WO1995023509A1

WO1995023509A1 - Herbicidal bicyclic hydantoins

Info

Publication number: WO1995023509A1
Application number: PCT/US1995/002665
Authority: WO
Inventors: Mathias Schäfer
Original assignee: E.I. Du Pont De Nemours And Company; Degussa Aktiengesellschaft
Priority date: 1994-03-01
Filing date: 1995-02-28
Publication date: 1995-09-08
Also published as: AU2115595A

Abstract

The invention is directed to the use of herbicides of formula (I) and their corresponding N-oxides and agriculturally suitable salts, wherein R1, R2, Q, and G are as defined in the text. Herbicides that comprise compounds of formula (I) provide broad spectrum weed control in citrus, sugarcane, coffee, banana, oil palm, loblolly pine, rubber, cocoa, grapes, plantain, pineapple, fruit trees, nut trees, and the like.

Description

HERBICIDAL BICYCLIC HYDANTOINS

BACKGROUND OF THE INVENTION

This invention comprises bicyclic hydantoins and their agriculturally suitable salts wherein the piperidine ring which is incorporated into ring system bears a non-hydrogen substituent, for weed control in plantation crops.

The compounds employed in the instant invention are disclosed in EP-A-493,323. There are, however, no teachings of their use in plantation crops such as citrus, sugarcane, coffee, banana, oil palm, loblolly pine, rubber, cocoa, grapes, plantain, pineapple, fruit trees such as apples, and nut trees. These crops represent important markets and are cultivated particularly in regions of the Pacific rim and South America. Citrus and loblolly pine also are grown elsewhere.

The yields of selected plantation crops such as citrus, sugarcane, coffee, banana, oil palm, loblolly pine, rubber, cocoa, grapes, and fruit trees tend to be lessened by undesired plants such as crabgrass, guineagrass, itchgrass and the like. In addition, the yields of these crops tend to be reduced by crop plants such as corn, cotton, wheat, rice, and the like. A need therefore exists for controlling undesired plants to improve the yields of plantation crops such as those mentioned above.

SUMMARY OF THE INVENTION

This invention comprises a method for controlling weeds in plantation crops comprising applying to the locus to be protected an effective amount of a compound of Formula I:

wherein

the dashed line indicates that the left-hand ring contains only single bonds or one bond in the ring is a double bond;

G is O; S or NH;

R¹ is halogen; hydroxy; cyano; C₁-C₃ alkoxy; C₁-C₃ haloalkoxy; C₂-C₄

alkylcarbonyloxy; or C₂-C₄ haloalkylcarbonyloxy;

R² is H; hydroxy; or halogen; or

R¹ and R² are bonded to the same carbon atom and are taken together with the carbon to which they are attached to form C=O; or R¹ and R² are bonded to adjacent carbon atoms and are taken together with the carbons to which they are attached to form

;

Q is

, , ,

or ;

W is O or S;

R³ is halogen;

R⁴ is H; C₁-C₈ alkyl; C₁-C₈ haloalkyl; halogen; OH; OR⁹; SH; S(O)_nR⁹; COR⁹;

CO₂R⁹; C(O)SR⁹; C(O)NR¹¹R¹²; CHO; CR¹¹=NOR¹⁸; CH=CR¹⁹CO₂R⁹;

CH₂CHR¹⁹CO₂R⁹; CO₂N=CR¹³R¹⁴; NO₂; CN; NHSO₂R¹⁵;

NHSO₂NHR¹⁵; NR⁹R²⁰; NH₂ or phenyl optionally substituted with at least one member independently selected from C₁-C₄ alkyl;

n is 0; 1 or 2;

R⁵ is C₁-C₂ alkyl; C₁-C₂ haloalkyl; OCH₃; SCH₃; OCHF₂; halogen; CN or NO₂; R⁶ is H; C₁-C₃ alkyl or halogen;

R⁷ is H; C₁-C₃ alkyl; halogen; C₁-C₃ haloalkyl; cyclopropyl; vinyl; C₂ alkynyl; CN;

C(O)R²⁰; CO₂R²⁰; C(O)NR²⁰R²¹; CR¹⁶R¹⁷CN; CR¹⁶R¹⁷C(O)R²⁰;

CR¹⁶R¹⁷CO₂R²⁰; CR¹⁶R¹⁷C(O)NR²⁰R²¹; CHR¹⁶OH; CHR¹⁶OC(O)R²⁰ or

OCHR¹⁶OC(O)NR²⁰R²¹; or Q is Q-2 and R⁶ and R⁷ are taken together with the carbon to which they are attached to form C=O; R⁸ is H; C₁-C₆ alkyl; C₁-C₆ haloalkyl; C₂-C₆ alkoxyalkyl; C₃-C₆ alkenyl; C₃-C₆ alkynyl;

or

R⁹ is C₁-C₈ alkyl; C₃-C₈ cycloalkyl; C₃-C₈ alkenyl; C₃-C₈ alkynyl; C₁-C₈

haloalkyl; C₂-C₈ alkoxyalkyl; C₂-C₈ alkylthioalkyl; C₂-C₈ alkylsulfmylalkyl; C₂-C₈ alkylsulfonylalkyl; C₄-C₈ alkoxyalkoxyalkyl; C₄-C₈ cycloalkylalkyl;

C₆-C₈ cycloalkoxyalkyl; C₄-C₈ alkenyloxyalkyl; C₄-C₈ alkynyloxyalkyl;

C₃-C₈ haloalkoxy alkyl; C₄-C₈ haloalkenyloxyalkyl; C₄-C₈

haloalkynyloxyalkyl; C₆-C₈ cycloalkylthioalkyl; C₄-C₈ alkenylthioalkyl;

C₄-C₈ alkynylthioalkyl; C₁-C₄ alkyl substituted with phenoxy or benzyloxy, each ring optionally substituted with at least one member independently selected from the group halogen, C₁-C₃ alkyl and C₁-C₃ haloalkyl; C₄-C₈ trialkylsilylalkyl; C₃-C₈ cyanoalkyl; C₃-C₈ halocycloalkyl; C₃-C₈ haloalkenyl;

