GB1582302A

GB1582302A - Herbicidally active carbanilic acid esters and their manufacture and use

Info

Publication number: GB1582302A
Application number: GB17085/77A
Authority: GB
Original assignee: Schering AG
Current assignee: Bayer Pharma AG
Priority date: 1976-04-30
Filing date: 1977-04-25
Publication date: 1981-01-07
Also published as: BR7702183A; IN155907B; GR70655B; SU655306A3; DD129732A5; NL7701416A; CS200510B2; AR218245A1; DE2619733A1; ES456423A1; AU2436577A; SU652861A3; IE44682B1; BG27715A3; FI771019A; ATA305977A; AT353549B; PT66319B; FR2349571A1; IL51971A0

Description

(54) HERBICIDALLY ACTIVE CARBANILIC ACID ESTERS AND THEIR MANUFACTURE AND USE (71) We, SCHERING AKTIENGESELLSCHAFT, a Body Corporate organised according to the laws of Germany, of Berlin and Bergkamen, Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention is concerned with new herbicidally active carbanilic acid esters, with a process for the manufacture of these compounds and with their use.

It has been known that certain carbanilic acid esters, for example carbanilic acid isopropyl ester and 3-chlorocabanilic acid isopropyl ester, are herbicidally active (German Patent Specification No. 833,274). However, these compounds do not act satisfactorily at low rates of application against dicotyledonous weeds and also have the disadvantage of a very limited selectivity towards crop plants.

The problem upon which the present invention is based has, therefore, been to provide an agent of the type referred to, which has a strong herbicidal action against dicotyledonous weeds even at low rates of application and also good selective properties.

This problem has now been solved in accordance with the present invention by the compounds of the general formula I, as defined below.

The present invention accordingly provides compounds of the general formula I

in which R represents an aliphatic or cycloaliphatic hydrocarbon groups, X represents an alkyl or alkoxy group or a halogen atom and n represents 0 or 1.

The compounds of the present invention are distinguished by an outstanding herbicidal action against dicotyledonous and also against monocotyledonous weeds (including certain undesired plants not normally considered as weeds) amongst which there may be mentioned, for example, Stellaria media, Senecio Vulgaris, Matricaria chamomilla, Lamium amplexicaule, Centaurea cyanus, Amaranthus retroflexus, Galium aparine, Chrysanthemum segetum, Ipomoea purpurea, Polygonum lapathifolium, Avena fatua, Alopecurus myosuroides, Echinochloa crus galli, Setaria italica, Digitaria sanguinalis and Poa annua.

Owing to their excellent selective properties these compounds can be used directly in agricultural crops amongst which there may be mentioned, for example, lucerne, bush-beans, cotton, soya beans, ground-nut and wheat crops.

It has also been found that the compounds of the present invention have in a narrower sense a defoliating action and growth regulating properties.

The compounds of the present invention act satisfactorily even at rates of application from 0.5 kg per hectare and, depending on the purpose of use, can be applied without damaging crops of useful plants at up to 5 kg per hectare or more both by pre-emergence and also by post-emergence methods. When two or more compounds of the general formula I are used the rates of 0.5 kg and 5 kg or more refer of course to the total amount applied to these compounds.

The present invention also provides a herbicidal preparation which comprises a compound of the general fromula I, in admixture or conjunction with a suitable carrier. The preparation may of course contain one or more compounds of the general formula I.

The present invention further provides a method of protecting a living plant against weeds, wherein the area of the vicinity of a living plant is treated with a compound of the general formula I.

The present invention further provides a method of protecting a crop area against weeds, wherein a crop area is treated with a compound of the general formula I.

The present invention further provides a pack which comprises a compound of the general formula I together with instructions for its use as a selective herbicide.

The compounds of the present invention can be used either alone, or in admixture with one another or with other active substances.

