WO1998039309A1

WO1998039309A1 - Heterocyclic herbicides

Info

Publication number: WO1998039309A1
Application number: PCT/AU1998/000146
Authority: WO
Inventors: Andris Juris Leipa; Roland Henry Nearne; Dionne Anne Jones
Original assignee: Dunlena Pty. Limited
Priority date: 1997-03-06
Filing date: 1998-03-06
Publication date: 1998-09-11
Also published as: AUPO550397A0

Abstract

The invention relates to novel compounds of Formula (I) wherein: B, E, G and L are the same or different and are independently selected from the group comprising C, N, O, S; and the optionally substituted heterocyclic ring may be saturated, partially saturated or unsaturated; R is a group selected from alkyl, alkenyl, alkynyl, aryl or heterocyclyl which is optionally substituted; R1, R2 may be the same or different and are independently selected from H and C¿1?-C4 alkyl or may together form a 3 to 8 membered carbocyclic or heterocyclic ring; R?3, R4¿ are selected from the group comprising hydrogen, optionally substituted alkyl, cycloalkyl, optionally substituted aryl, heterocyclyl, or R?3 and R4¿ together with the nitrogen to which they are attached form a saturated or unsaturated 5-, 6- or 7-membered heterocyclic ring containing 1-2 heteroatoms selected from the group consisting of 0-2 nitrogen, 0-1 oxygen and 0-2 sulfur atoms; said ring is optionally substituted with 1-4 CH¿3? groups. Agriculturally useful compositions containing these compounds and methods of using these compounds as pre-emergent and/or post-emergent herbicides, and plant growth regulators.

Description

Heterocyclic Herbicides

The present invention relates to organic compounds having herbicidal properties and plant growth regulating properties; to herbicidal compositions and processes utilizing such compounds and to plant growth regulating compositions and processes utilizing such compositions.

Background of the Invention

Compounds which incorporate a glycolamide moiety together with heterocyclic structures and claimed to control weeds are described in : -

Ger. Offen. 2,829,289

Eur. Pat, Appl. 29, 183 Eur. Pat. Appl. 18,497 and

Ger. Offen. DE 3,018,075.

In each of these, the glycolamide is bonded to the heterocyclic ring through a carbon atom unlike the novel structures of the present invention which are bonded through a nitrogen atom.

Summary of the Invention

The invention relates to novel compounds of Formula (1), to agriculturally useful compositions containing these compounds and to methods of using these compounds as pre-emergent and/or post-emergent herbicides, and plant growth regulators.

We have discovered that such compounds are highly active pre-emergent and/or post- emergent herbicides or plant growth regulators and are particularly useful for controlling certain weeds in crops. Accordingly, the invention provides a compound of the formula (I):

(I)

wherein:

B, E, G and L are the same or different and are independently selected from the group comprising C, N, O, S; and the optionally substituted heterocyclic ring may be saturated, partially saturated or unsaturated;

R is a group selected from alkyl, alkenyl, alkynyl, aryl or heterocyclyl which is optionally substituted;

Rl , R2 may be the same or different and are independently selected from H and C1-C4 alkyl. or may together form a 3 to 8 membered carbocyclic or heterocyclic ring;

R3, R4 are selected from the group comprising hydrogen, optionally substituted alkyl, cycloalkyl, optionally substituted aryl, heterocyclyl, or R3 and R4 together with the nitrogen to which they are attached form a saturated or unsaturated 5-, 6- or 7-membered heterocyclic ring containing 1-2 heteroatoms selected from the group consisting of 0-2 nitrogen, 0-1 oxygen and 0-2 sulfur atoms; said ring is optionally substituted with 1-4 CH3 groups.

In the above definitions:

"optionally substituted" group means that a group may or may not be substituted with one or more groups selected from: alkyl, alkenyl, alkynyl, aryl, halo, haloalkyl, haloalkenyl, haloalkynyl, haloaryl, hydroxy, alkoxy, alkenyloxy, aryloxy, haloalkoxy, haloalkenyloxy, haloaryloxy, nitro, nitroaryl, nitroheterocyclyl, amino, alkylamino, alkenylamino, alkynylamino, arylamino, acyl, aroyl, alkenylacyl, arylacyl, acylamino, alkylsulphonyloxy, arylsulphenyloxy, heterocyclyl, heterocycyloxy, heterocycylamino, haloheterocyclyl, alkoxycarbonyl, alkylthio, alkylsulphonyl, arylthio, arylsulphonyl, aminosulphonyl, dialkylamino, dialkylsulphonyl

"alkyl", used either alone or in compound words such as "alkylthio" or "haloalkyl", denotes straight chain or branched alkyl, e.g. methyl, ethyl, n-propyl, isopropyl or the different butyl, pentyl or hexyl isomers.

"Alkoxy" denotes methoxy, ethoxy, n-propoxy, isopropyloxy, and the different butyloxy isomers.

"Alkenyl" denotes straight chain or branched alkenes, e.g. vinyl, 1-propenyl, 2-propenyl, 3-propenyl, etc.