C₅-C₈ alkoxyalkenyl; C₅-C₈ haloalkoxy alkenyl; C₅-C₈ alkylthioalkenyl; C₃-C₈ haloalkynyl; C₅-C₈ alkoxy alkynyl; C₅-C₈ haloalkoxyalkynyl; C₅-C₈ alkylthioalkynyl; C₂-C₈ alkylcarbonyl; benzyl optionally substituted with at least one member independently selected from the group halogen, C₁-C₃ alkyl and C ₁-C₃ haloalkyl; CHR¹⁶COR¹⁰; CHR¹⁶P(O)(OR¹⁰)₂;

CHR¹⁶P(S)(OR¹⁰)₂; CHR¹⁶C(O)NR^{1 1}R¹²; CHR¹⁶C(O)NH₂;

CHR¹⁶CO₂R¹⁰; CO₂R¹⁰; SO₂R¹⁰; phenyl optionally substituted with at least one member independently selected from C₁ --C₄ alkyl; or

R¹⁰ is C₁-C₆ alkyl; C₁-C₆ haloalkyl; C₃-C₆ alkenyl or C₃-C₆ alkynyl;

R¹¹ and R¹³ are independently H or C1-C4 alkyl;

R¹² and R¹⁴ are independently C₁-C₄ alkyl or phenyl optionally substituted with at least one member independently selected from the group halogen, C₁-C₃ alkyl and C₁-C₃ haloalkyl; or

R^{1 1} and R¹² are taken together with the nitrogen to which they are attached to form a piperidinyl, pyrrolidinyl or morpholinyl ring, each ring optionally substituted with at least one member independently selected from the group C₁-C₃ alkyl, phenyl and benzyl; or

R¹³ and R¹⁴ are taken together with the carbon to which they are attached to form C₃-C₃ cycloalkyl;

R¹⁵ is C₁-C₄ alkyl or C₁-C₄ haloalkyl;

R¹⁶ and R¹⁷ are independently H or C₁-C₄ alkyl;

R¹⁸ is H; C₁-C₆ alkyl; C₃-C₆ alkenyl or C₃-C₆ alkynyl; R¹⁹ is H; C₁-C₄ alkyl or halogen;

R²⁰ is H or C₁-C₄ alkyl; and

R²¹ is C₁-C₂ alkyl; C₁-C₂ haloalkyl; OCH₃; SCH₃; OCHF₂; halogen; CN or NO₂; and their corresponding N-oxides and agriculturally suitable salts. Examples of structures of Formula I are:

For reasons such as ease of synthesis and/or greater herbicidal efficacy, preferred methods-of-use of the invention employ the following compounds:

Preferred 1 : Compounds of Formula I wherein:

G is O;

R¹ is halogen;

R² is H or halogen;

Q is selected from the group consisting of Q-1, Q-2 and Q-5;

R⁵ is C₁-C₂ haloalkyl, OCH₃, OCHF₂, CΝ, ΝO₂, or halogen;

R⁷ is H or methyl; and

W is O.

Preferred 2: Compounds of Preferred 1 wherein:

R⁴ is halogen, OR⁹, S(O)_nR⁹, COR⁹, CO₂R⁹, C(O)NR^{1 1}R¹², CH=CHCO₂R⁹,

NHSO₂R¹⁵ or NHSO₂NHR¹⁵;

R⁵ is halogen;

R⁶ is H or C₁-C₃ alkyl; and

haloalkyl; C₂-C₈ alkoxyalkyl; C₁-C₄ alkyl substituted with phenoxy or benzyloxy, each ring optionally substituted with at least one member independently selected from the group halogen, C₁-C₃ alkyl and C₁-C₃ haloalkyl; C₃-C₈ haloalkenyl; C₃-C₈ haloalkynyl; C₂-C₈ alkylcarbonyl; benzyl optionally substituted with at least one member independently selected from the group halogen, C₁-C₃ alkyl and C₁-C₃ haloalkyl; CHR¹⁶COR¹⁰;

CHR¹⁶CO₂R¹⁰; CHR¹⁶P(O)(OR¹⁰)₂; CHR¹⁶C(O)NR¹¹R¹²; or CHR¹⁶C(O)NH₂.

Preferred methods-of-use employ compounds selected from the group:

2-[4-chloro-2-fluoro-5-(1-methylethoxy)phenyl]- 7-fluorotetrahydroimidazo[1,5-α]pyridine-1,3(2H,5H)-dione;

2-[4-chloro-2-fluoro-5-(2-propynyloxy)phenyl]- 7-fluorotetrahydroimidazo[1,5-α]pyridine-1,3(2H,5H)-dione;

2-[4-chloro-2-fluoro-5-[(1-methyl-2-propynyl)oxy]phenyl]- 7-fluorotetrahydroimidazo[1,5-α]pyridine-1,3(2H,5H)-dione;

2-[4-chloro-2-fluoro-5-(2-propynyloxy)phenyl]- 8-fluorotetrahydroimidazo[1,5-α]pyridine-1,3(2H,5H)-dione;

2-[4-chloro-2-fluoro-5-[(1-methyl-2-propynyl)oxy]phenyl]- 8-fluorotetrahydroimidazo[1,5-α]pyridine-1,3(2H,5H)-dione;

2-[4-chloro-2-fluoro-5-[(1-methyl-2-propynyl)oxy]phenyl]- 7,7-difluorotetrahydroimidazo[1,5-α]pyridine-1,3(2H,5H)-dione; 2-[4-chloro-2-fluoro-5-(2-propynyloxy)phenyl]- 7,7-difluorotetrahydroimidazo[1,5-α]pyridine-1,3(2H,5H)-dione; 7-fluoro-2-[7-fluoro-3,4-dihydro-3-oxo-4-(2-propynyl)-2Η-1,4- benzoxazin-6-yl]tetrahydroimidazo[1,5-α]pyridine-1,3(2H,5H)-dione;

8-fluoro-2-[7-fluoro-3,4-dihydro-3-oxo-4-(2-propynyl)-2Η-1,4- benzoxazin-6-yl]tetrahydroimidazo[1,5-α]pyridine-1,3(2H,5H)-dione; and 7,7-difluoro-2-[7-fluoro-3,4-dihydro-3-oxo-4-(2-propynyl)-2Η- 1,4-benzoxazin-6-yl]tetrahydroimidazo[1,5-α]pyridine-1,3(2H,5H)-dione.