Depending on the purpose desired there may be mentioned in this connection. for example, the following herbicidally active substances, which, if desired, may be added to the compounds of the present invention immediately before use: substituted anilines, substituted aryloxy-carboxylic acids and also salts, esters and amides thereof, substituted ethers, substituted arsonic acids and also salts, esters and amides thereof substituted benzimidazoles, substituted benzisothiazoles, substituted benzthiadiazinone dioxides, substituted benzoxazines, substituted benzoxazinones, substituted benzthiazoles, substituted benzthiadiazoles, substituted biurets, substituted quinolines, substituted carbamates, substituted aliphatic carboxylic acids and also salts, esters and amides thereof, substituted aromatic carboxylic acids and also salts, esters and amides thereof, substituted carbamoylalkyl-thio- or dithio-phosphates, substituted quinazolines, substituted cycloalkylamidocarbonthiolic acids and also salts, esters and amides thereof, substituted cycloalkylcarbonamido-thiazoles, substituted dicarboxylic acids and also salts, esters and amides thereof, substituted dihydrobenzofuranyl-sulphonates substituted disulphides.

substituted diapyridylium salts, substituted dithiocarbamates.

substituted dithiophosphoric acids and also salts. esters and amides thereof, substituted ureas, substituted hexahydro-l H-cabothioates.

substituted hydantoins.

substituted hydrazides, substituted hydrazonium salts.

substituted isoxazolepyrimidones.

substituted imidazoles, substituted isothiazole-pyrimidones, substituted ketones, substituted naphthoquinones.

substituted aliphatic nitriles.

substituted aromatic nitriles.

substituted oxadiazoles.

substituted oxadiazinones.

substituted oxadiazolidine-diones.

substituted oxadiazine-diones.

substituted phenols and also salts and esters thereof.

substituted phosphonic acids and also salts, esters and amides thereof, substituted phosphonium chlorides, substituted phosphonalkylglycines, substituted phosphites, substituted phosphoric acids and also salts, esters and amides thereof, substituted piperidines, substituted pyrazoles, substituted pyrazole-alkyl-carboxylic acids and also salts, esters and amides thereof, substituted pyrazolium salts, substituted pyrazolium alkyl sulphates, substituted pyridazines, substituted pyridazones, substituted pyridine carboxylic acids and also salts, esters and amides thereof, substituted pyridines, substituted pyridine carboxylates, substituted pyridinones, substituted pyrimidones, substituted pyrrolidine carboxylic acids and also salts, esters and amides thereof, substituted pyrrolidines, substituted aryl sulphonic acids and also salts, esters and amides thereof, substituted styrenes, substituted tetrahydro-oxadiazine-diones, substituted tetrahydromethanoindenes, substituted tetrahydro-diazole-thiones, substituted tetrahydro-thiadiazine-thiones, substituted tetrahydro-thiadiazole-diones, substituted thiadiazoles, substituted aromatic thiocarboxylic acid amides, substituted thiocarboxylic acids and also salts esters and amides thereof, substituted thiolcarbamates, substituted thiophosphoric acids and also salts, esters and amides thereof, substituted triazines, substituted triazoles, substituted uracils and substituted uretidine-diones.

Furthermore, other additives may also be used, for example non-phytotoxic additives, which impart to herbicides a synegistic increase in action, for example wetting agents, emulsifiers, solvents and oily additives.

Advantageously. the active compounds of the general formula I or mixtures containing them are used in the form of herbicidal preparations for example powders, strewable preparations, granules. solutions, emulsions or suspensions, with the addition of liquid andlor solid vehicles or diluents, and, if desired, of surface-active agents, for example wetting, adherent, emulsifying and/or dispersing agents.

Suitable liquid carriers are, for example, water, aliphatic hydrocarbons, aromatic hydrocarbons, for example benzene, toluene and xylene, cyclohexanone, isophorone, dimethyl sulphoxide and dimethylformamide, and also mineral oil fractions.

As solid carriers there are suitable. for example, mineral earths, for example tonsil, silica gel, talcum, kaolin, attaclay, limestone and silicic acid, and vegetable products, for example meals.

As surface-active agents there may be mentioned, for example, calcium lignin sulphonate, polyoxyethylene-alkyl-phenyl ethers, naphthalene sulphonic acids and salts thereof, phenol sulphonic acids and salts thereof, formaldehyde condensates, fatty alcohol sulphates and also substituted benzene sulphonic acids and salts thereof.

The total amount of the active substance or substances in the various herbicidal preparations may vary within wide limits. By way of example, the preparations may contain approximately 10 to 80coo by weight of active compound(s), approximately 90 to 20% by weight of liquid or solid carrier and also. if desired, up to20 by weight of surface-active agent(s).

