4-Phenoxycoumarins as herbicidal agents

Abstract

There are provided methods to control monocotyledenous weed species in the presence of crops and particularly in the presence of cereal crops. Also provided are 4-(2,6-disubstituted-phenoxy)coumarin derivatives useful as herbicidal agents and methods to prepare same.

Description

BACKGROUND OF THE INVENTION

The selective control of weeds is a constant problem in crop production around the world. In particular the control of monocotyledenous weeds when growing in the presence of monocotyledenous crops such as cereal crops is burdensome. Not only do said weed species tend to proliferate under the same or similar cultivation conditions in which cereal crops flourish, but in addition, the very herbicidal agents which are most effective for controlling these weeds, also tend to cause harmful phytotoxic effects to cereal crop plants. Therefore, new effective methods for the selective control of unwanted monocotyledenous weeds in cereal crop production are continually sought.

It is an object of this invention to provide methods for the effective control of monocotyledenous weeds in the presence of crop plants, including monocotyledenous crop plants, without undue harm to said crop plants.

It is a further object or this invention to provide 4-(2,6-disubstituted-phenoxy)coumarin derivatives, useful as selective herbicides in crop production and particularly in cereal crop production.

It is an advantage of this invention that the 4-(2,6-disubstituted-phenoxy)coumarin derivatives are particularly effective for controlling grass and other monocotyledenous weeds under flooded paddy rice application conditions while having little or no phytotoxic effects on the rice crop.

SUMMARY OF THE INVENTION

The present invention relates to a method for the control of monocotyledenous annual, perennial and aquatic plant species which comprises applying to the soil or water containing the seeds or other propagating organs of said plant species a herbicidally effective amount of a compound of formula I ##STR1## wherein

X and X' are each independently halogen, C.sub.1 -C.sub.4 alkyl or C.sub.2 -C.sub.4 alkenyl;

W and Y are each independently O or S;

R is any combination of from one to three H, halogen, C.sub.1 -C.sub.4 alkyl, C.sub.3 -C.sub.6 cycloalkyl, C.sub.1 -C.sub.4 haloalkyl or C.sub.1 -C.sub.4 alkoxy groups;

R.sub.1 is any combination of from one to four H, halogen, OH, CN, SH, C.sub.1 -C.sub.6 alkyl optionally substituted with one or more halogen or OR.sub.2 groups, C.sub.3 -C.sub.6 cycloalkyl, C.sub.2 -C.sub.6 alkenyl, C.sub.2 -C.sub.6 haloalkenyl, C.sub.2 -C.sub.6 alkynyl, C.sub.2 -C.sub.6 haloalknyl, OR.sub.2, OCH.sub.2 COOR.sub.3, OCH.sub.2 OR.sub.4, OCOOR.sub.5, OCONHR.sub.6, OCOR.sub.7, S(O).sub.n R.sub.8, COR.sub.9, CH(OR.sub.10).sub.2, phenyl optionally substituted with one to three halogen, CN, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups, or benzyl optionally substituted with one to three halogen, CN, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl or C.sub.1 -C.sub.4 alkoxy groups;

R.sub.2 is H, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.2 -C.sub.6 alkenyl, C.sub.2 -C.sub.6 alkynyl, C.sub.2 -C.sub.6 haloalkenyl or C.sub.2 -C.sub.6 haloalkynyl;

R.sub.3, R.sub.4, R.sub.5, R.sub.6 and R.sub.7 are each independently H, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.3 -C.sub.6 cycloalkyl, phenyl optionally substituted with one to three halogen, CN, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups, or benzyl optionally substituted with one to three halogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl or C.sub.1 -C.sub.4 alkoxy groups;

R.sub.8 is C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl or phenyl optionally substituted with one to three halogen, CN, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups;

R.sub.9 is H, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, phenyl optionally substituted with one to three halogen, CN, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups, benzyl optionally substituted with one to three halogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups or NR.sub.11 R.sub.12 ;

R.sub.10 is H, C.sub.1 -C.sub.4 alkyl or --(CH.sub.2).sub.m --;

R.sub.11 and R.sub.12 are each independently H, C.sub.1 -C.sub.4 alkyl, C.sub.2 -C.sub.4 alkenyl or R.sub.11 and R.sub.12 may be taken together with the atoms to which they are attached to form a 5- or 6-membered ring optionally interrupted by oxygen;

n is an integer of 0, 1 or 2 and

m is an integer of 2 or 3.

The invention also relates to the selective control of monocotyledenous weed species in the presence of crops which comprises applying to the soil or water in which the seeds or propagating organs of the weed species are located and in which the crop has been planted or transplanted a herbicidally effective amount of a compound of formula I as described hereinabove.

The invention further relates to herbicidal compounds of formula I, compositions containing same, and a method to prepare said compounds.

DETAILED DESCRIPTION OF THE INVENTION

Crop production can be reduced by as much as 30% to 60% by the presence of persistent and pestiferous weed species. A particular weed problem in raising and harvesting a variety of crops, particularly cereal crops, is monocotyledenous weed species such as monochoria, saggitaria, sedges and grasses. This is a persistent problem in the production of cereals such as corn, wheat, barley, rice, rye and the like. Most particularly, the presence and proliferation of grass weeds such as barnyardgrass and watergrass in rice cultivation can significantly lower crop yields and quality. The problem is further complicated because, in general, those agents which control monocotyledenous plants inherently cause phytotoxic damage to cereal crops.

It has now been found that monocotyledenous, annual, perennial and aquatic, weed species such as monochoria, saggitaria, sedges and grasses are effectively controlled by the application of 4-phenoxycoumarin derivatives of formula I to the soil or water in which the seeds or propagating organs are located.

Surprisingly, said monocotyledenous weeds may be selectively controlled in the presence of cereal crops such as corn, wheat, barley, rice, rye and the like with little or no phytotoxic injury to said crops. Advantageously, 4-phenoxycoumarins of formula I may be applied preemergence to the monocotyledenous weeds and post-transplant to the rice crop seedlings under flooded paddy conditions to give effective weed control with little or no commensurate injury to the rice crop plants.

The 4-phenoxycoumarin derivatives of the invention which are useful as herbicidal agents are those compounds of formula I ##STR2## wherein

X and X' are each independently halogen, C.sub.1 -C.sub.4 alkyl or C.sub.2 -C.sub.4 alkenyl;

W and Y are each independently O or S;

R is any combination of from one to three H, halogen, C.sub.1 -C.sub.4 alkyl, C.sub.3 -C.sub.6 cycloalkyl, C.sub.1 -C.sub.4 haloalkyl or C.sub.1 -C.sub.4 alkoxy groups;

R.sub.1 is any combination of from one to four H, halogen, OH, CN, SH, C.sub.1 -C.sub.6 alkyl optionally substituted with one or more halogen or OR.sub.2 groups, C.sub.3 -C.sub.6 cycloalkyl, C.sub.2 -C.sub.6 alkenyl, C.sub.2 -C.sub.6 haloalkenyl, C.sub.2 -C.sub.6 alkynyl, C.sub.2 -C.sub.6 haloalknyl, OR.sub.2, OCH.sub.2 COOR.sub.3, OCH.sub.2 OR.sub.4, OCOOR.sub.5, OCONHR.sub.6, OCOR.sub.7, S(O).sub.n R.sub.8, COR.sub.9, CH(OR.sub.10).sub.2, phenyl optionally substituted with one to three halogen, CN, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups, or benzyl optionally substituted with one to three halogen, CN, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl or C.sub.1 -C.sub.4 alkoxy groups;

