CH662564A5 - N-PYRIDYLPYRAZOLE DERIVATIVES AND HERBICIDE COMPOSITION CONTAINING THEM. - Google Patents

Description

The invention relates to N-pyridylpyrazole derivatives, the compositions containing them and their use as herbicides.

The present invention provides new N-pyri-dylpyrazole derivatives having good herbicidal properties, of formula I as defined in claim 1, of formulas XXX and XXXI according to claims 7 and 8.

Preferably, - (CRaRb) m— represents an ethylene or propylene group, optionally substituted, on at least one carbon atom, by one or two alkyls, linear or branched, of 1 to 4 carbon atoms.

Unless stated otherwise, the term "halogen" refers to fluorine, chlorine, bromine and iodine.

When R1 and R2 each represent R5, these can be the same or different.

By "salts with bases acceptable in agriculture" is meant the salts whose cations are known and accepted for the formation of salts of acids with agrochemical action for agricultural or horticultural use.

Preferably, the salts are water-soluble. As suitable salts, there may be mentioned those of alkaline base (for example of sodium or potassium), or alkaline earth (for example of calcium or of magnesium), the ammonium and amine salts (for example dietha-nolamine , triethanolamine, octylamine, morpholine and dioctylmé-thylamine). When, in the following, reference is made to the compounds of general formula I, this also includes their salts as defined above, when they are possible:

Compound No.

1 5-amino-4-cyano-1 - (5-trifluoromethylpyridid-2-yl) pyrazole

2 5-amino-4-cyano-1- (3-chloro-5-trifiuoromethylpyrid-2-yl) py-razole.

3 5-acetamido- l- (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyanopyrazole.

4 l- (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyano-5-ethyl-aminopyrazole.

5 1 - (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyano-5-methoxy-carbonylene-aminopyrazole.

6 l- (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyano-5-propion-amidopyrazole.

7 l- (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyano-5-dichloro-acetamidopyrazole.

8 1 - (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyano-5-succin-imidopyrazole.

9 l- (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyano-5-di (phen-oxycarbonyl) aminopyrazole.

10 l- (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyano-5-isoprop-oxycarbonylaminopyrazole.

11 l- (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyano-5-methoxy-carbonylaminopyrazole.

12 5- (3-chloro-2-methylpropionamido) -1 - (3-chloro-5-trifluoro-methylpyrid-2-yl) -4-cyanopyrazole.

13 l- (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyano-5- (3-methyl-2-oxo-azetidin-1-yl) pyrazole.

14 l-P-chloro-5-trifluoromethylpyrid-2-yl) -4-cyano-5- (2-prop-enyloxocarbonylamino) pyrazole.

1 - (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyano-5-pentan-amidopyrazole.

A feature of the present invention is to provide a method for controlling the growth of weeds (i.e. unwanted vegetation) at a given location which includes applying a certain amount of effective herbicide, d at least one N-pyridylpyrazole derivative of general formula I. For this purpose, the N-pyridylpyrazole derivatives are normally used in the form of herbicidal compositions (that is to say in combination with diluents or compatible carriers, suitable for entering into herbicidal compositions), for example those which are described below.

The compounds of formula I demonstrate herbicidal activity against dicotyledonous and monocotyledonous weeds (for example grasses) in pre- and / or postemergence application.

The term "pre-emergent application" means application to the soil, in which the weed seeds or seedlings are present, before the emergence of the weeds above the soil surface. The term "postemergence application" means application to the aerial or exposed parts of weeds that have grown above the soil surface. For example, the compounds of general formula I can be used to combat the growth of dicotyledonous weeds, such as: Aethusa cynapium, Abutilon theophrasti, Amaranthus re-troflexus, Amsìnckia intermedia, Anagallis arvensis, Anthémis arven-sis, Atriplexpatula, Bidenspilosa , Brassica nigra, Capsella bursa-pastoris, Chenopodium album, Chrysanthemum segetum, Cirsium 25 arvense, Datura stramonium, Desmodium tortuosum, Emex australia, Euphorbia helioscopia, Fumaria officinalis, Galeopsis tetrahit, Galium aparine, Geranium dissectum, Ipea purpea communis, Matricaria inodora, Monochoria vaginalis, Papaver rhoeas, Physalis longifolia, Plantago lanceolata, Polygonum 30 spp., (eg Polygonum lapathifolium, Polygonum aviculare, Polygonum convolvulus and Polygonum persicaria), Portulaca oleracea, Raphanus raphanifum Saponaria vaccaria, Scandix pecten-veneris, Senecio vulgaris, Sesbania florida, Sida spinosa, Silene alba, Sinapis arvensis, Solanum nigrum, 35 Sonchus arvensis, Spergula arvensis, Stellaria media, Thlaspi arvense, Tribulus terrestria, Urtica urens, Veronica hederifolia, Veronica persica, Viola arvensis and Xanthium strumarium, and grasses, for example Aluminos , Apera spica-venti, Agrostis stolonifera, Avena fatua, Avena ludoviciana, Brachiaria spp., Bromus steri-40 lis, Bromus tectorum, Cenchrus spp., Cynodon dactylon, Digitarla sanguinalis, Echinochloa crus-galli, Eleusid indica, Soraria indica halepense, and laiches, for example Cyperus esculentus, Cyperus iria and Cyperus rotundus, and Eleocharis acicularis.

The amounts of compounds of formula I which are applied vary according to the nature of the weeds, the compositions used, the time of treatment, the climatic and edaphic conditions and (when they are used to combat the growth of weeds in cultivation areas ) the nature of the crops. For treatments in growing areas, the application dose must be sufficient to combat the growth of weeds without significantly or permanently harming the crop. In general, taking these factors into account, application rates of between 0.01 kg and 10 kg of active ingredient per hectare give satisfactory results. However, it is understood that the application doses used will be more or less high depending on the particular weeding problem which must be resolved.

