out of the soil at the hole on the bottom edge at the rate of 0.6 liter per 24 hours for 2 days immediately after the treatments. The water level was raised to 4 cm after the first 24 hours leaching and was raised to 3 cm when the leaching was finished. Then the test pots were maintained at that water depth for the remainder of the test. All treated weed species were compared to controls at 24 days after treatment and visually evaluated. Plant response ratings are reported on a 0 to 100 scale where 0 is no effect and 100 is complete control, and are listed in Table 8. TABLE 8 - Comparison of Compound 1 to Bensulfuron-methyl for Controlling Echinochloa oryzicola, Lindernia procumbens and Scirpus juncoides

In Test 8, Compound 1 gave as good or better control than bensulfuron-methyl particularly of E. oryzicola and S. juncoides.

Test 9 Protocol

Plastic pots having 100 cm² area were partially filled with non-sterilized light clay soil containing a 15:7:3 ratio of sand, silt and clay and 1.2% organic matter. The soil was then flooded with water and puddled. Seeds of biotypes of seven weed species were sown separately onto the soil surface. These included: one ordinary susceptible biotype from Italy (Ap-S), two resistant biotypes from Italy (Ap-Rl, Ap-R2) and one resistant biotype from Spain (Ap-R3) of Alisma plantago-aquatica (water plantain); three resistant biotypes from Japan (Ld-Rl, Ld-R2, Ld-R3) of Lindernia dubia; one ordinary susceptible biotype from Japan (Lp-S) of Lindernia procumbens; one ordinary susceptible biotype from Japan (Sj-S) and five resistant biotypes from Japan (Sj-Rl, Sj-R2, Sj-R4, Sj-R5, Sj-R6) of Scirpus juncoides; one ordinary susceptible biotype from Italy (Sm-S) and two resistant biotypes from Italy of Scirpus mucronatus (ricefield bulrush); one ordinary susceptible biotype from Japan (Cd-S) and one resistant biotype from Spain (Cd-R2) of Cyperus difformis (umbrella sedge); and one ordinary susceptible biotype from Japan (Mk-S) and one resistant biotype from Japan (Mk-Rl) of Monochoria korsakowii. The pots were maintained in a greenhouse for the duration of the test. The plants were treated when seedlings of A. plantago-aquatica, M. korakowii, S. juncoides and S. mucronatus attained the two leaf stage and seedlings of C. difformis, L. dubia and L. procumbens reached the one leaf stage. At time of treatment, test pots were flooded to 3 cm above the soil surface and maintained at that water depth for the remainder of the test. Chemical treatments were formulated in acetone and applied directly to the paddy water. Treated weeds were compared to controls at 23 days after treatment and visually evaluated. Plant response ratings are reported on a 0 to 100 scale where 0 is no effect and 100 is complete control, and are listed in Tables 9A, 9B and 9C.

TABLE 9A - Comparison of Compound 1 to Bensulfuron-methyl for Controlling Biotypes of Alisma plantago-aquatica and Lindernia dubia and procumbens

TABLE 9B - Comparison of Compound 1 to Bensulfuron-methyl for Controlling Biotypes of Scirpus juncoides and Scirpus mucronatus

TABLE 9C - Comparison of Compound 1 to Bensulfuron-methyl for Controlling Biotypes of Cyperus difformis and Monochoria korsakowii

In Test 9, Compound 1 gave as good or better control than bensulfuron-methyl of ordinary weed biotypes. Compound 1 provided much better control than bensulfuron-methyl of resistant weed biotypes. Test 10 Protocol