R.sub.2 is H, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.2 -C.sub.6 alkenyl, C.sub.2 -C.sub.6 alkynyl, C.sub.2 -C.sub.6 haloalkenyl or C.sub.2 -C.sub.6 haloalkynyl;

R.sub.3, R.sub.4, R.sub.5, R.sub.6 and R.sub.7 are each independently H, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.3 -C.sub.6 cycloalkyl, phenyl optionally substituted with one to three halogen, CN, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups, or benzyl optionally substituted with one to three halogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl or C.sub.1 -C.sub.4 alkoxy groups;

R.sub.8 is C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl or phenyl optionally substituted with one to three halogen, CN, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups;

R.sub.9 is H, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, phenyl optionally substituted with one to three halogen, CN, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups, benzyl optionally substituted with one to three halogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups or NR.sub.11 R.sub.12 ;

R.sub.10 is H, C.sub.1 -C.sub.4 alkyl or --(CH.sub.2).sub.m --;

R.sub.11 and R.sub.12 are each independently H, C.sub.1 -C.sub.4 alkyl, C.sub.2 -C.sub.4 alkenyl or R.sub.11 and R.sub.12 may be taken together with the atoms to which they are attached to form a 5- or 6-membered ring optionally interrupted by oxygen;

n is an integer of 0, 1 or 2 and

m is an integer of 2 or 3.

It is understood that R and R.sub.1 represent substituents on the phenyl ring in positions 3, 4 and 5 (in the case of R) and on the fused benzene ring in positions 5, 6, 7 and 8 (in the case of R.sub.1). In each instance the aromatic ring may range from being fully substituted to being fully unsubstituted (in the case of R.sub.1) or disubstituted by X and X' (in the case of R). When the phenyl ring is disubstituted with X and X', then R is designated H. When the fused benzene ring position of the 4-phenoxycoumarin of formula I is fully unsubstituted, then R.sub.1 is designated H.

The term haloalkyl designates an alkyl group, C.sub.n H.sub.2n+1, containing from one halogen atom to 2n+1 halogen atoms. Halogen atoms are Cl, Br, F or I.

Preferred compounds of formula I are those wherein X and X' are Cl or Br and W and Y are O. More preferred compounds are those wherein X and X' are Cl or Br; W and Y are O; R is H and R.sub.1 is one, two or three C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups.

The 4-(2,6-disubstituted-phenoxy)coumarin compounds of formula I may be prepared from readily available 2-hydroxyacetophenones of formula III or their salicylic acid precursors of formula II. The formula II acid may be converted to the corresponding acetophenone of formula III in the presence of methyl lithium using standard literature procedures such as that described by Helmark et al in the Journal of Labelled Compounds and Radiopharmaceuticals, 1986, Vol. 23, No. 2. The formula III acetophenone may be reacted with ethyl carbonate in the presence of at least 2 molar equivalents of a base such as sodium hydride to give the 4-hydroxycoumarin of formula IV. Said hydroxycoumarin may then be converted to the corresponding 4-chlorocoumarin derivative of formula V, using standard procedures such as POCl.sub.3 plus an amine scavenger. The formula V chlorocoumarin is then reacted with a 2,6-disubstituted-phenol or thiophenol of formula VI to give the desired formula I product wherein Y is oxygen (formula Ia). To obtain those formula I products wherein Y is sulfur (Ib), the coumarin of Ia may be reacted with Lawesson's reagent or P.sub.2 S.sub.5. The reaction scheme is shown in Flow Diagram I. ##STR3##

Alternatively, the formula II salicylic acid may be converted to the corresponding formula VII acid chloride. The acid chloride may be treated with ethyl malonate in the presence of a base as described in Journal of Medicinal Chemistry, 1975, Vol. 18, No. 4, pp. 391-394 by D. R. Buckle et al, to form an intermediate which is decarboxethoxylated by heating, optionally in the presence of a solvent, to afford the desired 4-hydroxycoumarin of formula IV. The formula IV hydroxycoumarin may be converted to 4-(2,6-disubstituted-phenoxy)coumarin compounds of formula I as shown hereinabove in Flow Diagram I. The reaction sequence is illustrated in Flow Diagram II. ##STR4##

The 4-(2,6-disubstituted phenoxy)coumarin herbicidal agents of formula I may also be effectively prepared from phenols of formula VIII by treatment with dimethyl acetylenedicarboxylate as described by H. Cairns, et al in the Journal of Medicinal Chemistry, 1972, Vol. 15, No. 6, pp. 583-589, to give the formula IX fumaric acid. Surprisingly, treatment of the formula IX fumaric acid with a mixture of phosphorous pentoxide and methane sulfonic acid affords the formula X chromone-2-carboxylic acid in high yield. The formula X intermediate may then be converted to the formula V chlorocoumarin by treatment with thionyl chloride in the presence of a catalytic amount of dimethyl formamide as described by V. A. Zagorevskii and E. K. Orlova in Zhurnal Obschei Khimii, Vol. 33, No. 6, 1963, pp. 1857-1863. The thus-prepared 4-chlorocoumarin may be employed to give the desired 4-(2,6-disubstituted phenoxy)coumarins of formula I as described hereinabove in Flow Diagram I. The reaction sequence is illustrated in Flow Diagram III. ##STR5##

The 4-phenoxycoumarin compounds of the present invention are those compounds of formula I wherein X, X', W, Y, R and R.sub.1 are as described hereinabove with the proviso that at least one of R.sub.1 must be other than H. Said compounds are effective herbicidal agents useful for the control of a variety of monocotyledenous annual and perennial weed species. Moreover, these compounds are effective for the control of weeds indigenous to both dry land and wet land areas. Effective control may be obtained with application rates of about 0.006 kg/ha to 4.0 kg/ha, preferably about 0.06 kg/ha to 2.0 kg/ha. It is, of course, clear that rates above 4.0 kg/ha may be used to effectively control undesirable monocoty-ledenous weed species; however, rates of application of herbicide above the required effective level should be avoided since application of excessive amounts of herbicide is costly and serves no useful function in the environment.

Surprisingly, it has been found that the formula I phenoxycoumarin compounds of the invention are selective herbicides, useful in crop production. In particular, the formula I compounds are effective for controlling pestiferous monocotyledenous weeds such as grasses, sedges, monochoria and saggitaria in the presence of cereal crop plants such as corn, wheat, rye, barley, rice and the like. More particularly, the formula I compounds are especially valuable for controlling grass weeds in the presence of transplanted rice plants under flooded paddy conditions.

In actual agronomic practice, the compounds of the invention are applied in the form of a composition comprising an agronomically acceptable solid or liquid carrier and an herbicidally effective amount of a formula I phenoxycoumarin compound. For example, application may be in the form of liquid compositions such as suspension concentrates, aqueous concentrates, emulsifiable concentrates, concentrated emulsions and the like or in the form of solid compositions such as wettable powders, dispersible granulars, granular formulations, dusts and the like. It is contemplated the compounds of the invention be applied in combination with other pesticides either sequentially or concurrently as a tank mixture or as a single combination composition. In particular the combination application of a formula I phenoxycoumarin with a co-herbicide such as a sulfamoylurea, sulfonylurea, dinitroaniline, imidazolinone, thiocarbamate, azolopyrimidine sulfonamide, .alpha.-haloacetamide and the like. Of particular interest are combinations comprising a formula I phenoxycoumarin and a sulfamoylurea, a dinitroaniline, a sulfonylurea, or an imidazolinone. While not required, the combination composition comprising a formula I compound and a co-herbicide may also comprise other components, for example, fertilizers, inert formulation aides such as surfactants, emulsifiers, defoamers, dyes, extenders and the like.

