EP0513028A1 - Herbicidal pyrones - Google Patents

Abstract

Compounds of formula (2) and its isomeric and / or tautomeric forms, in which A represents an alkylene group containing 1 to 4 carbon atoms or alkenylene containing 3 to 4 carbon atoms, optionally replaced by 1 to 4 alkyl substituents containing 1 to 3 carbon atoms; X represents O, S, SO, SO2, NR10 or a single bond; R1 represents H, or a group from a number of specified groups, or M; R2 represents alkyl containing 1 to 6 carbon atoms, or one of a number of other specified groups; R3 and R4 independently represent H or alkyl containing 1 to 4 carbon atoms; R5 and R6 independently represent alkyl containing 1 to 4 carbon atoms or one of a number of other specified groups; or, R5 and R6 as well as the carbon atom to which they are attached form a ring among a number of specified carbocyclic or heterocyclic rings, which may be replaced by specified substituents; R7, R8 and R9 independently represent H or a group from a number of specified groups; R10 represents H or a group from a number of specified groups; and M represents Li +, Na +, K +, NH4 + or N (R11) 4+, where R11 represents alkyl containing 1 to 4 carbon atoms. Also described are methods of preparing said compounds, herbicidal and plant growth regulating compositions containing them, and methods of regulating plant growth and inhibiting, damaging or selectively eliminating weeds. in a broadleaf culture using them.

Description

"HERBICIDAL PYRONES"

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. The use of certain cyclohexane-1,3-dione derivatives as grass herbicides is known in the art. Thus, for example, the

compendium "Agricultural Chemicals - Book II Herbicides 1983- 84 Revision" (W.T. Thomson Editor, Thomson Publications,

California U.S.A.) describes the cyclohexane-1,3-dione derivatives known commercially as Alloxydim sodium (methyl-3-[1-

(allyloxyimino)butyl]-4-hydroxy-6,6-dimethyl-2-oxocyclohex-3- ene carboxylate), Cycloproxydim ((E,E)-2[1 [1-[(3- chloro-2-propenyl)oxy]imino]butyl]-5-[2-(ethylthio)propyl]-3- hydroxy-2-cyclohexen-1-one), and Sethoxydim (2-[1-1- (ethoxyimino)butyl]-5-[2-ethylthio]propyl-3-hydroxy-2- cyclohexen-1-one) as selective post-emergent herbicides.

Alloxydim and Sethoxydim have been disclosed in Australian Patent No. 464,655 and Australian Patent Application No.

35314/78 respectively.

Australian patent No 560,716 (Application No 27196/84) in the name of ICI Australia Limited, published 22 November 1984, discloses herbicidal compounds of the formula:

wherein

R is substituted phenyl;

R¹ is H, alkyl, alkenyl, alkynyl, alkoxyalkyl, alkylthioalkyl, alkylsulfonyl, alkoxy, alkylthio, acyl, (un)substituted phenylalkyl or PhSO₂;

R² is alkyl, alkenyl, haloalkenyl, alkynyl, haloalkynyl, haloalkyl, alkoxyalkyl, alkylthioalkyl or (un)substituted phenylalkyl; and

R³ is alkyl, fluoroalkyl, alkenyl, alkynyl, or phenyl.

This specification teaches that tetrahydropyran-2,4-dione derivatives which are substituted in the 6- position with a substituted phenyl group exhibit particularly useful herbicidal activity.

United States patent No 4,008,067 (issued February 15, 1977) in the name of Hirono et al discloses herbicidal oxacyclohexane derivatives of the formula:

wherein:

R¹ is lower alkyl;

R² is lower alkyl, lower alkenyl or lower alkynyl;

A is

wherein

R³ is H or lower alkyl;

R⁴ is lower alkyl or phenyl; or

R³ forms cycloalkylene of 4 to 5 carbon atoms by

combining with R⁴; OR

wherein

R⁵ and R⁷ are selected from the group consisting of

H and lower alkyl;

R⁶ is lower alkyl;

OR

wherein

R⁸ is H or lower alkyl; and

R⁹ is lower alkyl.

The above compounds are substituted in the 5 and/or 6- positions of the pyran ring by one or two alkyl groups

International patent application PCT/AU87/00236, filed July 27, 1987 (International Patent Publication WO 8800945) in the name of the present applicants and corresponding to Australian patent application No 77583/87, European patent application No

87904820, Japanese patent application No 504 646 and United States application serial number 188,800, describes herbicidal pyrones of the formula:

wherein, in part,

R¹ is H;

R² is substituted alkyl wherein the alkyl group is substituted by optionally substituted phenyl and optionally substituted

heterocycle; R³ is alkyl;

R⁴ and R⁵ together with the carbon to which they are attached form a substituted or unsubstituted saturated or partially

saturated heterocyclic or carbocyclic ring containing 3 or more ring atoms; etc. This is only a brief listing of the relevant groups.

The last mentioned spirocyclic analogues are stated as being a preferred subgenus. Further preferred are compounds in which R¹ is H, R² is alkyl, alkenyl or haloalkenyl (specifically ethyl, allyl, 2- chloroallyl and 3-chloroallyl) and R³ is ethyl or n-propyl.

WO 8800945 at Tables 1-4 lists 91 individual spirocyclic compounds, all with R² as ethyl, allyl or chloroallyl only. At page 23A the specification teaches that " The compounds of the invention are substantially more effective against monocotyledenous plants or grass species than against dicotyledenous plants or broad-leaved species. " Although it is also stated on pages 23A and 25 of this specification that "certain of the compounds......show selective herbicidal activity against wild grasses in monocotyledenous crop species and hence may be used for selective control of wild grass in graminaceous crops", the application emphasises the use of the disclosed compounds for control of grass weeds in broadleaf crops without damage to the broadleaf crop. International patent application PCT/AU89/00191 also in the name of the present applicants, describes herbicidal pyrones that are similar to those described in WO 8800945, but which have an additional substituent, R⁶, on the pyrone ring. The compounds described in PCT/89/00191 are of the general formula:

wherein the substituted groups R¹ to R⁵ are similar to those described in WO 8800945, and,

R⁶ is selected from alkyl, alkoxy, alkylthio, halogen or substituted alkyl wherein the alkyl group is substituted with a substituent selected from the group consisting of alkoxy, alkylthio or halogen.

Preferred values for the oxime capping group R² are alkyl, alkenyl, alkynyl and haloalkenyl; specifically preferred are ethyl, propargyl, allyl, 2-chloroallyl and 3-chloroallyl. This specification states "certain of the compounds of Formula

2 may be used for selective control of wild grass in

graminaceous crops." However there is no specific mention of which compounds or of usefulness on rice crops. The specification of PCT/AU89/00191 includes 15 examples

relating to spirocyclic derivatives, but the oxime capping

groups shown are restricted to ethyl, allyl or chloroallyl.

We have discovered that compounds similar to those described in International Patent Application WO 8800945 and

PCT/AU89/00191 in which R² includes a phenyl or substituted phenyl group are highly active pre-emergent and/or post- emergent herbicides or plant growth regulators and are particularly useful for controlling certain grass and broadleaf weeds in dryland and paddy rice.