Plastic pots having 100 cm² area were partially filled with non-sterilized light clay soil containing a 15:7:3 ratio of sand, silt and clay and 1.2% organic matter. The soil was then flooded with water and puddled. Seeds of three resistant biotypes (Sj-Rl, Sj-R2, Sj-R7) and one ordinary susceptible biotype (Sj-S) from Japan of Scirpus juncoides and eleven resistant biotypes (Sm-Rl, Sm-R5, Sm-R6, Sm-R7, Sm-R8, Sm-R9, Sm-Rl 0, Sm-Rl 1, Sm-Rl 2, Sm- Rl 3, Sm-Rl 4) and one ordinary susceptible biotype (Sm-S) from Italy of Scirpus mucronatus were sown onto the soil surface. Test pots were maintained in a growth chamber (day / night = 16 h, 30 °C / 8 h, 25 °C) for the duration of the test. The weeds were freated when the Scirpus seedlings reached the two-leaf stage. At freatment time, test pots were flooded to 3 cm above the soil surface and maintained at that water depth for the remainder of the test. Chemical treatments were formulated in acetone and applied directly to the paddy water. The treated weeds were compared to controls after 11 days and visually evaluated. Plant response ratings are reported on a 0 to 100 scale where 0 is no effect and 100 is complete control and listed in Tables 10A and 10B.

TABLE 10A - Comparison of Compound 1 to Bensulfuron-methyl for Controlling Scirpus juncoides Biotypes

TABLE 10B - Comparison of Compound 1 to Bensulfuron-methyl for Controlling Scirpus mucronatus Biotypes

In Test 10, Compound 1 gave as good control as bensulfuron-methyl on ordinary biotypes of Scirpus weed species. Compound 1 gave undiminished control of resistant biotypes, while bensulfuron-methyl had little effect on them.

Test 11 Protocol

Plastic pots having 100 cm² area were partially filled with non-sterilized clay loam soil containing a 36:44:20 ratio of sand, silt and clay and 1.2% organic matter. The soil was then flooded with water and puddled. Seeds of six resistant biotypes (Sm-R2, Sm-R15, Sm-R16, Sm-Rl 7, Sm-Rl 8, Sm-Rl 9) and one ordinary susceptible biotype (Sm-S) from Italy of Scirpus mucronatus were sown onto the soil surface. The pots were maintained in a greenhouse for the duration of the test. The weeds were treated when the Scirpus seedlings reached the two-leaf stage. At freatment time, test pots were flooded to 3 cm above the soil surface and maintained at that water depth for the remainder of the test. Chemical treatments were formulated in acetone and applied directly to the paddy water. Treated weeds were compared to controls after 20 days and visually evaluated. Plant response ratings are reported on a 0 to 100 scale where 0 is no effect and 100 is complete confrol and are listed in Table 11.

TABLE 11 - Comparison of Compound 1 to Bensulfuron-methyl for Controlling Scirpus mucronatus Biotypes

In Test 11, Compound 1 gave as good confrol of resistant Scirpus mucronatus biotypes as it did of the susceptible biotype. The control of resistant biotypes by bensulfuron-methyl was much less. Even very high application rates of bensulfuron-methyl did not equal the confrol of resistant biotypes provided by Compound 1.