"Alkynyl" denotes straight chain or branched alkynes, e.g. , ethynyl, 1- propynyl, 2-propynyl, and the different butynyl isomers.

"Alkylsulfonyl" denotes methylsulfonyl, ethylsulfonyl, propylsulfonyl, and the different butylsulfonyl isomers.

Alkylthio, alkylsulfinyl, alkylamino, etc. are defined in an analogous manner.

"Cycloalkyl" denotes cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cycloheptyl.

"Heterocyclic" or "heterocyclyl" means a ring structure containing 3 to 10 atoms at least one of which is selected from O, N and S, which may or may not be aromatic. Examples of aromatic "heterocyclyl" moieties are pyridyl, furanyl, thienyl, pyrrolyl, pyrazoyl, benzthiazolyl, indolyl, benzofuranyl, benzothiophenyl, pyrazinyl, quinolyl, etc optionally substituted with one or more alkyl, haloalkyl, halo, nitro, or cyano groups.

The term "halogen", either alone or in compound words such as "haloalkyl" , denotes fluorine, chlorine, bromine or iodine. Further, when used in compound words such as "haloalkyl" said alkyl may be partially halogenated or fully substituted with halogen atoms which may be the same or different. Examples of haloalkyl include CH2CH2F, CF2CF3 and CH2CHFCI.

Alkylcarbonyl denotes acetyl, propionyl, and the different butyryl isomers.

Alkoxycarbonyl denotes methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, and the different butoxycarbonyl isomers.

The total number of carbon atoms in a substituent group is indicated by the Ci-Cj prefix where I and j are numbers from 1 to 10. For example, C2-C3 alkylthioalkyl would designate -CH2SCH3, -CH2SC2H5, -CH2CH2SCH3 or -CH(CH3)SCH3, and C2-C5 alkoxyalkyl would represent -CH2OCH3 through to -(CH2)4OCH3 or - CH2O(CH2)3CH3 and the various structural isomers embraced therein.

"Alkylene" denotes methylene (-CH2-), ethylene (-CH2CH2-), propylene and butylene; alkenylene denotes -CH=CHCH2-, -CH=CHCH2CH2-, and - CH2CH=CHCH2-.

Preferred groups of compounds of general formula (I), for reasons including ease of synthesis and greater herbicidal efficacy, include the compounds of Formula II

N =N

N N

O

R (II) O c N. where A = H₂ R

AND

R =

wherein

X, Y, Z are independently selected from the group comprising

H, Cl, Br, F, C1-C3 alkyl, C1-C3 alkoxy, C1-C3 alkylthio, C1-C3, alkysulfinyl, C1-C3 alkylsulfonyl, C1-C3 haloalkyl, Q-C3 haloalkoxy, nitro, cyano or -C3 alkoxy carbonyl; or benzenesulfonyl, benzoyl, benzyl, benzyloxy, phenoxy, phenylthio or phenylamino optionally substituted with 1-3 substituents selected from the group consisting of halogen, C1-C4 alkyl, C1-C4 alkoxy, or CF3; hereinafter referred to as compounds of Formula IIA OR

R is optionally substituted alkyl, alkenyl, alkynyl, or heterocyclyl; hereinafter referred to as compounds of Formula IIB.

In the compounds of Formula II, R^,R4 may together form a 3 to 8 membered ring or R3, R4 are independently selected from hydrogen, optionally substituted -Cό alkyl, cycloalkyl, optionally substituted aryl or heterocyclyl.

Examples of preferred A groups (hereinafter Ax where x = 1 to 37) include the following:- Al

A14 = Me A15 = Me

A18 =

Especially preferred in this group are compounds of Formula III:

(III) wherein R = optionally substituted heterocyclyl or

R =

wherein

X, Y, Z are independently selected from the group comprising

H, Cl, Br, F, C1-C3 alkyl, C1-C3 alkoxy, C1-C3 alkylthio, C1-C3 haloalkyl, C1-C3 haloalkoxy, nitro, cyano or -C3 alkoxycarbonyl; or benzenesulfonyl, benzoyl, benzyl, benzyloxy, phenoxy, phenylthio or phenylamino optionally substituted with 1-3 substituents selected from the group consisting of halogen, C1-C4 alkyl, C1-C4 alkoxy, or CF3

AND G is an optional substituent selected from the group comprising

C1-C3 alkyl, C1-C3 alkoxy, C1-C3 alkylthio, C1-C3 haloalkyl, C1-C3 haloalkoxy or C1-C3 alkoxycarbonyl.

Examples of compounds of Formula II within the scope of this invention are given in the Table 1 which follows.

Examples of compounds of Formula II with R being heterocyclyl are given in the Table 2 which follows. Table 2

Examples of compounds of Formula II with R being (substituted)alkyl, cycloalkyl or cycloalkenyl are given in the Table 3 which follows.