DETAILS OF THE INVENTION

Compounds of Formula I may exist as one or more stereoisomers. The various stereoisomers include enantiomers, diastereomers 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 and/or to selectively prepare said stereoisomers. Accordingly, the present invention comprises mixtures, individual stereoisomers, and optically active mixtures of compounds of Formula I as well as agriculturally suitable salts thereof.

In the above recitations, the term "alkyl", used either alone or in compound words such as "alkylthio" or "haloalkyl" includes straight-chain or branched alkyl, such as, methyl, ethyl, n-propyl, i-propyl, or the different butyl, pentyl or hexyl isomers.

"Alkenyl" includes straight-chain or branched alkenes such as 1-propenyl, 2-propenyl, and the different butenyl, pentenyl and hexenyl isomers. "Alkenyl" also includes polyenes such as 1,3-hexadiene and 2,4,6-heptatriene. "Alkynyl" includes straight-chain or branched alkynes such as ethynyl, 1-propynyl, 3-propynyl and the different butynyl, pentynyl and hexynyl isomers. "Alkynyl" can also include moieties comprised of multiple triple bonds such as 2,7-octadiyne and 2,5,8-decatriyne. "Alkoxy" includes, for example, methoxy, ethoxy, n-propyloxy, isopropyloxy and the different butoxy, pentoxy and hexyloxy isomers. "Alkoxyalkyl" denotes alkoxy substitution on alkyl. "Alkoxyalkoxy" denotes alkoxy substitution on alkoxy. Examples of "alkoxyalkyl" include CH₃OCH₂, CH₃OCH₂CH₂, CH₃CH₂OCH₂, CH₃CH₂CH₂CH₂OCH₂ and CH₃CH₂OCH₂CH₂. "Alkenyloxy" includes straight-chain or branched alkenyloxy moieties. Examples of alkenyloxy include H₂C=CHCH₂O, (CH₃)₂C=CHCH₂O, (CH₃)CH=CHCH₂O,

(CH₃)CH=C(CH₃)CH₂O and CH₂=CHCH₂CH₂O. "Alkynyloxy" includes straight-chain or branched alkynyloxy moieties. Examples include HC≡CCH₂O, CH₃C≡CCH₂O and CH₃C≡CCH₂CH₂O. "Alkylthio" includes branched or straight-chain alkylthio moieties such as methylthio, ethylthio, and the different propylthio, butylthio, pentylthio and hexylthio isomers. "Alkylsulfinyl" includes both enantiomers of an alkylsulfinyl group. For example, CH₃S(O), CH₃CH₂S(O), CH₃CH₂CH₂S(O), (CH₃)₂CHS(O) and the different butylsulfinyl, pentylsulfinyl and hexylsulfinyl isomers. Examples of

"alkylsulfonyl" include CH₃S(O)₂, CH₃CH₂S(O)₂, CH₃CH₂CH₂S(O)₂, (CH₃)₂CHS(O)₂ and the different butylsulfonyl, pentylsulfonyl and hexylsulfonyl isomers. "Cycloalkyl" includes, for example, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl. The term "cycloalkyloxy" includes the same groups linked through an oxygen atom such as cyclopentyloxy and cyclohexyloxy. "Cycloalkenyl" includes groups such as

cyclopentenyl and cyclohexenyl. Examples of "cycloalkylalkyl" include

cyclopropylmethyl, cyclohexylethyl, and other cycloalkyl moieties bonded to

straight-chain or branched alkyl groups. "Alkylcycloalkyl" denotes alkyl substitution on a cycloalkyl moiety. Examples include 4-methylcyclohexyl and 3-isopropylcyclopentyl.

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, ClCH₂, CF₃CH₂ and CF₃CCl₂. Examples of "haloalkenyl" include (Cl)₂C=CHCH₂ and

CF₃CH₂CH=CHCH₂. Examples of "haloalkynyl" include HC≡CCHCl, CF₃C≡C, CCl₃C≡C and FCH₂C≡CCH₂. Examples of "haloalkoxy" include CF₃O, CCl₃CH₂O, CF₂HCH₂CH₂O and CF₃CH₂O. Examples of "haloalkylthio" include CCl₃S, CF₃S, CCl₃CH₂S and CH₂ClCH₂CH₂S. Examples of "haloalkylsulfonyl" include CF₃SO₂, CCl₃SO₂, CF₃CH₂SO₂ and CF₃CF₂SO2. Examples of "haloalkoxyalkoxy" include CF₃OCH₂O, ClCH₂CH₂OCH₂CH₂O, Cl₃CCH₂OCH₂O as well as branched alkyl derivatives.

The total number of carbon atoms in a substituent group is indicated by the "C_i-C_j" prefix where i and j are numbers from 1 to 8. For example, C₁-C₃ alkylsulfonyl designates methylsulfonyl through propylsulfonyl; C₂ alkoxyalkoxy designates

CH₃OCH₂O; C₃ alkoxyalkoxy designates, for example, CH₃OCH₂CH₂O or

CH₃CH₂OCH₂O; and C4 alkoxyalkoxy designates the various isomers of an alkoxy group substituted with a second alkoxy group containing a total of four carbon atoms, examples including CH₃CH₂CH₂OCH₂O, and CH₃CH₂OCH₂CH₂O. Examples of "alkoxycarbonyl" include CH₃OC(=O), CH₃CH₂OC(=O), CH₃CH₂CH₂OC(=O), (CH₃)₂CHOC(=O) and the different butoxy-, pentoxy- or hexyloxycarbonyl isomers.

The compounds represented by Formula I can be prepared according to the methods described in EP-A-493,323 and illustrated below in Schemes 1-7, or by other procedures known in the art. The definitions of W, and R¹ through R²¹ in the compounds of Formulae 1-10 below are as defined above in the Summary of the Invention. Compounds of Formula la - If are within the definition of compounds of Formula I.