Test 12 Protocol

Four plastic pots per rate (three 16-cm diameter plus one 11 -cm diameter) were partially filled with sterilized Tama silt loam soil containing a 35:50:15 ratio of sand, silt and clay and 2.6% organic matter. Seeds of one ordinary susceptible biotype (Hl-S) from the U.S. of Heteranthera limosa (ducksalad), one ordinary susceptible biotype (Cd-S) from the U.S. of Cyperus difformis and one ordinary susceptible biotype (Aa-S) from the U.S. of Ammania auriculata (redstem) were planted into one 16-cm pot for each rate. Seeds of one ordinary susceptible biotype (Ci-S) from the U.S. of Cyperus iria, one ordinary susceptible biotype (Lf-S) from the U.S. of Leptochloa fascicularis (bearded sprangletop), one stand of 9 or 10 direct-seeded rice seedlings (Oryza sativa cv. 'Japonica - M202') and one stand of 6 transplanted rice seedlings (Oryza sativa cv. 'Japonica - M202') were planted into one 16- cm pot for each rate. Seeds of one ordinary susceptible biotype (Ec-S) from the U.S. of Echinochloa crus-galli (barnyardgrass), one ordinary susceptible biotype (Eo-S) from the U.S. of Echinochloa oryzicola (late watergrass), one ordinary susceptible biotype (Eoz-S) from the U.S. of Echinochloa oryzoides (early watergrass) and one ordinary susceptible biotype (Ecol-S) from the U.S. of Echinochloa colonum were planted into one 16-cm pot for each rate. One resistant biotype from the U.S. (Cd-Rl) of Cyperus difformis was planted into one 11 -cm pot for each rate. Plantings were sequential so that these weed species all reached the 2.0 to 2.5-leaf stage at time of freatment. Heteranthera limosa, Cyperus difformis and Ammania auriculata seeds were each mixed into 1 cm of Tama soil and planted in strategic positions within the same 16-cm pot. The water level was brought to a 'puddled' condition above the soil surface directly after planting. The second 16-cm pot contained Cyperus iria, Leptochloa fascicularis, and transplanted and direct-seeded Oryza sativa cv. 'Japonica M202' planted in strategic positions. This pot was brought to a 'puddled' condition directly after planting. The Cyperus iria was placed directly on the soil surface and the Leptochloa fascicularis, after being soaked in water for one week, was placed on a small mound (0.5 cm) of Tama soil on the pot soil surface. One set of Oryza sativa cv. 'Japonica M202' seeds were planted in cavity trays containing a 50:50 mixture of Tama soil and Metro-Mix 360. At the 2.0-leaf stage they were transplanted into the second test pot. The other set of Oryza sativa cv. 'Japonica M202' seeds were soaked in water for 24 hours and then spread on a tray and covered with burlap. The burlap was kept moist until the seeds germinated. At this time the seeds were placed on the 'puddled' soil surface. Echinochloa crus-galli, Echinochloa oryzicola, Echinochloa oryzoides and Echinochloa colonum were planted in the third 16-cm pot. The soil surface in this pot was kept moist after planting each species in its specified location. A 1-cm depression was made in the soil of each pot for each Echinochloa species. The Echinochloa crus-galli seeds were placed directly in the pot without any special freatment. The seeds of each species were put in the specified depression, covered with soil and tamped. Before planting, the Echinochloa oryzicola was soaked in a 50:50 mixture of water and sodium hypochlorite bleach solution for 15 minutes and rinsed with tap water. The Echinochloa oryzoides was soaked in water for three days before planting and the Echinochloa colonum was soaked in an 80:20 mixture of water and sodium hypochlorite bleach solution for 10 minutes and rinsed with tap water before planting. The resistant Cyperus difformis was planted separately in a 11-cm pot by mixing the seeds with 1 cm of Tama soil, spreading this soil/seed mixture across the soil surface, tamping and watering to a 'puddled' condition. Plants were grown in a greenhouse with day/night temperatures of about 29.5/26.7 °C, and supplemental balanced lighting was provided to maintain a 16-hour photoperiod.

At treatment time the test pots were flooded to 3 cm above the soil surface and maintained at that water depth for the duration of the test. Chemical treatments were formulated in acetone and applied directly to the paddy water. Test pots were maintained in the greenhouse. The freated rice and freated weeds were compared to controls after 20 days and visually evaluated. Plant response ratings are reported on a 0 to 100 scale where 0 is no effect and 100 is complete control. Plant response ratings are shown in Table 12.