For a more clear understanding of the invention, specific examples thereof are set forth below. The invention described and claimed herein is not to be limited in scope by these merely illustrative examples. Indeed, various modifications of the invention in addition to those exemplified and described herein will become apparent to those skilled in the art from the following examples and the foregoing description. Such modifications are also intended to fall within the scope of the appended claims. The terms .sup.1 H, .sup.13 C, .sup.19 FNMR designate proton, carbon and fluorine nuclear magnetic resonance spectroscopy, respectively. IR designates infrared spectroscopy and HPLC designates high performance liquid chromatography.

EXAMPLE 1

Preparation of 2-hydroxy-3-methoxyacetophenone ##STR6##

A mixture of 3-methoxysalicylic acid (4.0 g, 24 mmole) in tetrahydrofuran, under nitrogen, is treated dropwise with methyl lithium (56 mL of 1.4M solution in ether, 78.4 mmole) at a rate sufficient to maintain reflux temperature. The reaction mixture is stirred at reflux temperature for 17 hours, cooled to room temperature and poured over a mixture of brine, ice and 6N HCl. The resultant mixture is extracted with ethyl acetate. The organic extracts are combined, washed with brine, dried over Na.sub.2 SO.sub.4 and filtered. The filtrate is concentrated in vacuo to give a dark orange residue which is taken up in 1:2 ethyl acetate:hexane, filtered through a silica gel plug and re-evaporated to give a residue. This residue is crystallized from cyclohexane to give the title product as yellow needles, 2.08 g (53% yield), mp 49.degree.-51.degree. C., identified by HPLC, .sup.1 HNMR and mass spectral analyses.

EXAMPLE 2

Preparation of 8-methoxy coumarin ##STR7##

A stirred mixture of NaH (0.58 g 60% NaH, 14.5 mmole) and ethyl carbonate (2.84 g, 24 mmole) in chloroform, under N.sub.2, is treated dropwise with a solution of 2-hydroxy-3-methoxyacetophenone (0.80 g, 4.8 mmole) in chloroform, heated at reflux temperature for 40 hours, cooled to room temperature, treated with about 45 mL 1N NaOH and stirred vigorously for 24 h. The phases are separated and the aqueous phase is acidified with 6N HCl. The resultant precipitate is filtered, washed with water and dried to give the title product as a white solid, 0.88 g (96% yield), identified by .sup.1 HNMR analysis.

EXAMPLE 3

Preparation of 4-chloro-6-methoxycoumarin ##STR8##

A stirred mixture of 4-hydroxy-6-methoxycoumarin (116 g, 0.603 mole) and POCl.sub.3 (462.29 g, 3.015 mole) in toluene is treated dropwise with tri-n-butylamine (250 mL, 1.73 mole) at 25.degree. C., heated at 100.degree.-110.degree. C. and monitored by HPLC analysis. When the reaction is complete, the mixture is cooled to room temperature, poured over ice, stirred mechanically for about 2 hours and filtered. The filtercake is washed with water and toluene, dissolved in methylene chloride and filtered through diatomaceous earth. The methylene chloride filtrate is concentrated and treated with a mixture of dimethylformamide and acetonitrile to afford crystallization. The mixture is filtered to give the title product, 81.7 g, (64% yield) identified by HPLC analysis.

EXAMPLE 4

Preparation of 4-(2,6-dichlorophenoxy)-6-methoxycoumarin ##STR9##

A stirred mixture of 4-chloro-6-methoxycoumarin (1.0 g, 4.75 mmole) , 2,6-dichlorophenol (0.85 g, 5.22 mmole) and K.sub.2 CO.sub.3 (0.98 g, 7.12 mmole) in acetonitrile, under N.sub.2, is heated at reflux temperature for 16 hours, cooled to room temperature and poured into ice water. This mixture is extracted several times with ether. The extracts are combined and concentrated in vacuo to give a tan solid residue. The residue is crystallized from ethyl acetate/hexane to afford the title product as tan crystals, 1.17 g (73% yield), mp 170.degree.-171.degree. C., identified by IR, .sup.1 HNMR, .sup.13 CNMR, and mass spectral analyses.

EXAMPLE 5

Preparation of 4-(2-6-dichlorophenoxy)-6-hydroxycoumarin ##STR10##

A solution of 4-(2,6-dichlorophenoxy)-6-methoxycoumarin (25 g, 0.074 mol) in methylene chloride, under N.sub.2, is treated dropwise with 296 mL of a 1.0M solution of BBr.sub.3 in methylene chloride at -70.degree. C. When addition is complete, the dry ice/acetone cooling is removed and the reaction is allowed to come to room temperature over a 16 hour period. The reaction mixture is diluted with additional methylene chloride, poured into ice water with mechanical stirring and filtered to give a pale yellow solid filtercake. The solid is air-dried and crystallized from dimethylformamide/acetonitrile/water (1:1:0.1) to afford the title product as white crystals, 19.7g (86% yield), mp>250.degree. C. identified by .sup.1 HNMR analysis.

EXAMPLE 6

Preparation of 4-(2,6-dichlorophenoxy)-6-(difluoromethoxy)coumarin ##STR11##

A stirred suspension of 4-(2,6-dichlorophenoxy)-6-hydroxycoumarin (1.3 g, 3.71 mole) in acetone is bubbled through with chlorodifluoromethane at room temperature, under N.sub.2, for about 30-45 minutes, cooled to 5.degree.-10.degree. C., treated with 50% NaOH solution (2.4 g, 1.2 g NaOH, 29.7 mole NaOH), stirred for 2 hours at room temperature and filtered. The solid filtercake is washed with methylene chloride and crystallized from acetonitrile/methanol/water to afford the title product as a white solid, 0.95 g (69% yield), mp 145.degree.-148.degree. C., identified IR, .sup.1 HNMR, .sup.19 FNMR, .sup.13 CNMR, and mass spectral analyses.

EXAMPLE 7

Preparation of 4-hydroxy-8-nitrocoumarin ##STR12##

A solution of NaH (6.94 g, 0.291 mole) in dimethoxyethane is cooled using dry ice/acetone cooling, treated dropwise with diethyl malonate (46.6 g, 0.29 mole), allowed to warm to 0.degree. C., treated dropwise with a solution of 3-nitrosalicylyl chloride (19.5 g, 0.10 mole) in dimethoxyethane, allowed to warm to room temperature, stirred for 3 hours at room temperature, heated at 60.degree. C. until reaction is complete by HPLC analysis, cooled to room temperature, poured onto a mixture of ice water and methylene chloride and stirred for about 0.5 hour. The phases are separated, the aqueous phase is acidified with 50% HCl to pH 5 and filtered. The filtercake is dispersed in acetic acid, heated and filtered. This filtercake is air-dried and 8.6 g is dispersed in dimethyl sulfoxide, heated at 100.degree. C. for about 2 hours, cooled to room temperature, poured onto ice water and filtered. The solid is taken up in acetonitrile, filtered hot, cooled and filtered to give the title product, mp 242.degree.-245.degree. C., identified by IR, .sup.1 HNMR and mass spectral analyses.