The compounds of formula I can be used to selectively combat the growth of weeds, for example to combat the growth of the species mentioned above, in pre- or postemergence treatment by directed or non-directed application, ie spraying. o directed or not, from a land invaded by weeds, which is used, or intended to be used, for cultivation, for example cereals, i.e. wheat, barley, oats, corn and rice, soybeans, baby beans, fèverolles, peas, alfalfa, cotton, peanut, flax, onions, carrots, cabbage, rapeseed, sunflower, sugar beet and permanent or cultivated meadow, before or after sowing or before or after emergence of the culture. To selectively control weeds in a weed overgrown field that is used or intended to be used for cultivation, for example the crops mentioned

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above, it is particularly advisable to apply doses of between 0.01 kg and 4.0 kg and preferably between 0.01 kg and 2.0 kg of active ingredient per hectare. More specifically, the compounds of general formula I can be used to selectively combat the growth of dicotyledons, for example the dicotyledonous species mentioned above, in pre-emergence or better post-emergence treatment, applied non-directionally, for example by spraying , land used for growing cereals,

before or after the emergence of crops and weeds.

To do this, that is to say selectively combat dicotyledonous weeds by pre- or post-emergence treatment of a soil used for the cultivation of cereals, application doses between 0 , 01 kg and 4.0 kg, and preferably between 0.01 kg and 2.0 kg of active ingredient per hectare.

The compounds of formula I can also be used to combat the growth of weeds, especially those mentioned above, by applying pre- or post-emergence in established orchards and other arboreal areas, for example forests, woods, parks, and plantations, such as sugar cane, oil palm and rubber plantations. To do this, it is necessary to apply in a directed manner or not (for example by spraying) to the weeds or to the soil which probably contains them, before or after the planting of the trees or plantations, at doses of between 0.25 kg and 10, 0 kg and preferably between 1.0 kg and 4.0 kg of active ingredient per hectare.

The compounds of formula I can also be used to combat the growth of weeds, especially those mentioned above, in places which are not growing areas but where it is nevertheless desired to get rid of the weeds. Examples of these uncultivated areas include airfields, industrial sites, railways, roadsides, river banks, irrigation or other canals, brush and land uncultivated or fallow, especially where you want to control weed growth to reduce the risk of fire. Used for this purpose, for which a total herbicidal effect is most often sought, the active compounds are generally employed at higher application rates than those which have been mentioned above for the cultivation areas. The precise dosage will depend on the nature of the vegetation and the desired effect. It will be recommended to carry out these pre- or post-emergence applications, whether directed or not (by spraying) at application doses between 2.0 kg and 10.0 kg and preferably between 10.0 kg and 20.0 kg of active ingredient per hectare.

If used to combat weed growth, in pre-emergence applications, the compounds of general formula I are incorporated into the soil that contains the weeds.

When the compounds of formula I are used to combat the growth of weeds in postemergence application, that is to say application to the aerial or exposed parts of the weeds raised, it will be appreciated that the compounds of general formula I also come into contact with the soil and can then exercise a pre-emergence control on the weeds present in the soil which will subsequently rise. If a particularly prolonged control is desired, the application of the compounds of formula I may be renewed if necessary.

According to another characteristic, the present invention relates to compositions for herbicidal use comprising one or more N-pyridylpyrazole derivatives, of general formula I, in association with, and preferably dispersed homogeneously in, one or more compatible, acceptable diluents or carriers for herbicides, that is to say diluents or carriers of a type generally recognized by those skilled in the art as being able to enter into the composition of herbicides, and which are compatible with the compounds of formula I. L the expression “homogeneously dispersed” makes it possible to include the compositions for which the compounds of formula I are dissolved in the other components. The term "herbicidal compositions" is used in the broad sense, etc., not only ready-to-use herbicidal compositions, but also concentrates which must be diluted before use.

The compositions preferably contain between 0.05 and 90% by weight of one or more compounds of general formula I.

The herbicidal compositions can contain both a diluent or a carrier and a surface-active agent (for example a wetting, dispersing or emulsifying agent). The surface-active agents which can enter into the herbicidal compositions of the present invention can be of ionic or non-ionic type, for example sulforicinoleates, quaternary ammonium derivatives, products based on oxide condensates. ethylene with alkyl- or polyaryl-phenols, for example nonyl- or octyl-phenols, esters of carboxylic acid and anhydrosorbitols made soluble by the etherification of free hydroxy groups by condensation with oxide ethylene, the alkali or alkaline earth metal salts of sulfuric and sulfonic acid esters, such as sodium dinonyl- and dioctyl-sulfo-nosuccinates, the alkali or alkaline earth metal salts of sulfonic acid derivatives of high molecular weight, such as sodium and calcium lignosulfates.

The compositions according to the invention can comprise up to 10%, for example from 0.05% to 10%, of surfactant, but higher proportions can be used, in particular concentrated emulsifiable liquid suspensions (the proportion can then go up to 15%) or in water-soluble liquid concentrates (the proportion can then go up to 25%).

Examples of suitable diluents or solid supports that may be mentioned include aluminum silicate, talc, calcined magnesia, kieselguhr, tricalcium phosphonate, cork powder, absorbent carbon black, and clays such as kaolin or bentonite. The solid compositions (which may be powders for dusting, granules or wettable powders) are preferably prepared by grinding the compounds of formula I dissolved in volatile solvents, then evaporation of the solvents and, if necessary.

grinding of the products so as to obtain powders. The granule formulations are prepared by absorbing the compounds of formula I (dissolved in volatile solvents) by the diluents or solid supports in the form of granules, then by evaporating the solvents, or by putting the powder compositions in the form of granules. obtained as described above. Solid herbicidal compositions, in particular wettable powders, can contain wetting or dispersing agents (for example those of the types mentioned above), which can also, in solid form, serve as diluents or carriers.

The liquid compositions according to the invention may be in the form of aqueous, organic or hydro-organic solutions, suspensions or emulsions which may contain a surfactant.