Table 3

Specifically preferred for reasons of greatest herbicidal efficacy, greatest selectivity on rice and/or most favourable ease of synthesis are:

Compound 37 2-[5-(2-Chlorophenyl)tetrazol-l-yloxy]acetopiperidide

Compound 43 2-[5-(4-Chlorophenyl)tetrazol-l-yloxyJacetopiperidide

Compound 135 2-[5-(2,4Dichlorophenyl)tetrazol-l-yloxy]acetopiperidide Compound 2 N-Ethyl-N-methyl(2-[5-(Phenyl)tetrazol-l-yloxy])acetamide

Compound 4 2-[5-(Phenyl)tetrazol-l-yloxy]acetopyrrolidide Compound 47 2-[5-(2-Fluorophenyl)tetrazol-l-yloxy]aceto(2-methyl)piperidide Compound 49 2-[5-(2-Fluorophenyl)tetrazol-l-yloxy]aceto(4-methyl)piperidide Compound 50 N-Methyl(2-[5-(2-fluorophenyl)tetrazol- 1 -yloxy])acetanilide Compound 53 2-[5-(3-Fluorophenyl)tetrazol-l-yloxy]acetopiperidide Compound 54 2-[5-(4-Fluorophenyl)tetrazol- 1 -yloxy]acetopiperidide Compound 66 2-[5-(2-Methylphenyl)tetrazol-l-yloxy]aceto(2-methyl)piperidide Compound 68 2-[5-(2-Methylphenyl)tetrazol-l-yloxy]aceto(4-methyl)piperidide Compound 170 2-[5-(2,3-Difluorophenyl)tetrazol-l-yloxy]acetopiperidide Compound 197 N-Methyl(2-[5-(2, 6-difluorophenyl)tetrazol- 1 -yloxy])acetanilide Compound 263 2-[5-(3-Methyl-2-thienyl)tetrazol- 1 -yloxy] acetopiperidide

The general procedure for preparation of Compounds of the Invention is described in detail in the following section.

General Method of Preparation

The compounds of the present invention may be produced in accordance with the following reaction (Scheme 1)

(A) (B)

Scheme 1

wherein R, R^ and R4 are as defined above and X represents a halogen atom.

Thus a 1-N-hydroxy tetrazole is reacted with a halo acetamide in the presence of a suitable base to produce compound ^® of the present invention. Suitable bases are inorganic bases such as potassium hydroxide, potassium carbonate, potassium bicarbonate, sodium hydroxide, sodium carbonate, sodium hydride etc. or organic bases such as triethylamine, pyridine, DBU, etc. The reaction may be carried out in the presence of water, or in the presence of an organic solvent inert to the reactants or under phase transfer conditions. The reaction temperature may be freely selected from the range between - 30 ° C to 150 °C but is preferably in the range between 0 ° and 50 ° C.

The starting materials for the reaction may be prepared by reference to the literature. Thus 1-N-hydroxy tetrazoles(A) may be synthesised by referring to the methods described by J. Plenkiewicz in Tetrahedron, vol 34, pages following 2961 (1978), and haloacetamides(B) can be prepared by following the example described in S. L. Shapiro, H. Soloway and L. Freedman in Journal of Organic Chemistry, vol 24, pages following 1607(1959).

Preparation of Example Compounds

2- Chlorophenylazidoxime

A solution of sodium azide(2.68g) in water(16ml) was added to a stirred solution of 2- chlorophenylchlorooxime(7.85g) in methanol( 100ml). The reaction was stirred at room temperature for 5 hrs. The solution was concentrated by partial evaporation under reduced pressure to about 40 ml, diluted with water (100ml) and extracted with benzene (3 x 100ml). The combined benzene extracts were dried over sodium sulfate, filtered and concentrated by evaporation to 20ml and the solution of crude product used as described below.

5—(2-Chlorophenyl)-l-hydroxytetrazole

The benzene solution of the crude azidoxime(20ml), obtained as described above, was treated with a solution of acetyl chloride(6.2g) in benzene (10ml) and the reaction was stirred at 20deg for 16hrs. Excess acetyl chloride was removed under reduced pressure and the residue was stirred with a mixture of benzene(20ml) and water(20ml) for 24hrs. The mixture was extracted with ether(3x50ml), the organic extracts combined and extracted with saturated aqueous sodium bicarbonate(2 x 50ml). The combined aqueous extracts were acidified by addition of ION HC1, the precipitate collected by filtration, washed on the filter with water and dried to afford the hydroxy tetrazole as a colourless crystalline solid(3.17g) m.p. 194-6 °. Compound 37 (Table 1) . 2-[5-(2-Chlorophenyl)tetrazol-l-yloxy]acetopiperidide

N-(2-Chloroacetylpiperidine(0.88g) was added to a mixture of 2-(2-chlorophenyl)-l- hydroxytetrazole(0.98g) and potassium carbonate(1.66g) in N, N- dimethylformamide(DMF)(3ml) and the mixture was stirred at 20° for 16 hrs. The reaction was diluted with water(20ml) and extracted with ether (3x10ml). After evaporation of the solvent the residue was purified by radial chromatography over a silica adsorbent to give the title compound as a colourless solid after recrystallisation from ether(128 mg), m.p. 79-82° ; IH NMR (CDCI3) δ 1.55, m, 6H; 3.18, broad t, 2H(NCH2); 3.36, 2H, broad t, 2H(NCH2); 5.16, s, 2H(OCH2); 7.5, m, 3H(ArH) and 7.63, m, H(ArH).