The active compounds may be applied in the usual manner, for example with water as carrier in quantities of spray liquor of approximately 100 to 1000 litres per hectare. It is also possible to use the active compounds in the so-called 'low volume" and 'ultra-low volume" methods and also to apply them in the form of so-called microgranules.

Among the compounds of the present invention those of the general formula I. in which R represents an alkyl. alkenyl or alkynyl group containing up to 6 carbon atoms, X represents a methyl or methoxy group or a chlorine atom and n represents 0 or 1 are especially distinguished by an outstanding herbicidal action.

As such alkyl, alkenyl and alkynyl groups there may be mentioned, for example, methyl, ethyl, propyl, isopropyl, neopentyl, allyl, 2-methyl-2-propenyl, 2-propynyl and l-methyl-2propynyl groups.

Among the compounds of the present invention 3-cyanocarbanilic acid isopropyl ester is outstanding with regard to its herbicidal selective properties.

The new compounds of the present invention of the general formula I may be prepared, for example, by the process of the present invention, as defined below.

The present invention accordingly further provides a process for the manufacture of a compound of the general formula I, wherein (a) a 3-aminobenzonitrile of the general formula

in which X and n have the meanings given above, is reacted in the presence of an acid-binding agent with a chloroformic acid ester of the general formula Cl-CO-OR , in which R has the meaning give above, or (b) a 3-cyanophenyl isocyanate of the general formula

in which X and n have the meanings given above, is reacted with an alcohol of the general formula R-OH in which R has the meaning give above.

The compounds of the present invention readily dissolve in ethyl acetate, acetone and alcohol. On the other hand, they dissolve only moderately well in benzene and are practically insoluble in saturated hydrocarbons and water.

The following Examples illustrate the invention. Examples 1 and 2 illustrate the manufacture of compounds of the general formula I and Examples 3 to 5 illustrate the possibilities of use of the compounds of the general formula I.

EXAMPLE l 3- Cyanocabanific acid isopropyl ester To a mixture of 11.8 grams ((1.1 mol) of 3-aminobenzonitrile, 140 ml of ethyl acetate, 90 ml of water and 2.5 grams (0.063 mole) of magnesium oxide were added dropwise while stirring 13.5 grams (().1i mole) of chloroformic acid isopropyl ester. The mixture was further stirred for 3 hours at room temperature. then the aqueous phase was acidified with dilute hydrochloric acid, and the organic phase was washed until neutral with water. The ethyl acetate phase was separated. dried over magnesium sulphate. filtered and rotated.

The crude product was recrystallized from ethyl acetate/hexane.

Yield: 15.3 grams = 75C/c of the theoretical yield.

M.p.: 94 - 96"C.

EXAMPLE 2 3-Cyanocarbanilic acid cvclopesltvl ester A solution of 7.2 grams (0.05 mole) of 3-cyanophenyl isocyanate in 5() ml of ether was added dropwise. while stirring. to a solution of 4.3 grams of (0.05 mole) of cyclopentanol and 0.1 ml of triethylamine in 50 ml of ether. The reaction solution was heated to about 30 C. To complete the reaction the mixture was stirred for about 5 hours at room temperature. The solvent was then removed by rotation and the residue was recrystallized from methanol/water.

Yields: 9.3 grams = 81% of the theoretical yield.

M.P.: 101 - 102 C The following compounds of the present invention can be prepared in a manner analogous to that described in Example 1 or 2.

