GB2041926A - Phenoxy- and thiophenoxy nitriles and their uses as herbicides - Google Patents

Abstract

Phenoxy- and thiophenoxynitriles, which are efficient herbicides, conform to the general formula:- <IMAGE> R1 is a hydrogen or halogen atom or an alkyl of haloalkyl radical having 1-4 carbon atoms; R2 and R3 represent hydrogen, an alkyl radical having 1-4 carbon atoms, or a phenyl radical optionally substituted by (R1)n; R4 and R5 either are each defined similarly to R2 and R3 or together with the conjoining carbon atom form a 5- 6- or 7-membered polymethylene ring, provided however that when one of R4 and R5 is hydrogen the other is not CH3; Y is defined similarly to R1 or is the group <IMAGE> (wherein X is -O, -S- or-CH2-, and R6 is defined similarly to R1 or may be an NO2 or CN group); Z is sulphur or when Y represents the group of formula II can also be oxygen; and n and n1 are 0-3. These compounds are new but their preparation is conventional. Preferred herbicidal formulations and treatments are disclosed.

Description

SPECIFICATION Phenoxy- and thiophenoxynitriles and their uses as herbicides The invention relates to phenoxy- and thiophenoxynitriles, and their use as herbicides.

The phenoxy- and thiophenoxynitriles in accordance with the invention are represented by the following general formula:

in which: -A is one of the linkages -0-, -S-,

and

- R; represents a hydrogen or halogen atom, or an alkyl or halo-alkyl radical having 1 to 4 carbon atoms; - R2 and R3, which may be the same or different, each represents a hydrogen atom, an alkyl radical having 1 to 4 carbon atoms, a phenyl radical or a phenyl radical substituted by (R1)n;; - R4 and R5 are each defined in the same manner as R2 and R3 or together with the carbon atom which bears them constitute a polymethylene ring with 5, 6 or 7 links, subject always to the proviso that when one of the radicals R4 and R5 is a hydrogen atom then the other is not -CH3; - Y is defined in the same manner as R, or represents the group:

(in which X is one of the linkages -0-, -S- and -CH2-; and R6is defined in the same manner as R1, with which it may be identical, or may also be an NO2 or CN group); - Z either is a sulphur atom or when Y represents the

x (R6) nl group is either a sulphur atom or an oxygen atom; and - n and n,, which may be the same or different, are each zero or an integer from 1 to 3.

A first advantageous group of compounds corresponding to the aforesaid general formula I is that in which: - Y and R1, which may be the same or different, each represents a hydrogen or chlorine atom of a halo-alkyl group; - A is the-NR3 group; - R2 to R5, which may be the same or different,.each represents H, CH3 or C2H5, subject always to the proviso that when one of R4 and R5 is hydrogen the other is not-CH3; and - n is zero or the integer 1.

A second group of advantageous compounds corresponding to the aforesaid general formula I is that in which: - This the

group wherein R6 is either Cl or CF3; - A is the group

- n, is the integer 1 or 2; - R, represents a hydrogen atom; - Z represents an oxygen atom: and - R2 to R5, which may be the same or different, each represents a hydrogen atom or a -CH3 or -C2H5 radical, subject always to the proviso that when one of R4 and R5 is hydrogen the other is not -CH3.

A third group of advantageous compounds corresponding to the aforesaid general formula I is that in which: - A is an oxygen atom; -Y is the

group wherein R6 is CI or CF3; and - Z represents an oxygen atonal.

Particularly advantageous compounds corresponding to the aforesaid general formula I are the following:

(denoted below as "compound 11") (denoted below as "compound 12") as well as those which, in the description which follows, are denoted respectively as compound 13, compound 15, compound 16, compound 19, compound 20, compound 34, compound 39, compound 40, compound 41, compound 43, compound 44, compound 45, compound 47 and compound 48.

The compounds of general formula I may be prepared by processes which are analogous to known procedures and are illustrated by the examples given hereinafter. Nevertheless for general guidance the preparation of the compounds will here be indicated schematically by the following reaction diagrams, in which the various groups of course retain the meanings assigned to them above.

Firstly, it may be assumed that:

The processes then can be indicated as follows:

The reaction conditions appear clearly from the examples which are given subsequently.

The compounds of general formula I are herbicides of special interest as anti-graminaceous herbicides.

They exhibit an interesting selectivity on cereals and dicotyledons.

They can be applied after planting and prior to emergence or after planting and after emergence.

The application rates generally employed will be, dependent upon: - the duration of the effect which is sought, - the technique of application, - the nature of the soils, - the cultivation techniques, and - the nature of the cultivations, between 500 g and 5,000 g of active material per hectare or a.m./ha, preferably between 1,000 and 5,000 g of a.m./ha.

The invention also relates to herbicidal treatments, principally anti-graminaceous, selective with respect to certain dicotyledons, and more or less selective with regard to cultivated cereals, using the compounds according to the invention.

The compounds according to the present invention can be used as herbicides, for application prior to emergence, with or without incorporation, or after emergence, at the locus where it is desired to provide the control.

These compounds should desirably be formulated suitably for the applications contemplated; such formulations may, beside the active material, contain additives and inert of active vehicles or supports.

The herbicidal compounds are generally formulated in the form of powders, wettable powders, granules, emulsifiabie concentrated solutions, and aqueous or oily micronised dispersions.

Distribution is carried out by means of equipment adapted for the use of each type of formulation.

Some typical formulations are exemplified below: a) Example of wettable powders containing any of the compounds 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 identified subsequently.

In a ribbon mixer there are mixed 52.6 parts of the chosen compound (of 95% purity), 41.4 parts of kaolin clay known under the trademark "Argirec B 24", 2 parts of wetting agent of the sodium alkyl naphthalene sulphonate type (for example that sold under the trademark "Galoryl MT 701" by us) and 4 parts of a dispersing agent, for example sodium lignosulphonate.

The mixture is then passed into a grinder of the Forplex type. There is thus obtained a wettable powder with 50% of active material, which has the properties normally required of such formulations,.

namely a wettability of less than one minute and suspendibility of approximately 90% after one hour.

b) Example of emulsifiable concentrates containing any of the compounds 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12 identified subsequently 253 g of the chosen compound (of 95% purity), 25 g of calcium dodecylbenzene sulphonate in 70% solution in isobutyl alcohol, 35 g of castor oil condensed with 30 moles of ethylene oxide and an amount of a petroleum solvent, for example that sold under the SHELL SOL (Registered Trade Mark) R brand (82% of aromatics, closed cup flash point 790C) to make 1 litre, are mixed together. In this way, an emulsifiable concentrate is obtained, containing 240 g/I of active material, which upon dilution will form emulsions which are stable for 8 hours.