The bicyclic hydantoins of Formula la are obtained by condensing arylisocyanates (G¹ = O) or arylisothiocyanates (G¹ = S) of Formula 1 with piperidine carboxylic acids or esters of Formula 2 as illustrated in Scheme 1.

When Y = alkyl, the reaction can take place in an inert organic solvent, such as toluene, chlorobenzene, chloroform, methylene chloride, diisopropyl ether, acetonitrile, dimethylformamide and the like, optionally with base catalysis at a preferred temperature of 20-120°C. Preferred bases are organic bases, for example; organic amines such as triethylamine or pyridine (see EP-A-272,594). When the reaction is complete, the desired product is obtained by extraction into an organic solvent, washing with water, and evaporation of the solvent under reduced pressure.

When Y = H, the reaction can take place in water as the solvent or, preferably, in a two-phase system containing water and an organic solvent. Especially preferred is the mode of operation in which the acid of Formula 2, or salt of 2, is added with an inorganic base, for example, an alkali or alkaline-earth metal hydroxide, carbonate or hydrogen carbonate, such as sodium hydroxide or potassium carbonate, or an organic base, for example, an organic amine such as triethylamine, to water, and then the iso- or isothio-cyanate of Formula 1 (dissolved in an inert solvent such as toluene,

chlorobenzene or chloroform) is added. The reaction mixture is then held at a temperature between about -40°C and 120°C, preferably -10-40°C, for up to several days, preferably between 3 and 50 hours.

The aqueous phase is then adjusted to a pH between 1 and 3 with acid, preferably with an inorganic acid such as aqueous hydrochloric acid or aqueous sulfuric acid. The intermediate ureas of Formula 4 thus formed (see Scheme 2) are then cyclized by (1) heating at a temperature between about 50°C and 100°C or, (2) by heating in the presence of an acid such as aqueous hydrochloric acid and/or hydroformic acid or, (3) by conversion to the alkyl ester by known methods (see Houben-Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], Vol. XV (1974)).

The iso- and isothio-cyanates of Formula 1 are known or can be prepared by known methods.

Compounds of Formula la can also be obtained as illustrated in Scheme 2. The piperidine carboxylic acid or ester of Formula 2 is reacted with phosgene (G¹ = O), thiophosgene (G¹ = S), or a phosgene- or thiophosgene-equivalent (e.g.,

1,1'-carbonyldiimidazole, 1,1'-thiocarbonyldiimidazole, or triphosgene [(CCl₃O)₂C=O]), to form carbamoyl chlorides of Formula 3. Compounds of Formula 3 are then contacted with anilines of Formula Q-NH₂ to form ureas of Formula 4. Subsequent cyclization is either spontaneous or accomplished by gentle heating and affords the bicyclic hydantoins of Formula la. Anilines of Formula Q-NH₂ are known or can be prepared by known methods; for example, anilines where Q is Q-1, Q-4, and Q-5 can be prepared as described in U.S. 4,902,335 and anilines where Q is Q-2 and Q-3 can be prepared as described in U.S. 5,053,071 or by well known modifications thereof.

Another method for preparing of compounds of Formula la which is outlined in Scheme 3 involves contacting an iso- or isothio-cyanate of Formula 1 with a piperidine nitrile of Formula 5, optionally in the presence of an acid acceptor and optionally in the presence of a solvent, to form a urea of Formula 6.

The urea of Formula 6 so obtained is then hydrolyzed with aqueous acid or base to give the acid of Formula 7, and then cyclized by dehydration to form the bicyclic hydantoin of Formula la. In some instances, treatment of nitriles of Formula 6 with aqueous acid provides the bicyclic hydantoins of Formula la directly.

For some compounds of Formula I, the introduction of R¹ and/or R² is more conveniently accomplished after cyclization to form the bicyclic hydantoin. For example, as illustrated in Scheme 4, an alcohol of Formula lb can be fluorinated with DAST (diethylaminosulfur trifluoride) to give a fluoride of Formula Ic. Fluorination of the alcohol with DAST at a temperature between about -78°C and 100°C in an inert solvent such as dichloromethane affords the fluoride of Formula Ic.

One skilled in the art will recognize that in some cases it is desirable to first prepare the bicyclic system using a protected form of the desired Q group, and then deprotect and functionalize the Q group appropriately. For example, bicyclic hydantoins of Formula 8 can be prepared using the methods described above wherein the R⁴ group on Q is protected with a suitable group T (Scheme 5, for suitable protecting groups see T. W. Greene and P. G. M. Wuts, Protective Groups in Organic Synthesis, 2nd Edition, John Wiley and Sons, Inc., New York, (1991)). Deprotection liberates compounds of Formula Id bearing a free phenol (Z = O), thiol (Z = S), or amine (Z = NH), and then treatment with a halide of Formula 9 affords compounds of Formula Ie.

Compounds of Formula If, compounds of Formula I wherein G is NH, can be prepared as illustrated in Scheme 6.

The amino amide of Formula 9 is treated with trimethylsilyl isothiocyanate to afford the N-trimethylsilyl bicyclic hydantoin. Hydrolysis of the trimethylsilyl group with aqueous acid affords the compound of Formula If. Similar methods for preparing guanidines are taught in Barton, D. and Ollis, W. D., in Comprehensive Organic Chemistry, Vol. 4; Sammes, P. G., Ed.; Pergamon, New York, (1979); p 1116.

The amides of Formula 9 can be prepared by treating the corresponding carboxylic acid or ester with the aniline Q-NH₂ and a trialkylaluminum reagent (e.g.,

trimethylaluminum), in a non-coordinating solvent such as an aromatic hydrocarbon (e.g., benzene and toluene) or halogenated hydrocarbon (e.g., methylene chloride, chloroform, carbon tetrachloride, and dichlorobutane) to obtain the amide. Generally, the reaction requires 0.1 to 48 hours at a temperature of 0°C to 25°C to proceed to completion. The amides of Formula 9 are isolated by extraction into an organic solvent, aqueous wash, and removal of the solvent under reduced pressure. Purification can be accomplished by chromatography or recrystallization.