Name of the compound Physical constant 3-Cyanocarbanilic acid methyl ester M.p.: 93 - 95"C 3-Cyanocarbanilic acid ethyl ester M.p.: 48 - 50"C 3-Cyanocarbanilic acid allyl ester M.p.: 67 - 68"C 5-Cyano-2-methylcarbanilic acid methyl ester M.p.: 100 - 101"C 5-Cyano-2-methylcarbanilic acid ethyl ester M.p.: 96 - 97"C 5-Cyano-2-methylcarbanilic acid propyl ester M.p.: 101 - 102"C 5-Cyano-2-methylcarbanilic acid allyl ester M.p.: 94 - 95"C 5-Cyano-2-methylcarbanilic acid allyl ester M.p.: 90 - 91"C 5-Cyano-2-methylcarbanilic acid ethyl ester M.p.: 104 - 105"C 5-Cyano-2-methylcarbanilic acid methyl ester M.p.: 120 - 121"C 5-Cyano-2-methylcarbanilic acid isopropyl ester M.p.: 127 - 128"C 3-Cyanocarbanilic acid propyl ester M.p.: 38 - 39 C 5-Cyano-2-methoxycarbanilic acid propyl ester M.p.: 60 - 61 C 5-Cyano-2-methoxycarbanilic acid isopropyl ester M.p.: 111 - 112"C 3-Cyanocarbanilic acid cyclohexyl ester M.p.: 72 - 74 C 3-Cyanocarbanilic acid neopentyl ester M.p.: 125 - 126"C 3-Cyanocarbanilic acid (2-methyl-2-propenyl) ester M.p.: 75 - 76 C 3-Cyanocabanilic acid (I-methyl-2-propynyl) ester M.p.: 113 - 114"C 3-Cyanocarbanilic acid 2-propynyl ester M.p.: 135 - 136"C 2-Chloro-5-cyanocarbanilic acid isopropyl ester M.p.: 127 - 129"C 2-Chloro-5-cyanocarbanilic acid allyl ester M.p.: 84 - 85 C 4-Chloro-3-cyanocarbanilic acid isopropyl ester M.p.: 95 - 96 C EXAMPLE 3 In a series of tests carried out in a green house the compounds of the present invention listed in the following Table were sprayed over mustard. beetroots and tomatoes as test plants at the pre-emergence stage at the rate of 5 kg of the active substance being tested per hectare. For this purpose the active compounds were in each case applied in the form of a suspension using 500 litres of water per hectare. Three weeks after the treatment the results of the treatment were evaluated according to a numerical scale extending from 0 to 4, 0 representing no action and 4 representing destruction of the plants.

Compound of the invention Mustard Tomato Beetroot 3-Cyanocarbanilic acid methyl ester 4 3 3-Cyanocarbanilic acid isopropyl ester 4 4 4 5-Cyano-2-methylcarbanilic acid ethyl ester 4 4 4 5-Cyano-2-methylcarbanilic acid methyl ester 4 4 3 5-Cyano-2-methylcarbanilic acid propyl ester 4 4 3 5-Cyano-2-methylcarbanilic acid allyl ester - - 3 2-Methyl-5-cyanocarbanilic acid isopropyl ester 4 4 4 3-Cyanocarbanilic acid ethyl ester 4 4 4 3-Cyanocarbanilic acid allyl ester 4 4 4 2-Chloro-5-cyanocarbanilic acid isopropyl ester 4 4 3 3-Cyanocarbanilic acid propyl ester 4 4 4 2-Chloro-5-cyanocarbanilic acid allyl ester 3 4 4 - means not tested EXAMPLE 4 In a series of tests carried out in a greenhouse the plants listed in the following Table were treated before their emergence with the indicated active compounds being tested at a rate of 1 kg of active substance per hectare. For this purpose the active compounds were in each case uniformly applied to the soil in the form of an aqueous suspension using 500 litres per hectare. Three weeks after the treatment the results showed that the compound of the present invention was better than the agent used for comparison. The results are expressed by a numerical scale extending from 0 to 10, the value 0 representing total destruction and the value 10 representing non damage.

Compound of the Agent used for invention comparison 3-Cvanocarbanilic 3-Chlorocarbanilic acid isopropyl acid isopropyl ester ester Cotton 10 10 Soya 10 10 Stellarin media 0 0 Senecio vulgaris 0 8 Matricaria chamomilla 0 6 Lamium amplexicaule 0 3 Centaitrea cyanlis 0 8 Amaranthus retroflexus 0 2 Galium aparine 0 1 Chrysanthemum segetum 0 6 Ipomoea purpurea 0 3 Polygonum lapathifolium 0 0 Ecllillocllloa crits galli 0 0 Digitaria sanguinalis 0 0 EXAMPLE 5 In a series of tests carried out in a greenhouse the plants listed in the following Table were treated before their emergence with the indicated active compounds being tested at a rate of 1 kg of active substance per hectare. For this purpose the active compounds were in each case uniformly applied to the soil in the form of an aqueous suspension using 500 litres per hectare. Three weeks after the treatment the results showed that the compound of the present invention had a better selective action than the agent used for comparison. The results are expressed by a numerical scale extending from 0 to 10, the value 0 representing total destruction and the value 10 representing no damage.