EXAMPLE 8

Preparation of 4-(2,6-dichlorophenoxy)-6-methoxythionocoumarin ##STR13##

A mixture of 4-(2,6-dichlorophenoxy)-6-methoxycoumarin (0.40 g, 1.2 mmol) and Lawesson's Reagent.sup.1 (0.53 g, 1.3 mmol) in dioxane is heated at reflux temperature, stirred for about 4 hours, cooled to room temperature, stirred at room temperature for 16 hours and filtered. The filtercake is washed with petroleum ether and air-dried to give the title product as a yellow solid, 0.28 g (57% yield), mp 231.degree.-232.degree. C., identified by .sup.1 HNMR, .sup.13 CNMR and mass spectral analyses.

.sup.1 Methoxyphenylthionophosphine sulfide dimer

EXAMPLES 9-15

Preparation of 4-phenoxythionocoumarin derivatives ##STR14##

Using essentially the same procedure described in Example 8 and substituting the appropriate 4-phenoxycoumarin substrate, the following compounds are obtained.

TABLE I______________________________________ ##STR15##ExampleNo. X X' R W R.sub.1______________________________________9 Cl Cl H O 5-OH10 Br Br H O 7-OCH.sub.311 Cl Cl H O 7-OCH.sub.312 Cl Cl H O 6,7-di-OCH.sub.313 Cl Cl H O 7-NO.sub.214 Cl Cl H O 5-OC.sub.2 H.sub.515 Cl Cl H O 5-OCHF.sub.2______________________________________

EXAMPLE 16

Preparation of 4-(2,6-dichlorophenoxy)-6-(N-methylcarbamoyl)coumarin ##STR16##

A solution of 4-(2,6-dichlorophenoxy)-6-hydroxycoumarin (0.5 g, 1.55 mmole) in dimethyl formamide, under nitrogen, at room temperature is treated with triethylamine (0.7 mL, 5 mole), then treated with CH.sub.3 NCO (0.5 mL, 5.5 mole) and allowed to stir at room temperature for about 1 hour. When the reaction is complete by HPLC analysis, the reaction mixture is poured onto water and extracted with methylene chloride. The extracts are concentrated in vacuo to give a residue. The residue is crystallized from methylene chloride/hexane to afford the title product as white crystals, 0.382 (71% yield), mp 292.degree.-299.degree. C., identified by .sup.1 HNMR, .sup.13 CNMR and IR analyses.

EXAMPLE 17

Preparation of 4-(2,6-dichlorophenoxy)-6-(methoxymethyloxy)coumarin ##STR17##

A mixture of 4-(2,6-dichlorophenoxy)-6-hydroxycoumarin (1.2 g, 3.2 mmole), dimethoxymethane (0.565 g, 7.4 mmole), POCl.sub.3 (0.74 g, 4.8 mmole) and dimethylformamide (0.43 g, 5.94 mmole) in toluene is heated at 90.degree.-100.degree. C. for 4 hours, cooled to room temperature, poured onto ice water and filtered. The filtercake is dried and recrystallized from acetonitrile/water to afford the title product, 0.45 g (38% yield), mp 302.degree.-305.degree. C. (dec), identified by .sup.1 HNMR, .sup.13 CNMR and IR analyses.

EXAMPLE 18

Preparation of 2-hydroxy-4,5-dimethoxyacetophenone ##STR18##

A solution of 3, 4-dimethoxyphenol (0.50 g, 3.24 mole) in acetic acid is treated with boron trifluoride etherate (1.20 ml, 9.72 mmole) at 25.degree. C., heated at reflux temperature until reaction is complete by thin layer chromatographic analysis, cooled to room temperature and poured onto ice water. The resultant mixture is filtered, the filtercake is washed with water and ether and dried in vacuo to give the title product as an orange powder, 0.64 g (100% yield), identified by .sup.1 HNMR.

EXAMPLE 19

Preparation of 2-[4-(trifluoromethoxy)phenoxy]fumaric acid ##STR19##

A mixture of 4-(trifluoromethoxy)phenol (2.75 g, 12.5 mole) and dimethyl acetylene dicarboxylate (1.69 ml, 13.7 mmole) in dioxane is treated with benzyltrimethylammonium hydroxide (0.15 ml, 40% aqueous) at room temperature under a nitrogen atmosphere, heated to 90.degree.-95.degree. C. (condensation complete by thin layer chromatographic analysis) cooled to 40.degree. C., treated with sodium hydroxide (10 ml, 20% aqueous), heated at 90.degree. C. for 1 hour and cooled to room temperature. The reaction mixture is treated with 10% aqueous HCl to pH 7 and filtered. The filtrate is acidified to about pH 1 with HCl to afford a yellow precipitate. The solid is filtered and dried to give the title product, 2.56 g (70% yield), mp 208.degree.-210.degree. C., identified by 1H, .sup.13 C and .sup.19 FNMR, mass spectral and elemental analyses.

EXAMPLE 20

Preparation of 6-(trifluoromethoxy)chromone-2-carboxylic acid ##STR20##

A solution of phosphorous pentoxide (1.17 g, 8.21 mole) in methanesulfonic acid (14.38 g) is treated with 2-[4-(trifluoromethoxy)phenoxy]fumaric acid (2.00 g, 6.85 mmole), stirred for 16-18 hours at ambient temperatures and for 7 hours at 70.degree. C., cooled to room temperature and poured onto ice. The resultant mixture is filtered and the filtercake is dried to afford the title product, 1.75 g, (93% yield), mp 192.degree.-194 .degree. C., identified by 1H and .sup.13 CNMR, IR, mass spectral and elemental analyses.

EXAMPLE 21

Preparation of 4-chloro-6-(trifluoromethoxy)coumarin ##STR21##

A stirred mixture of 6-(trifluoromethoxy)chromone-2-carboxylic acid (1.50 g, 5.47 mmole) in thionyl chloride (6.0 ml) is treated with 1 drop of dimethyl formamide (DMF), heated at reflux temperature for 6 hours, cooled to room temperature and concentrated in vacuo. The residue is dispersed in toluene, treated with a saturated NaHCO.sub.3 solution and stirred until neutralized. The phases are separated and the toluene phase is concentrated in vacuo. The resultant residue is purified in acetonitrile and methylene chloride to give the title product, 1.04 g, (72% yield), mp 85.degree.-87.degree. C., identified by .sup.1 H, .sup.13 C and .sup.19 FNMR, IR, mass spectral and elemental analyses.

EXAMPLES 22-95

Preparation of 4-(2,6-substituted-phenoxy)coumarin derivatives

Using essentially the same procedures described in Examples 1 through 21, the following 4-(2,6-disubstituted-phenoxy)coumarin derivatives shown in Table II are obtained.