Accordingly, the invention provides a compound of the formula (2):

wherein

A is a C₁-C₄ alkylene or C₃-C₄ alkenylene group optionally substituted with 1-4 C₁-C₃ alkyl substituents;

X is O, S, SO, SO₂, NR¹⁰ or a single bond;

R¹ is H, C₁-C₄ alkyl, C₂-C₄ alkenyl, C₂-C₄ alkynyl,

C₅-C₆ cycloalkyl, C₅-C₆ cycloalkenyl, phenyl optionally substituted with 1-3 substituents selected from the group consisting of halogen, C₁-C₄ alkyl, C₁-C₄ alkoxy,

C₁-C₄ alkylthio, nitro, cyano, C₁-C₄ haloalkyl, amino, and C₁-C₄ haloalkoxy, C₁-C₄ alkylsulfonyl, benzenesulfonyl, C₁-C₄ alkylcarbonyl, C₂-C₈ alkoxyalkyl, C₂-C₈

alkylthioalkyl, C₇-C₁₀ phenylalkyl or M; R² is C₁-C₆ alkyl, C₂-C₆ alkenyl, C₂-C₆ alkynyl, C₁-C₄ haloalkyl, C₁-C₄ alkylthio, C₃-C₆ cycloalkyl, C₅-C₆ cycloalkenyl, phenyl optionally substituted with 1-3 substituents selected from the group consisting of halogen, C₁-C₄ alkyl, C₁-C₄ alkylthio, nitro, cyano, C₁-C₄ haloalkyl, amino, and C₁-C₄ haloalkoxy, C₂-C₈ alkoxyalkyl, C₂-C₈ alkylthioalkyl, or C₁-C₄ alkyl substituted with a substituent selected from the group consisting of phenyl, phenoxy and

thiophenoxy wherein said phenyl groups may be

substituted with 1-3 substituents selected from halogen, C₁-C₄ alkyl, C₁-C₄ alkoxy, C₁-C₄ alkylthio, nitro, cyano, amino, C₁-C₄ haloalkyl and C₁-C₄ haloalkoxy;

R³ and R⁴ are independently H or C₁-C₄ alkyl; R⁵ and R⁶ are independently C₁-C₄ alkyl, C₂-C₄ alkenyl, C₂-C₆

alkylthioalkyl, C₁-C₄ haloalkyl, C₂-C₄ haloalkenyl, C₃-C₆ cycloalkyl optionally substituted with a substituent selected from the group consisting of

C₁-C₄ alkoxycarbonyl and phenyl which may be

substituted with a substituent selected from halogen, C₁-C₄ alkyl, C₁-C₄ alkoxy, C₁-C₄ alkylthio, nitro, cyano, C₁-C₄ haloalkyl and C₁-C₄ haloalkoxy;

or

R⁵ and ^R6 together with the carbon to which they are attached form a fully saturated or an unsaturated 3- to 7- membered carbocyclic ring, or a fully saturated or an unsaturated 5- to 7-membered heterocyclic ring

containing 1-3 heteroatoms selected from the group consisting of 0-3 nitrogen, 0-2 oxygen and 0-2 sulfur atoms; said ring may be substituted with 1-4 substituents selected from the group consisting of halogen, C₁-C₄ alkyl, C₁-C₄ haloalkyl, C₂-C₄ alkenyl, C₂-C₄ alkynyl,

C₁-C₄ alkylcarbonyl, C₁-C₄ alkoxy, C₁-C₄ alkylthio,

C₁-C₄ alkoxycarbonyl, -COOH, C₂-C₈ alkoxyalkyl, C₂-C₈ alkylthioalkyl, and phenyl which is optionally substituted with a substituent selected from halogen, C₁-C₄ alkoxy, C₁-C₄ alkylthio, C₁-C₄ haloalkyl, nitro, cyano and C₁-C₄ haloalkoxy; one of the carbon atoms of said ring may be in the form of a carbonyl group or its corresponding dimethyl, diethyl or ethylene or propylene ketal; R⁷, R⁸ and R⁹ are independently H, halogen, C₁-C₄ alkyl,

C₁-C₄ alkoxy, C₁-C₄ alkylthio, C₁-C₄ alkylsulfinyl,

C₁-C₄ alkylsulfonyl, C₁-C₄ haloalkyl, C₁-C₄ haloalkoxy, nitro, cyano, C₁-C₄ alkoxycarbonyl, C₁-C₄

alkylaminocarbonyl, C₂-C₆ dialkylaminocarbonyl, aminocarbonyl, phenyl, amino, C₁-C₄ alkylamino,

C₂-C₆ dialkylamino;

R¹⁰ is H, C₁-C₄ alkyl or phenyl optionally substituted with 1-3 substituents selected from the group consisting of halogen, C₁-C₄ alkyl, C₁-C₄ alkoxy, C₁-C₄ alkylthio, C₁-C₄ haloalkyl and C₁-C₄ haloalkoxy; and

M is Li⁺, Na⁺, K⁺, NH₄ ⁺, or N(R¹¹)₄ ⁺ where R¹¹ is C₁-C₄ alkyl. In the above definitions, the term "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.

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 CH₂CHFCl.

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 (2), for reasons including ease of synthesis and greater herbicidal efficacy, include the following: (1) Compounds of Formula 2 wherein

R¹ is H or M; and

R² is C₁-C₄ alkyl, C₁-C₄ haloalkyl, C₂-C₄ alkenyl or C₂-C₄ alkynyl . (2) Compounds of 1 above wherein

A is C₁-C₂ alkylene or C₃-C₄ alkenylene optionally

substituted with CH₃ or C₂H₅;

R⁷, R⁸ and R⁹ are independently H, Cl, Br, F, C₁-C₃ alkyl, C₁-C₃ alkoxy, C₁-C₃ alkylthio, C₁-C₃ haloalkyl, C₁-C₃ haloalkoxy, nitro, cyano, or C₁-C₃ alkoxycarbonyl ; and

R ¹⁰ is H or CH₃.

(3) Compounds of 2 above wherein X is O

(4) Compounds of 2 above wherein X is S, SO or SO₂.

(5) Compounds of 2 above wherein X is NR¹⁰. (6) Compounds of 2 above wherein X is a single bond.

(7) Compounds of 6 above wherein:

A is -CH₂-, -CH₂CH₂- or -CH₂CH=CH- ;

R¹ is H, Li+, Na+, or K+;

R² is CH₃, C₂H₅, n-C₃H₇ or n-C₄H₉ ;

R³ and R⁴ are independently H, CH₃ or C₂H₅ ; and

R⁷, R⁸ and R⁹ are independently H, Cl, Br, F, CH³, C₂H₅, OCH₃, OC₂H₅, SCH₃, SC₂H₅, CF₃, CHF₂, CF₂CF₃, OCHF₂, OCF₃, OCH₂CF₃, NO₂, CN or CO₂CH₃. (8) Compounds of 6 above wherein R⁵ and R⁶ are

independently C₁-C₄ alkyl, C₂-C₄ alkenyl, C₂-C₄ alkynyl, C₁-C₄ alkylthio or C₂-C₆ alkylthioalkyl.

(9) Compounds of 6 above wherein R⁵ and R⁶ together with the carbon to which they are attached form a saturated or unsaturated 5-, 6- or 7-membered

carbocyclic ring which is optionally substituted with 1-4 CH₃ groups.

(10) Compounds of 9 above wherein:

A is -CH₂-, -CH₂CH₂- or CH₂CH=CH- ;

R¹ is H, Li+, Na+ or K+; R² is CH₃, C₂H₅, n-C₃H₇ or n-C₄H₉; R³ and R⁴ are independently H or CH₃; and

R⁷, R⁸ and R⁹ are independently H, Cl, Br, F, CH₃, C₂H₅, OCH₃, OC₂H₅, SCH₃, SC₂H₅, CF₃, CHF_2, CF₂CF₃, OCHF₂, OCF₃, OCH₂CF₃, NO₂, CN, or CO₂CH₃.