Compounds of Formula 2 are either known or can be prepared from known compounds by known procedures. Compounds of Formula 2 wherein R¹ is other than OH can be prepared from the corresponding R¹ = OH compound. Fluorination of the alcohol with DAST (diethylaminosulfur trifluoride) at a temperature between about -78°C and 100°C in an inert solvent such as dichloromethane gives the corresponding fluoride. The chloro, bromo, and iodo R¹-substituted compounds of Formula 2 can be prepared from the alcohol using methods known to those skilled in the art. The hydroxy group in compounds can be acylated by known methods to prepare the alkylcarbonyloxy and haloalkylcarbonyloxy derivatives. In addition, the hydroxy or halo group can be converted by known methods to afford the R¹ = alkoxy and haloalkoxy derivatives (March, J., Advanced Organic Chemistry, (1992), 4th Ed., John Wiley and Sons, Inc., pp 386-389).

Compounds of Formula 2 wherein R¹ is 6- or 7-OH can be prepared by selective reduction of the corresponding ketone or epoxide in the presence of the acid or ester group as illustrated in Scheme 7. Depending on the reducing agent chosen, protection of the amine with a suitable protecting group can improve the yield of alcohol.

The epoxide of Formula 2b can be prepared from the alkene by epoxidation, for example using m-chloroperoxybenzoic acid in methylene chloride. The ketones of Formulae 2a and 2d are known and can be prepared from the epoxide of Formula 2b by reduction to give the alcohols of Formulae 2c and 2e followed by oxidation with, for example, pyridinium chlorochromate. G. J. Hanson and M. A. Russell, Tetrahedron Lett., (1989), 30, 5751-5754 discusses the preparation of compounds of Formulae 2a and 2b. P. D. Bailey and J. S. Bryans, Tetrahedron Lett., (1988), 29, 2231-2234 discusses compounds of Formula 2e and their conversion to other compounds of Formula 2.

Alternatively, alcohols of Formula 2c can be prepared as shown in Scheme 8. 4-Hydroxypiperidine (10) is commercially available from Aldrich Chemical Co., Milwaukee, Wisconsin. The piperidine 10 is treated with HOC1 and NaOMe to afford the corresponding imine followed by the addition of HCN to afford the nitrile 5 a.

Hydrolysis of nitrile 5 a affords the carboxylic acid 2c (Y=H) which, if desired, can be converted to the ester (Y=C₁-C₄ alkyl) by methods well known in the art.

Geminally substituted difluoro compounds of Formula 2 can be prepared by treating the ketones of Formula 2a and 2d with DAST as described above. Compounds of Formula 2 wherein R¹ is F and R² is OH and R¹ and R² are bound to adjacent carbon atoms can be obtained by treating the epoxide of Formula 2b with DAST. A mixture of isomeric fluorohydrins is obtained, and the isomers can be separated by chromatography.

Compounds of Formula 2 wherein R¹ is 8-OH, compounds of Formula 2f, can be prepared by the method illustrated in Scheme 9. N-Benzyl-piperidin-3-one 11 is commercially available from Aldrich Chemical Co., Milwaukee, Wisconsin. The ketone can be reduced to the alcohol and converted to the other R¹ groups as described above. Removal of the benzyl group can be accomplished by hydrogenolysis using hydrogen over palladium on carbon catalyst. The carboxylic acid functionality is introduced using the method taught in EP-A-272,594 and illustrated in Scheme 9.

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.

It is recognized that some reagents and reaction conditions described 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 group will be apparent to one skilled in chemical synthesis.

By the procedures described herein the following compounds of Tables 1 to 7 can be prepared. The following abbreviations have been used in Tables 1-7: n = normal Ph = phenyl Me = methyl i = iso Pr = propyl

Formulation/Utility

Compounds of this invention will generally be 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 ingredient, 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 ingredient 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 ingredient. 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 ingredient, 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 0-74 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, N,N-dialkyltaurates, lignin sulfonates, naphthalene sulfonate formaldehyde condensates, polycarboxylates, and

polyoxyethylene/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,

N,N-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 and tetrahydrofurfuryl alcohol.

Solutions, including emulsifiable concentrates, can be prepared by simply mixing the ingredients. 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 U.S. 3,235,361,

Col. 6, line 16 through Col. 7, line 19 and Examples 10-41; 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 1-4; Klingman, Weed Control as a Science, John Wiley and Sons, Inc., New York, 1961, pp 81-96; and Hance et al., Weed Control Handbook, 8th Ed., Blackwell Scientific Publications, Oxford, 1989.

In the following Examples, all percentages are by weight and all formulations are prepared in conventional ways.

Example A

High Strength Concentrate

2-[4-chloro-2-fluoro-5-[(1-methyl-2-propynyl)oxy]phenyl]-7- fluorotetrahydroimidazo[1,5-α]pyridine-1,3-(2H,5H)-dione 98.5%

silica aerogel 0.5%

synthetic amorphous fine silica 1.0%.

Example B

Wettable Powder

2-[4-chloro-2-fluoro-5-[(1-methyl-2-propynyl)oxy]phenyl]-7- fluorotetrahydroimidazo[1,5-α]pyridine-1,3-(2H,5H)-dione 65.0%

dodecylphenol polyethylene glycol ether 2.0%

sodium ligninsulfonate 4.0%

sodium silicoaluminate 6.0%

montmorillonite (calcined) 23.0%. Example C

Granule

2-[4-chloro-2-fluoro-5-[(1-methyl-2-propynyl)oxy]phenyl]-7- fluorotetrahydroimidazo[1,5-α]pyridine-1,3-(2H,5H)-dione 10.0%

attapulgite granules (low volatile

matter, 0.71/0.30 mm; U.S.S. No.

25-50 sieves) 90.0%.