To a stirred suspension of 2-pyridylchlorooxime(6.4g) cooled in an ice bath was added dropwise a solution of sodium azide(4.0g) in water(15ml). The mixture was allowed to warm to room temperature, stirring continued for 48 hours and then diluted with water( 100ml). The mixture was cooled with ice and the precipitated solid filtered off, washed on the filter with water, drained as thoroughly as possible and washed lightly with petroleum ether to give the crude azidoxime as a white powder(7.5g)

5-(2-Pyήdyl)-l-hydroxytetrazole

The crude azidoxime(7.5g, obtained as described above) was added in portions to an ice- cooled mixture of acetyl chloride( 100ml) and benzene(50ml). After 30 mins the container was removed from the ice bath, stoppered well and stirred at room temperature for five weeks. At the end of this time the mixture was diluted with light petroleum(50ml) and then filtered to afford 5-(2-Pyridyl)-l -hydroxy tetrazole (6.2g) as a hydrochloride salt IH NMR(CD3)2SO δ 7.7, m, H; 8.2, m, 2H and 8.85, m, IH. The product was used in further reactions without any additional purification.

5—(2-Methylphenyl)-l-hydroxytetrazole N-Chlorosuccinimide (9.07g) was added in portions over 2 hours to a stirred solution of 2-methylbenzaldoxime(8.1g) in acetonitrile(40ml) containing concentrated hydrochloric acid(0.2ml) maintained at about 25° by external water cooling. The solution was diluted with benzene(80ml) and washed with one portion of water(80ml). The organic phase was added dropwise to a solution of sodium azide(7.8g) and sodium hydrogen carbonate(2.52g) in water maintained at 5-10° . After the addition was complete the mixture was stirred at room temperature for 16 hours, the organic phase was separated, washed with water(2x50ml) and dried over sodium sulfate.

The solution of crude azidoxime was added dropwise over 15 minutes to a mixture of acetyl chloride(15ml) and benzene(45ml) maintained at 0-5° and after the addition was completed at room temperature for 72 hours. The solution was concentrated to about 40ml by partial evaporation, water(40ml) added and the whole stirred at 80° for 3 hours. The mixture was cooled to room temperature and extracted with ether(3x50ml) and the ether solution was washed with water(2x50ml). The organic phase was then extracted with saturated aqueous sodium hydrogen carbonate(4x25ml). The aqueous solution was acidified with concentrated hydrochloric acid and the organic material which precipitated was extracted into ether(50ml). Evaporation of the ether left a light brown residue of the tetrazole(6.05g); a sample recrystallised from water yielded colourless needles, m.p. 120- 121 ° ; IH NMR (CDCI3) δ 2.22, s, 3H(ArCH3), 7.15-7.46, m, 4H(ArH) and 9.2, broad, ΙH(OH).

Compound 66(Tablel) 2-[5-(2-Methylphenyl)tetrazol-l-yloxy]aceto(2- methyl)piperidide

To a stirred mixture of 5-(2-methylphenyl)-l-hydroxytetrazole(194mg), tetrabutylammonium chloride(50mg), sodium hydrogen carbonate(400mg) and dichloromethane(4ml) in water(4ml) was added chloroacetyl(2-methyl)piperidine(178mg). the reaction mixture was stirred at ambient temperature for 18 hours, diluted with water(20ml) and extracted with ether(2x20ml). The combined organic extracts were washed with water(20ml), dried over sodium sulfate and evaporated to dryness. The residue was purified by crystallisation from ether to give 2-[5-(2-methylphenyl)tetrazol-l- yloxy]aceto(2-methyl)piperidide as colourless crystals, m.p.90-91 ° ; *H NMR (CDCI3X mixture of rotational isomers) δ 0.9 - 1.7, m, 9H(CH2CH2CH2 and CHCH3); 2.36, s, 3H(ArCH3); 2.6, 3.1, 3.3, 3.8, 4.2 and 4.6, each m, 3H(CHCH3 and NCH2); 5.1 , m, 2H(OCH2) and 7.2 - 7.7, m, 4H(ArH).