The preparation of compounds of the first group of advantageous compounds will now be illustrated as follows: EXAMPLE I Preparation of N-(1 ,1 -dimethyl cyanomethyll p-chlorothiophenoxyacetamide (n=1, R1=p-Cl, R2=R3=CH3, R4=R5CH3, Y=H) or compound 1 7.25 g of p-chlorothiophenol, 8 g of the N-chloroacetyl derivative of n-aminoisobutyronitrile and 13.8 g of potassium carbonate are introduced into 120 ml of butanone and heated for 10 hours with reflux. It is filtered, the solvent is removed under vacuum, the residue is taken up again with water, extracted with chloroform, dried and distilled. The residue is chromatographed on a silica column with ether as the eluant.

Compound 1 is obtained with a yield of 35% and has a m.p. of 120 to 1 220C.

EXAMPLE II Preparation of N-(1,1-dimethyl cyanomethyl) 2-p-chlorothiophenoxy propionamide (n=1, R1=p-Cl.

R2=CH3, R3=H, R4=R5=CH3, Y=H)or compounnd 2.

98 g of 50% soda are added gradually, with stirring and cooling, to a mixture of 59 g of pchlorothiophenol, 73.2 g of &alpha;-bromopropionic acid and 70 ml of water. It is then taken to reflux for 2 hours, acidified with concentrated HCI and extracted with ether. In this way, 87 g of 2-pchlorothiophenoxy propionic acid of m.p. 99-101 OC are isolated.

42 g of this acid and 130 g of thionyl chloride are heated overnight under reflux. The excess of thionyl chloride is removed under vacuum. A benzene solution of the crude acid chloride is then added drop by drop with stirring and cooling into a mixture of 16 g of &alpha;-aminoisobutyronitrile and 19 g of triethylamine in 100 ml of anhydrous benzene. When the addition is over, it is stirred for another 2 hours at room temperature. The solvent is removed under vacuum, the residue is taken up again with water, extracted with chloroform, dried and distilled. The residue is recrystallized in an ether-chloroform mixture. The melting point of the product thus obtained is 11 50C (yieid 60%).

A certain number of other compounds belonging to the first group of advantageous compounds according to the invention, were prepared by similar operational methods. These compounds are identified by their formula and their melting point in Table A. It should be noted that in the case of all these compounds, R3 is a hydrogen atom.

TABLE A

Compound No. n Y R1 R2 R4 R5 M.P.

3 O Cl H C2H5 CH3 118-119 4 2 H 2,5-Cl C2H5 CH3 CH3 110-112 5 1 Cl 2-Cl H CH3 CH3 113-115 6 1 Cl 2-Cl CH3 CH3 CH3 107-109 7 1 Cl 2-Cl C2H5 CH3 CH3 127-129 8 2 H 2,5-Cl H CH3 CH3 136-138 9 2 H 2,5-Cl CH3 CH3 CH3 120-122 10 1 Cl 3-Cl H CH3 CH3 96-97 11 1 Cl 3-Cl CH3 CH3 CH3 144 12 1 Cl 3-Cl C2H5 CH3 CH3 103-104 13 1 Cl 3-Cl CH3 H H 116-118 14 1 Cl 3-Cl C2H5 H H 96-98 Compounds belonging to the second group of advantageous compounds were also prepared.

EXAMPLE III Preparation of N-(1,1-dimethyl cyanomethyl) 2-[4-(4'-chlorophenoxyl) phenoxyj propionamide (n1=1, n=O, P6=p-Cl, X=Z=O, R2=R4=Rs=CH3, R3=H) or compound 15 To a solution of 0.19 mole of triethylamine and 0.19 mole of a-aminoisobutyronitrile in 300 ml benzene, was added drop by drop with stirring and cooling 0.19 mole of &alpha;-chloropropionyl chloride. The stirring was then continued for 2 hours. The solvent was removed under vacuum, the residue was taken up with water, extracted with chloroform, dried and the solvent removed.

The &alpha;-aminoisobutyronitrile N-a-chloropropionamide was isolated by distillation and obtained with a yield of 50%.

Its boiling point was B.P.0.25=1 200 C.

To 200 ml of butanone, was added 0.12 mole of the preceeding product, 0.12 mole of 4-(4' chloro phenoxy) phenol and 0.24 mole of potassium carbonate. It was taken to reflux for 10 hours, filtered and the solvent removed under vacuum. The residue was taken up again with water; and extracted with chloroform, dried and the solvent removed The residue was chromatographed on silica (ether and petroleum ether 60:40). A solid product m.p.=82-830C was obtained.

EXAMPLE IV Preparation of N-(cyanomethyl) 2-[4-(4'-chlorophenoxy) phenoxy] propionamide (n1 =1, n=O, R6=p-CI, X=Z=O, R3=H, R2=CH3, P4=P5=H) or compound 16.

12 g of 2-[4-(4'-chloro phenoxy) phenoxy] propionic acid and 21 g of thionyl chloride were heated for 10 hours under reflux.

The excess of thionyl chloride was eliminated under vacuum.

11 g of the acid chloride thus obtained were added dropwise with stirring to a chloroform-water mixture (50:50) containing 3.4 g of aminoacetonitrile hydrochloride and 6.2 g of sodium bicarbonate.

The organic phase was washed with water, dried and the solvent was removed under vacuum. The residue was chromatographed on a silica column with ether as the eluant. The desired product was obtained with a yield of 35% and had a melting point of 90-91 OC.

EXAMPLE V Preparation of N-(1,1 dimethyl cyanomethyl) 2-[4-(4'-trifluoromethyl phenoxy) phenoxyj propionamide (n=O, n =l, R0=p-CF3, X=Y=O, P3=H, P2=P4=R5=CH3) or compound 17.

1 9 g of 2-[4-(4'-trifluoromethyl phenoxy) phenoxy] propionic acid and 40 g of thionyl chloride were heated for 12 hours under reflux. The excess of thionyl chloride was driven off under vacuum. A benzene solution of the crude acid chloride was then added dropwise with stirring and cooling to a solution of 5 9 of a-aminoisobutyronitrile and 6 g of triethylamine in 200 ml benzene. When the addition was finished, it was stirred for 2 hours at room temperature. The benzene was removed under vacuum, the residue was taken up with water, it was extracted with chloroform, dried, the solvent removed and the residue chromatographed.

The final product which is sought was obtained with a yield of 35% and had a melting point of 68-70 C.

By employing similar operational methods a certain number of other derivatives belonging to the second group of advantageous compounds of the invention were prepared.

These other compounds, in which n=O, are identified by their formula and their melting point in the following Table B.

TABLE B

n1 R6 X Z R3 R2 R4 R5 M.P.