Liquid diluents which are suitable in liquid compositions include water, acetophenone, cyclohexanone, isophorone, toluene, xylene and mineral, animal or vegetable oils (as well as mixtures of these diluents). The surface-active agents which can be found in the liquid compositions are ionic or non-ionic (for example of the types mentioned above) and can, in liquid form, also serve as diluents or carriers.

Wettable powders and liquid compositions in the form of concentrates can be diluted in water or other suitable diluents, for example vegetable or mineral oils, particularly in the case of liquid concentrates, in which the diluent or carrier is an oil , to give ready-to-use compositions. If desired, the liquid compositions of compound of general formula I can be used in the form of self-emulsifying concentrates, in which the active materials are dissolved in emulsifying agents or in solvents containing emulsifying agents compatible with the active materials. : the simple addition of water to these concentrates makes them ready to use.

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30

35

40

45

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60

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Liquid concentrates for which the diluent or carrier is an oil are used without additional dilution with the electrostatic spraying technique.

The herbicidal compositions according to the present invention can also contain, if desired, usual adjuvants such as adhesives, dyes, protective colloids, thickeners,

penetrating agents, stabilizers, sequestering agents, anti-caking agents, corrosion inhibitors and preservatives. These adjuvants can also serve as carriers or diluents.

The preferred herbicidal compositions according to the invention are aqueous concentrates in suspension comprising, by weight / volume, from 10 to 70% of at least one compound of general formula I, from 2 to 10% of a surfactant, from 0 , 1 to 5% of a thickener, and the balance to 100% by volume of water; wettable powders comprising by weight from 10 to 90% of at least one compound of general formula I, from 2 to 10% of a surfactant and from 8 to 88% of a solid diluent or support; water-soluble liquid concentrates comprising from 5 to 50% by weight / volume, for example from 10 to 30% of at least one compound of general formula I, from 5 to 25% of a surfactant and of 25 to 90%, preferably 45 to 85%, of a water-miscible solvent, for example dimethylformamide or a water-water-miscible solvent mixture; liquid concentrates in emulsifiable suspension, comprising in weight / volume from 10 to 70% of at least one compound of general formula I, from 5 to 15% of a surfactant, from 0.1 to 5% of a thickening agent and the complement to 100% by volume of organic solvent; the granules comprising by weight from 1 to 90%, for example 2 to 10%, of at least one compound of general formula I, from 0.5 to 7% for example from 0.5 to 2% of a surfactant -active, from 3 to 98.5% for example from 88 to 97.5% of a granulated support, emulsifiable concentrates comprising from 0.05 to 90% by weight / volume (preferably from 1 to 60% of compounds of general formula II), from 0.01 to 10% by weight / volume, preferably from 1 to 10% of surfactant and the remainder by 100% by volume of organic solvent.

The herbicidal compositions according to the present invention may also comprise the compounds of general formula I in association with, and preferably homogeneously distributed in, one or more other active compounds as a pesticide, and, if desired, one or more diluents or compatible supports acceptable for pesticides, surfactants and usual adjuvants as mentioned above.

The following examples illustrate the herbicidal compositions according to the present invention.

Example 1

A wettable powder was prepared with:

- 5-Amino-1 - (- 3-chloro-5-trifluoromethyl-pyrid-2-yl) -4-cyanopyrazole 50% w / w

- Ethylan BCP (condensation product of ethylene oxide (9 moles) and nonyphenol) 5% w / w

- Aerosil (silicon dioxide in microfine particles) 5% w / w

- Celite PF (support: synthetic magnesium silicate) 40% w / w

Ethylan BCP has been absorbed by the Aerosil, it is mixed with the other ingredients, it is ground in a hammer mill to obtain a wettable powder to be diluted in water and applied at the rate of 1 kg of wettable powder for 300 liters of spraying fluid per hectare, to compost Galium aparine, Veronica persica, Viola arvensis, as a postemergence treatment on a raised winter wheat crop.

It can be prepared in this way in the form of a similar wettable powder, by replacing 5-amino-1 - (- 3-chloro-5-trifluoromethyl-pyrid-2-yl) -4-cyanopyrazole with other compounds of formula I .

Example 2

A concentrate in aqueous suspension was prepared from:

- 5-Amino-1 - (- 3-chloro-5-trifluoromethyl-pyrid-2-yl) -4-cyanopyrazole

- Ethylan BCP

- Sopropon T 36 (sodium salt of polycarboxylic acid)

- Ethylene glycol

- Rhodigel 23 (Polysaccharide gum)

- Distilled water at

50% weight / volume 1.0% weight / volume

0.2% w / v 5% w / v 0.15% w / v 100% by volume by thoroughly mixing the ingredients, then grinding them for 24 hours in a ball mill.

The concentrate thus obtained can be dispersed in water and applied at the rate of 1 kg of concentrate in aqueous suspension per 300 liters of fluid to be sprayed per hectare to combat Galium aparine, Veronica persica, Viola arvensis, in postemergence treatment 15 a raised crop of winter barley.

It can be prepared in this way as a concentrate in similar aqueous suspension, replacing 5-amino-1 - (- 3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyanopyrazole with other compounds of formula II .

In herbicide efficacy experiments carried out on representative compounds of formula I, the following results were obtained:

Experimentation methods Weed efficacy test 25 a) General:

Appropriate quantities of the compounds to be tested, identified by their numbers, are dissolved in acetone to obtain solutions corresponding to application doses of 2, 8, 31, 125, 500 and 2000 g per hectare (g / ha) of compound tested. These solutions are applied using a laboratory herbicide sprayer, equipped with a flat jet, traveling at a speed of 2.6 km / hour and spreading the equivalent of 530 liters of fluid per hectare.

b) Weeding: pre-emergence treatment 35 Weed seeds were sown on the surface of John Innés N ° 1 potting compost (7 volumes of sterilized soil, 3 volumes of peat and 2 volumes of fine sand) in pots of plastic (surface 70 mm, depth 75 mm). The quantities of seeds per pot were as follows:

40 Weed species

50 30-40 15

15-20 30

Approximate number of seeds per pot

1) Dicotyledonous weeds:

Chenopodium album Brassica kaber

45 Abutilon theophrasti Ipomea purpurea

2) Grass weeds:

Avena fatua Echinochloa crus-galli

50

The experimental compounds were applied to the seeds not covered as described above in (1), at doses of 2, 8, 31, 125, 500, 2000 g / ha; the seeds were then covered with 25 ml of fine sand. Each treatment corresponded to a single pot of each 55 species of weed, controls sprayed with acetone alone. After the treatment, the pots were placed in a greenhouse and watered from above. The weedkiller properties of the products were checked during visual observations made 20 days after spraying. The results were expressed in minimum effective dose 60 (DEM) (in kg / ha) which makes it possible to obtain a size reduction of 90% or the total suppression of the weeds, taking as plants the control pots. The results obtained are presented in Table I below.

c) Weeding: postemergence treatment 65 We first grew different weed species, then transplanted them at the seedling stage into 7 cm diameter paper-based paper pots containing John Innés potting compost N ° 1, except for Avena fatua which has not been transplanted but

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sown directly in the pot. The rate plants were then allowed to grow. The number of plants per pot and their stage of growth in the greenhouse until the time of application of the experimental compounds - time of spraying were as follows:

Weed species

Number of plants per pot

Growth stage

(1) Dicotyledonous weeds

Chenopodium album

4

4 sheets

Brassica kaber

4

2 sheets

Abutilon theophrasti

3

1 to 2 sheets

Ipomea purpurea

3

2 sheets

(2) Grass weeds

Avena fatua

10

1 to 2 sheets

Echinochloa crus-galli

4

1 to 2 sheets

(3) Laiches

Cyperus esculentus

3

2 to 3 sheets

The experimental compounds were applied as described above in (I) (a) on the plants, at doses of 2, 8, 31, 125, 500, 2000 g / ha. Each treatment corresponded to a single pot of each species of weed, untreated controls, and controls sprayed with acetone alone. After spraying, the plants were watered from above. The herbicide efficacy of the compounds was checked 20 days after treatment, counting the number of plants removed or the reduction in size. The results were expressed in minimum effective doses (DEM) (in g / ha) making it possible to obtain a size reduction of 90% or the total suppression of the weeds compared to the control pots. The results obtained are presented in Table II below.

Abbreviations used for weed species

(a) Grass weeds (b) Dicot weeds

Af = Avena fatua At = Abutilon theophrasti

Ec = Echinochloa crus-galli Ip = Ipomeapurpurea

Bk = Brassica kaber Ca = Chenopodium album

(c) Laiches

Cr = Cyperus rotondus / esculentus

The meaning of the symbols used in the tables below is as follows:

T.C. N °: number of the compound tested

A.R. g / ha: application rate (g / ha) of the test compound

<: smaller than

Table I

T.C.

No.

Preemergence DEM (g / ha)

A.R.

g / ha

It

Bk

At

Ip

Af

Ec

1

19

64

60

71

125

95

8-2000

2

18

21

18

20

180

48

8-2000

3

12

49

14

50

172

59

8-2000

Table II

T.C.

No.

Preemergence DEM (g / ha)

A.R. g / ha

It

Bk

At

Ip

Af

Ec

This

1

75

100

125

22

2000

810

2000

8-2000

2

32

210

8

50

2000

88

2000

8-2000

3

<8

172

<8

<8

615

49

956

8-2000

The compounds of formula I in which R1 and R2 each represent a hydrogen atom, that is to say the compounds of general formula IA appended, are prepared by cyclization of a compound of general formula IV (for example 3 -5-chloro-trifluoromethylpyrid-2-ylhydrazino-methylenemalonitrile) annexed, in the presence of an inert organic solvent, for example an alkanol of 1 to 4 carbon atoms (for example ethanol), acetic acid or ethoxyethanol, at a temperature from ambient to reflux of the reaction medium.

The compounds of formula IV can be prepared by reaction of a compound of general formula V (for example 3-chloro-2-hydrazino-5-trifluoromethylpyridine) appended, or a salt thereof,

with a compound of the appended formula VI, in which R7 represents an alkyl of 1 to 4 carbon atoms, preferably ethyl.

55 The reaction of a compound of formula V with a compound of general formula VI can be carried out in the presence of an inert organic solvent, for example alkanol of 1 to 4 carbon atoms (pj. Example ethanol), acetic acid or rethoxyethanol. at a temperature from ambient to reflux of the reaction mixture. and 60 optionally in the presence of acetate, carbonate or bicarbonate or alcoholate, from 1 to 4 carbon atoms, for example alkaline ethanolate (for example sodium or potassium). If a salt of the compound of formula V is used, the reaction is carried out in the presence of acetate, carbonate or alkaline bicarbonate (sodium or potassium). The compounds of formula IA can also be prepared by reacting a compound of general formula V with a compound of formula VI without isolating the intermediate compound of formula IV from the reaction medium. When the reaction is carried out in acetic acid

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that, in the presence or absence of alkaline acetate (for example of sodium or potassium), the intermediate of formula IV can separate from the reaction medium according to its solubility in this medium and can, if necessary, be isolated before cyclization into compound of general formula IA, preferably by reflux heating, in an inert solvent (for example ethoxyethanol).

The compounds of formula IV exhibit herbicidal activities analogous to those of the compounds of general formula IA, activities supposed to result from their cyclization into compounds of formula IA.