TABLE II__________________________________________________________________________ ##STR22##Example mpNo. X X' R W Y R.sub.1 .degree.C.__________________________________________________________________________22 Cl Cl H O O H 15923 F F H O O H 195.624 Br Br H O O H .sup. 162-170.degree.25 CH.sub.3 CH.sub.3 H O O H 163-16426 F OCH.sub.3 H O O H 145-14627 F NO.sub.2 H O O H 203-20528 OCH.sub.3 OCH.sub.3 H O O H 17529 Cl Cl H O O 6-(2Cl,4CF.sub.3,6FC.sub.6 H.sub.2) 155-15730 Cl Cl H O O 6-CH.sub.3 191-19231 Br Br H O O 6-OCH.sub.3 174-11532 Br Br H O O 6-CH.sub.3 182-18333 Cl Cl H O O 6(OCONHC.sub.2 H.sub.5) 220-22134 OCH.sub.3 OCH.sub.3 H O O 6-OCH3 206-20835 Cl Cl H O O 7-OCH3 165-16836 OCH.sub.3 OCH.sub.3 H O O 7-OCH3 205.5-20737 OCH.sub.3 OCH.sub.3 H O O 5-OCH3 186.5-188.538 Cl Cl H O O 7(OCH.sub.2 CHCH.sub.2) 185.5-18239 Cl Cl H O O 5(OCH.sub.2 CHCH.sub.2) 156.5-158.540 Cl Cl H O O 5(OCH.sub.2 COOCH) 161.2-162.641 Cl Cl H O O 6(OCH.sub.2 COOCH) 135-13642 Cl Cl H O O 6(OCH.sub.2 CHCH.sub.2) 145-14643 Cl Cl H O O 6(OCH.sub.2 C CH) 15344 Cl Cl H O O 6(OCH.sub.2 CH.sub.2 CFCF.sub.2) 14645 Cl Cl H O O 6-OCH(CH.sub.3).sub.2 14146 Cl Cl H O O 6-OCH(CH.sub.3)C.sub.2 H.sub.5 13847 Cl Cl H S O 6-OCH.sub.3 216-21748 Cl Cl H O O 6-OSO.sub.2 CF.sub.3 13749 Br Br H O O 6-F 16550 Cl Cl H O O 6-C.sub.2 H.sub.5 18451 Cl Cl H O O 6-F 18352 Cl Cl H S O 6-F 16853 Cl Cl H S O 6-C.sub.2 H.sub.5 18254 Cl Cl 4-Cl O O 6,7-di-CH.sub.3 26455 Br Br H O O 6,7-di-OCH.sub.3 19156 Cl Cl 4-F O O 6-OCH.sub.3 21757 Cl Cl H O O 6-Cl 20458 Br Br H O O 6-Cl 18859 Cl Cl H S O 6-Cl 21460 Cl Cl 4-Cl O O 6-OCH.sub.3 19661 Cl Cl 4-F O O 6,7-di-CH.sub.3 25562 Cl Cl H O O 6-OCH.sub.2 CHF.sub.2 16763 Cl Cl H O O 6,7-di-CH.sub.3 21264 Cl Cl H S O 6,7-di-CH.sub.3 24665 Cl Cl H O O 6,7-di-OCH.sub.3 19166 Cl Cl H S O 6,7-di-OCH.sub.3 17267 Cl Cl H O O 6,8-di-Cl 20668 Cl Cl H S O H 21269 Br Br H O O 6-C.sub.2 H.sub.5 15970 Br Br H O O 6,7-di-CH.sub.3 21071 Br Br H O O 6,8-di-Cl 21872 Cl Cl 4-F O O 6-F 18773 Cl Cl 4-Cl O O 6-F 20874 Cl Cl 4-F O O 6,7-di-OCH.sub.3 20575 Cl Cl 4-Cl O O 6-Cl 22176 Cl Cl 4-F O O 6-Cl 20077 Cl Cl H O O 6-OC.sub.2 H.sub.5 16278 F F 3,4,5-tri-F O O 6-F 17379 Br Br 4-CH.sub.3 O O 6,7-di-OCH.sub.3 15480 Cl Cl H O O 6-OCH.sub.2 C.sub.6 H.sub.4 OCF.sub.3 - 12981 Br Br 4-F O O 6-OCH.sub.3 20082 Br Br 4-Br O O 6-OCH.sub.3 195-19783 Cl Cl 3-Cl O O 6-OCH.sub.3 218-22084 F F H O O 6-OCH.sub.3 213-21485 Cl Cl H O O 6-CN 249-25086 Cl Cl H O O 5,6,7-tri-OCH.sub.3 169-17087 Cl Cl H O O 5-OCH.sub.3 203.6-207.588 Cl Cl H O O 7-OH 263-264.589 Cl Cl H O O 5-OH 250-25690 Cl Cl H S O 5-OCH.sub.3 204-20591 Br Br H O O 5-OCH.sub.3 201-20392 Cl Cl H S O 8-OCH.sub.3 183-18593 Br Br H O O 8-OCH.sub.3 15794 Cl Cl H O O 8-OCH.sub.3 142-14495 Br Br H O O 5,6,7-tri-OCH.sub.3 179-181__________________________________________________________________________

EXAMPLE 96

Preemergence Herbicidal Evaluation of Test Compounds in the Presence of Transplanted Rice Under Flooded Paddy Conditions

The preemergence herbicidal activity and rice crop tolerance under post-transplant application conditions is determined in the following manner. Grass weed seeds or tubers are planted in the top 0.5 cm of silt loam soil in plastic containers with no drainage holes and 4-6 rice seedlings (CV. Tebonnet), at the two-leaf stage, are transplanted into the same containers. The plastic containers may be 32 oz. containers having a diameter of 10.5 cm or 13 cm.times.13 cm square by 8 cm deep. After seeding and transplanting, the containers are placed on greenhouse benches and the soil is kept saturated for 3 days. On the 3rd day, the containers are flooded to a level of 2-3 cm of water above the soil surface. The flooded soil surface is then treated with selected aqueous acetone (20/80 v/v water/acetone) mixtures and sufficient test compound to provide the equivalent of about 4.0 kg/ha to 0.50 kg/ha of active ingredient. After treatment, the containers are kept on greenhouse benches and watered such that the water level is maintained at 2-3 cm above the soil surface.

Three to four weeks after treatment, the plants are evaluated and rated for herbicidal effect based on visual determination of stand, size, vigor, chlorosis, growth malformation and overall appearance. The rating system used is shown below. If more than one test is run, the data are averaged. The results are reported in Table III.