TABLE 12 - Greenhouse Test of Compounds on Ten Rice Weeds

Test 13 Protocol

Three plastic pots (16-cm diameter) per rate were partially filled with sterilized Tama silt loam soil containing a 35:50:15 ratio of sand, silt and clay and 2.6% organic matter. Cuttings of one ordinary susceptible biotype (Mq-S) from the U.S. of Marsilea quadrifolia (four-leaf water clover), and seeds of one ordinary susceptible biotype (Sz-S) from the U.S. of Sphenoclea zeylanica (gooseweed) were planted into one 16-cm pot for each rate. Seeds of one ordinary susceptible biotype (Ap-S) from the U.S. of Alisma plantago-aquatica (water plantain), one ordinary susceptible biotype (Sm-S) from the U.S. of Scirpus mucronatus (rice field bulrush), one stand of 9 or 10 direct-seeded rice seedlings (Oryza sativa cv. 'Japonica - M202') and one stand of 6 transplanted rice seedlings (Oryza sativa cv. 'Japonica - M202') were planted into one 16-cm pot for each rate. Seeds of one ordinary susceptible biotype (Ec-S) from the U.S. of Echinochloa crus-galli (barnyardgrass), one ordinary susceptible biotype (Eo-S) from the U.S. of Echinochloa oryzicola (late watergrass), one ordinary susceptible biotype (Eoz-S) from the U.S. of Echinochloa oryzoides (early watergrass) and one ordinary susceptible biotype (Ecol-S) from the U.S. of Echinochloa colonum were planted into one 16-cm pot for each rate. Plantings were sequential so that these weed species all reached the 2.0 to 2.5-leaf stage at time of treatment. Plugs of mature Marsiliea quadrifolia were cut back and then planted in a specified location in the first 16-cm pot. Sphenoclea zeylania seeds were mixed into 1 cm of Tama soil and planted in a specified location in the first pot. The water level in the pot was brought to a 'puddled' condition directly after planting. The second 16-cm pot contained Alisma plantago-aquatica, and Scirpus mucronatus, and both transplanted and direct-seeded Oryza sativa cv. 'Japonica M202' planted in strategic positions. This pot was brought to a 'puddled' condition directly after planting. The Alisma plantago-aquatica seeds were soaked in water for two weeks before planting. They were then rinsed and placed in a glass petri dish containing 50 mL of water. When the radical emerged, the seeds were planted on the soil surface of the pots. About three days before planting, the Scirpus mucronatus seed was placed in a petri dish and covered with 1 cm of water and placed in the greenhouse. When the seeds germinated and had one leaf, they were planted directly on the soil surface. One set of Oryza sativa cv. 'Japonica M202' seeds was planted in cavity trays containing a 50:50 mixture of Tama soil and Metro-Mix® 360 growing medium. At the 2.0-leaf stage they were transplanted into the test pot. The other set of Oryza sativa cv. 'Japonica M202' seeds was soaked in water for 24 hours and then spread on a fray and covered with burlap. The burlap was kept moist until the seeds germinated. At this time the seeds were placed on the 'puddled' soil surface. Echinochloa crus-galli, Echinochloa oryzicola, Echinochloa oryzoides and Echinochloa colonum were planted in the third 16-cm pot. The soil surface in this pot was kept moist after planting each species in its specified location. A 1-cm depression was made in the soil of each pot for each Echinchloa species. The seeds of each species were put in the specified depression, covered with soil and tamped. The Echinochloa crus-galli seeds were placed directly in the pot without any special freatment. Before planting the Echinochloa oryzicola was soaked in a 50:50 mixture of water and sodium hypochlorite bleaching solution for 15 minutes and rinsed with tap water. The Echinochloa oryzoides was soaked in water for three days before planting. The Echinochloa colonum was soaked in an 80:20 mixture of water and sodium hypochlorite bleaching solution for 10 minutes and rinsed with tap water before planting. Plants were grown in a greenhouse with day/night temperatures of about 29.5/26.7 °C, and supplemental balanced lighting was provided to maintain a 16-hour photoperiod.

At treatment time the test pots were flooded to 3 cm above the soil surface and maintained at that water depth for the duration of the test. Chemical treatments were formulated in acetone and applied directly to the paddy water. Test pots were maintained in the greenhouse. Treated rice and treated weeds were compared to controls after 21 days and visually evaluated. Plant response ratings are reported on a 0 to 100 scale where 0 is no effect and 100 is complete control. Plant response ratings are shown in Table 13.