The following related compounds were prepared in a similar manner to the above:

Compound 2(Tablel) ; N-Ethyl-N-methyl(2-[5-(phenyl)tetrazol-l-yloxy])acetamide ; m.p. 86-87°; H NMR (CDCl3)(equal mixture of rotational isomers) 1.03, 1.22, t, t, 3H(CH2CH3); 2.89, 2.98, s, s, 3H(CH3); 3.30, 3.40, q, q, 2H(CH2CH3); 5.28, 5.34, s, s, 2H(OCH2); 7.56, m, 3H(ArH) and 8.26, m, 2H(ArH),

Compound 4; 2-[5-(Phenyl)tetrazol-l-yloxy]acetopyrrolidide

Compound 47; 2-[5-(2-Fluoropkenyl)tetrazol-l-yloxy]aceto(2-methyl)piperidide

Compound 49; 2-[5-(2-Fluorophenyl)tetrazol-l-yloxy]aceto(4-methyl)piperidide;

Compound 50; N-MethyI-(2-[5-(2-fluorophenyl)tetrazol-l-yloxy])acetanilide; m.p. 76° ; *H NMR (CDCI3) δ 3.20, s, 3H(CH3); 4.94, s, 2H(CH2); 7.1-7.7, m,

8H(ArH) and 8.86, m, lH(ArH).

Compound 53; 2-[5-(3-Fluorophenyl)tetrazol-l-yloxy]acetopiperidide; m.p. 99° ; !H NMR (CDCI3) δ 1.5-1.8, m, 6H(CH2CH2CH2); 3.3, 3.5, m, m, 2H,

2H(CH2NCH2); 5.36, s, 2H(CH2θ); 7.22, m, lH(ArH); 7.54, m, lH(ArH) and

8.18, m, 2H(ArH).

Compound 54; 2-[5-(4-Fluorophenyl)tetrazol-l-yloxy]acetopiperidide; m.p. 84-87° ; IH NMR (CDCI3) δ 1.4-1.8, m, 6H(CH2CH2CH2); 3.3, 3.5, m, m,

2H, 2H(CH2NCH2); 5.35, s, 2H(CH2θ); 7.22, m, 2H(ArH) and 8.34, m, 2H(ArH) . Compound 68; 2-[5-(2-Methylphenyl)tetrazol-l-yloxy]aceto(4-methyl)piperidide; colourless oil; IH NMR (CDCI3) δ 0.84, d, 3H(CHCH3); 1.0, m, 2H(piperidine H); 1.8, m, 3H(piperidine H); 2.37, s, 3H(ArCH3); 2.4, 2.86, 3.5 and 4.3, each m, each 1H(CH2NCH2); 5.05, s, 2H(OCH2); 7.3, m, 3H(Ar H) and 7.6, d, lH(ArH).

Compound 73; N-Methyl-(2-[5-(2-methylphenyl)tetrazol-l-yloxy])acet(2- methyl)anilide; colourless oil; *H NMR (CDCI3) δ 2.20, s, 3H(ArCH3); 2.38, s, 3H(ArCH3); 3.09, s, 3H(NCH3); 4.73, q, 2H(OCH2) and 7.2-7.45, m, 4H(ArH).

Compound 170; 2-[5-(2,3-Difluorophenyl)tetrazol-l-yloxy]acetopiperidide; m.p. 91-93° ; !H NMR (CDCI3) δ 1.4-1.8, m, 6H(CH2CH2CH2); 3.3, 3.45, m, m, 2H, 2H(CH2NCH2); 5.31, s, 2H(CH2θ); 7.2 - 7.5, m, 2H(ArH) and 7.75, m, lH(ArH).

Compound 197; N-Methyl-(2-[5-(2,6-difluorophenyl)tetrazol-l-yloxy])acetaniIide; m.p. 95-98°; !H NMR (CDCI3) δ 3.14, s, 3H(NCH3); 4.85, s, 2H(OCH2) and 7.0 - 7.7, m, 8H(ArH).

Compound 263; 2-[5-(3-Methyl-2-thienyl)tetrazol-l-yloxy]acetopiperidide; m.p. 83-85° ; !H NMR (CDCI3) δ 1.5-1.8, m, 6H(CH2CH2CH2); 2.69, s, 3H(ArCH3); 3.38, 3.57, m, m, 2H, 2H(CH2NCH2); 5.22, s, 2H(CH2θ); 7.04, 7.54, d, d, each lH(ArH).

Compound 277; 2-[5-(2-Pyridyl)tetrazol-l-yloxy]acetopiperidide; m.p. 114-6° ; !H NMR (CDCI3) δ 1.64, m, 6H(CH2CH2CH2); 3.53, m, 4H(CH2NCH2); 5.37, s, 2H(OCH2) and 7.48, 7.86, 8.22, each m, 4H(PyH).

Activity of Compounds of the Invention

Test results indicate that the compounds of the invention are highly active pre-emergent and/or post-emergent herbicides or plant growth regulants. These compounds are useful for controlling certain weeds in small grain cereals such as wheat (Triticum aestivum) and barley (Hordeum vulgare), examples of which include, but are not limited to, Centurk wheat, Era wheat, Igri barley and Klages barley. Many of the compounds of this invention are especially useful for the control of selected weeds, such as wild oats (Avena fatua) , black grain (Alopecurus myosoides), crabgrass (Digitaria sanguinalis), foxtails (Setaria spp.) and Italian ryegrass (Lolium multiflorum). These compounds are also particularly useful for controlling certain weeds in dryland and paddy rice (Orysa sativa) , examples of which include, but are not limited to, Indica and Japonica varieties of the crop. Many of the compounds of this invention are useful for the control of selected weeds, such as barnyard grass (eg Echinochloa crusgalli ), in paddy rice.