Example D

Extruded Pellet

2-[4-chloro-2-fluoro-5-[(1-methyl-2-propynyl)oxy]phenyl]-7- fluorotetrahydroimidazo[1,5-α]pyridine-1,3-(2H,5H)-dione 25.0%

anhydrous sodium sulfate 10.0%

crude calcium ligninsulfonate 5.0%

sodium alkylnaphthalenesulfonate 1.0%

calcium/magnesium bentonite 59.0%.

The compounds of Formula I are active herbicides for selective and/or general broadleaf and grass weed control in plantation crops including coffee, cocoa, oil palm, sugarcane, citrus, grapes, fruit trees, nut trees, banana, plantain, rubber, pineapple and loblolly pine. Preferred is the method of using compounds of Formula I in sugarcane, citrus, grapes, and fruit trees.

The compounds of Formula I can be applied as a preemergence or postemergence treatment using techniques such as banding, directed sprays, or broadcast applications. By selecting the appropriate rate which would be apparent to one skilled in the art, the compounds of Formula I can be used in areas where control of vegetation is desired, such as around fuel storage tanks, industrial storage areas, oil well sites, drive-in theaters, around billboards, highway and railroad structures and in fence rows.

Alternatively, by selecting the proper rates, adjuvants and application methods, the compounds of Formula I can be used for selective weed control in plantation crops such as citrus, sugarcane, coffee, oil palm, rubber, cocoa, grapes, fruit trees, and pineapple. In general, the compounds of this invention are used at 5 to 5000 g/ha with a preferred rate range of 10 to 2000 g/ha rate. One skilled in the art can select the proper rates for a given situation.

Compositions comprising the active compounds of Formula I are generally used alone or in combination with other commercial herbicides, insecticides or fungicides. The compounds of Formula I are particularly useful in combinations with other herbicides for total vegetation control in plantation crops. Examples of other herbicides with which compounds of Formula I can be formulated are: acetochlor, acifluorfen, acrolein, 2-propenal, alachlor, ametryn, amidosulfuron, ammonium sulfamate, amitrole, anilofos, asulam, atrazine, barban, benefin, bensulfuron methyl, bensulide, bentazon, benzofluor, benzoylprop, bifenox, bromacil, bromoxynil, bromoxynil heptanoate, bromoxynil octanoate, butachlor, buthidazole, butralin, butylate, cacodylic acid,

2-chloro-N,N-di-2-propenylacetamide, 2-chloroallyl diethyldithiocarbamate, chloramben, chlorbromuron, chloridazon, chlorimuron ethyl, chlormethoxynil, chlornitrofen, chloroxuron, chlorpropham, chlorsulfuron, chlortoluron, cinmethylin, cinosulfuron, clethodim, clomazone, cloproxydim, clopyralid, calcium salt of methylarsonic acid, cyanazine, cycloate, cycluron, cyperquat, cyprazine, cyprazole, cypromid, dalapon, dazomet, dimethyl 2,3,5,6-tetrachloro-1,4-benzenedicarboxylate, desmedipham, desmetryn, dicamba, dichlobenil, dichlorprop, diclofop, diethatyl, difenzoquat, diflufenican, dimepiperate, dinitramine, dinoseb, diphenamid, dipropetryn, diquat, diuron, 2-methyl-4,6-dinitrophenol, disodium salt of methylarsonic acid, dymron, endothall, S-ethyl dipropylcarbamothioate, esprocarb, ethalfluralin, ethametsulfuron methyl, ethofumesate, fenac, fenoxaprop, fenuron, salt of fenuron and trichloroacetic acid, flamprop, fluazifop, fluazifop-P, fluchloralin, flumesulam, flumipropyn, fluometuron, fluorochloridone, fluorodifen, fluoroglycofen, flupoxam, fluridone, fluroxypyr, fluzasulfuron, fomesafen, fosamine, glyphosate, haloxyfop, hexaflurate, hexazinone, imazamethabenz, imazapyr, imazaquin, imazamethabenz methyl, imazethapyr, imazosulfuron, ioxynil, isopropalin, isoproturon, isouron, isoxaben, karbutilate, lactofen, lenacil, linuron, metobenzuron, metsulfuron methyl, methylarsonic acid, monoammonium salt of methylarsonic acid, (4-chloro-2-methylphenoxy)acetic acid,

S, S-dimethyl-2-(difluoromethyl)-4-(2-methylpropyl)-6-(trifluoromethyl)-3,5-pyridinedica rbothioate, mecoprop, mefenacet, mefluidide, methalpropalin, methabenzthiazuron, metham, methazole, methoxuron, metolachlor, metribuzin,

1,2-dihydropyridazine-3,6-dione, molinate, monolinuron, monuron, monuron salt and trichloroacetic acid, monosodium salt of methylarsonic acid, napropamide, naptalam, neburon, nicosulfuron, nitralin, nitrofen, nitrofluorfen, norea, norflurazon, oryzalin, oxadiazon, oxyfluorfen, paraquat, pebulate, pendimethalin, perfluidone, phenmedipham, picloram, 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitroacetophenone oxime-O-acetic acid methyl ester, pretilachlor, primisulfuron, procyazine, profluralin, prometon, prometryn, pronamide, propachlor, propanil, propazine, propham, prosulfalin, prynachlor, pyrazolate, pyrazon, pyrazosulfuron ethyl, quinchlorac, quizalofop ethyl, rimsulfuron, secbumeton, sethoxydim, siduron, simazine,

1-(α,α-dimethylbenzyl)-3-(4-methylphenyl)urea, sulfometuron methyl, trichloroacetic acid, tebuthiuron, terbacil, terbuchlor, terbuthylazine, terbutol, terbutryn, thifensulfuron methyl, thiobencarb, tri-allate, trialkoxydim, triasulfuron, tribenuron methyl, triclopyr, tridiphane, trifluralin, trimeturon, (2,4-dichlorophenoxy)acetic acid,

4-(2,4-dichlorophenoxy)butanoic acid, vernolate, and xylachlor. In certain instances, combinations with other herbicides having a similar spectrum of control but a different mode of action will be particularly advantageous for management of resistant weeds.

The following Tests demonstrate the control efficacy of two compounds of Formula I against specific weeds. The weed control afforded by the compounds is not limited, however, to these species. See Index Tables A-C for compound descriptions.