18 1 p-CI O O H H CH3 CH3 98-100 19 1 p-CF3 O O H H CH3 CH3 104-105 20 1 p-CF3 O O H C2Hs CH3 CH3 92-94 21 1 p-CF3 O O CH3 CH3 H- H 102-104 22 1 p-CF3 O O H CH3 H H 74-76 23 1 p-CF3 F3 O O H H H H 93-94 24 1 m-CF3 O O H H CH3 CH3 90-92 25 1 m-CF3 O O H CH3 CH3 CH3 114-116 26 1 m-CF3 O O H C2H5 CH3 CH3 91-92 27 2 2,4-Cl O O H H CH3 CH3 102-103 28 1 p-CI S O H H CH3 CH3 93" 29 1 p-Cl CH2 O H H CH3 CH3 108-110 30 1 p-Cl CH2 O H CH3 CH3 CH3 98-100 31 2 2,4-Cl CH2 O H H CH3 CH3 121-123 In the following Tables B' and B", some other compounds according to the invention are identified and their melting point indicated.

These compounds were prepared by employing the above-indicated processes.

TABLE B' (Compounds of formula I with Y =

and Z = 0)

Compound R6 R1 R2 A R4 R5 M.P.

32 p-Cl H CH3 N-CH3 CH3 CH3 44-46 33 p-CF3 H CH3 N-CH3 CH3 CH3 56-58 35 p-CF3 H CH3 NH C2H5 C2H5 76-78 36 p-CF3 H CH3 NH CH3 C2H5 58-60 37 3,4-Cl H CH3 NH CH3 CH3 109-111 38 p-CF3 H CH3 NH C6H5 H 105-107 TABLE B'' (compounds of formula I with Y =

and Z = 0)

B.P. (mm) and/or Compound R6 R1 R2 A R4 R5 M.P. ( C) 34 p-CF3 H CH3 O CH3 CH3 135-140 C (0,5 mm) 43-45"C 39 p-CF3 H CH3 O CH3 C2H5 160-170 C (0,03 mm) pasty 40 p-CF3 H CH3 O C2H5 C3H, 160-170" (0.04 mm) 41 p-CF3 H CH3 O C6H5 H 140-145 (0,01 mm) pasty 42 di-CI-3,5 H CH3 O CH3 CH3 180-190" (0,06 mm) pasty 43 di-CI-2,4 H CH3 O CH3 CH3 200" (0,01 mm) pasty 44 m-CF3 H CH3 O CH3 CH3 160 (0,05 mm) 45 m-CF3 H CH3 H H 190 (0,1 mm) 46 p-Cl H CH3 O CH3 CH3 180-185 (0,04 mm) pasty 47 p-CF3 H CH3 O H H 185-190 (0.1 mm) 60-62 C 48 p-CF3 H CH3 O C2H5 H 160 (0,02 mm) pasty Compound nO 34 has a refractive index of 1.5125 and a boiling point of 135-1 400C at 0.5 mm of mercury.

The interesting antigraminaceous herbicidal properties and the selectivity with respect to cultivated cereals and dicotyledons of the compounds according to the invention. have been demonstrated both by experiments in the greenhouse and by experiments in the open fields.

They relate to the compound n 11 and 12 of the first group, to the compounds n 15,17,21,22 and 30 of the second,as well as to compounds 34,35,36,39,40,41 and 43.

Tests carried out in the greenhouse will first be described and then the tests in the open fields whose results are grouped in Tables.

Systematic observations were made at regular intervals after the treatment according to a notation running from 0 to 10: - 0 indicating 0% destruction, - 10 indicating 100% destruction, the notations 1 to 9 representing the intermediate values according to the Table below: 9 = 97.5% 8 = 95.0% 7 = 85.0% 6=70.0% 5 = 50.0% 4=30.0% 3=15.0% 2= 5.0% 1 = 2.5% The products are applied: - either prior to planting with incorporation, - or after emergence, - or after planting and prior to emergence.

TEST GROUP I: Compound nO 12 The test compound is applied at the rate of 5,000 g/a.m./ha, either prior to planting with incorporation, or after emergence.

Species tested in this test Results Before Post Graminaceous plants: planting emergence Agrostic spica venti 10 2 Alopecurus 8 0 Avena 8 0 Echinochloa 10 0 Dicotyledons: A triplex O 0 Amaranthus O 0 Chenopodium O 0 Chrysanthemum 2 0 Daucus 2 2 Medicago 0 0 Raphanus O 0 Solanum 2 0 This test shows anti-graminaceous activity of the compound and its innocuousness with respect to dicotyledons.

TEST GROUP II: Compound nO 11 The test compound is applied at the rate of 5,000 gla.mjha, either prior to planting, either after emergence.

Species tested in this test Results Before Post planting emergence Graminaceous plants: Agrosticspicaventi 10 4 Alopecurus 8 0 Avena 8 0 Echinochloa 8 0 Dicotyledons: Triplex O 0 Amaranthus O 0 Chenopodium O 0 Chrysanthemum 2 0 Daucus 2 2 Medicago O 0 Raphanus 2 0 Solanum 2 0 This test shows anti-graminaceous activity prior to planting of the compound and its innocuousness with respect to dicotyledons.

TEST GROUP III: Compound nO 15 a) The test compound is applied at the rate of 5,000 g"a.m./ha. either prior to planting or after emergence.

Species tested in this test Results Before Post planting emergence Graminaceous plants: Agrostis spica venti 10 0 Alopecurus 8 -(not seeded) Arena sativa 10 2 Lolium 10 2 Dicotyledons: Triplex 0 6 Chrysanthemum 0 4 Daucus 2 0 Medicago 0 4 Rumex acetosa 0 4 Solanum nigrum 0 2 This test shows an interesting anti-graminaceous action on the application prior to planting and an interesting innocuousness with respect to dicotyledons under the same conditions.

b. Following the preceeding test, the compound was applied prior to planting at 3 rates: 1,250, 2,500 and 5,000 g/a.m./ha.

Species tested Results 1,250 2,500 5,000 Anti-graminaceous action: Winter graminaceae Agrostis spica venti 4 6 6 Agropyrum 4 6 10 Poa 10 10 10 Lolium 8 10 10 Alopecurus 8 10 10 Summer graminaceae Andropogon 8 8 8 Digitaria 10 10 10 Anti-dicotyledon action: Colza o Raphanus 2 Beet O Chicory 2 Tomato 2 Lucern 2 Carrot O Flax 2 Allium Cepa O This test fuily confirms the anti-graminaceous effectiveness of the test compound as well as its innocuousness to dicotyledon plants.

TEST GROUP IV: Compound nO 17 a) The test compound was applied at the rate of 5,000 g/a.m./ha prior to planting or after emergence.

Species tested in this test Results Prior to After planting emergence Graminaceae: Agrostis spica venti 10 10 Alopecurus 10 8 Andropogon 10 4 Avena sativa 10 2 Lolium 10 6 Dicotyledons: Triplex 4 0 Amaranthus 4 unseeded Chrysanthemum 2 0 Daucus 0 4 Medicago O 0 Raphanus O 0 Rumex O 0 Solanum O 0 This test shows an interesting anti-graminaceous activity notably prior to planting, as well as a good selectivity on cultivated dicotyledons.

b) Following the preceeding test, the same compound was applied prior to planting at 3 rates: 1,250,2,500 and 5,000 g/a.m./ha.