(11) Compounds of 6 above wherein:

R⁵ and R⁶ together with the carbon 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. (12) Compounds of 11 above wherein:

A is -CH₂-, -CH₂CH₂- or -CH₂CH=CH- ;

R¹ is H, Li+, Na+ or K+;

R² is CH₃, C₂H₅, n-C₃H₇ or n-C₄H₉;

R³ and R⁴ are independently H, CH₃ or C₂H₅ ;

and R⁷, R⁸ and R⁹ are independendy H, Cl, Br, F, CH₃, C₂H₅,

OCH₃, OC₂H₅, SCH₃, SC₂H₅, CF₃, CHF₂, CF₂CF₃, OCHF₂, OCF₃,

OCH₂CF₃, NO₂, CN, or CO₂CH₃.

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

8-[ 1 -((3-Chlorophenyl)methoxyimino)butyl]-9-hydroxy- 6-oxaspiro[4.5]dec-8-en-7-one, which has the formula:

(m.p. 98ºC) and 9-hydroxy-8-[1 -(3-phenylallyloxyimino)butyl]-6- oxaspiro[4.5]dec-8-en-7-one, which has the formula

Specific examples of compounds of the invention of Formula (2) include those compounds detailed in Tables 1-4 below. Unless otherwise specified in the Tables, X is taken to be a single bond.

Table 1

Table 2 Table 3

Table 4

It should be recognized that when R¹ is hydrogen the

compounds (2) of the invention may undergo tautomerisation. All tautomeric forms are included in the scope of this

invention.

The compounds of the invention may be prepared by a method similar to that disclosed in W08800945, with appropriate alteration of starting reagents. For example, the compounds of the invention may be prepared from the dianion of an acetoacetate ester by condensation with an appropriate ketone (cf. Hukin, S.N., and Weller, L. Can J Chem, 1974, 52, 2157) followed by cyclization with or without intermediate hydrolysis to novel tetrahydro-2H-pyran-2,4-diones. The pyrandiones or their tautomeric 4-hydroxy-5,6-dihydro-2H- pyran-2-one equivalents can also be obtained by customary methods described in the literature. The 6,6-disubstituted pyran-2,4-diones thus obtained may be acylated on oxygen and the enol esters isomerized (Fries rearrangement) to give novel C-substituted products. The C-acylated derivatives may be reacted with O-substituted hydroxylamines which may in turn be generated in situ from appropriate precursors, to afford derivatives of the general Formula(2) wherein R¹ is hydrogen. Compounds of the invention of Formula(2) wherein R¹ is not hydrogen may be prepared by standard synthetic procedures. For example, compounds of the invention of Formula(2) wherein R¹ is is an organic or inorganic cation may be prepared from compounds of the invention of Formula(2) wherein R¹ is hydrogen by reacting these latter compounds with an

appropriate inorganic or organic base.

Esterification of the vinylogous acid in compounds of the invention of Formula(2) wherein R¹ is hydrogen provides further herbicidal and growth regulating derivatives. The general procedure for preparation of Compounds of the

Invention is described in detail in the following section.

General Procedure for Preparation of Compounds of the Invention

(a) Synthesis of the Pyran-2,4-diones To a stirred solution of the sodium salt of an (alkyl) acetoacetate ester [ca. 55 mmol, either preformed or made in situ from the (alkyl) acetoacetate ester ( 55 mmol) and sodium hydride (55 mmol) according to the method of Huckin, S.N., and Weiler, L., Can. J. Chem., 1974, 52, 2157] in dry tetrahydrofuran (50 ml) under nitrogen and cooled to 0°C, was added dropwise a solution of n-butyllithium (21.2 ml, 2.6M in hexane, 55 mmol). After 1 h the mixture was treated with an appropriate ketone (50 mmol) (solid ketones were dissolved in tetrahydrofuran prior to addition ) and left stirring at 0°C for 120 min before being quenched with methanol (2.4 ml, 60 mmol). After addition of further methanol (20 ml) and water (10 ml) [and in certain instances acid] the mixture was boiled for ca. 30 min then diluted further with water (40ml) and concentrated (to ca. 40 ml) at reduced pressure. Upon cooling and addition of water (ca. 150 ml) the mixture was extracted with ether (2 x 100 ml). The ether extracts were washed with water (50 ml); and the combined aqueous phases were acidified to pH 1-2 with cone, hydrochloric acid and

extracted with ether (100 ml). (At this stage of some reactions a first crop of the pyrandione crystallized from the ether solution and was recovered by filtration.) The ether solution was then evaporated and the residual water removed from the product mixture by azeotropic distillation with ethanol/benzene and then with benzene. The residue was either chromatographed (SiO₂, dichloromethane) or, in some instances, crystallization of the pyrandione was achieved by diluting a concentrated benzene solution (ca. 20 ml) of the residue cautiously with cyclohexane to a faint turbidity, and then stirring vigorously. When crystallization ensued, the mixture was cautiously diluted with more cyclohexane (ca. 20 ml) and stirred for a further 4 h, after which the

precipitate was collected and washed with cyclohexane/benzene (4:1) to afford the pyrandione. Method B

A solution of n-butyllithium (45 ml, 2.45M in hexane, 110 mmol) was added to a stirred solution of diisopropylamine (15.6 ml, 111 mmol) in tetrahydrofuran (50 ml) maintained at 0°C under argon. The stirring was continued for 15 min at room temperature; the mixture was then chilled in ice. The (alkyl) acetoacetate

ester(52.5 mmol) was then added and the resultant mixture stirred at 0°C for 30 min whereupon an appropriate ketone (50 mmol dissolved in the minimum quantity of tetrahydrofuran to form a homogeneous solution) was added and stirring continued for an additional 90 min (or until the reaction mixture paled to light orange or yellow) before quenching with methanol (4.8 ml, 120 mmol). The reaction mixture was then worked up as in Method A to give the pyrandione.

(b) Acylation of Pyrandiones

To a stirred solution of the pyrandione (6.10 mmol) and DBU

[1,8-diazabicyclo(5.4.0)-7-undecene](0.99g, 6.5 mmol) in toluene (20ml) at 0°C was added an appropriate acyl chloride (6.6 mmol) and the mixture stirred at 0°C for 2 h, then at room temperature for 24 h. Dilution with water (50 ml) and toluene (30 ml) and shaking the mixture gave an organic phase which was quickly washed with 5% hydrochloric acid, dried (sodium sulfate) and evaporated in vacuo. The residue and 4-dimethylaminopyridine (40 mg, 0.3 mmol) were heated under reflux in toluene (10 ml) for 3 h (or until thin layer chromatography showed that the reaction was complete) and then the toluene was removed in vacuo and the residue chromatographed [SiO₂,

dichloromethane:light petroleum (b.p. 40-60C): ethyl acetate (4:4:1)] to give the C-acylated compound. (c) Oximation of Acylated Compounds.

A mixture of the C-acylated compound (3.75 mmol), the

appropriate O-substituted hydroxylamine hydrochloride (4.00 mmol), triethylamine (0.41 g, 4.0 mmol) and methanol (5 ml) was stirred at room temperature for 48 h, then poured into water (50 ml). Acidification of the mixture to pH 4 with 5M hydrochloric acid, extraction with diethyl ether or ethyl acetate (2 x 50 ml), evaporation of the organic phase and chromatography [SiO₂, dichlorome thane or dichloromethane:light petroleum (b.p. 40- 60C):ethyl acetate (4:4:1)] of the residue then afforded examples of compounds of the invention (2).