At the appropriate application rates, these compounds also have utility for broad-spectrum pre- and/or post-emergence weed control in areas where control of all vegetation is required. Alternatively, these compounds are useful to regulate plant growth.

Rates of application for compounds of this invention are determined by a number of factors. These factors include formulation selection, method of application, amount of vegetation present, growing conditions, etc. In general, the subject compounds should be applied at rates of 0.001 to 10 kg/ha with a preferred rate range of 0.01 to 1.0 kg/ha. One skilled in the art can easily determine application rates necessary for the desired level of weed control.

Compounds of this invention may be used alone or in combination with other commercial herbicides, insecticides or fungicides. Accordingly, in yet a further embodiment, the invention provides a herbicidal composition comprising a mixture of at least one herbicidal compound of formula (I) as hereinbefore defined with at least one other herbicide.

In yet a still further embodiment, the invention provides a method for regulating the growth of a plant comprising applying to the plant, to the seed of the plant, or to the growth medium of the plant an effective amount of a compound of Formula (I) hereinbefore defined. Rates of application of these compounds can be influenced by many factors of the environment and should be determined under actual use conditions. Weeds in graminaceous crops can normally be killed when treated at a rate of from O.OOlkg/Ha to lOKg/Ha, preferably in the range from 0.01 to 1.0 Kg active ingredient/ha.

The compounds of this invention can be mixed with fungicides, bactericides, acaricides, nematicides, insecticides, or other biologically active compounds in order to achieve desired results with a minimum expenditure of time, effort and material. Amounts of these biologically active materials added for each part by weight of the composition of this invention may vary from 0.05 to 25 parts by weight. Suitable agents of this type are well known to those skilled in the art.

Formulation

Useful formulations of the compounds within the scope of this invention can be prepared in conventional ways. They include dusts, granules, pellets, solutions, emulsions, wettable powders, emulsifiabie concentrates and the like. Many of these may be applied directly. Spray able formulations can be extended in suitable media and used at spray volumes of from one litre to several hundred litres per hectare. High strength compositions are primarily used as intermediates for further formulations. The formulations, broadly, contain about 1 % to 99% by weight of active ingredient(s) and at least one of (a) about 0.1 % to 20% surfactant(s) and (b) about 5 % to 99% solid or liquid inert diluent(s). More specifically, they will contain these ingredients in the approximate proportions given in the table below:

Percent by Weight

Formulation Type Active

Ingredient Diluent(s) Su rfactant(s.

Wettable Powders 20-90 0-74 1-10 Oil Suspensions, Emulsions, 5-50 40-95 0-15

Solutions(including Emulsifiabie

Concentrates)

Aqueous Suspensions 10-50 40-84 1-20

Dusts 1-25 70-99 0-5 Granules and Pellets 1-95 5-99 0-15

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

Lower or higher levels of active ingredients can, of course, be present depending on the intended use and the physical properties of the compound. Higher ratios of surfactant to active ingredient are sometimes desirable and are achieved by incorporation into the formulation or by tank mixing.

The compositions may be in the form of dusting powders or granules comprising the active ingredient and a solid diluent or carrier therefor, for example, kaolin, bentonite, kieselguhr, dolomite, calcium carbonate, talc, powdered magnesia, Fuller's earth, gypsum, Hewill's earth, diatomaceous earth, and China clay. The compositions may also be in the form of dispersible powders or grains comprising a wetting agent to facilitate the dispersion in liquids of the powder or grains which may contain also solid diluents, fillers and suspending agents.

Typical solid diluents are described in Watkins, et al. , "Handbook of Insecticide Dust Diluents and Carriers", 2nd Ed., Dorland Books, Caldwell, N.J. The more absorptive diluents are preferred for the wettable powders and the denser ones for dusts. All formulations can contain minor amounts of additives to reduce foam, caking, corrosion, microbiological growth, etc. Compositions for dressing seed, for example, may contain an agent (for example a mineral oil) for assisting the adhesion of the composition to the seed.

The aqueous dispersions or emulsions may be prepared by dissolving the active ingredient(s) in an organic solvent optionally containing wetting, dispersing or emulsifying agent(s) and then adding the mixture to water which may also contain wetting, dispersing or emulsifying agent(s). Suitable solvents are acetone, ethylene dichloride, isopropyl alcohol, propylene glycol, diacetone alcohol, toluene, kerosene, methylnaphthalene, the xylenes and trichloroethylene amongst others. Solubility under 0.1 % is preferred for suspension concentrates; solution concentrates are preferably stable against phase separation at 0°C. "McCutcheon's Detergents and Emulsifiers Annual", MC Publishing Corp. , Ridgewood, N.J. , as well as Sisely and Wood, "Encyclopedia of Surface Active Agents", Chemical Publishing Co. , Inc. , New York, 1964, list surfactants and recommended uses.