Species tested in this test Results Anti-graminaceous action: 1,250 2,500 5,000 Winter graminaceae Agrostis 10 10 10 Poa 10 10 10 Lolium 10 10 10 Alopecurus 10 10 10 Summer graminaceae: Andropogon 8 10 10 Digitaria 10 10 10 Echinochloa 10 10 10 Setaria 10 10 10 Anti-dicotyledon action: Colza O 0 0 Raphanus O 0 0 Triplex O 0 2 Chrysanthemum O 0 0 Taraxacum O 0 0 Tomato O 0 0 Solanum O 0 0 Medicago O 0 0 Daucus O 0 0 Amarånthus O 0 0 Allium Cepa O 0 0 Papaver O 0 0 Flax O 0 0 This test confirms the interest of the anti-graminaceous action of this compound as well as its perfect selectivity on dicotyledons.

c) The same compound is applied according to the Post-planting-prior-emergence technique. The doses are the same as in bj.

Species tested in this test Results Anti-graminaceous action: 1,250 2,500 5.000 Crops: Oats O 0 2 Wheat O 0 0 Corn 2 4 6 Barley 2 0 2 Winter graminaceae: Agrostis 10 10 10 Poa 10 10 10 Lolium 4 6 8 Alopecurus 10 10 10 Summer graminaceae: Andropogon 8 8 10 Digitaria 10 1.0 10 Echinochloa 8 10 10 Setaria 10 10 10 This method of application permits the use of the compound on cultivated graminaceae, notably oats, wheat and barley. The test confirms also the high effectiveness on adventitious graminaceae.

TESTS GROUP.V: Compound nO 21 a) The Test compound is applied at the rate of 5,000 g/a.mlha, either prior to planting or after emergence.

Species tested in this test Results Prior to After planting emergence Graminaceae: Agrostis spica venti 8 2 Alopecurus 10 4 Echinochloa 10 8 Lolium 10 6 Dicotyledons: Amaranth us 0 2 Chenopodium O 0 Chrysanthemum 2 2 Daucus O 0 Medicago 2 0 Raphanus 2 0 Solanum nigrum O 0 This test shows good anti-graminaceous activity prior to planting (also a specific action on Echinochloa after emergence) and a satisfactory selectivity on dicotyledons.

b) Following the preceeding test, the compound was applied on prior planting at 3 rates: 1,250, 2,500 and 5,000 g/a.m./ha.

Species tested in this test Results Anti-graminaceous action: 1 250 2,500 5,000 Crops: Oats 4 6 8 Wheat 8 10 10 Corn 10 10 10 Barley 6 8 8 Winter graminaceae: Agrostis 10 10 10 Poa 10 10 10 Lolium 10 10 10 Alopecurus 10 10 10 Summer graminaceae: Andropogon 10 10 10 Digitaria 10 10 10 Echinochloa 10 10 10 Setaria 8 10 10 This test does confirm the anti-graminaceous action of the compound. On the other hand, because of the aggressiveness of the compound on cultivated graminaceae, test c) is again undertaken.

c) The compound is applied after planting, prior to emergence at the same rates as above: Species tested in this test Results Anti-graminaceous action: 1,250 2,500 5,000 Crops: Oats 2 2 2 Wheat 2 4 4 Corn 2 2 4 Barley 2 4 4 Winter graminaceae: Agrostis 10 10 10 Poa 8 8 10 Lolium 10 10 10 Alopecurus 8 10 10 Summer graminaceae: Andropogon 4 8 8 Digitaria 10 10 10 Echinochloa 8 10 10 Setaria 8 10 10 The application after planting, prior to emergence notably reduced the aggressiveness of the compound on cultivated graminaceae, but reduces its effectiveness on adventitious graminaceae only to a very slight extent or not at all.

TESTS GROUPS VI: Compound nO 22 a) The test compound was applied at the rate of 5,000 g/a.m./ha, either prior to planting, or after emergence.

Species tested in this test Results Prior to After Graminaceae: planting emergence Agrostis 10 4 Alopecurus 10 8 Avena 10 6 Echinochloa 10 10 Lolium 10 8 Dicotyledons: Amaranthus 4 2 Chenopodium O 0 Chrysanthemus 4 2 Medicago O 0 Raphanus 2 2 Solanum O 0 Daucus 0 2 'This test shows good anti-graminaceous activity prior to planting (and its specific action on Echinochloa after emergence) as well as a satisfactory selectivity on cultivated dicotyledons.

b) Following the preceeding test, the compound was then applied prior to planting at 3 rates: 1,250, 2,500 and 5,000 g/a.m./ha.

Species tested in this test Results Anti-graminaceous action: 1,250 2,500 5,000 Crops: Oats 8 10 10 Wheat 10 10. 10 Corn 10 10 10 Barley 8 8 10 Winter graminaceae: Agrostis 10 10 10 Poa 10 10 10 Lolium 10 10 10 Alopecurus 10 10 10 Summer graminaceae: Andropogon 10 10 10 Digitaria 10 10 10 Echinochloa 10 1Q 10 Setaria 10 10 10 This test confirms the interesting action of the compound as regards the anti-graminaceae. The latter being aggressive to certain cultivated cereals, the following test was undertaken.

c) The compound was applied after planting, prior to emergence at rates of 1,250, 2,500 and 5,000 gl'a.m.iha.

Species tested in this test Results Anti-gramonaceous action: Crops: 1,250 2,500 5,000 Oats 6 10 10 Wheat 10 10 10 Corn 10 10 10 Barley 6 10 10 Winter graminaceae: Alopecurus 10 10 10 Lolium 10 10 10 Poa 10 10 10 Summer graminaceae: Andropogon 10 10 10 Digitaria 10 10 10 Echinochloa 10 10 10 Setaria 10 10 10 This test confirms the interesting anti-graminaceous action of the compound nO 20, but does not show improved selectivity on cereals.

TESTS GROUP VII: Compound nc 34 TESTS IN GREENHOUSE a) The test compound was applied at the rate of 5,000 g/a.m./ha, either prior to planting or after emergence.

Species tested in this test Results Prior to After planting emergence Graminaceae: Agrostis spica venti 10 10 Alopecurus 10 10 Avena 8 8 Echinochloa 10 2 Lolium 10 8 Dicotyledons: Triplex 2 10 Amaranth us 2 6 Chrysanthemum 6 6 Daucus 0 2 Medicago o 0 Raphanus O 0 Solanum O 0 This test shows the anti-graminaceous activity of the compound and its innocuousness with respect to cultivated dicotyledons.

b) Further to the preceeding test, the compound is then applied prior to planting in 3 rates: 625, 1,250 and 2,500 g/a.m./ha.

The results relative to these three rates are assembled in Table F hereunder.

This test confirms the interesting anti-graminaceous activity of the compound. Then, the following test was undertaken.

Further to this test, a formulation of the compound was prepared in a concentrated form capable of ernulsification by techniques which are well known by the man skilled in the art, and the results which were obtained by applying the compound according to the invention, at rates of 750 and 1,500 g/a.m./ha, are assembled in Table F.