______________________________________RATING SYSTEM USED % ControlRating Meaning Compared to Check______________________________________0 No Effect 01 Trace Effect 1-52 Slight Effect 6-153 Moderate Effect 16-294 Injury 30-445 Definite Injury 45-646 Herbicidal Effect 65-797 Good Herbicidal Effect 80-908 Approaching Complete Kill 91-999 Complete Kill 100-- Not Tested______________________________________ ______________________________________PLANT SPECIES USEDAbbreviation Common Name Scientific Name______________________________________ECHCG Barnyard Grass Echinochloa crus-galli (L.) Beauv.ECHORC Water Grass Echinochloa oryzoides (ARD.) FritschORYSAT Rice, Tebonnet Oryza sativa, L. CV. Tebonnet______________________________________ TABLE III______________________________________Example RateNo. kg/ha ECHCG ECHORC ORYSAT______________________________________8 2.0 9.0 -- 0.0 1.0 9.0 9.0 0.3 0.5 9.0 9.0 0.39 1.0 9.0 -- 1.5 0.5 9.0 -- 1.510 1.0 9.0 9.0 0.0 0.5 9.0 9.0 0.012 1.0 -- 9.0 0.0 0.5 -- 8.0 0.021 1.0 8.0 -- 0.0 0.5 7.0 -- 0.022 1.0 9.0 -- 0.5 0.5 9.0 -- 0.523 1.0 0.0 -- 0.0 0.5 0.0 -- 0.024 1.0 9.0 -- 2.0 0.5 9.0 -- 2.025 1.0 -- 6.0 0.0 0.5 -- 2.0 0.029 1.0 7.0 -- 3.0 0.5 7.0 -- 2.030 1.0 9.0 -- 0.5 0.5 9.0 -- 0.331 1.0 9.0 -- 0.0 0.5 9.0 -- 0.032 1.0 9.0 -- 0.0 0.5 9.0 -- 0.033 1.0 0.0 -- 0.0 0.5 0.0 -- 0.034 4.0 9.0 -- 0.0 1.0 9.0 9.0 0.0 0.5 9.0 7.0 0.038 1.0 8.0 -- 0.0 0.5 7.0 -- 0.039 1.0 7.0 -- 0.0 0.5 7.0 -- 0.040 1.0 9.0 -- 0.0 0.5 6.0 -- 0.041 1.0 9.0 -- 0.0 0.5 9.0 -- 0.042 1.0 0.0 -- 0.0 0.5 0.0 -- 0.043 1.0 8.0 -- 1.0 0.5 7.0 -- 0.044 1.0 9.0 -- 0.0 0.5 7.0 -- 0.045 1.0 9.0 -- 0.0 0.5 9.0 -- 0.046 1.0 1.0 -- 0.0 0.5 0.0 -- 0.047 1.0 0.0 -- 0.0 0.5 0.0 -- 0.048 1.0 0.0 -- 0.0 0.5 0.0 -- 0.049 1.0 -- 9.0 0.0 0.5 -- 9.0 0.050 1.0 -- 9.0 0.0 0.5 -- 9.0 0.051 1.0 -- 9.0 0.0 0.5 -- 9.0 0.052 4.0 3.0 -- 0.0 1.0 7.0 0.0 0.0 0.5 2.0 0.0 0.053 4.0 0.0 -- 0.0 1.0 2.0 -- 0.0 0.5 1.0 -- 0.054 1.0 0.0 -- 0.0 0.5 0.0 -- 0.055 1.0 9.0 9.0 0.0 0.5 9.0 9.0 0.056 1.0 9.0 -- 0.0 0.5 8.0 -- 0.057 1.0 90 -- 0.0 0.5 90 -- 0.058 1.0 90 -- 0.0 0.5 90 -- 0.059 1.0 0.0 -- 0.0 0.5 0.0 -- 0.060 1.0 9.0 -- 0.0 0.5 9.0 -- 0.061 1.0 2.0 -- 0.0 0.5 1.0 -- 0.062 1.0 0.0 -- 0.0 0.5 0.0 -- 0.063 1.0 9.0 -- 0.0 0.5 9.0 -- 0.064 1.0 0.0 -- 0.0 0.5 0.0 -- 0.065 1.0 9.0 9.0 0.0 0.5 9.0 9.0 0.066 1.0 7.0 -- 0.0 0.5 1.0 -- 0.067 1.0 9.0 -- 0.0 0.5 6.0 -- 0.068 1.0 0.0 -- 0.0 0.5 0.0 -- 0.069 1.0 9.0 -- 0.0 0.5 9.0 -- 0.070 1.0 9.0 -- 0.0 0.5 9.0 -- 0.071 1.0 0.0 -- 0.0 0.5 0.0 -- 0.072 1.0 9.0 -- 0.0 0.5 9.0 -- 0.073 1.0 0.0 -- 0.0 0.5 0.0 -- 0.074 1.0 9.0 -- 0.0 0.5 9.0 -- 0.075 1.0 0.0 -- 0.0 0.5 0.0 -- 0.076 1.0 4.0 -- 0.0 0.5 2.0 -- 0.077 1.0 0.0 -- 0.0 0.5 0.0 -- 0.078 1.0 -- 0.0 0.0 0.5 -- 0.0 0.079 1.0 -- 9.0 0.0 0.5 -- 9.0 0.080 1.0 -- 0.0 0.0 0.5 -- 0.0 0.081 1.0 -- 0.0 0.0 0.5 -- 0.0 0.082 1.0 -- 9.0 0.0 0.5 -- 8.0 0.083 1.0 -- 0.0 0.0 0.5 -- 0.0 0.084 1.0 -- 6.0 0.0 0.5 -- 1.0 0.085 1.0 9.0 -- 0.0 0.5 9.0 -- 0.086 1.0 9.0 9.0 0.0 0.5 9.0 9.0 0.087 4.0 9.0 -- 0.0 1.0 9.0 9.0 0.0 0.5 9.0 9.0 0.088 1.0 7.0 -- 0.0 0.5 6.0 -- 0.089 1.0 6.0 -- 0.0 0.5 6.0 -- 0.090 1.0 4.5 -- 0.0 0.5 3.5 -- 0.091 1.0 9.0 -- 0.0 0.5 9.0 -- 0.092 1.0 2.0 -- 0.0 0.5 2.0 -- 0.093 1.0 9.0 -- 0.0 0.5 9.0 9.0 0.094 1.0 9.0 -- 0.0 0.5 9.0 9.0 0.095 1.0 -- 9.0 0.0 0.5 -- 9.0 0.0______________________________________

EXAMPLE 97

Preemergence Herbicidal Evaluation of Test Compounds in the Presence of Transplanted Rice Under Flooded Paddy Conditions

In this example, Deluvian paddy soil (Toyokawa paddy soil) is placed in plastic pots, 100 cm.sup.2 .times.9 cm in depth. Water is added to the level of the soil surface in the pot and the mixture is paddled 3 cm in depth.

Pots are then variously sown with monocotyledenous weed seeds and tubers at 0-2 cm in soil depth, as well as transplanted rice plants at the 2.5 leaf stage. The rice plants are transplanted at about 3 cm soil depth. Water is then added to all of the pots to 3 cm deep and kept at a depth of 3 cm for the duration of the test. Test compounds are applied in the manner described in Example 96 two days after transplanting the rice plants and sowing the weed seeds and tubers. The pots are then placed on greenhouse benches and cared for in the conventional manner. Tests are evaluated at 20 and 30 days after treatment. Evaluations made at 30 days after treatment are shown on Table IV. The rating system used is the same as that described in Example 96.