TABLE 13 - Greenhouse Test of Compounds on Rice and Eight Rice Weeds

Test 14 Protocol

Plastic pots (11 cm diameter) were partially filled with non-sterilized silt loam soil containing a 35:50:15 ratio of sand, silt and clay and 2.6% organic matter. Seeds of one ordinary susceptible biotype (Hl-S) from the U.S. of Heteranthea limosa (ducksalad), one resistant biotype from the U.S. (Cd-Rl) of Cyperus difformis, optionally one ordinary biotype (Ec-S) of Echinochloa crus-galli (barnyardgrass) from the U.S., and one stand of four rice seedlings (Oryza sativa cv. 'Cypress', a tropical japonica variety) were planted into one 11-cm pot for each rate. Plantings were sequential so that these weed species all reached the 2.0-2.5 leaf stage at time of treatment. Cyperus difformis and ducksalad seeds were mixed into 1 cm of Tama silt loam soil and planted in strategic positions within the same 11-cm pot. Water levels were brought to a 'puddled' condition above the soil surface directly after planting. E. crus-galli and Oryza sativa cv. 'Cypress' seeds were planted in cavity trays and transplanted at the 1.5 and 2.0 leaf stage, respectively. Plants were grown in a greenhouse with day/night temperatures of about 29.5/26.7 °C, and supplemental balanced lighting was provided to maintain a 16 hour photoperiod.

At freatment time test pots were flooded to 3 cm above the soil surface and maintained at that water depth for the duration of the test. Chemical freatments were formulated in acetone and applied directly to the paddy water. Test pots were maintained in the greenhouse. Treated weeds were compared to controls after 14 days and visually evaluated. Plant response ratings are reported on a 0 to 100 scale where 0 is no effect and 100 is complete control and are listed in Table 14.

Rice grown in the greenhouse tends to be more susceptible to herbicide injury than when it is grown outdoors. Bensulfuron-methyl is commercially used for selective weed control in japonica and indica varieties of rice with sufficient crop safety at about 40-70 g a.i. / ha. ("a.i." means "active ingredient".) Therefore use rates of compounds showing 40% injury in this greenhouse test can be expected to be sufficiently safe to rice crops.

Test 15 Protocol

Plastic pots (11 cm diameter) were partially filled with non-sterilized silt loam soil containing a 35:50:15 ratio of sand, silt and clay and 2.6% organic matter. Seeds of one ordinary susceptible biotype (Hl-S) from the U.S. of Heteranthea limosa (ducksalad), one ordinary biotype (Ec-S) of Echinochloa crus-galli (barnyardgrass) from the U.S., one susceptible (ordinary) biotype (Cd-Sl) of Cyperus difformis from the U.S., one resistant biotype (Cd-Rl) of Cyperus difformis from the U.S., and one stand of four rice seedlings (Oryza sativa cv. 'Japonica - M202') were planted into two 11-cm pots for each rate. Plantings were sequential so that these weed species all reached the 2.0-2.5 leaf stage at time of treatment. Cyperus difformis (Cd-Sl) and ducksalad seeds were mixed into 1 cm of Tama silt loam soil and planted in strategic positions within the same 11-cm pot. E. crus-galli and Oryza sativa cv. 'Japonica (M202)' seeds were planted in cavity trays and transplanted at the 1.5 and 2.0 leaf stage, respectively. In a separate pot, seeds of Cyperus difformis (Cd-Rl) were mixed into 1 cm of Tama silt loam soil and planted within an 11-cm pot. Water levels were brought to a 'puddled' condition above the soil surface directly after planting. Plants were grown in a greenhouse with day/night temperatures of about 29.5/26.7 °C, and supplemental balanced lighting was provided to maintain a 16 hour photoperiod.

At treatment time, test pots were flooded to 3 cm above the soil surface and maintained at that water depth for the duration of the test. Chemical treatments were formulated in acetone and applied directly to the paddy water. Bensulfuron-methyl and metsulfuron- methyl, which are commercially used for selective weed confrol in rice crops, were included in this test for comparison. Test pots were maintained in the greenhouse. Treated weeds were compared to controls after 21 days and visually evaluated. Plant response ratings are reported on a 0 to 100 scale where 0 is no effect and 100 is complete confrol and are listed in Table 15.