The compounds of formula I in which:

- R1 represents a group R8C (= 0), in which R8 represents:

- either an alkyl of 1 to 7 carbon atoms,

- either an alkoxy of 1 to 4 carbon atoms,

- either an alkenyloxy of 3 or 4 carbon atoms,

either the alkyl or alkoxy above substituted with an alkoxy of 1 to 4 carbon atoms, an alkoxycarbonyl of 2 to 5 carbon atoms, or at least one halogen atom, for example chlorine,

either a cycloalkyl of 3 to 6 carbon atoms optionally substituted by a methyl or ethyl group,

- either a phenyl group,

- R2 represents a hydrogen atom or a group R8C (= 0) identical to that of R1, that is to say compounds of annexed formula IB, in which R9 represents the group R8C (= 0) -, R10 represents a hydrogen atom or a group R8C (= 0) identical to the group R8C (= 0) of R9, are prepared by reaction of a compound of general formula IA, with a compound of general formula VII appended, in which X represents a chlorine or bromine atom, or with a compound of formula VIII annexed, in the presence or not of an inert organic solvent, for example a ketone, such as acetone, an aromatic hydrocarbon such as benzene or toluene, chloroform, dichloromethane or dimethylform-amide, and optionally in the presence of an acid-fixing agent, for example pyridine, triethylamine or an alkali carbonate or bicarbonate (sodium or potassium), at a temperature from 0 C until the reaction medium refluxed, to give a compound of formula IB in which R10 represents te a hydrogen atom or an R8C group (= 0) according to the reaction conditions chosen and / or the use of an excess of compound of formula VII or VIII. An alkaline derivative of the compound of formula IA can be used.

The compounds of formula I in which R1 represents the group R4aC (= 0), in which R4a represents a hydrogen atom, R2 represents a hydrogen atom, that is to say compounds of general formula IC appended, are prepared by reacting a compound of formula IA with formic acid, in an inert organic solvent, for example a ketone, such as methyl isobutyl ketone, or an aromatic hydrocarbon, such as toluene or benzene, or reflux of reaction mixture.

The compounds of formula I, in which R1 represents the group R4a (C = 0) in which R4a represents a hydrogen atom, R2 represents a hydrogen atom or a group R4aC (= 0) in which R4a represents a atom d hydrogen, that is to say the compounds of formula ID in which R11 represents a hydrogen atom or an HC group (= 0), are prepared by reaction of a compound of formula IA with formylacetic anhydride ( which can be prepared from formic acid and acetic anhydride) optionally in the presence of an inert organic solvent, for example a ketone, such as acetone, or an aromatic hydrocarbon, for example benzene or toluene, and optionally in the presence of an acid-fixing agent, for example pyridine, triethylamine or an alkali carbonate or bicarbonate, for example of sodium or potassium, at a temperature from 0 ° C. until the reaction mixture reflux, to give a compound of formula ID in which R11 represents a hydro atom gene or a group HC (= O) according to the reaction conditions chosen and / or the use of an excess of formylacetic anhydride.

The compounds of formula I in which R1 represents a group R4C (= 0), R2 represents a hydrogen atom, that is to say the compounds of formula IE appended, in which R12 represents a group R4C (= 0) -, are prepared by selective elimination by hydrolysis of a group R8C (= 0) represented by R10, of a compound of formula IB or a group HC (= 0) - represented by R11 of a 5 of compound of general formula ID . The hydrolysis is carried out under mild conditions, for example by treatment with a hydroethanolic solution or suspension, of an alkaline bicarbonate, for example of sodium or potassium, or with ammonia.

The compounds of formula I, in which R1 represents a group R4bC (= 0) -, in which R4b represents an alkoxy of 1 to 4 carbon atoms, optionally substituted by an alkoxy of 1 to 4 carbon atoms, an alkoxycarbonyl of 2 to 5 carbon atoms or at least one halogen atom, for example chlorine, R2 represents a hydrogen atom, i.e. compounds of the appended formula IF, in which R13 represents a group R14C (= 0), in which R14 represents an alkoxy of 1 to 4 carbon atoms, optionally substituted by an alkoxy of 1 to 4 carbon atoms, an alkoxycarbonyl of 2 to 5 carbon atoms or at least one halogen atom, for example chlorine, are prepared by reaction of a compound of formula IG in which R15 represents a group R16C (= 0) -, in which R16 represents R14 or a phenoxy, with a compound of general formula IX appended, to replace Rls either by a hydrogen atom or by R13, when Rls represents a group R16C (= 0), in the which R16 is phenoxy or, if desired, R14.

The desired compound of formula IF is obtained, in a known manner, by selection of the appropriate compounds of formulas IG and IX.

The reaction can be carried out in water or an inert hydro-organic or organic solvent, for example an alkanol of 1 to 4 carbon atoms, such as ethanol, or an aromatic hydrocarbon, such as benzene or toluene , or which is preferably an excess of the compound of formula IX, at a temperature from ambient to reflux of the reaction mixture and, if necessary, at elevated pressure, optionally in the presence of a base, for example an alcoholate alkaline, for example the compound of formula IX.

The compounds of formula I in which R1 and R2, identical or different, each represent a group R4C (= 0) -, that is to say the compounds of formula IH annexed in which R17 represents a group R4C (= 0 ), identical or different from that representing R12, are prepared by reaction of an alkaline derivative, for example of sodium or potassium, of a compound of formula IB in which R10 represents a hydrogen atom or of a compound of formula IC, i.e. a compound of formula IE with formic acid, formylacetic anhydride or a compound of formula VII. The reaction can be carried out in a suitable aprotic solvent, for example dimethylformamide, at a temperature from ambient to reflux of the reaction mixture.

The compounds of formula I in which R1 and R2 represent 50 together - CO— (CRaRb) mCO— are prepared by reaction of a compound of formula IA with a compound of formula X appended or with a compound of formula XI appended, optionally in presence of a suitable inert organic solvent, for example a ketone, such as acetone, an aromatic hydrocarbon, such as benzene 55 or toluene, chloroform, dichloromethane or dimethylformamide, optionally in the presence of a fixing agent acid, for example pyridine, triethylamine or an alkali carbonate or bicarbonate, for example of sodium or potassium, at a temperature from 0 ° C until the reaction medium reflux. If desired, an alkaline derivative of the compound of formula IA can be used.

The alkaline derivatives of compounds of formula IA or IE can be prepared in situ by reaction of compounds of formula IA or IE with an alkaline hydride, for example of sodium or potassium, in a suitable inert organic solvent, such as dimethylformamide , at a temperature from ambient to reflux of the reaction mixture.