Compound of the Agent used for invention comparison 3-Cyanocarbanilic 3-Chlorocarbanilic acid isopropyl acid isopropyl ester ester Wheat 1(1 6 Alopecurus myosuroides 0 0 WHAT WE CLAIM IS: l. A carbanilic aid ester of the eeneral formula I

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

Compound of the Agent used for invention comparison

3-Cvanocarbanilic 3-Chlorocarbanilic acid isopropyl acid isopropyl ester ester Cotton 10 10 Soya 10 10 Stellarin media 0 0 Senecio vulgaris 0 8 Matricaria chamomilla 0 6 Lamium amplexicaule 0 3 Centaitrea cyanlis 0 8 Amaranthus retroflexus 0 2 Galium aparine 0 1 Chrysanthemum segetum 0 6 Ipomoea purpurea 0 3 Polygonum lapathifolium 0 0 Ecllillocllloa crits galli 0 0 Digitaria sanguinalis 0 0 EXAMPLE 5 In a series of tests carried out in a greenhouse the plants listed in the following Table were treated before their emergence with the indicated active compounds being tested at a rate of 1 kg of active substance per hectare. For this purpose the active compounds were in each case uniformly applied to the soil in the form of an aqueous suspension using 500 litres per hectare. Three weeks after the treatment the results showed that the compound of the present invention had a better selective action than the agent used for comparison. The results are expressed by a numerical scale extending from 0 to 10, the value 0 representing total destruction and the value 10 representing no damage.

Compound of the Agent used for invention comparison

3-Cyanocarbanilic 3-Chlorocarbanilic acid isopropyl acid isopropyl ester ester Wheat 1(1 6 Alopecurus myosuroides 0 0 WHAT WE CLAIM IS: l. A carbanilic aid ester of the eeneral formula I

in which R represents an aliphatic or cycloaliphatic hydrocarbon group, X represents an alkyl group or a halogen atom and n represents 0 or 1.
2. A compound as claimed in claim 1, wherein R represents an alkyl, alkenyl or alkynyl group containing up to 6 carbon atoms.
3. A compound as claimed in claim 1 or 2, wherein X represents a methyl or methoxy group or a chlorine atom.
4. 3-Cyanocarbanilic acid methyl ester.
5. 3-Cyanocarbanilic acid ethyl ester.
6. 3-Cyanocarbanilic acid allyl ester.
7. 5-Cyano-2-methylcarbanilic acid ethyl ester.
8. 5-Cyano-2-methylcarbanilic acid methyl ester.
9. 5-Cyano-2-methylcarbanilic acid propyl ester.
10. 5-Cyano-2-methylcarbanilic acid allyl ester.
11. 5-Cyano-2-methoxycarbanilic acid allyl ester.
12. 5-Cyano-2-methoxycarbanilic acid ethyl ester.
13. 5-Cyano-2-methoxycarbanilic acid methyl ester.
14. 5-Cyano-2-methylcarbanilic acid isopropyl ester.
15. 3-Cyanocarbanilic acid propyl ester.
16. 5-Cyano-2-methoxycarbanilic acid propyl ester.
17. 5-Cyano-2-methoxycarbanilic acid isopropyl ester.
18. 3-Cyanocarbanilic acid cyclohexyl ester.
19. 3-Cyanocarbanilic acid isopropyl ester.
20. 3-Cyanocarbanilic acid cyclopentyl ester.
21. 3-Cyanocarbanilic acid neopentyl ester.
22. 3-Cyanocarbanilic acid (2-methyl-2-propenyl) ester.
23. 3-Cyanocarbanilic acid (1-methyl-2-propynyl) ester.
24. 3-Cyanocarbanilic acid 2-propynyl ester.
25. 2-Chloro-5-cyanocarbanilic acid isopropyl ester.
26. 2-Chloro-5-cyanocarbanilic acid allyl ester.
27. 4-Chloro-3-cyanocarbanilic acid isopropyl ester.
28. A process for the manufacture of a compound of the general formula I given in claim 1, in which R, X and n have the meanings given in claim 1, wherein (a) a 3-aminobenzonitrile of the general formula

in which X and n have the meanings given above, is reacted in the presence of an acid-binding agent with a chloroformic acid ester of the general formula Cl-CO-OR in which R has the meaning given above. or b) a 3-cyanophenyl isocyanate of the general formula

in which X and n have the meanings given above, is reacted with an alcohol of the general formula R-OH.