Activity of Compounds of the invention

Test results indicate that the compounds of this invention are highly active pre-emergent and/or post-emergent herbicides or plant growth regulants. These compounds are particularly useful for controlling certain grass and broadleaf weeds in dryland and paddy rice (Oryza 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

especially useful for the control of selected grass weeds, such as barnyardgrass (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 0.05 to 10 kg/ha with a preferred rate range of 0.1 to 2 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. A list of such commercial compounds is given in

Appendix A of this specification. Accordingly, in yet a further embodiment, the invention provides a herbicidal composition comprising a mixture of at least one herbicidal compound of formula (2) 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 (2) as 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. Weed grasses in graminaceous crops can normally be killed when treated at a rate of from less than 0.1 to about 20 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 formulation of the compounds within the scope of this invention can be prepared in conventional ways. They include dusts, granules, pellets, solutions, emulsions, wettable powders, emulsifiable concentrates and the like. Many of these may be applied directly. Sprayable 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 ingredients(s) and at least one of (a) about 0.1% to 20%

surfactants(s) and (b) about 5% to 99% solid or liquid inert diluent(s). More specifically, they will contain these ingredients in the following approximate proportions:

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 therefore, for example, kaolin, bentonite, kieselguhr, dolomite, calcium carbonate, talc, powdered magnesia, Fuller's earth, gypsum, Hewitt'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, U.S. 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 synthesis of the compounds of the invention is further illustrated by the descriptions in the following examples.

Example 1 (Compound 1.15)

Preparation of 8-[1-((3-Chlorophenyl)methoxyimino)butyl]-9- hydroxy-6-oxaspiro[4.5]dec-8-en-7-one.

A mixture of N-((3-chlorophenyl)methoxy)phthalimide (1.15 g) and 2-diethylaminoethylamine (0.522 g) in ethanol (10.0 ml) was stirred at 20C until thin layer chromatography showed that the starting phthalimide was no longer present. To the resulting solution was added 8-butyryl-6-oxaspiro[4.5]dec-7,9-dione (0.785 g) and after 24 hours at 20C the mixture was diluted with water (100 ml), acidified to pH 3 with 5 N hydrochloric acid and

extracted with diethyl ether. Evaporation of the organic phase and chromatography of the residue over silica gel then gave the

product (0.47 g) as colorless crystals, m.p. 98-100C,

1H nmr. δ(CDCl₃) 0.94, broad t, J 7 Hz, CH₃; 1.4-2.2, m, 10 H, cyclopentyl and CH₂CH₃; 2.61, s, COCH₂; 2.96, broad t, J 8Hz,

CH₂CH₂CH₃; 5.0, s, OCH₂ and 7.34, broad s, aromatic H. Example 2 (Compound 1.36)

Preparation of 9-hydroxy-8-[1-(3-phenylallyloxyimino)butyl] -6- oxaspiro[4.5]dec-8-en-7-one.

A mixture of N-(1-(3-phenylallyl)oxy)phthalimide (1.12 g) and 2-diethylaminoethylamine (0.522 g) in ethanol (10.0 ml) was stirred at 20C until thin layer chromatography showed that the starting phthalimide was no longer present. To the resulting solution was added 8-butyryl-6-oxaspiro[4.5]dec-7,9-dione (0.785 g) and after 24 hours at 20C the mixture was diluted with water (100 ml), acidified to pH 3 with 5 N hydrochloric acid and extracted with diethyl ether. Evaporation of the organic phase and chromatography of the residue over alumina gave the product (0.37 g) as a pale yellow oil, ¹H nmr. δ(CDCl₃) 0.97, broad t, J 8 Hz; 1.3-2.4, m, cyclopentyl and CH₂CH₃; 2.62 s, COCH₂; 3.0, broad t, J 8 Hz, CH₂CH₂CH₃; 4.66, d, J 6 Hz, OCH₂; 6.3-6.7, m, CH=CH and 7.35, broad s, aromatic H.

Example 3 (Compound 1.5)

Preparation of 8-[1-((3-Chlororophenyl)methoxyimino)butyl]-10- ethyl-9-hydroxy-6-oxaspiro[4.5]dec-8-en-7-one.

A mixture of N-((3-chlorophenyl)methoxy)phthalimide (0.86 g) and 2-dimethylaminoethylamine (0.38g) in ethanol (10.0 ml) was stirred at 20C for 4 hours. To the resulting solution was added 8- butyryl-10-ethyl-6-oxaspiro[4.5]dec-7,9-dione (0.53 g) and after 24 hours at 20C the mixture was diluted with water (100 ml), acidified to pH 3 with 5 N hydrochloric acid and extracted with diethyl ether. Evaporation of the organic phase and

chromatography of the residue over silica gel followed by

crystallization from light petroleum gave the product (0.33 g) as a colourless oil,

¹H nmr. δ(CDCl₃) 0.95, broad t, J 7 Hz, 2x CH₂CH₃; 1.2-2.3, m, 12 H, cyclopentyl and 2x CH₂CH₃; 2.7-3.1, broad m, CH₂CH₂CH₃ and CHCH₂; 5.0, s, OCH₂ and 7.22, broad s, aromatic H. Example 4 (Compound 1.13)

Preparation of 9-hydroxy-8-[1-(phenylmethoxyimino)butyl]-6- oxaspiro[4.5]dec-8-en-7-one. A mixture of N-(phenylmethoxy)phthalimide (1.01 g) and 2- diethylaminoethylamine (0.522 g) in ethanol (10.0 ml) was stirred at 20C for 8 hours. To the solution was added 8-butyryl-6- oxaspiro[4.5]dec-7,9-dione (0.785 g) and after 24 hours at 20C the mixture was diluted with water (100 ml), acidified to pH 3 with 5 N hydrochloric acid and extracted with diethyl ether. Evaporation of the organic phase and chromatography of the residue over silica gel gave the product (0.38 g) as a pale yellow oil,

1H nmr. δ(CDCl₃) 0.97, broad t, J 7 Hz, CH₃; 1.2-2.3, m, 10 H, cyclopentyl and CH₂CH₃; 2.6, s, COCH₂; 2.98, broad t, J 8Hz,

CH₂CH₂CH₃; 5.04, s, OCH2 and 7.3, s, aromatic H.

Example 5 (Compound 1.21)

Preparation of 9-hydroxy-8-[1-((4- methylphenyl)methoxyimino)butyl]-6-oxaspiro[4.5]dec-8-en-7- one.