TABLE F RESULTS OF THE TESTS CARRIED OUT WITH COMPOUND 34 PRIOR TO PLANTING

Compound n" 34 (doses in q/a.m./ha) Species treated during the test 625 750 1,250 1,500 2,500 Crops: - Oats 0 5 4 7 7 - Wheat 4 7 5 9 9 - Barley 4 4 5 5 7 - Corn 7 7 7 9 9 Winter graminaceae - Agrostic 4 9 7 10 7 -Alopecurus 0 7 5 9 9 -Lolium 9 10 9 10 10 - Poa 7 10 10 10 10 Summer graminaceae - Echinochloa 10 9 10 10 10 -Setaria 9 10 9 10 10 - Festuca 0 9 7 9 9 sorghum 9 10 9 10 10 c) In this test, the compound was applied after planting and prior to emergence at rates of 625, 1,250 and 2,500 gla.m.iha. The results relative to the three rates are assembled in Table G hereunder.

This method of application improves the selectivity as regards the cultivated cereals and the efficiency as regards adventitious graminaceae.

The test is further carried out as in the preceeding test described under b), by applying the compound n at rates of 750 and 1,500 g/a.m./ha.

The results relativs to the rates of 750 and 1,500 g/a.m./ha are assembled in Table G hereunder.

TABLE G RESULTS OF THE TESTS CARRIED OUT WITH COMPOUND 34 AFTER PLANTING AND PRIOR TO EMERGENCE

Compound n 34 (doses in g/a.m./ha) Species treated during the test 625 750 1250 1500 2500 Crops Oats 2 2 | 4 4 4 6 - Wheat 0 4 4 7 5 - Barley 2 4 4 7 7 - Corn 5 5 7 7 9 Winter graminaceae - Agrostis 7 9 9 10 9 -Alopecurus 7 7 9 9 9 - Lolium 9 10 9 10 10 ~Poa 7 9 9 10 10 Summer graminaceae ~Echinochloa 10 10 10 10 10 ~Setaria | 10 | 9 | 10 | 10 | 10 Ftu 5 7 7 10 9 -Sorghum | 9 | 10 | 10 | 10 | 10 d) As in the preceding tests, the compound is applied after emergence at rates of 625, 1 250 and 2,500 g/a.m./ha. The results relative to the three rates are assembled in Table H hereunder.

The efficiency of the compound remains good.

Further tests were then performed in the manner described at b) and c), applying the compound no. 34 at rates of 750 and 1,500 g/a.m./ha. and said compound is compared with a "reference product" which is a standard post-emergence herbicide.

The results relative to the rates of 750 and 1,500 g/a.m./ha are assembled in Table H hereunder.

TABLE H RESULTS OF THE TESTS CARRIED OUT WITH COMPOUND 34 AFTER EMERGENCE

Compound n 34 Reference product (rates in g/a.m./ha) (rates in g/a.m./ha) Species treated during 625 750 1250 1500 2500 750 1500 Winter graminaceae -Agrostis 5 9 5 9 9 9 10 -Alopecurus 9 10 10 10 10 7 9 -Alopecurus 9 10 10 10 10 5 7 -Lolium 9 10 9 10 10 9 10 -Poa 4 7 7 9 10 7 7 Summer graminaceae -Echinochloa 10 10 10 10 10 10 10 -Setaria 10 10 10 10 10 9 10 -Festuca 5 7 9 7 10 7 9 Sorghum 9 10 10 10 10 7 The series of the three tests-before planting, after planting but prior to emergence, and after emergence-on the product which is in a concentrated formulation which can be emulsified (applied at respective rates of 750 and 1,500 g/a.m./ha) shows that the efficiency of compound nO 34 is still good, but confirms the difference in the selectivity according to the method of application.

TESTS IN THE OPEN FIELDS In view of the interesting properties displayed by the compound during the tests carried out in the greenhouse and which are hereunder gathered, this experiment was followed in the open fields and compared according to several methods of application.

The results obtained, one month after treatment, in the open fields with the compound nO 44 are assembled in the following tables.

A. PRIOR TO PLANTING; INCORPORATED (efficiency on graminaceae)

Rate Agrostis Festuca Lolium Poa Digitaria Active matter g/ha Oats tenuis eliator hybridum annua sanguinalis 500 5 1,000 5-6 9 Compound n 34 1,250 9 10 9 10 10 1,500 5-6 9 2,500 10 10 10 10 10 B.AFTER PLANTING; PRIOR TO EMERGENCE (efficiency on graminaceae)

Rate Agnostis Festuca Lolium Poa Digitaria Active matter g/ha Oats tenuis elatior hybridum annua sanguinalis 250 7 9 500 8 9 1,000 9 9 Compound n 34 1,250 3 10 7 3 8 1,500 9 9 2,500 3 10 8 9 9 C. AFTER EMERGENCE 1) Annual graminaceae (when they are young)

Rate Agrostis Festuca Lolium Poa Lolium Active matter g/ha Oats tenuis elatior hybridum annua multiflorum 250 5-6 500 6-7 Compound n"34 625 4 8 3 2 5 1,000 8-9 1,250 7 9 5 3 7 2) Perreinal graminaceae a) stock treated after emergence

Rate Festuca Festuca Festuca Festuca Phleum Agrostis Dactylis Poa Lolium Lolium Loulium Bromus Active matter g/ha Observations elatior pratensis nubra ovina pratense tenuis glomerata pratensis perenne multiflorum hybridum apratus Compound 4,000 1 month 7 8 4 3 9 9 8 8 8 9 8 6 n 34 4,000 3 months 7 10 2 2 9 8 8 7 7 8 8 5 2) Perennial graminaceae b) rhizomes treated after emergence

Paspalum distichum Rate one month and half Active g/ha after treatment 2,000 9 Comopound n 34 3,000 9 4,000 10 SELECTIVE ACTION ON DICOTYLEDONS A.Prior to planting

Compound n" 34 1,250 2,500 Beet 3 4 Carrat 2 2 Chicory 1 2 Co Cabbage 1 2 o I Bean 0 0 Flax 0 1 Lucerne 0 3 Pea 0 2 Morel O 0 Chenopodium O 0 X Fumitory 0 0 a, B Knot grass 0 0 Chickweed 0 2 SELECTIVE ACTION ON DICOTYLEDONS B - After planting - prior to emergence

Compound n- 34 1,250 1 2,500 Beet 3 5 Carrot 1 2 Chicory 2 2 Cabbage 4 4 0 o Bean 2 2 Flax 0 0 Lucerne 0 3 Pea 0 2 Morel 0 0 Chenopodium 0 0 '0 Fumitory 0 I 0 Knot grass 0 0 Chick weed 0 0 SELECTIVE ACTION ON DICOTYLEDONS After emergence

Compound n" 34 625 1,250 2.500 Beet 2 3 3 Carrot 2 2 2 Chicory 0 0 0 Cabbage 2 2 2 g o Bean 0 1 2 Flax 2 2 2 Lucerne 0 0 0 Pea 2 2 2 Morel 0 0 0 Chenopodium 0 0 0 9 Fumitory 0 0 0 0) Knot grass 0 0 0 Chick weed 0 0 0 Conclusion The compound nO 34 according to the invention turns out to be a remarkable graminicide compound which is efficient on many species of annual or perennial adventitious graminaceae.