In general, rice grown in the greenhouse tends to be more sensitive to herbicides than when it is grown outdoors. Furthermore, the rice cultivar 'M202' used in this test is a japonica variety known to be generally more sensitive to injury from herbicides including sulfonylureas than are typical indica varieties of rice. Metsulfuron-methyl is commercially used for selective weed control in particularly indica rice with sufficient crop safety at 2-6 g a.i. / ha. Therefore use rates of compounds showing 30% injury in tests with japonica rice can be expected to be sufficiently safe to indica rice crops.

Test 16 Protocol

Weed species were planted at approximately 1-cm depth in 6.4-cm square pots containing sterilized soil media consisting of a 60:40 ratio of Sassafras sandy loam and Metro-Mix® 360 (Scotts-Sierra Horticultural Products, Marysville, Ohio) potting media and later thinned to a uniform stand of 1 plant per pot. Wheat and barley were planted similarly in a Redi-Earth® Plug and Seedling Mix (Scotts-Sierra Horticultural Products, Marysville, Ohio) potting media and selected for uniform height and plant density. All test species were greenhouse grown under a 14-hour photoperiod and watered as needed with a dilute nutrient solution for optimum growth. Day temperature was 26.7 ± 1.6 °C, and night temperature was 18.9 ± 1.6 °C. Relative humidity ranged from 30 to 90 percent. Species tested, and age and growth stage at time of treatment are listed in Table 16A. TABLE 16A - Age and Growth Stage of Test Species

Spray solutions of the test substances were prepared with non-phytotoxic surfactant- containing solvent mixtures of the Compound 1 technical active ingredient, or the 75% active water dispersible granules of tribenuron-methyl or chlorsulfuron, and or the 60% active water-dispersible granules of metsulfuron-methyl, respectively. The surfactant- containing solvent mixtures without active ingredients exhibited no effect on the test species. The test chemicals were applied at application rates within ranges of acceptable phytotoxicity to barley; Compound 1 was applied at rates of 16, 32, 64 and 125 g a.i./ha; tribenuron-methyl and chlorsulfuron were each applied at 4, 8 and 16 g a.i./ha.; metsulfuron- methyl was applied at 2, 4 and 8 g a.i./ha. All spray solutions were applied in a spray volume of 309 L/ha using a calibrated, belt sprayer with a flat fan nozzle set approximately 41 cm above plant canopy. After treatment, the pots containing test species were returned to the greenhouse where they were placed on a bench in a randomized complete block design consisting of 3 replicates (2 for Descurainia sophia) which included an ordered first block. Test species were maintained in the greenhouse for the duration of the experiment.

The plants were visually evaluated at 20 days after treatment using a rating scale of 0 to 100, with 0 representing no effect in comparison to untreated controls and 100 representing complete plant death. Mean plant response ratings are shown in Table 16B. TABLE 16B - Greenhouse Test of Compound 1 and Comparison Cereal Herbicides on

Wheat, Barley and Cereal Weeds

TABLE 16B continued - Greenhouse Test of Compound 1 and Comparison Cereal Herbicides on Wheat, Barley and Cereal Weeds

As can be seen from the results from Test 16, Compound 1 gave no injury to wheat at application rates up to 125 g/ha and only slight injury to barley at the high rate. Compound 1 gave excellent control of the susceptible biotype of Galium aparine, better confrol than provided by the comparison compounds within the limits of acceptable safety to barley. Compound 1 also retained significant efficacy against the resistant biotype, while the comparison herbicides lost all effect at the rates tested. Compound 1 also gave excellent control of susceptible biotypes of Anthemis cotula and Sonchus asper, and still gave very good control of resistant biotypes of these weed species. On the other hand, the comparison herbicides showed much diminished effect on these resistant biotypes. Compound 1 provided good confrol of the susceptible biotype of Polygonum scabrum and diminished control of the resistant biotype, as did the comparison herbicides. Compound 1 gave excellent control of susceptible biotypes of Papaver rhoeas, Descurainia sophia and Rudbeckia hirta, as did the comparison herbicides.