A mixture of N-((4-methylphenyl)methoxy)phthalimide (1.28 g) and 2-diethylaminoethylamine (0.522 g) in ethanol (10.0 ml) was stirred at 20C for 24 hours. To the resulting solution was added 8- butyryl-6-oxaspiro[4.5]dec-7,9-dione (0.785 g) and after 24 hours at 20C the mixture was diluted with water (100 ml), acidified to pH 3 with 5 N hydrochloric acid and extracted with diethyl ether. Evaporation of the organic phase and chromatography of the residue over silica gel gave the product (0.48 g) as colorless crystals, m.p. 85-87C,

¹H nmr. δ(CDCl₃) 0.98, broad t, J 7 Hz, CH₃; 1.2-2.2, m, 10 H, cyclopentyl and CH₂CH₃; 2.40, s, aromatic CH₃; 2.64, s, COCH₂; 2.96, broad t, J 8Hz, CH₂CH₂CH₃; 4.96, s, OCH₂ and 7.3, s, aromatic H. Example 6 (Compound 1.25)

Preparation of 8-[1-((3-Bromophenyl)methoxyimino)butyl]-9- hydroxy-6-oxaspiro[4.5]dec-8-en-7-one. A mixture of N-((3-bromophenyl)methoxy)phthaIimide (1.33 g) and 2-diethylaminoethylamine (0.52 g) in ethanol (10.0 ml) was stirred at 20C for 6 hours. To the solution was added 8-butyryl-6- oxaspiro[4.5]dec-7,9-dione (0.785 g) and after 24 hours at 20C the mixture was diluted with water (100 ml), acidified to pH 3 with 5 N hydrochloric acid and extracted with diethyl ether. Evaporation of the organic phase and chromatography of the residue over silica gel gave the product (0.47 g) as colorless crystals, m.p. 94- 96C,

1H nmr. u(CDCI₃) 0.98, broad t, J 7 Hz, CH₃; 1.2-2.2, m, 10 H, cyclopentyl and CH₂CH₃; 2.65, s, COCH₂; 3.05, broad t, J 8Hz,

CH₂CH₂CH₃; 5.04, s, OCH₂ and 7.2-7.5, broad m, aromatic H.

Example 7 (Compound 1.28)

Preparation of 9-hydroxy-8-[1-((3- trifluoromethylphenyl)methoxyimino)butyl]-6-oxaspiro[4.5]dec- 8-en-7-one.

A mixture of N-((3-trifluoromethylphenyl)methoxy)phthalimide (1.28 g) and 2-diethylaminoethylamine (0.522 g) in ethanol (10.0 ml) was stirred at 20C for 4 hours. To the resulting solution was added 8-butyryl-6-oxaspiro[4.5]dec-7,9-dione (0.785 g) and after 24 hours at 20C the mixture was diluted with water (100 ml), acidified to pH 3 with 5 N hydrochloric acid and extracted with diethyl ether. Evaporation of the organic phase and

chromatography of the residue over silica gel followed by crystallization from light petroleum gave the product (0.52 g) as colorless crystals, m.p. 89-91C,

¹H nmr. δ(CDCl₃) 0.97, broad t, J 7 Hz, CH₃; 1.2-2.4, m, 10 H, cyclopentyl and CH₂CH₃; 2.63, s, COCH₂; 2.96, broad t, J 8Hz,

CH₂CH₂CH₃; 5.28, s, OCH₂ and 7.6-7.9, broad s, aromatic H. Example 8 (Compound 1.135)

Preparation of 8-[1-((2-Chloro-4,5- methylenedioxyphenyl)methoxyimino)butyl]-9-hydroxy-6- oxaspiro[4.5]dec-8-en-7-one.

A mixture of N-((2-chloro-4,5- methylenedioxyphenyl)methoxy)phthalimide (1.33 g) and 2- diethylaminoethylamine (0.52 g) in ethanol (10.0 ml) was stirred at 60C for 2 hours. To the solution was added 8-butyryl-6- oxaspiro[4.5]dec-7,9-dione (0.785 g), followed by acetic acid (0.2g) and after 24 hours at 20C the mixture was diluted with water (100 ml), acidified to pH 3 with 5 N hydrochloric acid and

extracted with diethyl ether. Evaporation of the organic phase and chromatography of the residue over silica gel gave the product (0.38 g) as a colorless oil, ¹H nmr. δ(CDCl₃) 0.95, broad t, J 7 Hz,

CH₃; 1.1-2.4, m, 10 H, cyclopentyl and CH₂CH₃; 2.63, s, COCH₂; 2.96, broad t, J 8Hz, CH₂CH₂CH₃; 5.04, s, OCH2 ; 5.98, s, OCH₂O and 6.82, s, aromatic H.

Example 9 (Compound 1.140)

Preparation of 8-[1-((3,5-Dichlorophenyl)methoxyimino)butyl]-9- hydroxy-6-oxaspiro[4.5]dec-8-en-7-one. A mixture of N-((3,5-dichlorophenyl)methoxy)phthalimide (1.29 g) and 2-dimethylaminoethylamine (0.5 g) in ethanol (10.0 ml) was stirred at 20C for 8 hours. To the resulting solution was added 8-butyryl-6-oxaspiro[4.5]dec-7,9-dione (0.785 g) and after 24 hours at 20C the mixture was diluted with water (100 ml), acidified to pH 3 with 5 N hydrochloric acid and extracted with diethyl ether. Evaporation of the organic phase and

chromatography of the residue over silica gel then gave the

product (0.48 g) as colorless crystals, m.p. 91-94C,

1H nmr. u(CDCl₃) 0.98, broad t, J 7 Hz, CH3; 1.2-2.3, m, 10 H, cyclopentyl and CH₂CH₃; 2.6, s, COCH₂; 2.9, broad t, J 8Hz,

CH₂CH₂CH₃; 4.98, s, OCH₂ and 7.0-7.5, broad m, aromatic H. Example 10 (Compound 1.142)

Preparation of 8-[1-((2,5-Difluorophenyl)methoxyimino)butyl]-9- hydroxy-6-oxaspiro[4.5]dec-8-en-7-one.

A mixture of N-((2,5-difluorophenyl)methoxy)phthalimide (0.87 g) and 2-diethylaminoethylamine (0.41 g) in ethanol (10.0 ml) was stirred at 20C for 6 hours. To the solution was added 8- butyryl-6-oxaspiro[4.5]dec-7,9-dione (0.6 g) and after 24 hours at 20C the mixture was diluted with water (100 ml), acidified to pH 3 with 5 N hydrochloric acid and extracted with diethyl ether. Evaporation of the organic phase and chromatography of the residue over silica gel gave the product (0.36 g) as a colorless oil, ¹H nmr. δ(CDCl₃) 0.96, broad t, J 7 Hz, CH₃; U-2.3, m, 10 H, cyclopentyl and CH₂CH₃; 2.67, s, COCH₂; 2.97, broad t, J 8Hz,

CH₂CH₂CH₃; 5.15, s, OCH₂ and 6.8-7.3, broad m, aromatic H.

Example 11 (Compound 1.143)

Preparation of 3-[1-((2-Chloro-4,5- methylenedioxyphenyl)methoxyimino)butyl]-4-hydroxy-1- oxaspiro[5.5]undec-3-en-2-one.