The same reactions which exist between the cultivated graminacea or wild graminaceae of the same species enable to appreciate the interest of this compound in order to obtain notably the destruction, on the one hand, of autumn or winter emergence of graminaceae such as: wild barley, alep sorghum, summergraminaceae such as panic grass, setaria, digitaria, etc., spring, summer or autumn perennial graminaceae such as cynodon dactylon, paspalum distichum agropyrum repents.

The methods of destruction may vary and can be undertaken: - prior to planting with incorporation, - after planting and prior to emergence, and - after emergence.

The rates to be used may vary according to the species, the aim which is sought (slow down of vegetation or total destruction), and the method of treatment may vary from: - less than 500 g of a.m.iha to more than 5 kg of a.m./ha.

This compound according to the rates which are used and the method of application: - is efficient on annuai graminaceae: has an efficiency on the underground part of the stem of perennial graminaceae and those possessing rhizomes: which is nearly the same or is better than graminicides which are now used; on cultivated dicotyledons or weeds according to the species and the method of use, this compound has a selectivity which is nearly the same as the other graminicide herbicides which are already used in this field.

TESTS GROUP VIII: Compound nO 35 The compound was applied at the dose of 5,000 gla.m./ha, either prior to planting or after emergence.

Species tested in this test Results Prior to After planting emergence Graminaceae: Agrostis spica venti 10 10 Alopecurus 0 10 Avena 8 10 Echinochloa 10 10 Lolium 10 8 Dicotyledons: A triplex 0 4 Amaranthus 2 8 Chrysanthemum 0 6 Daucus 0 4 Medicago 4 4 Raphanus 0 8 Solanum O 0 This test shows the anti-graminaceous activity of the compound, whatever the mode of application, and its innocuousness with respect to dicotyledons when it is applied prior to planting TESTS GROUP IX: Compound nO 36 The compound was applied at the rate of 5,000 g/a.m./ha, either prior to planting or after emergence.

Results Prior to After Graminaceae: planting emergence Agrostis spica venti 10 10 Alopecurus ' 10 8 Avena 8 4 Echinochloa 10 10 Lolium 10 6 Dicotyledons: Triplex 2 6 Amaranthus 0 6 Chrysanthemum 0 2 Daucus 2 0 Medicago 2 6 Raphanus 0 6 Solanum O 0 This test shows the anti-graminaceous action of the compound and its innocuousness with respect to dicotyledons when it is applied prior to planting.

TEST GROUP X: Compound nO 39 a) The compound is applied at the rate of 5,000 g/a.m.1ha either prior to planting, or after emergence.

Species tested in this trial Results Prior to After Graminaceae: planting emergence Agrostis 10 9 Alopecurus 10 10 Echinochloa 10 10 Lolium 10 10 Dicotyledons: Medicago 0 9 Raphanus 0 10 Daucus 2 9 Amarantus 0 5 Triplex 0 10 Solanum 0 2 A good antigraminaceous activity is obtained, whatever the method of application.

b) Further to the preceeding example, the compound is applied prior to planting in two rates: 1,250 and 2,500 g/a.m./ha.

Species tested in this trial Results Antigraminaceous action 1,250 2,500 Crops: Oats 4 5 Triticum -5 7 Ordeum 4 4 Winter graminaceae: Agrostis 7 10 Alopecurus 9 9 Poa 10 10 Summer graminaceae: Echinochloa 9 10 Setaria 9 10 Festuca 9 9 This test confirms the antigraminaceous activity of the compound; the following test was then carried out.

c) The compound is applied after planting, prior to emergence at rates of 1,250 and 2,500 g/a.m./ha.

Species tested in this trial Results Antigraminaceous action 1,250 2,500 Crops: Oats 0 0 Triticum O 0 Ordeum O 0 Zea 2 4 Winter graminaceae: Agrostis 7 9 Alopecurus 9 10 Poa 7 9 Lolium 9 9 Summer graminaceae: Echinochloa 10 10 Setaria 10 10 Festuca 7 9 This method of application clearly improves the selectivity on cultivated crops, except sorghum, without reducing notably the antigraminaceous action.

d) As in the preceeding test, the compound is applied in the doses of 1,250 and 2,500 g/a.mlha Species tested in this trial Results Antigraminaceous action 1,250 2,500 Winter graminaceae: Agrostis 7 10 Alopecurus 9 10 Poa 4 5 Lolium 9 9 Summer graminaceae: Echinochloa 10 10 Setaria 10 10 Festuca 4 7 By means of this method of application, the anti-graminaceous activity is confirmed.

TEST GROUP Xl: Compound nO 40 a) The test compound is applied in the dose of 5000 gla.m.1ha either prior to planting or after emergence.

Species tested in this trial Results Prior to After planting emergence Graminaceae: Agrostis 10 7 Alopecurus 10 10 Echinochloa 10 9 Lolium 10 10 Dicotyledons: Medicago 0 4 Raphanus 0 9 Daucus 2 5 Amarantus 0 9 A triplex 0 7 Chrysanthemum 0 7 Solanum o 0 A good antigraminaceous activity is obtained, whatever the method of application.

b) Further to the preceeding test, the compound is applied prior to planting at two rates: 1,250 and 2,500 g/a,..m./ha.

Species tested in this trial Results Antigraminaceous action 1,250 2,500 Crops: Oats 5 7 Ordeum 5 7 Winter graminaceae: Agrostis 10 10 Alopecurus 9 9 Poa 10 10 Festuca 10 10 Summer graminaceae: Echinochloa 10 10 Setaria 9 10 Lolium 10 10 This test confirms the antigraminaceous action of the compound; then the following test was undertaken.

c) The compound is applied after planting, prior to emergence, in the same doses.

Species tested in this trial Results Antigraminaceous action 1,250 2,500 Crops: Oats 2 2 Triticum 0 4 Ordeum 0 2 Zea 4 6 Winter graminaceae: Agrostis 7 10 Alopecurus 9 10 Poa 7 10 Festuca 7 9 Summer graminaceae: Echinochloa 10 10 Setaria 7 9 Lolium 9 10 The selectivity on cultivated crops is slightly improved as regards test b); the antigraminaceous action remains good.

d) As in the preceeding test, the compound is applied after emergence in the same doses.

Species tested in this trial Results Antigraminaceous action 1,250 2,500 Winter graminaceae: Agrostis 9 10 Alopecurus 9 9 Poa 7 9 Festuca 7 10 Summer graminaceae: Echinochloa 10 10 Setaria 10 10 Lolium 10 10 This method of application confirms the anti-graminaceous action of the compound.