Index Table C

Cmpd. No. ¹H-NMR Data (CDCl₃ solution unless indicated otherwise)^a

1 δ: 1.52 (bs,3H), 1.65-3.40 (m,8H), 3.85-4.15 (m,1H) 4.25-4.52 (m,1H),

4.80-5.15 (m,1H), 7.05 (bs,1H).

3 δ: 1.55 (s.1H), 1.70 (d,3H), 1.70-1.80 (m,1H), 1.53-1.68 (m,1H), 2.17

(s,3H, minor diastereomer), 2.25 (s,3H, minor diastereomer), 2.46- 2.67 (m,1H), 3.02-3.30 (m,1H), 4.10-4.12 (m,1H), 4.28-4.36 (m,1H),

4.84 (q,1H), 5.00 (p,1H, minor diastereomer), 5.38 (s.1H, major diastereomer), 7.10 (d.1H), 7.20 (d.1H).

4 δ: 1.35 (d.6H), 1.78-1.92, 2.04-2.12 and 2.51-2.60 (3m,4H total), 3.14- 3.29 (m,1H), 4.15-4.30 (m,2H), 4.46 (septet,1H), 5.10-5.40 (m,1H),

5.60 (s,1H), 6.86 (d,1H), 7.28 (d,1H).

5 δ: 1.35 (d,6H), 1.60-1.98 (m,4H), 2.38 and 3.40 (AB quartet,2H total),

4.10 (dd.1H), 4.35-4.52 (m,2H), 6.88 (d,1H), 7.27 (d,1H).

6 δ: 1.35 (d,6H), 1.61-1.81, 2.18-2.28 and 2.67-2.78 (3m,4H total), 2.94- 3.05 and 4.30-4.39 (2m,2H total), 4.04-4.11 (dm,1H), 4.40-4.51 (septet,1H), 4.78 (dm,1H), 6.86 (d.1H), 7.26 (d,1H).

7 [in CD₃S(O)CD₃] δ: 1.29 (d,6H), 2.32-2.40 (m,1H), 2.57-2.71 (m,1H),

3.94 and 4.22 (AB quartet,2H total), 4.52-4.65 (m,2H), 4.86 (bs.1H),

5.00 (bs.1H), 7.28 (d,1H) and 7.67 (d.1H). ^a1H-NMR data are in ppm downfield from tetramethylsilane. Couplings are designated by (s)-singlet, (d)-doublet, (t)-triplet, (q)-quartet, (ρ)-pentet, (m)-multiplet, (bs)-broad singlet, (dd)-doublet of doublets, (dm)-doublet of multiplets.

TEST A

Seeds of barley (Hordeum vulgare), barnyardgrass (Echinochloa crus-galli), bedstraw (Galium aparine), blackgrass (Alopecurus myosuroides), cheatgrass (Bromus secalinus), chickweed (Stellaria media), cocklebur (Xanthium pensylvanicum), corn (Zea mays), cotton {Gossypium hirsutum), crabgrass {Digitaria spp.), downy brome (Bromus tectorum), giant foxtail (Setariafaberi), lambsquarters (Chenopodium album), morningglory (Ipomoea hederacea), rape (Brassica napus), rice (Oryza sativa), sorghum (Sorghum bicolor), soybean (Glycine max), sugar beet (Beta vulgaris), velvetleaf (Abutilon theophrasti), wheat (Triticum aestivum), wild buckwheat

(Polygonum convolvulus), wild oat (Avenafatua) and purple nutsedge {Cyperus rotundus) tubers were planted and treated preemergence with test chemicals formulated in a non-phytotoxic solvent mixture which includes a surfactant. At the same time, these crop and weed species were also treated with postemergence applications of test chemicals formulated in the same manner. Plants ranged in height from two to eighteen cm (one to four leaf stage) for postemergence treatments. 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 A, are based on a scale of 0 to 10 where 0 is no effect and 10 is complete control. A dash (- -) response means no test results.

Table A^a

COMPOUND NO. 1 1 1 1 2 2 2 2

POST POST PRE PRE POST POST PRE PRE

Rate (g/ha) 200 50 200 50 200 50 200 50

Barnyardgrass 3 2 0 0 2 3 1 0

Bedstraw 5 4 0 0 10 10 1 0

Blackgrass 5 3 1 0 4 2 5 1

Chickweed 4 4 1 0 ╌ ╌ 10 5

Cocklebur 4 2 0 0 7 4 0 0

Corn 2 2 0 0 4 3 2 0

Cotton 9 9 1 0 9 8 2 0

Crabgrass 3 3 0 0 5 3 9 2

Downy brome 4 3 0 0 ╌ ╌ ╌ ╌

Giant foxtail 3 2 0 0 5 4 9 4

Lambsquarter 8 8 3 0 8 5 10 10

Morningglory 6 4 1 1 4 3 2 0

Nutsedge 4 1 0 0 3 1 0 0

Rape 4 4 1 0 5 4 3 0

Rice 3 2 0 0 5 4 0 0

Sorghum 2 2 0 0 4 3 1 0

Soybean 2 1 0 0 9 8 2 0

Spring wheat 4 4 0 0 4 3 1 0

Sugar beet 4 2 2 0 10 4 8 2

Velvetleaf 7 3 2 1 8 5 3 1

Winter barley 4 3 0 0 2 2 0 0

Wild buckwheat 7 4 3 0 10 7 10 0

Wild oats 5 4 0 0 3 3 1 0

Claims

1. A method for controlling weeds in plantation crops comprising applying to the locus to be protected an effective amount of a compound of Formula I:

wherein

G is O; S or NH;

alkylcarbonyloxy; or C₂-C₄ haloalkylcarbonyloxy;

R² is H; hydroxy; or halogen; or

R¹ and R² are bonded to the same carbon atom and are taken together with the carbon to which they are attached to form C=O; or

R¹ and R² are bonded to adjacent carbon atoms and are taken together with the carbons to which they are attached to form

;

Q is

, , ,

or ;

W is O or S;

R³ is halogen;