A mixture of N-((2-chloro-4,5- methylenedioxyphenyl)methoxy)phthalimide (1.33 g) and 2- diethylaminoethylamine (0.52 g) in ethanol (10.0 ml) was stirred at 60C for 2 hours. To the solution was added 3-butyryl-1- oxaspiro[4.5]dec-2,4-dione (0.8 g) followed by acetic acid (0.2g) and after 24 hours at 20C the mixture was diluted with water (100 ml), acidified to pH 3 with 5 N hydrochloric acid and extracted with diethyl ether. Evaporation of the organic phase and chromatography of the residue over silica gel gave the product (0.42 g) as colorless crystals, m.p. 91-92C,

1H nmr. δ(CDCl₃) 0.96, broad t, J 7 Hz, CH₃; 1.2-2.2, m, 12 H, cyclohexyl and CH₂CH₃; 2.6, s, COCH₂; 2.95, broad t, J 8Hz,

CH₂CH₂CH₃; 5.01, s, OCH₂ ; 5.96, s, OCH₂ O and 6.8, s, aromatic H. Example 12 (Compound 1.144)

Preparation of 8-[1-((3-Fluorophenyl)methoxyimino)butyl]-9- hydroxy-6-oxaspiro[4.5]dec-8-en-7-one. A mixture of N-((3-fluorophenyl)methoxy)phthalimide (1.08 g) and 2-diethylaminoethylamine (0.522 g) in ethanol (10.0 ml) was stirred at 20C for 6 hours. To the resulting solution was added 8- butyryl-6-oxaspiro[4.5]dec-7,9-dione (0.785 g) and after 24 hours at 20C the mixture was diluted with water (100 ml), acidified to pH 3 with 5 N hydrochloric acid and extracted with diethyl ether. Evaporation of the organic phase and chromatography of the residue over silica gel then gave the product (0.51 g) as colorless crystals, m.p. 74-77C,

1H nmr. δ(CDCl₃) 0.96, broad t, J 7 Hz, CH₃; 1.2-2.2, m, 10 H, cyclopentyl and CH₂CH₃; 2.62, s, COCH₂; 2.97, broad t, J 8Hz,

CH₂CH₂CH₃; 5.04, s, OCH₂ and 6.9-7.4, broad m, aromatic H.

Example 13 (Compound 4.36)

Preparation of 3-[1-((2-Chloro-4,5- methylenedioxyphenyl)methoxyimino)butyl]-"6,6-dimethyl-4- hydroxy-5,6-dihydro-2H-pyran-2-one.

A mixture of N-((2-chloro-4,5- methylenedioxyphenyl)methoxy)phthalimide (1.33 g) and 2- diethylaminoethylamine (0.522 g) in ethanol (10.0 ml) was stirred at 20C for 6 hours. To the resulting solution was added crude 3- butyryl-6,6-dimethylpyran-2,4-dione (0.74 g) and after 24 hours at 20C the mixture was diluted with water (100 ml), acidified to pH 3 with 5 N hydrochloric acid and extracted with diethyl ether. Evaporation of the organic phase and chromatography of the residue over silica gel gave the product (0.92 g) as a colorless oil, 1H nmr. δ(CDCl₃) 0.98, broad t, J 7 Hz, CH₃; 1.43 ,s , C(CH₃)2; 1.4-1.8, broad m, CH₂CH₂CH₃; 2.59, s, COCH₂; 3.0, broad t, J 8Hz, CH₂CH₂CH₃; 5.04, s, OCH₂; 5.98, s, OCH₂O and 6.82, s, aromatic H. Example 14 (Compound 4.39)

Preparation of 3-[1-((3-Chlorophenyl)methoxyimino)butyl]-6,6- dimethyl-4-hydroxy-5,6-dihydro-2H-pyran-2-one. A mixture of N-((3-chlorophenyl)methoxy)phthaIimide (1.15 g) and 2-diethylaminoethylamine (0.522 g) in ethanol (10.0 ml) was stirred at 20C for 6 hours. To the resulting solution was added crude 3-butyryl-6,6-dimethylpyran-2,4-dione (0.74 g) and after 24 hours at 20C the mixture was diluted with water (100 ml), acidified to pH 3 with 5 N hydrochloric acid and extracted with diethyl ether. Evaporation of the organic phase and

chromatography of the residue over silica gel then gave the

product (0.17 g) as colorless crystals, m.p. 74-78C,

1H nmr. δ(CDCl₃) 0.98, broad t, J 7 Hz, CH₃; 1.42,s , C(CH₃)2; 1.4-1.8, broad m, CH₂CH₂CH₃; 2.57, s, COCH₂; 3.0, broad t, J 8Hz, CH₂CH₂CH₃; 5.08, s, OCH₂ and 7.2-7.5, broad m, aromatic H.

Example 15 (Compound 4.40)

Preparation of 6,6-Dimethyl-4-hydroxy-3-[1- (phenylmethoxyimino)butyl]-5,6-dihydro-2H-pyran-2-one.

A mixture of N-(phenylmethoxy)ρhthalimide (1.0 g) and 2- diethylaminoethylamine (0.522 g) in ethanol (10.0 ml) was stirred at 20C for 6 hours. To the resulting solution was added crude 3- butyryl-6,6-dimethylpyran-2,4-dione (0.74 g) and after 24 hours at 20C the mixture was diluted with water (100 ml), acidified to pH 3 with 5 N hydrochloric acid and extracted with diethyl ether. Evaporation of the organic phase and chromatography of the residue over silica gel then crystallization from light petroleum gave the product (0.65 g) as colorless crystals, m.p. 81C,

¹H nmr. δ(CDCl₃) 0.97, broad t, J 7 Hz, CH₃; 1.40 ,s , C(CH₃)2; 1.4-1.8, broad m, CH₂CH₂CH₃; 2.56, s, COCH₂; 3.0, broad t, J 8Hz, CH₂CH₂CH₃; 5.02, s, OCH₂ and 7.40, broad s, aromatic H. Example 16 (Compound 4.41)

Preparation of 6,6-Dimethyl-3-[1-((4- fluorophenyl)methoxyimino)butyl]-4-hydroxy-5,6-dihydro-2H- pyran-2-one.

A mixture of N-(4-fluorophenylmethoxy)phthalimide (1.1 g) and 2-diethylaminoethylamine (0.522 g) in ethanol (10.0 ml) was stirred at 20C for 6 hours. To the resulting solution was added crude 3-butyryl-6,6-dimethylpyran-2,4-dione (0.75 g) and after 24 hours at 20C the mixture was diluted with water (100 ml), acidified to pH 3 with 5 N hydrochloric acid and extracted with diethyl ether. Evaporation of the organic phase and

chromatography of the residue over silica gel gave the product (0.47 g) as colorless crystals, m.p. 80C,

1H nmr. δ(CDCl₃) 0.95, broad t, J 7 Hz, CH₃; 1.41 ,s , C(CH₃)2; 1.4-1.8, broad m, CH₂CH₂CH₃; 2.58, s, COCH₂; 2.99, broad t, J 8Hz,

CH₂CH₂CH₃; 5.0, s, OCH₂ and 6.9-7.5, m, aromatic H.

Example 17 (Compound 4.42)

Preparation of 5,6-Dimethyl-6-ethyl-3-[1-((4- nitrophenyl)methoxyimino)butyl]-4-hydroxy--5,6-dihydro-2H- pyran-2-one. A mixture of N-(4-nitrophenylmethoxy)phthalimide (0.95 g) and

2-diethylaminoethylamine (0.5 g) in ethanol (10.0 ml) was stirred at 20C for 6 hours. To the resulting solution was added crude 3- butyryl-5,6-diethyl-6-methylpyran-2,4-dione (0.85 g) and after 24 hours at 20C the mixture was diluted with water (100 ml), acidified to pH 3 with 5 N hydrochloric acid and extracted with diethyl ether. Evaporation of the organic phase and

chromatography of the residue over silica gel gave the product (0.56 g) as a colorless oil, ¹H nmr. δ(CDCl₃) 0.8-2.0, broad m, 2xCH₂CH₃ and 2xCH₃; 2.3-2.8, m, COCH; 3.03, broad t, J 8Hz,

CH₂CH₂CH₃; 5.2, s, OCH₂; 7.6, d, J 8Hz, aromatic H and 8.2, d, J 8Hz, aromatic H. Example 18 (Compound 4.43)

Preparation of 3-[1-((3-Chlorophenyl)methoxyimino)butyl]-4- hydroxy-5,5,6,6-tetramethyl-5,6-dihydro-2H-pyran-2-one.