The above tests illustrate the superb utility of the compounds of the invention for controlling weeds in barley, wheat and rice cultivation. The effect of these compounds on resistant biotypes is very surprising and commercially valuable.

Claims

CLAIMSWhat is claimed is:

1. A compound of Formula I

or an agriculturally suitable salt thereof wherein

R¹ is C_!-C₃ alkyl, C1-C₂ haloalkyl, C₂-C₃ alkenyl, cyclopropyl orNR³R⁴; R² is C_!-C₄ alkyl, C₁-C₃ haloalkyl, C₂-C₄ alkenyl, C₂-C₃ haloalkenyl, C₂-C₄ alkynyl, cyclopropyl, halocyclopropyl, C₂-C₃ alkoxyalkyl, C₂-C₄ alkylcarbonyl, C₂~C₄ alkoxycarbonyl, Cl or Br; or R² is phenyl optionally substituted with 1 to

2 substituents independently selected from halogen, C₁-C₃ alkyl and C₁-C₂ alkoxy; R³ is H or Cp-C^ alkyl; and R⁴ is C_!-C₃ alkyl or

alkoxy; provided that when R¹ is CF₃ then R² is other than CH₂OCH₃, when R¹ is N(CH₃)₂ then R² is other than CH₃, and when R¹ is CH₂CH₃ then R² is other than 2-fluorophenyl.

2. The compound of Claim 1 wherein

R² is C_!-C₄ alkyl, C1-C₃ haloalkyl, C₂-C₄ alkenyl, C₂-C₃ haloalkenyl, C₂-C₄ alkynyl, cyclopropyl, C₂-C₄ alkylcarbonyl, C₂~C₄ alkoxycarbonyl or Cl; or R² is phenyl optionally substituted with 1 to 2 substituents selected from F, Cl or

C_!-C₂ alkyl.

3. The compound of Claim 2 wherein

R¹ is C₁-C₃ alkyl, cyclopropyl or dimethylamino.

4. The compound of Claim 3 wherein R² is C_J-C₃ alkyl, -C₃ fluoroalkyl, cyclopropyl, C₂-C₄ alkoxycarbonyl, Cl or phenyl.

5. The compound of Claim 4 wherein

R² is C_!-C₃ alkyl, C_!-C₃ fluoroalkyl or C₂-C₃ alkoxycarbonyl.

6. The compound of Claim 5 wherein R¹ is -C₃ alkyl or cyclopropyl; and

R² is C_!-C₃ fluoroalkyl.

7. The compound of Claim 6 wherein R² is Cj fluoroalkyl.

8. The compound of Claim 7 wherein R¹ is C₁-C₃ alkyl.

9. The compound of Claim 8 wherein R¹ is methyl or ethyl.

10. The compound of Claim 9 wherein R² is CH₂F.

11. The compound of Claim 9 wherein R² is CHF₂.

12. The compound of Claim 9 wherein R² is CF₃.

13. The compound of Claim 1 which is 2-(difluoromethyl)-N-[[(4,6-dimethoxy- 2-pyrimidinyl)amino]carbonyl]-6-[(methylsulfonyl)oxy]benzenesulfonamide.

14. An agriculturally suitable composition for controlling the growth of undesired vegetation comprising an effective amount of a compound of any one of Claims 1 to 13 and at least one of the following: surfactant, solid or liquid diluent.

15. A method for controlling the growth of undesired vegetation comprising applying to the locus of the vegetation a herbicidally effective amount of a compound of any one of Claims 1 to 13.

16. The method of Claim 15 wherein the locus of the vegetation is a rice crop.

17. The method of Claim 15 wherein the undesired vegetation comprises at least one biotype resistant to acetolactate synthase-inhibiting herbicides.

18. The method of Claim 17 wherein the resistant biotype is a Scirpus species.

19. The method of Claim 15 wherein the locus of the vegetation is a wheat crop.

20. The method of Claim 15 wherein the locus of the vegetation is a barley crop.