The compounds of formula I in which R1 represents a group R5, R2 represents a hydrogen atom or a group of

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R5, that is to say a compound of annexed formula IJ, in which Rt7 represents a hydrogen atom or a group of R5, are prepared by reaction of a compound of annexed formula XII in which R18 represents an alkyl of 1 to 4 carbon atoms, preferably ethyl, with a compound of the attached formula V, or one of its salts, for example hydrochloride.

This reaction can be carried out in the presence of an alkanol of 1 to 4 carbon atoms, for example ethanol, acetic acid or ethoxyethanol, at a temperature from ambient to reflux of the reaction mixture, optionally in the presence of an alkaline acetate, carbonate or bicarbonate, for example sodium or potassium. If the compound of formula V is used in the form of a salt, the reaction with the compounds of general formula XII is carried out in the presence of an alkali acetate, carbonate or bicarbonate, for example sodium or potassium.

The compounds of formula I, in which R1 represents a group R5 and R2 represents a hydrogen atom or a group R1, that is to say the compounds of formula IK in which R5a represents a group R5, are prepared by reaction of a compound of formula IA attached or one of its alkaline derivatives, for example of sodium or potassium, with a compound of formula XIII in which X1 represents a chlorine, bromine or iodine atom, optionally in the presence of a suitable inert organic solvent, for example an aromatic hydrocarbon, such as benzene or toluene, chloroform, dichloromethane, tetrahydrofuran or dimethylformamide, optionally in the presence of an acid-fixing agent, for example pyridine or triethylamine, an alkaline bicarbonate of sodium or potassium, optionally in the presence of a crown ether (for example 15-crown-5 (1,4,7,10,13,16 pentaoxacyclo pentadiene) or 15-crown-6 (1,4,7 , 10,13,16 hexaoxacyclo octodé-cane] at a temperature since 0 ° C until reflux of the reaction mixture. The reaction is promoted by an excess of compound of formula XIII. If necessary, a mixture of compounds of formula IK can be separated by known means, such as crystallization or chromatography on silica gel.

The compounds of formula I in which R1 represents Rs which represents an alkyl of 1 to 8 carbon atoms, optionally substituted by a cyano, hydroxyl, alkoxy, from 1 to 6 and preferably 1 to 4 carbon atoms, a carboxy, a alkoxycarbonyl of 2 to 9 and preferably of 2 to 5 carbon atoms or at least one halogen atom, for example of chlorine, R2 represents a hydrogen atom, that is to say the compounds of formula IL attached , in which R18 represents an alkyl of 1 to 7 carbon atoms, optionally substituted by a cyano, hydroxyl, alkoxy, from 1 to 6 and preferably from 1 to 4 carbon atoms, a carboxy, an alkoxycarbonyl from 2 to 9 and preferably from 2 to 5 carbon atoms, or at least one halogen atom, for example chlorine, R19 represents a hydrogen atom or R18, R18 and R19 representing together with the carbon atom to which they are bonded a alkyl of 1 to 7 carbon atoms, optionally substituted by cyano, hydroxyl, alkoxy, of 1 to 6 and of preferably from 1 to 4 carbon atoms, a carboxy, an alkoxycarbonyl from 2 to 9 and preferably from 2 to 5 carbon atoms, or at least one halogen atom, for example of chlorine, are prepared by reduction of the double imine bond of a compound of formula XIV attached. This reaction can be carried out with an alkali boro or cyanoborohydride, for example sodium or potassium, in the presence of a suitable inert organic solvent, for example a lower alkanol, such as methanol or ethanol, or tetrahydrofuran at a temperature from ambient to reflux of the reaction mixture.

The compounds of formula I in which R1 represents a group R5, R2 represents a hydrogen atom, that is to say the compounds of annexed formula IM, are prepared by elimination of the group R20CO— from a compound of formula XV annexed, in which R20 represents a linear or branched alkyl or alkoxy of 1 to 4 carbon atoms. This reaction can be carried out by selective hydrolysis under mild conditions when R20 is an alkyl, or when R20 is an alkoxy (for example tert.-butoxy) under alkaline or acidic conditions, for example by treatment with an alkali hydroxide, for example sodium or potassium, in water or a suitable inert organic or hydro-organic solvent, for example a lower alkanol, such as methanol, or a mixture of water and lower alkanol, at a temperature from ambient to at reflux of the reaction mixture.

When R5 represents an alkyl, alkenyl or alkynyl, substituted by an alkoxycarbonyl, the elimination of R20C (= O) can be accompanied by hydrolysis or, when the reaction medium contains a lower alkanol, by a transesterification of the alkoxycarbonyl,

to give a compound of formula IM in which R5 alkyl, alkenyl or alkynyl is substituted respectively by a carboxy or an alkoxycarbonyl corresponding to the lower alkanol present in the medium, according to the reaction conditions.

By "lower alkanol" is meant in this description an alkanol of 1 to 4 carbon atoms.

The compounds of formula I, in which R1 and R2 each represent methyl, are prepared by reaction of a compound of formula IA with formic acid in the presence of acetic acid. The reaction can optionally be carried out in the presence of an inert organic solvent, for example a ketone, such as acetone, or an aromatic hydrocarbon, such as benzene or toluene, at a temperature from 0 ° C. to reflux of the reaction mixture. and, if desired, at high pressure.

The compounds of formula I in which R1 is R5 which represents an alkyl, linear or branched, of 2 to 8 carbon atoms, optionally substituted by a cyano, hydroxy, alkoxy of 1 to 6 and preferably of 1 to 4 carbon atoms or at least one halogen atom, for example chlorine, R2 represents a hydrogen atom, that is to say the compounds of annexed formula IN, in which R21 represents an alkyl, linear or branched, from 1 to 7 carbon atoms, optionally substituted by a cyano, hydroxyl, alkoxy from 1 to 6 and preferably from 1 to 4 carbon atoms or at least one halogen atom, for example chlorine, are prepared by reduction of the carbonyl group d 'a compound of formula XVI attached. This reaction can be carried out with an alkali boro-ethanedithiolate, for example of sodium, in a suitable inert organic solvent, for example a lower alkanol, such as methanol or ethanol, or tetrahydrofuran, at a temperature from! ambient until reflux of the reaction mixture.