A mixture of N-((3-chlorophenyl)methoxy)phthalimide (0.48 g) and 2-diethylaminoethylamine (0.3 g) in ethanol (6.0 ml) was stirred at 20C for 6 hours. To the resulting solution was added crude 3-butyryl-5,5,6,6-tetramethylpyran-2,4-dione (0.54 g) and after 24 hours at 20C the mixture was diluted with water (70 ml), acidified to pH 3 with 5 N hydrochloric acid and extracted with diethyl ether. Evaporation of the organic phase and

chromatography of the residue over silica gel then gave the

product (0.19 g) as a colorless oil. ¹Η nmr. δ(CDCl₃) 0.8-1.8, broad m, CH₂CH₃ ; 1.18, 1.36, s, s, 2xC(CH₃)2; 3.0, broad t, J 8Hz,

CH₂CH₂CH₃; 5.02, s, OCH₂ and 7.2, broad s, aromatic H.

Example 19 (Compound 4.44)

Preparation of 6,6-Diethyl-3-[1-((3- fluorophenyl)methoxyimino)butyl]-4-hydroxy-5,6-"dihydro-2H- pyran-2-one.

A mixture of N-(3-fluorophenylmethoxy)phthalimide (1.1 g) and 2-diethylaminoethylamine (0.522 g) in ethanol (10.0 ml) was stirred at 20C for 6 hours. To the resulting solution was added crude 3-butyryl-6,6-diethylpyran-2,4-dione (0.85 g) and after 24 hours at 20C the mixture was diluted with water (100 ml), acidified to pH 3 with 5 N hydrochloric acid and extracted with diethyl ether. Evaporation of the organic phase and

chromatography of the residue over silica gel gave the product (0.53 g) as a colorless oil,

¹H nmr. δ(CDCl₃) 0.7-1.2, broad m, 3x CH₂CH₃; 1.2-1.9, broad m, 3x CH₂CH₃; 2.58, s, COCH₂; 3.01, broad t, J 8Hz, CH₂CH₂CH₃;

5.03, s, OCH₂ and 6.9-7.4, m, aromatic H. Barnyard grass is one of the most difficult grasses to eliminate from rice crops because of its similarity to rice, currently available herbicides do not have satisfactory selectively for barnyard grass in rice crops. To demonstrate the effectiveness of compounds of Formula (2) of the present invention as selective herbicidal agents for the control of weeds in rice crops, compounds of Formulae 1.22 and 1.49 of Table 1 were applied to barnyard grass and rice. Compounds according to US 4008067 (Hirono et. al.), and AU560716 (27196/84) (Watson et al ), were also applied to Barnyard grass and rice for comparative purposes. The herbicidal data are shown in Table 4. In this table 0 signifies no effect and 10 signifies plant dead.

As can be seen from Table 5 compounds according to the present invention are clearly superior to prior art compounds at providing selective weed control in rice crops.

Table 5 Comparison of Compounds of this Invention with known com ounds

Disclosure of Hirono et al ;

A: 8-(1-allyloxyaminobutylidine)-6,10-dioxaspiro[4.5]decene-7,9-dione B: 9-(1-allyloxyaminobutylidine)-7,11-dioxaspiro[5.5]-4- methylundecene-8,10-dione Disclosure of Watson et al;

C: 3-(1-allyloxyiminobutyl)-6-(4-chlorophenyl)-4-hydroxypyran

-2-one

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Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. It is therefore to be understood that the invention includes all such variations and modifications which fall within its spirit and scope.

Claims

1. Compounds of the formula (2) and isomeric and/or tautomeric forms thereof:

wherein:

A is a C₁-C₄ alkylene or C₃-C₄ alkenylene group optionally substituted with 1-4 C₁-C₃ alkyl substituents;

X is O, S, SO, SO₂, NR¹⁰ or a single bond;

R¹ is H, C₁-C₄ alkyl, C₂-C₄ alkenyl, C₂-C₄ alkynyl, C₅-C₆ cycloalkyl, C₅-C₆ cycloalkenyl, phenyl optionally substituted with 1-3 substituents selected from the group consisting of halogen, C₁-C₄ alkyl, C₁-C₄ alkoxy, C₁-C₄ alkylthio, nitro, cyano, C₁-C₄ haloalkyl, amino, and C₁-C₄ haloalkoxy, C₁-C₄ alkylsulfonyl, benzenesulfonyl, C₁-C₄ alkylcarbonyl, C₂-C₈ alkoxyalkyl, C₂-C₈ alkylthioalkyl, C₇-C₁₀ phenylalkyl or M; R² is C₁-C₆ alkyl, C₂-C₆ alkenyl, C₂-C₆ alkynyl, C₁-C₄ haloalkyl, C₁-C₄ alkylthio, C₃-C₆ cycloalkyl, C₅-C₆ cycloalkenyl, phenyl optionally substituted with 1-3 substituents selected from the group consisting of halogen, C₁-C₄ alkyl, C₁-C₄ alkylthio, nitro, cyano, C₁-C₄ haloalkyl, amino, and C₁-C₄ haloalkoxy, C₂-C₈ alkoxyalkyl, C₂-C₈ alkylthioalkyl, or C₁-C₄ alkyl substituted with a substituent selected from the group consisting of phenyl, phenαxy and thiophenoxy wherein said phenyl groups may be substituted with 1-3 substituents selected from halogen, C₁-C₄ alkyl, C₁-C₄ alkoxy, C₁-C₄ alkylthio, nitro, cyano, amino, C₁-C₄ haloalkyl and C₁-C₄ haloalkoxy, R³ and R⁴ are independently H or C₁-C₄ alkyl;

R⁵ and R⁶ are independently C₁-C₄ alkyl, C₂-C₄ alkenyl, C₂-C₆ alkylthioalkyl, C₁-C₄ haloalkyl, C₂-C₄ haloalkenyl, C₃-C₆ cycloalkyl optionally substituted with a substituent selected from the group consisting of C₁-C₄ alkoxycarbonyl and phenyl which may be substituted with a substituent selected from halogen, C₁-C₄ alkyl, C₁-C₄ alkoxy, C₁-C₄ alkylthio, nitro, cyano, C₁-C₄ haloalkyl and C₁-C₄ haloalkoxy, or

R⁵ and R⁶ together with the carbon to which they are attached form a fully saturated or an unsaturated 3- to 7- membered carbocyclic ring, or a fully saturated or an unsaturated 5- to 7-membered heterocyclic ring containing 1-3 heteroatoms selected from the group consisting of 0-3 nitrogen, 0-2 oxygen and 0-2 sulfur atoms; said ring may be substituted with 1-4 substituents selected from the group consisting of halogen, C₁-C₄ alkyl, C₁-C₄ haloalkyl, C₂-C₄ alkenyl, C₂-C₄ alkynyl, C₁-C₄ alkylcarbonyl, C₁-C₄ alkoxy, C₁-C₄ alkylthio, C₁-C₄ alkoxycarbonyl, - COOH, C₂-C₈ alkoxyalkyl, C₂-C₈ alkylthioalkyl, and phenyl which is optionally substituted with a substituent selected from halogen, C₁-C₄ alkoxy, C₁-C₄ alkylthio, C₁-C₄ haloalkyl, nitro, cyano, C₁-C₄ haloalkoxy; one of the carbon atoms of said ring may be in the form of a carbonyl group or its corresponding dimethyl, diethyl or ethylene or propylene ketal; R⁷, ⁸ and R⁹ are independently H, halogen, C₁-C₄ alkyl, C₁-C₄ alkoxy, C₁-C₄ alkylthio, C₁-C₄ alkylsulfinyl, C₂-C₄ alkylsulfonyl, C₁-C₄ haloalkyl, C₁-C₄ haloalkoxy, nitro, cyano, C₁-C₄ alkoxycarbonyl, C₁-C₄

alkylaminocarbonyl, C₂-C₆ dialkylaminocarbonyl, aminocarbonyl, phenyl, amino, C₁-C₄ alkylamino or C₂-C₆ dialkylamino;