CO₂R⁹; C(O)SR⁹; C(O)NR¹¹R¹²; CHO; CR¹¹=NOR¹⁸; CH=CR¹⁹CO₂R⁹; CH₂CHR¹⁹CO₂R⁹; CO₂N=CR¹³R¹⁴; NO₂; CN; NHSO₂R¹⁵;

n is 0; 1 or 2;

CR¹⁶R¹⁷CO₂R²⁰; CR¹⁶R¹⁷C(O)NR²⁰R²¹; CHR¹⁶OH; CHR¹⁶OC(O)R²⁰ or OCHR¹⁶OC(O)NR²⁰R²¹; or Q is Q-2 and R⁶ and R⁷ are taken together with the carbon to which they are attached to form C=O;

R⁸ is H; C₁-C₆ alkyl; C₁-C₆ haloalkyl; C₂-C₆ alkoxyalkyl; C₃-C₆ alkenyl; C₃-C₆ alkynyl;

or _:

haloalkyl; C₂-C₈ alkoxyalkyl; C₂-C₈ alkylthioalkyl; C₂-C₈ alkylsulfinylalkyl;

C₂-C₈ alkylsulfonylalkyl; C₄-C₈ alkoxyalkoxyalkyl; C₄-C₈ cycloalkylalkyl; C₆-C₈ cycloalkoxyalkyl; C₄-C₈ alkenyloxyalkyl; C4-C₈ alkynyloxyalkyl; C₃-C₈ haloalkoxyalkyl; C₄-C₈ haloalkenyloxyalkyl; C4-C₈

haloalkynyloxyalkyl; C₆-C₈ cycloalkylthioalkyl; C₄-C₈ alkenylthioalkyl; C₄-C₈ alkynylthioalkyl; C₁-C₄ alkyl substituted with phenoxy or benzyloxy, each ring optionally substituted with at least one member independently selected from the group halogen, C₁-C₃ alkyl and C₁-C₃ haloalkyl; C₄-C₈ trialkylsilylalkyl; C₃-C₈ cyanoalkyl; C₃-C₈ halocycloalkyl; C₃-C₈ haloalkenyl; C₅-C₈ alkoxyalkenyl; C₅-C₈ haloalkoxyalkenyl; C₅-C₈ alkylthioalkenyl; C₃-C₈ haloalkynyl; C₅-C₈ alkoxy alkynyl; C₅-C₈ haloalkoxyalkynyl; C₅-C₈ alkylthioalkynyl; C₂-C₈ alkylcarbonyl; benzyl optionally substituted with at least one member independently selected from the group halogen, C₁-C₃ alkyl and C₁-C₃ haloalkyl; CHR¹⁶COR¹⁰; CHR¹⁶P(O)(OR¹⁰)₂; CHR¹⁶P(S)(OR¹⁰)₂; CHR¹⁶C(O)NR^{1 1}R¹²; CHR¹⁶C(O)NH₂;

CHR¹⁶CO₂R¹⁰; CO₂R¹⁰; SO₂R¹⁰; phenyl optionally substituted with at least one member independently selected from C₁-C₄ alkyl; or

;

R^{1 1} and R¹³ are independently H or C₁-C₄ alkyl;

R¹¹ and R¹² are taken together with the nitrogen to which they are attached to form a piperidinyl, pyrrolidinyl or morpholinyl ring, each ring optionally substituted with at least one member independently selected from the group C₁-C₃ alkyl, phenyl and benzyl; or

R¹³ and R¹⁴ are taken together with the carbon to which they are attached to form C₃-C₈ cycloalkyl;

R¹⁵ is C₁-C₄ alkyl or C₁-C₄ haloalkyl;

R¹⁶ and R¹⁷ are independently H or C₁-C₄ alkyl;

R¹⁸ is H; C₁-C₆ alkyl; C₃-C₆ alkenyl or C₃-C₆ alkynyl;

R¹⁹ is H; C₁-C₄ alkyl or halogen;

R²⁰ is H or C₁-C₄ alkyl; and

R²¹ is C₁-C₂ alkyl; C₁-C₂ haloalkyl; OCH₃; SCH₃; OCHF₂; halogen; CN or NO₂; and their corresponding N-oxides and agriculturally suitable salts.

2. A method according to Claim 1 wherein:

G is O;

R¹ is halogen;

R² is H or halogen;

Q is selected from the group consisting of Q-1, Q-2 and Q-5;

R⁵ is C₁-C₂ haloalkyl, OCH₃, OCHF₂, CΝ, ΝO₂, or halogen;

R⁷ is H or methyl; and

W is O.

3. A method according to Claim 2 wherein:

R⁴ is halogen, OR⁹, S(O)_nR⁹, COR⁹, CO₂R⁹, C(O)NR¹¹R¹², CH=CHCO₂R⁹,

NHSO₂R¹⁵ or NHSO₂NHR¹⁵;

R⁵ is halogen;

R⁶ is H or C₁-C₃ alkyl; and

CHR¹⁶CO₂R¹⁰; CHR¹⁶P(O)(OR¹⁰)₂; CHR¹⁶C(O)NR^{1 1}R¹²; or CHR¹⁶C(O)NH₂.

4. A method according to Claim 3 wherein the compounds are selected from the group:

8-fluoro-2-[7-fluoro-3,4-dihydro-3-oxo-4-(2-propynyl)-2Η-1,4- benzoxazin-6-yl]tetrahydroimidazo[1,5-α]pyridine-1,3(2H,5H)-dione; and

7,7-difluoro-2-[7-fluoro-3,4-dihydro-3-oxo-4-(2-propynyl)-2Η- 1,4-benzoxazin-6-yl]tetrahydroimidazo[1,5-α]pyridine-1,3(2H,5H)-dione.

5. A method according to Claim 1 wherein the plantation crops are selected from the group consisting of coffee, cocoa, oil palm, sugarcane, citrus, grapes, fruit trees, nut trees, banana, plantain, rubber, pineapple and loblolly pine.

6. A method according to Claim 5 wherein the plantation crops are selected from the group consisting of sugarcane, citrus, grapes, and fruit trees.