______________________________________PLANT SPECIES USEDAbbreviation Common Name Scientific Name______________________________________ECHCG Barnyard Grass Echinochloa crus-galliSAGPY Arrowhead (Pygmaea) Sagittaria pygmaeaCYPSE Flatsedge, Cyperus serotinus perennialMOOVA Monochoria Monochoria vaginalisCYPDI Flatsedge, Cyperus difformis smallflowerSCPJU Bulrush, Japanese Scirpus juncoidesORYSAK Rice, Koshihikari Oryza sativa, L. CV. Koshihikari______________________________________ TABLE IV__________________________________________________________________________PREEMERGENCE/POST-TRANSPLANT EVALUATIONEx. RateNo. kg/ha ECHCG SAGPY CYPSE MOOVA CYPDI SCPJU ORYSAK__________________________________________________________________________8 1.0 9 2 2 9 9 8 0 0.5 9 1 0 9 9 7 09 1.0 7 0 0 1 2 0 0 0.5 6 0 0 0 0 0 010 1.0 9 2 0 9 9 5 0 0.5 9 0 0 8 9 4 012 1.0 9 0 0 7 3 0 0 0.5 9 0 0 6 2 0 021 1.0 8 0 7 3 5 0 0 0.5 7 0 2 0 3 0 022 1.0 9 1 1 9 8 7 0 0.5 9 0 0 8 7 5 023 2.0 9 0 0 3 2 2 0 1.0 6 0 0 0 0 0 0 0.5 4 0 0 0 0 0 025 1.0 9 0 0 9 6 3 0 0.5 9 0 0 8 3 0 031 1.0 9 0 4 7 7 3 0 0.5 9 0 0 7 6 0 032 1.0 9 0 2 8 8 2 0 0.5 9 0 1 7 7 0 033 2.0 6 9 9 9 9 7 8 1.0 4 8 9 9 9 6 8 0.5 2 7 9 9 8 5 535 2.0 8 2 .0 0 1 0 0 1.0 8 0 0 0 0 0 0 0.5 7 0 0 0 0 0 038 1.0 8 0 0 0 0 0 0 0.5 6 0 0 0 0 0 039 1.0 7 0 0 0 0 0 0 0.5 5 0 0 0 0 0 040 1.0 9 0 0 0 0 0 0 0.5 9 0 0 0 0 0 041 1.0 9 1 7 8 9 2 1 0.5 9 0 3 7 7 1 042 2.0 2 0 0 0 0 0 0 1.0 0 0 0 0 0 0 0 0.5 0 0 0 0 0 0 043 1.0 8 0 0 0 0 0 0 0.5 6 0 0 0 0 0 044 1.0 8 0 0 0 0 0 0 0.5 5 0 0 0 0 0 045 1.0 7 0 0 0 0 0 0 0.5 4 0 0 0 0 0 046 2.0 0 0 0. 0 0 0 0 1.0 0 0 0 0 0 0 047 2.0 0 0 0 0 0 0 0 1.0 0 0 0 0 0 0 .048 2.0 0 0 0 0 0 0 0 1.0 0 0 0 0 0 0 049 1.0 9 0 5 9 9 8 0 0.5 9 0 2 9 8 5 050 1.0 9 0 0 8 8 1 0 0.5 9 0 0 8 7 0 051 1.0 9 0 2 8 7 0 0 0.5 8 0 0 8 5 0 055 1.0 9 1 9 9 9 9 0 0.5 9 0 8 9 9 8 056 1.0 8 0 0 3 2 0 0 0.5 6 0 0 2 1 0 057 1.0 9 0 2 2 2 0 0 0.5 9 0 0 1 1 0 058 1.0 9 0 0 4 3 0 0 0.5 9 0 0 2 1 0 059 1.0 5 0 0 1 2 2 0 0.5 3 0 0 0 0 0 060 1.0 9 0 5 6 5 0 0 0.5 9 0 0 5 3 0 061 1.0 4 0 0 1 1 0 0 0.5 3 0 0 0 0 0 062 1.0 2 0 0 0 0 0 0 0.5 0 0 0 0 0 0 063 1.0 9 0 0 2 1 1 0 0.5 9 0 0 1 0 0 064 1.0 1 0 0 0 0 0 0 0.5 0 0 0 0 0 0 065 1.0 9 4 5 9 9 2 1 0.5 9 2 2 9 9 0 066 1.0 9 0 0 2 2 0 0 0.5 8 0 0 0 0 0 067 1.0 9 0 1 2 3 0 1 0.5 8 0 0 0 2 0 068 1.0 0 0 0 0 0 0 0 0.5 0 0 0 0 0 0 069 1.0 9 0 2 7 7 2 1 0.5 9 0 0 6 6 0 070 1.0 9 0 5 2 1 0 0 0.5 9 0 0 0 0 0 071 1.0 6 0 0 0 0 0 0 0.5 5 0 0 0 0 0 072 1.0 9 0 1 1 4 0 0 0.5 9 0 0 3 2 0 073 1.0 7 0 2 0 0 0 0 0.5 3 0 0 0 0 0 074 1.0 9 0 0 4 6 2 0 0.5 9 0 0 2 3 0 075 1.0 4 0 0 2 1 0 0 0.5 2 0 0 0 0 0 076 1.0 7 0 0 2 1 1 0 0.5 6 0 0 0 0 0 077 1.0 6 0 0 2 0 0 0 0.5 6 0 0 1 0 0 078 1.0 2 1 4 2 0 6 0 0.5 0 0 2 1 0 4 079 1.0 9 2 0 9 9 7 0 0.5 9 1 0 8 7 6 085 1.0 9 0 0 4 4 2 0 0.5 7 0 0 1 2 1 086 1.0 9 5 5 9 9 9 0 0.5 9 2 2 9 9 8 087 1.0 9 0 4 8 8 4 0 0.5 9 0 2 7 8 2 088 1.0 5 0 0 0 0 0 0 0.5 4 0 0 0 0 0 089 1.0 4 0 0 0 0 0 0 0.5 2 0 0 0 0 0 090 1.0 3 0 0 0 0 0 0 0.5 0 0 0 0 0 0 091 1.0 9 0 0 5 8 0 0 0.5 9 0 0 3 5 0 093 1.0 9 0 2 9 9 7 0 0.5 9 0 0 8 8 5 094 1.0 9 0 7 9 9 8 0 0.5 9 0 3 9 9 5 0__________________________________________________________________________

Claims

1. A method for the control of monocotyledenous annual, perennial and aquatic plant species which comprises applying to the soil or water containing seeds or other propagating organs thereof a herbicidally effective amount of a compound of formula I ##STR23## wherein X and X' are each independently halogen, C.sub.1 -C.sub.4 alkyl or C.sub.2 -C.sub.4 alkenyl;

W and Y are each independently O or S;

R is any combination of from .one to three H, halogen, C.sub.1 -C.sub.4 alkyl, C.sub.3 -C.sub.6 cycloalkyl, C.sub.1 -C.sub.4 haloalkyl or C.sub.1 -C.sub.4 alkoxy groups;

R.sub.1 is any combination of from one to four H, halogen, OH, CN, SH, C.sub.1 -C.sub.6 alkyl optionally substituted with one or more halogen or OR.sub.2 groups, C.sub.3 -C.sub.6 cycloalkyl, C.sub.2 -C.sub.6 alkenyl, C.sub.2 -C.sub.6 haloalkenyl, C.sub.2 -C.sub.6 alkynyl, C.sub.2 -C.sub.6 haloalknyl, OR.sub.2, OCH.sub.2 COOR.sub.3, OCH.sub.2 OR.sub.4, OCOOR.sub.5, OCONHR.sub.6, OCOR.sub.7, S(O).sub.n R.sub.8, COR.sub.9, CH(OR.sub.10).sub.2, phenyl optionally substituted with one to three halogen, CN, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups, or benzyl optionally substituted with one to three halogen, CN, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl or C.sub.1 -C.sub.4 alkoxy groups;

R.sub.2 is H, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.2 -C.sub.6 alkenyl, C.sub.2 -C.sub.6 alkynyl, C.sub.2 -C.sub.6 haloalkenyl or C.sub.2 -C.sub.6 haloalkynyl;

R.sub.3, R.sub.4, R.sub.5, R.sub.6 and R.sub.7 are each independently H, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.3 -C.sub.6 cycloalkyl, phenyl optionally substituted with one to three halogen, CN, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups, or benzyl optionally substituted with one to three halogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl or C.sub.1 -C.sub.4 alkoxy groups;

R.sub.8 is C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl or phenyl optionally substituted with one to three halogen, CN, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups;

R.sub.9 is H, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, phenyl optionally substituted with one to three halogen, CN, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups, benzyl optionally substituted with one to three halogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups or NR.sub.11 R.sub.12 ;

R.sub.10 is H, C.sub.1 -C.sub.4 alkyl or --(CH.sub.2).sub.m --;

R.sub.11 and R.sub.12 are each independently H, C.sub.1 -C.sub.4 alkyl, C.sub.2 -C.sub.4 alkenyl or R.sub.11 and R.sub.12 may be taken together with the atoms to which they are attached to form a 5- or 6-membered ring optionally interrupted by oxygen;

n is an integer of 0, 1 or 2 and

m is an integer of 2 or 3.