The methods of making such compositions are well known. Solutions are prepared by simply mixing the ingredients. Fine solid compositions are made by blending and, usually, grinding as in a hammer or fluid energy mill. Suspensions are prepared by wet milling (see, for example, Littler, US Pat. No. 3,060,084). Granules and pellets may be made by spraying the active material upon preformed granular carriers or by agglomeration techniques. The biological activity of the compounds of Formula I is illustrated by the following non- limiting examples.

Example 1 :

To demonstrate the effectiveness of compounds of Formula (I) of the present invention as herbicidal agents, compounds of Formula (II) listed in Table 1 were applied to selected crops and weeds in both post-emergent and pre-emergent treatment at a rate equivalent to 0.2 kg/hectare. The herbicidal data are shown in Table 4 In the table 0 signifies no effect and 10 signifies plant dead. As can be seen the compounds of Formula (I) selectively control several weed species in a number of crops.

Table 4

Compound Test Rating

(Table 1) Species pre-emergent. post-emergent

37 Barnyard grass 10 9

Giant foxtail 10 7

Crabgrass 9 6

Corn 0 0

Rice 0 1

Soybean 0 0

Sugarbeet 0 0

Morning glory 0 0

Velvet leaf 0 0

Lambs quarter 8 0

135 Barnyard grass 9 8

Giant foxtail 9 7

Crabgrass 8 3

Corn 0 0

Rice 0 3

Soybean 0 1

Sugarbeet 0 0

Morning glory 2 0

Velvet leaf 0 2

Lambs quarter 8 0

Barnyard grass 10 9

Giant foxtail 9 9

Crabgrass 9 8

Corn 4 6

Rice 0 9

Soybean 0 1

Sugarbeet 3 0

Morning glory 2 2

Velvet leaf 5 7

Lambs quarter 10 7

In a further demonstration of the effectiveness of compounds of Formula (I) of the present invention as herbicidal agents, compounds of Formula (II) listed in Table 1 were applied to selected crops and weeds in both post-emergent and pre-emergent treatment at a rate equivalent to 0.25 kg/hectare. The herbicidal data are shown in Table 5 In the table 0 signifies no effect and 10 signifies plant dead. As can be seen, the compounds of Formula (I) may be used to selectively control several weed species in a number of crops.

Table 5

Compound Test Rating

(Table 1) Species pre-emergent. post- emergent

2 Barnyard grass 7 Giant foxtail 10 8

Crabgrass 8 7

Corn 0 0

Rice - 7

Soybean 2 3 Sugarbeet 0 0

Morning glory 0 2 Velvet leaf 0 3

4 Barnyard grass 9 Giant foxtail 9 3

Crabgrass 9 5 Corn 0 2

Rice - 7

Soybean 0 0 Sugarbeet 6 2 Morning glory 2 0 Velvet leaf 0 0

11 Barnyard grass 8 Giant foxtail 10 8

Crabgrass 0 4 Corn 0 0

Rice - 0

Soybean 0 3 Sugarbeet 0 0

Morning glory 0 0 Velvet leaf 0 0 Barnyard grass 7 Giant foxtail 10 9

Crabgrass 9 6

Corn 0 0

Rice - 2

Soybean 0 3 Sugarbeet 0 0

Morning glory 0 1 Velvet leaf 0 0

Barnyard grass 9 Giant foxtail 10 9

Crabgrass 10 9 Corn 2 2

Rice - 6

Soybean 0 2 Sugarbeet 2 0

Morning glory 0 0 Velvet leaf 2 3

Barnyard grass - 9

Giant foxtail 10 9

Crabgrass 7 9

Corn 0 5

Rice - 7

Soybean 0 1

Sugarbeet 2 0

Morning glory 0 1 Velvet leaf 2 4

Barnyard grass - 9

Giant foxtail 10 8

Crabgrass 10 9

Corn 5 0

Rice - 7

Soybean 0 3

Sugarbeet 7 0

Morning glory 0 1 Velvet leaf 7 0

Barnyard grass - 9

Giant foxtail 10 9

Crabgrass 10 9

Corn 2 2

Rice - 7

Soybean 0 3

Sugarbeet 0 0

Morning glory 0 0 Velvet leaf 0 5

Barnyard grass - 9

Giant foxtail 10 8

Crabgrass 6 8

Corn 0 0

Rice - 7

Soybean 0 2

Sugarbeet 5 3

Morning glory 0 4 Velvet leaf 0 3

Claims

1. Compounds of the formula (I):

(I)

characterised in that:

R! , R2 may be the same or different and are independently selected from H and C1-C4 alkyl. or may together form a 3 to 8 membered carbocyclic or heterocyclic ring;

R3, R4 are selected from the group comprising hydrogen, optionally substituted alkyl, cycloalkyl, optionally substituted aryl, heterocyclyl, or R3 and R4 together with the nitrogen to which they are attached form a saturated or unsaturated 5-, 6- or 7-membered heterocyclic ring containing 1-2 heteroatoms selected from the group consisting of 0-2 nitrogen, 0-1 oxygen and 0-2 sulfur atoms; said ring is optionally substituted with 1-4 CH3 groups. Compounds of Formula II