R¹⁰ is H, C₁-C₄ alkyl or phenyl optionally substituted with 1-3

substituents selected from the group consisting of halogen, C₁-C₄ alkyl, C₁-C₄ alkoxy, C₁-C₄ alkylthio, C₁-C₄ haloalkyl, and C₁-C₄ haloalkoxy, and

M is Li⁺, Na⁺, K⁺, NH₄ ⁺, or N(R¹¹)₄ ⁺ where R¹¹ is C₁-C₄ alkyl.

2. Compounds as claimed in Claim 1, characterized in that:

R¹ is H or M; and

R² is C₁-C₄ alkyl, C₁-C₄ haloalkyl, C₂-C₄ alkenyl, or

C₂-C₄ alkynyl.

3. Compounds as claimed in Claim 2, characterized in that:

A is C₁-C₂ alkylene or C₃-C₄ alkenylene optionally substituted with CH₃ or C₂H₅;

R⁷, R⁸ and R⁹ are independendy H, Cl, Br, F, C₁-C₃ alkyl, C₁-C₃ alkoxy, C₁-C₃ alkylthio, C₁-C₃ haloalkyl, C₁-C₃ haloalkoxy, nitro, cyano or C₁-C₃ alkoxycarbonyl; and

R¹⁰ is H or CH₃.

4. Compounds as claimed in Claim 3, characterized in that X is O.

5. Compounds as claimed in Claim 3, characterized in that X is S, SO or SO₂.

6. Compounds as claimed in Claim 3, characterized in that X is NR¹⁰.

7. Compounds as claimed in Claim 3, characterized in that X is a single bond.

8. Compounds as claimed in Claim 7, characterized in that:

A is -CH₂-, -CH₂CH₂- or -CH₂CH = CH-;

R¹ is H, Li⁺, Na⁺ or K⁺;

R² is CH₃, C₂H₅, n-C₃H₇ or n-C₄H₉;

R³ and R⁴ are independendy H, CH₃ or C₂H₅; and

R⁷, R⁸ and R⁹ are independendy H, Cl, Br, F, CH₃, C₂H₅,

OCH₃, OC₂H₅, SCH₃, SC₂H₅, CF₃, CHF₂ CF₂CF₃, OCHF₂, OCF₃,

OCH₂CF₃, NO₂ CN or CO₂CH₃.

9. Compounds as claimed in Claim 7, characterized in that:

R⁵ and R⁶ are independendy C₁-C₄ alkyl, C₂-C₄ alkenyl, C₂-C₄ alkynyl, C₁-C₄ alkylthio or C₂-C₆ alkylthioalkyl.

10. Compounds as claimed in Claim 7, characterized in that:

R⁵ and R⁶ together with the carbon to which they are attached form a saturated or unsaturated 5-, 6- or 7-membered carbocyclic ring which is optionally substituted with 1-4 CH₃ groups.

11. Compounds as claimed in Claim 10, characterized in that:

A is -CH₂-, -CH2CH₂- or -CH₂CH = CH-;

R¹ is H, Li⁺, Na⁺ or K⁺;

R² is CH₃, C₂H₅, n-C₃H₇ or n-C₄H₉;

R³ and R⁴ are independendy H, CH₃; and

R⁷, R⁸ and R⁹ are independendy H, Cl, Br, F, CH₃, C₂H₅,

OCH₃, OC₂H₅, SCH₃, SC₂H₅, CF₃, CHF₂ CF₂CF₃, OCHF₂, OCF₃, OCH₂CF₃, NO₂ CN or CO₂CH₃.

12. Compounds as claimed in Claim 7, characterized in that:

R⁵ and R⁶ together with the carbon 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.

13. Compounds as claimed in Claim 12, characterized in that:

A is -CH₂-, -CH₂CH₂- or -CH₂CH = CH-;

R¹ is H, Li⁺, Na⁺ or K⁺;

R² is CH₃, C₂H₅, n-C₃H₇ or n-C₄H₉;

R³ and R⁴ are independendy H, CH₃ or C₂H ₅; and

R⁷, R⁸ and R⁹ are independendy H, d, Br, F, CH₃, C₂H₅,

OCH₃, OC₂H₅, SCH₃, SC₂H₅, CF₃, CHF₂ CF₂CF₃, OCHF₂, OCF₃,

OCH₂CF₃, NO₂ CN or CO₂CH₃.

14. 8-[1 -((3-Chlorophenyl)memoxyimino)butyl]-9-hydroxy-6-oxaspiro[4.5]dec- 8-en-7-one, which has the formula:

15. 9-hydroxy-8-[1-(3-phenylallyloxyimino)butyl]-6-oxaspiro[4.5]dec-8-en-7- one, which has the formula:

16. Any of the compounds listed in the foregoing Tables 1 to 4.

17. A process for preparing a compound of the general formula (2) as

stated and defined in Claim 1, characterized in that a compound of the general formula (8):

wherein R², R³, R⁴, R⁵ and R⁶ are as defined in Claim 1, is reacted with an Q-substituted hydroxyiamine of the formula:

wherein R⁷, R⁸ and R⁹ are as defined in Claim 1, to yield a compound of formula (2), wherein R¹ - H and thereafter, if desired converting the compound thus obtained by a known method to a compound in which R¹ is other than H.

18. A process as claimed in Claim 17, characterized in that the compound of formula (8) is prepared by acylating and isomerizing a compound of formula (7):

wherein R⁴ and R⁵ are as defined in Claim 1, by a Fries rearrangement.

19. A process as claimed in Claim 18, characterized in that the compound of formula (7) is prepared by reacting the di-anion (a) of an

acetoacetate ester where M⁺ is Li⁺ with a ketone (b), wherein R³, R⁴, R⁵ and R⁶ are as defined in Claim 1:

(-C(R³R⁴)COCΗ₂COOR)Li⁺M⁺ R⁵-CO-R⁶

(a) (b) and cyclizing the resulting product, with or without intermediate hydrolysis.

20. A plant growth inhibiting, plant damaging, or plant killing composition comprising a compound of formula (2), as defined in Claim 1, and an inert carrier therefor.

21. A method for regulating the growth of a plant which process 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 (2), as defined in Claim 1.

22. A method for selectively inhibiting, damaging or killing weed grasses in a broad-leaf crop which comprises applying to the crop or its locus an effective amount of a compound of formula (2), as defined in Claim 1.

23. A herbicidal composition comprising a compound of formula (2), as defined in Claim 1, and at least one other herbicide.

24. A plant growth regulating composition comprising a compound of formula (2), as defined in Claim 1, and an inert carrier therefor.

25. The use of a compound of formula (2) as herbicide or plant growth regulator.

26. A compound of formula (7) as stated and defined in Claim 18.

27. A compound of formula (8) as stated and defined in Claim 17.