2. The method according to claim 1 having a formula I compound wherein X and X' are each independently Cl, Br or CH.sub.3 and W and Y are O.

3. The method according to claim 2 having a formula I compound wherein R is H and R.sub.1 is one, two or three C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups.

4. The method according to claim 3 having a formula I compound wherein X and X' are Cl or Br, R is H and R.sub.1 is one, two or three methoxy or halomethoxy groups.

5. The method according to claim 4 wherein the formula I compound is 4-(2,6-dichlorophenoxy)-6-methoxycoumarin; 4-(2,6-dibromophenoxy)-8-methoxycoumarin; 4-(2,6-dichlorophenoxy)-8-methoxycoumarin; 4 -(2,6-dichlorophenoxy)-6,7-dimethoxycoumarin; 4-(2,6-dichlorophenoxy)-6,7-dimethoxycoumarin; 4-(2,6-dichlorophenoxy)-5,6,7-trimethoxycoumarin; or 4-(2,6-dibromophenoxy)-5,6,7-trimethoxycoumarin.

6. A method for the selective control of monocotyledenous weeds in the presence of a crop plant which comprises applying to the soil or water in which the seeds or propagating organs of said weeds are located add in which the crop plant has been planted or transplanted a herbicidally effective amount of a compound of formula I ##STR24## wherein X, X', W, Y, R and R.sub.1 are as defined in claim 1.

7. The method according to claim 6 wherein the crop is a cereal crop.

8. The method according to claim 7 wherein the cereal crop is wheat, oat, barley, rye, rice or corn.

9. The method according to claim 8 wherein the cereal crop is rice.

10. The method according to claim 9 wherein the monocotyledenous weed is a grass weed.

11. The method according to claim 9 wherein the formula I compound is applied at a rate of about 4.0 kg/ha to 0.06 kg/ha.

12. The method according to claim 11 wherein the formula I compound is applied at a rate of about 2.0 kg/ha to 0.06 kg/ha.

13. The method according to claim 11 wherein the formula I compound is 4-(2,6-dichlorophenoxy)-6-methoxycoumarin; 4-(2,6-dibromophenoxy)-8-methoxycoumarin; 4-(2,6-dichlorophenoxy)-8-methoxycoumarin; 4 -(2,6-dichlorophenoxy)-6,7-dimethoxycoumarin; 4-(2,6-dichlorophenoxy)-6,7-dimethoxycoumarin; 4-(2,6-dichlorophenoxy)-5,6,7-trimethoxycoumarin; or 4-(2,6-dibromophenoxy)-5,6,7-trimethoxycoumarin.

14. A compound of formula I ##STR25## wherein X and X' are each independently halogen, C.sub.1 -C.sub.4 alkyl or C.sub.2 -C.sub.4 alkenyl;

W and Y are each independently O or S;

R is any combination of from one to three H, halogen, C.sub.1 -C.sub.4 alkyl, C.sub.3 -C.sub.6 cycloalkyl, C.sub.1 -C.sub.4 haloalkyl or C.sub.1 -C.sub.4 alkoxy groups;

R.sub.1 is any combination of from one to four H, halogen, OH, CN, SH, C.sub.1 -C.sub.6 alkyl optionally substituted with one or more halogen or OR.sub.2 groups, C.sub.3 -C.sub.6 cycloalkyl, C.sub.2 -C.sub.6 alkenyl, C.sub.2 -C.sub.6 haloalkenyl, C.sub.2 -C.sub.6 alkynyl, C.sub.2 -C.sub.6 haloalknyl, OR.sub.2, OCH.sub.2 COOR.sub.3, OCH.sub.2 OR.sub.4 OCOOR.sub.5, OCONHR.sub.6, OCOR.sub.7, S(O).sub.n R.sub.8, COR.sub.9, CH(OR.sub.10).sub.2, phenyl optionally substituted with one to three halogen, CN, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups, or benzyl optionally substituted with one to three halogen, CN, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl or C.sub.1 -C.sub.4 alkoxy groups with the proviso that at least one of R.sub.1 must be other than H;

R.sub.2 is H, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.2 -C.sub.6 alkenyl, C.sub.2 -C.sub.6 alkynyl, C.sub.2 -C.sub.6 haloalkenyl or C.sub.2 -C.sub.6 haloalkynyl;

R.sub.3, R.sub.4, R.sub.5, R.sub.6 and R.sub.7 are each independently H, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.3 -C.sub.6 cycloalkyl, phenyl optionally substituted with one to three halogen, CN, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups, or benzyl optionally substituted with one to three halogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl or C.sub.1 -C.sub.4 alkoxy groups;

R.sub.8 is C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl or phenyl optionally substituted with one to three halogen, CN, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups;

R.sub.9 is H, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, phenyl optionally substituted with one to three halogen, CN, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups, benzyl optionally substituted with one to three halogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups or NR.sub.11 R.sub.12 ;

R.sub.10 is H, C.sub.1 -C.sub.4 alkyl or --(CH.sub.2).sub.m --;

R.sub.11 and R.sub.12 are each independently H, C.sub.1 -C.sub.4 alkyl, C.sub.2 -C.sub.4 alkenyl or R.sub.11 and R.sub.12 may be taken together with the atoms to which they are attached to form a 5- or 6-membered ring optionally interrupted by oxygen;

n is an integer of 0, 1 or 2 and

m is an integer of 2 or 3.

15. The compound according to claim 14 wherein X and X' are each independently Cl, Br or CH.sub.3 and W and Y are O.

16. The compound according to claim 15 wherein R is H and R.sub.1 is one, two or three C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy or C.sub.1 -C.sub.4 haloalkoxy groups.

17. The compound according to claim 16 wherein X and X' are Cl or Br, R is H and R.sub.1 is one, two or three methoxy or halomethoxy groups.

18. The compound according to claim 17 4-(2,6-dichlorophenoxy)-6-methoxycoumarin.

19. The compound according to claim 17 4-(2,6-dibromophenoxy)-8-methoxycoumarin.

20. The compound according to claim 17 4-(2,6-dichlorophenoxy)-6,7-dimethoxycoumarin.

21. The compound according to claim 17 4-(2,6-dibromophenoxy)-6,7-dimethoxycoumarin.

22. The compound according to claim 17 4-(2,6-dichlorophenoxy)-5,6,7-trimethoxycoumarin.

23. The compound according to claim 17 4-(2,6-dibromophenoxy)-5,6,7-trimethoxycoumarin.

24. A herbicidal composition which comprises an agronomically acceptable carrier and a compound of formula I ##STR26## wherein X, X', W, Y, R and R.sub.1 are defined in claim 14.

25. The composition according to claim 24 wherein X and X' are each independently Cl, Br or CH.sub.3 and W and Y are O.

26. The composition according to claim 25 wherein R is H and R.sub.1 is one, two or three C.sub.1 -C.sub.4 alkoxy groups.