TEST GROUP XII: Compound nO 41 The test compound is applied at the rate of 5,000 g1a.mjha, either prior to planting or after emergence.

Species tested in this trial Results Prior to After planting emergence Graminaceae: Agrostis 10 4 Alopecurus 10 10 Echinochloa 10 10 Lolium 10 10 Dicotyledons: Medicago 0 0 Raphanus 0 0 Daucus 0 4 Amarantus 2 4 A triplex 0 5 Chrysanthemum O 0 Solanum O 0 This test shows that the compound is efficient against the graminaceae and appears to be selective as regards some cultivated dicotyledons.

TEST GROUP Xl II: Compound nO 43 The test compound is applied at the rate of 5,000 g/a.m./ha either prior to planting or after emergence.

Species tested in this trial Results Prior to After planting emergence Graminaceae: Avena 4 7 Agrostis 10 0 Alopecurus 7 4 Echinochloa 9 10 Lolium 10 9 Dicotyledons: Medicago O 0 Raphanus 0 0 Dauctis O 0 Amarantus 4 0 A triplex o 9 Chrysanthemum o 0 Ma tricaria o 0 Solanum 0 8 The compound shows an antigraminaceous efficiency and a good selectivity on certain cultivated dicotyledons.

TESTS IN THE OPEN FIELDS The tests in the open fields were carried out on plots of 5 m2.

The methods of application are those indicated above, namely prior to planting, after planting prior to emergence and after emergence.

The observations were made 1 5 days, 1 month and 2 months after the treatment for the first two methods of application; and 1 5 days and 1 month after treatment for the third method of application.

The results recorded after treatment prior to planting are assembled in Table C below, in which columns 1, 2 and 3 shown for each plant treated correspond respectively to observation after 1 5 days, 1 month and 2 months. The notations are those explained above.

TABLE C

Corn Wheat Barley Oats Ray grass Agrostis Fesque Beet Lucerne Cabbage Compound Dose No. g/a.m./ha 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 15 5000 2 5 2 0 3 2 2 4 4 3 5 3 3 8 7 4 6 8 0 7 6 0 0 0 0 1 0 0 0 1 0 1250 2 3 0 0 0 0 0 3 0 3 4 2 2 4 5 10 8 7 3 4 5 0 0 0 0 0 0 0 0 0 17 2500 2 3 2 2 4 3 3 4 3 4 6 7 3 9 9 10 10 9 5 9 9 0 2 2 2 2 0 0 0 0 5000 3 3 3 2 5 3 3 6 3 5 6 7 5 9 9 10 10 9 7 9 10 0 2 2 3 2 0 0 0 0 12 2500 0 2 0 2 2 0 2 3 0 3 3 0 2 2 3 6 3 4 3 4 3 0 0 0 0 0 0 0 0 1250 4 3 3 3 6 4 4 4 5 4 7 6 3 7 7 8 10 10 5 9 9 0 0 0 0 0 0 2 1 0 22 2500 4 4 4 3 6 6 4 5 5 6 7 7 10 9 10 10 10 10 6 9 9 0 0 0 0 0 0 2 1 0 5000 6 6 8 5 7 7 4 6 7 6 7 8 10 9 10 10 10 10 10 10 10 0 1 2 2 1 0 2 3 0 This group of tests confirms the anti-graminaceous action of the various (except compound 12), confirms a variable selectivity on cereals according to the nature of the cultivated cereal, and finally confirms a good selectivity on cultivated dicotyledons.

The results recorded after planting prior to emergence are combined in Table D bellow, in which the column 1, 2 and 3 under each plant mentioned have the same meanings as for Table C.

TABLE D

Corn Wheat Barley Oats Ray grass Agrostis Fesque Beet Lucerne Cabbage Compound Dose No. g/a.m./ha 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 2500 0 0 0 0 0 0 0 0 2 0 0 2 3 4 2 5 3 2 4 2 0 0 0 2 0 0 0 0 0 15 5000 0 2 2 0 0 0 0 0 0 2 0 1 2 3 4 2 5 4 2 4 5 2 2 2 2 2 0 0 1 0 1250 0 0 0 0 0 0 0 0 0 2 0 0 0 2 0 5 10 10 2 4 4 0 0 0 0 0 0 0 0 0 17 2500 0 0 1 0 0 0 0 0 0 3 2 2 2 4 5 9 10 10 2 5 7 0 0 0 0 0 0 0 0 0 5000 0 0 1 0 0 0 0 2 0 3 2 2 5 4 5 9 10 10 2 6 8 0 0 0 0 0 0 0 0 0 12 2500 2 0 0 2 0 0 2 1 0 2 1 0 0 2 2 1 3 2 3 2 3 0 2 0 3 0 0 1 0 0 30 2500 0 0 0 0 0 0 1 0 0 0 0 0 1 2 3 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 11 2500 1 0 1 2 1 0 0 0 0 0 2 1 0 1 3 2 5 3 0 3 3 2 0 0 0 0 0 0 0 1 0 0 1250 2 3 3 0 0 0 0 2 0 0 0 1 2 3 3 9 7 10 2 6 8 0 0 0 2 0 0 0 0 0 22 2500 2 6 6 0 4 4 0 4 3 1 2 3 4 9 10 10 10 10 6 9 10 2 2 2 2 2 5 0 1 0 5000 2 7 10 0 5 8 0 4 5 2 3 6 4 9 10 10 10 10 7 9 10 3 4 3 6 7 8 0 1 0 By this method of application, the selectivity on cereals is strictly improved: the selectivity on cultivated dicotyledons also remains good.

As regards the anti-graminaceous effectiveness, the latter is generally more specific and more variable than by the preceding application technique, with the exception of compound No. 22 for which this effectiveness remains ramrkable.

The results recorded after treatment after emrgence are collected in Table E bellow, in which columns 1,2 represented under each plant treated, correspond to observation made respectivelly carried out 15 days and 1 month after treatment.

TABLE E

Corn Wheat Barley Oats Ray grass Agrostis Fesque Beet Lucerne Cabbage Compound Dose No. g/a.m./ha 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1250 2 1 0 0 0 0 0 0 0 3 5 8 3 4 1 0 0 0 0 0 0 18 2500 2 1 0 0 0 0 0 1 0 3 7 10 4 5 1 0 0 0 0 0 5000 2 1 0 0 0 0 0 1 1 5 7 10 4 5 2 0 0 0 0 0 1250 7 8 2 6 0 2 1 4 7 7 9 9 5 7 2 0 0 0 0 0 22 2500 7 10 5 8 2 3 2 6 7 8 9 10 7 8 2 0 0 0 0 0 5000 7 10 6 9 2 4 2 7 7 8 9 10 7 8 2 0 0 0 0 0 The post emergence application gives a selectivity to cereals which is variable according to the nature of the cereals. The selectivity on cultivated dicotyledons remains good.