The compounds of formula XIV can be prepared by reaction of a compound of formula IA, with a compound of formula XVII, in the presence of a lower alkanol, such as methanol or ethanol, optionally in the presence of a mineral acid, such as hydrochloric or sulfuric acid, at a temperature from ambient to reflux of the reaction mixture.

The compounds of formula XV can be prepared by reaction of a compound of formula XVIII attached, or of one of its alkaline derivatives, for example of sodium or potassium, with a compound of formula XIX attached, in a suitable inert organic solvent , for example dichloromethane, tetrahydrofuran or dimethylformamide, at a temperature from ambient to reflux of the reaction medium and, when a compound of formula XVIII is used, in the presence of a base such as Triton B.

The alkaline derivatives of the compounds of formula XVIII can be prepared in situ by the reaction of a compound of formula XVIII with an alkaline hydride, for example of sodium or potassium, at a temperature from ambient to reflux of the reaction mixture .

The compounds of formula XVIII can be prepared by reaction of a compound of formula IA with a compound of formula XX or XXI annexed, optionally in the presence of an inert organic solvent, for example a ketone such as acetone, an aromatic hydrocarbon , for example benzene or toluene, chloroform, dichloromethane or dimethylformamide, optionally in the presence of an acid-fixing agent, for example pyridine, triethylamine or an alkali carbonate or bicarbonate, for example sodium or potassium, at a temperature from 0 "C until reflux of the reaction mixture.

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The compounds of formula XVI can be prepared by reaction of a compound of formula IA with a compound of formula XXII or XXIII appended, as for the reaction described above of a compound of formula IA with a compound of formula XX or XXI .

The compounds of formula XVIII, in which R20 represents an alkoxy of 1 to 4 carbon atoms, that is to say compounds of annexed formula XXIV, in which R22 represents an alkoxy of 1 to 4 carbon atoms, can be prepared by reaction of a compound of annexed formula XXV in which R23 represents a phenoxy, with a compound of annexed formula XXVI. This reaction can be carried out in water or a suitable hydro-organic or organic solvent, for example an alkanol of 1 to 4 carbon atoms, such as ethanol, or an aromatic hydrocarbon, such as benzene or toluene, or which is preferably an excess of the compound of formula XXVI, at a temperature from ambient to reflux of the reaction mixture and, if necessary, at high pressure, optionally in the presence of a base, for example an alkaline alcoholate, such as that of the compound of formula XXVI.

The compounds of formula XXV can be prepared by reacting a compound of formula IA with an appended formula XXVII, as described for the reaction of a compound of formula IA with a compound of formula XX.

The compounds of formula I, in which:

- R1 represents Rs which is an alkyl of 1 to 8 carbon atoms or alkenyl or alkynyl of 2 to 8 carbon atoms, substituted by an alkoxycarbonyl of 2 to 9 carbon atoms or by an aminocarbonyl optionally substituted by one or two alkyls ( identical or different), each from 1 to 8 carbon atoms, or by one or two alkenyls or alkynyls (identical or different), each from 2 to

8 carbon atoms, or substituted by an alkoxy aminocarbonyl of which the alkoxy has from 1 to 8 carbon atoms, or substituted by an alca-nesulfonamidocarbonyl of which falcane has from 1 to 8 carbon atoms, or substituted by a HetC group (= 0), and

R 2 represents a hydrogen atom, that is to say the compounds of annexed formula IP, in which R r represents an alkylene of 1 to 8 carbon atoms or an alkenylene or alkynylene of 2 to 8 carbon atoms, and T represents an alkoxy of 1 to 8 carbon atoms, an amino optionally substituted by one or two alkyls (identical or different), each of 1 to 8 carbon atoms, or by one or two alkenyls or alkynyls (identical or different) , each of 2 to 8 carbon atoms, or substituted by an amino alkoxy of which the alkoxy has from 1 to 8 carbon atoms, or substituted by an alkanesulfonamido of which the alkane has from 1 to 8 carbon atoms, or substituted by a group Het—, can be prepared by reaction of a compound of formula XXXIII appended, with a compound of formula XXXIV, in which R24 represents an alkoxy of 1 to 8 carbon atoms, an amino optionally substituted by one or two alkyls ( identical or different), each from 1 to 8 carbon atoms, or by one or two alkenyls or alkynyls (identical or different), each from 2 to 8 carbon atoms, or substituted by an amino alkoxy of which the alkoxy has from 1 to 8 carbon atoms, or substituted by an alkanesulfonamido of which the alkane has from 1 to 8 carbon atoms, or substituted by a group Het—, or, when R24 represents an alkanesulfonamido, an alkaline salt, for example of sodium, of the compound of formula XXXIV. The reaction can be carried out, when R24 is an alkoxy, in the presence of an alkanol of formula XXXIV or, when R24 is an optionally substituted amino, an alkoxy-amino or an alkanesulfonamido or the Het group, can be prepared by reaction of a compound of formula XXXIII appended, with a compound of formula XXXIV, in which R24 represents an alkoxy of 1 to

8 carbon atoms, an amino optionally substituted by one or two alkyls (identical or different), each from 1 to 8 carbon atoms, or by one or two alkenyls or alkynyls (identical or different), each from 2 to 8 atoms carbon, or substituted by an amino alkoxy in which the alkoxy has from 1 to 8 carbon atoms, or substituted by an alkanesulfonamido in which the alkane has from 1 to 8 carbon atoms, or substituted by a Het— group, or, when R24 represents an alkanesulfonamido, an alkaline salt, for example sodium,

of the compound of formula XXXIV. The reaction can be carried out, when R24 is an alkoxy, in the presence of an alkanol of formula XXXIV or, when R24 is an optionally substituted amino, an alkoxy-amino or an alkanesulfonamido or the Het group, in the presence of an organic solvent suitable inert, for example a ketone, such as methyl isobutyl ketone, dimethylformamide or toluene, in the presence, when R 24 is an alkoxy or alkanesulfonamido, of a base, for example alkali carbonate, for example potassium, or, when R 24 is an optionally substituted amino or the Het group or an alkoxyamino, in the presence of an alkali carbonate, for example of potassium, or of an excess of ammonia, of a mono- or dialkoxyl-, -alkenyl- or -alkynylamine, an alkoxyamine or the heterocyclic compound of formula XXXIV, at a temperature from ambient to reflux of the reaction medium.