N =N

-A

0 R (II)

wherein A =

AND

wherein

X, Y, Z are independently selected from the group comprising H, Cl, Br, F, C1-C3 alkyl, C1-C3 alkoxy, C1-C3 alkylthio, C1-C3, C1-C3 alkysulfinyl, Ci-C3 alkylsulfonyl, C1-C3 haloalkyl, C1-C3 haloalko_xy, nitro, cyano or C1-C3 alkoxycarbonyl; or benzenesulfonyl, benzoyl, benzyl, benzyloxy, phenoxy, phenylthio or phenylamino optionally substituted with 1-3 substituents selected from the group consisting of halogen, C1-C4 alkyl, C1-C4 alkoxy, or CF3; AND R^and R4 together form a 3 to 8 membered ring or R^ and R4 are independently selected from hydrogen, optionally substituted C1-C6 alkyl, cycloalkyl, optionally substituted aryl or heterocyclyl.

3. Compounds of formula II as stated in Claim 2, characterised in that R is optionally substituted alkyl, alkenyl, alkynyl, or heterocyclyl, and A, X, Y, Z, R^and R4 are as defined in Claim 2

4. Compounds as claimed in Claim 2 or claim 3, characterised in that the group A is one of the groups Al to A37 hereinbefore described.

5. Compounds of Formula III:

(III) characterised in that R = optionally substituted heterocyclyl or

R =

wherein

X, Y, Z are independently selected from the group comprising H, Cl, Br, F, C1-C3 alkyl, C1-C3 alkoxy, C1-C3 alkylthio, C1-C3 haloalkyl, C1-C3 haloalkoxy, nitro, cyano or -C3 alkoxycarbonyl; or benzenesulfonyl, benzoyl, benzyl, benzyloxy, phenoxy, phenylthio or phenylamino optionally substituted with 1-3 substituents selected from the group consisting of halogen,

C1-C4 alkyl, C1-C4 alkoxy, or CF3

AND G is an optional substituent selected from the group comprising C1-C3 alkyl, C1-C3 alkoxy, Q-C3 alkylthio, C1-C3 haloalkyl, C1-C3 haloalkoxy or C1-C3 alkoxycarbonyl.

6. A compound as claimed in Claim 1, which is selected from the following: 2-[5-(2-Chlorophenyl)tetrazol- 1 -yloxy] acetopiperidide 2-[5-(4-Chlorophenyl)tetrazol-l-yloxy]acetopiperidide 2-[5-(2,4Dichlorophenyl)tetrazol-l-yloxy]acetopiperidide N-Ethyl-N-methyl(2-[5-(Phenyl)tetrazol-l-yloxyJ)acetamide 2-[5-(Phenyl)tetrazol- 1 -yloxy] acetopyrrolidide

2-[5-(2-Fluorophenyl)tetrazol-l-yloxy]aceto(2-methyl)piperidide 2-[5-(2-Fluorophenyl)tetrazol- 1 -yloxy] aceto(4-methyl)piperidide N-Methyl(2-[5-(2-fluorophenyl)tetrazol- 1 -yloxy])acetanilide 2-[5-(3-Fluorophenyl)tetrazol-l-yloxy]acetopiperidide 2-[5-(4-Fluorophenyl)tetrazol-l -yloxy] acetopiperidide

2-[5-(2-Methylphenyl)tetrazol- 1 -yloxy] aceto(2-methyl)piperidide 2-[5-(2-Methylphenyl)tetrazol-l-yloxy]aceto(4-methyl)piperidide 2-[5-(2,3-Difluorophenyl)tetrazol-l-yloxy]acetopiperidide N-Methyl(2-[5-(2,6-difluorophenyl)tetrazol-l-yloxy])acetanilide 2-[5-(3-Methyl-2-thienyl)tetrazol-l-yloxy]acetopiperidide

7. A herbicidal composition characterised in that it comprises at least one herbicidal compound of formula (I) as defined in any one of the preceding claims, togther with an agriculturally acceptable carrier or diluent.

8. A herbicidal composition as claimed in Claim 7, characterised in that it includes at least one other herbicide, other than the compound of formula (I).

9. A method for pre- and/or post-emergent control of unwanted plants, characterised in that it comprises application to the plants, or their locus, a herbicidally effective amount of a compound of formula (1) or a composition as claimed in Claim 7 or Claim 8.

10. A plant growth regulating composition characterised in that it comprises at least one herbicidal compound of formula (I) as defined in any one of Claims 1 to 6, together with an agriculturally acceptable carrier or diluent.

11. A method for regulating the growth of a plant, characterised in that it comprises applying to the plant, to the seed of the plant, or to the growth medium of the plant an effective amount of a compound of Formula (I) or a composition as claimed in

Claim 10.

12. A composition as claimed in any one of Claims 7, 8 and 10 characterised in that it includes one more of fungicides, bactericides, acaricides, nematicides, insecticides, or other biologically active compounds.