The anti-graminaceous effectivennes is, here again, more specific and more variable except for compound No. 22 for which this effectiveness remains good.

Claims (1)

1. Phenoxy- and thiophenoxynitriles having the general formula:

in which: - A is one of the linkages -0--S-,

and

- R, represents a hydrogen or halogen atom, or an alkyl or halo-alkyl radical having 1 to 4 carbon atoms; - R2 and R3, which may be the same or different, each represents a hydrogen atom, an alkyl radical having 1 to 4 carbon atoms, a phenyl radical or a phenyl radical substituted by (R1)n; - R4 and R5 are each defined in the same manner as R2 and R3 or together with the carbon atom which bears them constitute a polymethylene ring with 5, 6 or 7 links, subject always to the proviso that when one of the radicals R4 and R5 is a hydrogen atom then the other is not -CH3;; - Y is defined in the same manner as R1 or represents the group:

(in which X is one of the linkages-O, -S- and -CH2-; and R6 is defined in the same manner as R1, with which it may be identical, or may also be an NO2 or CN group); - Z either is a sulphur atom or when Y represents the

ox (Rb)nl group, is either a sulphur atom or an oxygen atom; and - nandn1, which may be the same or different, are each zero or an integer from 1 to 3.

2. Phenoxy- and thiophenoxynitriles having the general formula I defined in claim 1 and in which: -V Y and R1, whidh maybe the same or different, each represents a hydrogen atom or chlorine atom or a halo-alkyl group; - A is an NR3- group; - R2 to R5, which may be the same or different, each represents H, CH3 or C2H5, subject always to the proviso that when one of R4 and R5 is hydrogen the other is not -CH3; and - n is zero or the integer 1.

3. Phenoxy- and thiophenoxynitriles having the general formula I defined in claim 1 and in which: - Y is the group

wherein R6 is CI and/or CF3; - Aisan

group; - is the integer 1 or 2; - R1 represents a hydrogen atom; - Z represents an oxygen atom; and - R2 to R5, which may be the same or different, each represents a hydrogen atom or a -CH3 or -C2H5 radical, subject always to the proviso that when one of R4 and R5 is hydrogen the other is not -CH3.

4. Phenoxy- and thiophenoxynitriles having the general formula I defined in claim 1 and in which: - A is an oxygen atom; - is the

group, wherein R6 is Cl and/or CF3; and - Z is an oxygen atom.

5. N-(1,1 -Dimethyl cyanomethyl) 2-(3,4-dichloro thiophenoxy) propionamide (compound no. 11).

6. N-( 1,1 -Dimethyl cyanomethyl) 2-(3,4-dichloro thiophenoxy) butyramide (compound no. 12).

7. N-(1,1-Dimethyl cyanomethyl) 2-[4-(4'-chlorophenoxy) phenoxy] propionamide (compound no.

15).

8. N-(Cyanomethyl) 2-[4-(4'-chlorophenoxy) phenoxy] propionamide (compound no. 16).

16).

9. N-( 1,1 -Dimethyl cyanomethyl) 2-[4-(4'-trifluoromethyl phenoxy) phenoxy] propionamide (compound no. 17).

10. N-(Cyanomethyl) N-methyl 2-[4-(4'-trifluoromethyi phenoxy) phenoxyj propionamide (compound no. 21).

11. N-(Cyanomethyl) 2-[4-(4'-trifluoromethyl phenoxy) phenoxy] propionamide (compound no.

22).

12. [(Trifluoromethyl-4' phenoxy)-4 phenoxy]-2 propanoate of cyano 2 propanol 2 (compound no.

34).

13. [(Trifluoromethyl-4' phenoxy)-4 phenoxy]-2 propanoate of cyano 2 butanol 2 (compound no.

39).

14. [(Trifluoromethyl-4' phenoxy)-4 phenoxy]-2 propanoate of cyano 3 pentanol 3 (compound no.

40).

1 5. [(Trifluoromethyl-4' phenoxy)-4 phenoxy]-2 propanoate of a cyano-benzylic alcohol (compound no. 41).

16. [(Dichloro-2',4' phenoxy)-4 phenoxy]-2 propanoate of cyano 2 propanol 2 (compound no.

43).

1 7. [(Trifluoromethyl-3' phenoxy)-4 phenoxy]-2 propanoate of cyano 2 propanol 2 (compound no.

44).

1 8. [(Trifluoromethyl-3' phenoxy)-4 phenoxy]-2 propanoate of glycolonitrile (compound no. 45).

19. [(Trifluoromethyl-4 phenoxy)-4 phenoxy]-2 propanoate of glycolonitriie (compound no. 47).

20. [(Trifluoromethyl-4' phenoxy)-4 phenoxy]-2 propanoate of cyano-1 propanol (compound no.

48).

21. Herbicide, characterised by the fact that it contains an effective amount of a compound according to any of claims 1 to 20.

22. Anti-graminaceous agent, selective with respect to dicotyledons and cultivated cereals, which comprises, as an active substance, an effective amount of a compound according to any of claims 1 to 20.

23. Herbicides and anti-graminaceous agents as claimed in claim 21 or claim 22 and substantially as herein described.

24. Anti-graminaceous wettable powder containing substantially 50% of active material as claimed in claim 22 or claims 22 and 23, which is or is equivalent to a mixture of 52.6 parts of compound(s) according to any of claims 1 to 20 (of 95% purity), 41.4 parts of kaolin clay, 2 parts of wetting agent of the sodium alkyl-naphthalene sulphonate type, and 4 parts of dispersing agent, all said parts being by weight.

25. Emulsifiable concentrate as claimed in claim 22 or claims 22 and 23, which is or is equivalent to a mixture of 253 parts by weight of compound(s) according to any of claims 1 to 20 (of 95% purity), 25 parts by weight of calcium dodecylbenzyne sulphonate in 70% solution in isobutyl alcohol, 35 parts by weight of castor oil condensed with 30 moles of ethylene oxide, and an amount of a petroleum solvent to form a solution containing substantially 253 g/l of said compound(s) of 95% purity.

26. For use in a method of herbicidal or anti-graminaceous treatment, the compound(s) and/or the agents according to any of claims 1 to 25.

27. Anti-graminaceous treatment, selective with regard to dicotyledons, which comprises applying prior to planting an effective amount of a compound according to any of claims 1 to 20 to the locus.

28. Anti-graminaceous treatment, selective with respect to dicotyledons and cultivated cereals, which comprises applying at post-planting and prior to emergence an effective amount of a compound according to any of claims 1 to 20.

29. Anti-graminaceous treatment, selective with respect to dicotyledons, which comprises applying after emergence an effective amount of a compound according to any of claims 1 to 20 to the locus.

30. Treatment according to any of claims 27 to 29, which comprises applying from 500 to 5,000 g of active material per ha to the locus.

31. Treatment according to any of claims 28 to 30, in which one applies 1,000 to 5,000 g of active material per ha.