in which R has the meaning given above.
29. A process as claimed in claim 98. conducted substantially as described in Example 1 or 2 herein.
30. A herbicidal preparation which comprises a compound of the general formula I given in claim 1, in which R, X and n have the meanings given in claim 1, in admixture or conjunction with a suitable carrier.
31. A herbicidal preparation which comprises a compound as claimed in claim 2 or 3, in admixture or conjunction with a suitable carrier.
32. A herbicidal preparation which comprises the compound claimed in any one of claims 4 to 25, in admixture or conjunction with a suitable carrier.
33. A herbicidal preparation which comprises the compound claimed in claim 26 or 27, in admixture or conjunction with a suitable carrier.
34. A preparation as claimed in any one of claims 30 to 33, which is in the form of a powder, a strewable preparation, granules, a solution, an emulsion or a suspension.
35. A preparation as claimed in any one of claims 30 to 34, containing a single compound of the general formula I in an amount of approximately 10 to 80% by weight.
36. A preparation as claimed in any one of claims 30 to 34, containing two or more compounds of the general formula I in a total amount of approximately 10 to 80% by weight.
37. A preparation as claimed in any one of claims 30 to 36, containing a single surface-active agent in an amount of up to 20% by weight.
38. A preparation as claimed in any one of claims 30 to 36, containing two or more surface-active agents in a total amount of up to 20% by weight.
39. Any one of the herbicidal preparations as claimed in claim 30 and substantially as described in Example 3 herein.
40. A herbicidal preparation as claimed in claim 30 and substantially as described in Example 4 herein.
41. A method of protecting a living plant against weeds, wherein the area in the vicinity of a living plant is treated with a compound of the general formula I given in claim 1, in which R, X and n have the meanings given in claim 1.
42. A method as claimed in claim 41, wherein the area is treated with a compound as claimed in claim 2 or 3.
43. A method as claimed in claim 41, wherein the area is treated with the compound claimed in any one of claims 4 to 25.
44. A method as claimed in claim 41, wherein the area is treated with the compound claimed in claim 26 or 27.
45. A method as claimed in claim 41, wherein the area is treated with a herbicidal preparation as claimed in any one of claims 30 to 40.
46. A method as claimed in any one of claims 41 to 45, wherein a single compound of the general formula I is used for the treatment in an amount within the range of from 0.5 to 5 kg per hectare.
47. A method as claimed in any one of claims 41 to 45, wherein two or more compounds of the general formula I are used for the treatment in a total amount within the range of from 0.5 to 5 kg per hectare.
48. A method as claimed in claim 41, conducted substantially as described in Example 4 or 5 herein.
49. A method of protecting a crop area against weeds, wherein a crop area is treated with a compound of the general formula I given in claim 1, in which R, X and n have the meanings given in claim 1.
50. A method as claimed in claim 49, wherein the crop area is treated with a compound as claimed in claim 2 or 3.
51. A method as claimed in claim 49. wherein the crop area is treated with the compound claimed in any one of claims 4 to 25.
52. A method as claimed in claim 49. wherein the crop area is treated with the compound claimed in claim 26 or 27.
53. A method as claimed in claim 49, wherein the crop area is treated with a herbicidal preparation as claimed in any one of claims 30 to 40.
54. A method as claimed in any one of claims 49 to 53, wherein a single compound of the general formula I is used for the treatment in an amount within the range of from 0.5 to 5 kg per hectare.
55. A method as claimed in any one of claims 49 to 53, wherein two or more compounds of the general formula I are used for the treatment in a total amount within the range of from 0.5 to 5 kg per hectare.
56. A method as claimed in any one of claims 49 to 55, wherein the crop is a lucerne, bush-bean. cotton. soya bean, ground-nut or wheat crop.
57. A pack which comprises a compound of the general formula I given in claim 1, in which R, X and n have the meanings given in claim 1, together with instructions for its use as a selective herbicide.
58. A pack which comprises a compound as claimed in claim 2 or 3 together with instructions for its use as a selective herbicide.
59. A pack which comprises the compound claimed in any one of claim 4 to 25 together with instructions for its use as a selective herbicide.
60. A pack which comprises the compound claimed in claim 26 or 27 together with instructions for its use as a selective herbicide.