The compounds of formula I, in which R1 represents R5 which is an alkyl of 1 to 8 carbon atoms or an alkenyl or alkynyl of 2 to 8 carbon atoms, substituted by a carboxy, with thionyl chloride or oxychloride phosphorus, in the presence of an inert organic solvent, for example toluene, at a temperature from ambient to reflux of the reaction mixture. The compounds of formula XXXIII can be prepared in situ and reacted with the compounds of formula XXXIV without first isolating them. A convenient process for preparing the compounds of formula I, in which R1 represents R5 which is an alkyl of 1 to 8 carbon atoms, alkenyl or alkynyl of 2 to 8 carbon atoms, substituted by an aminocarbonyl substituted by one or two alkyls of 1 to 8 carbon atoms, and R2 represents a hydrogen atom, consists in reacting a compound of formula I in which R1 represents R5 which is an alkyl of 1 to 8 carbon atoms, an alkenyl or alkynyl of 2 to 8 carbon atoms, substituted by a carboxy, with phosphorus oxychloride and the appropriate mono- or dialkoylamine, in the presence of potassium carbonate at a temperature from ambient to reflux of the reaction medium.

The compounds of formula XXXIII can also be prepared by treatment of a compound of formula I, in which R1 and R2 can form, with the nitrogen atom to which they are linked, with anhydrous hydrogen chloride in the presence of an inert organic solvent, for example chloroform at a temperature from ambient to reflux of the reaction mixture.

The compounds of formula I, in which R1 represents R5 which is an alkyl of 1 to 8 carbon atoms substituted by an alkanesul-fonamidocarbonyl, the alkane part of which has from 1 to 8 carbon atoms and R2 represents a hydrogen atom ( that is to say compounds of formula IQ annexed in which T ° represents an alkanesulfonamido in which the alkane part has from 1 to 8 carbon atoms), can be prepared by reaction of a compound of formula I, in which R1 represents Rs which is an alkyl of 1 to 8 carbon atoms or an alkenyl or alkynyl of 2 to 8 carbon atoms, substituted by an unsubstituted aminocarbonyl (i.e. a compound of formula IP, in which T represents an unsubstituted amino), with an alkanesulfonyl chloride, the alkane part of which contains from 1 to 8 carbon atoms. The reaction can be carried out at temperature from ambient to reflux of the reaction medium, optionally in the presence of a suitable inert organic solvent, for example a ketone such as methylethylketone, or toluene, optionally in the presence of a base. , for example an alkali carbonate, for example potassium.

The compounds of formula I, in which R1 represents Rs which is an alkyl of 2 to 8 carbon atoms or an alkenyl or alkynyl of 3 to 8 carbon atoms, substituted by a hydroxyl and R2 represents a hydrogen atom (c ' that is to say the compounds of formula IR in which Rs represents an alkylene of 2 to 8 carbon atoms or an alkenylene or alkynylene of 3 to 8 carbon atoms), can be prepared by reduction of the carboxylic acid group or ester of a compound of the appended formula XXXV, in which R1 represents an alkylene of 1 to 7 carbon atoms or an alkenylene or alkynylene of 2 to 7 carbon atoms, Ru represents an atom

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hydrogen or an alkyl of 1 to 8 carbon atoms and T1 represents a hydrogen atom, or, when Ru represents an alkyl, T1 can also represent an RsC group (= 0), in which R2S represents an alkyl or alkoxy of 1 to 4 carbon atoms. When Ru represents a hydrogen atom, the reduction is carried out with sodium dihydro bis (2-methoxyethoxy) aluminate in the presence of a suitable inert organic solvent, for example toluene, at a temperature from ambient to reflux of the reaction mixture. When Ru represents an alkyl, the reduction is carried out with sodium borohydride in the presence of methanol or tertiary butanol as solvent, at reflux of the reaction mixture.

The compounds of formula I, in which R1 represents R5 which is an alkyl of 1 to 8 carbon atoms, an alkenyl or alkynyl of 2 to 8 carbon atoms, substituted by a chlorine atom, and R2 represents a hydrogen atom (i.e. the compounds of formula IS appended) can be prepared by reaction of a compound of formula I, in which R1 represents R5 which is an alkyl of 1 to 8 carbon atoms or alkenyl or alkynyl of 2 with 8 carbon atoms, substituted by a hydroxyl ^ and R2 represents a hydrogen atom, with thionyl chloride, optionally in a suitable inert organic solvent, for example dichloromethane or trichloromethane, at a temperature from ambient to 'at reflux of the reaction mixture.

The compounds of formula I, in which R1 represents R5 which is an alkylthio of 1 to 4 carbon atoms, and R2 represents a hydrogen atom (that is to say compounds of annexed formula II in which Ru represents a alkyl of 1 to 4 carbon atoms) can be prepared by reacting an alkaline salt, for example of sodium or potassium, of a compound of formula IA with an alkane-sulfenyl chloride of 1 to 4 carbon atoms , for example by cooling in particular to 0 ° C., in the presence of a suitable inert organic solvent, for example toluene, optionally in the presence of a crown ether such as 15-crown-5 or 18-crown-6.

The compounds of formula I, in which R1 and R2 form, with the nitrogen atom to which they are bonded, a group of formula XXXII, in which Rp represents an alkoxy of 1 to 4 carbon atoms, that is to say say compounds of formula IU, can be prepared by reaction of a compound of formula IA with a compound of formula XXXVI in which Rw represents a hydrogen atom or an alkyl of 1 to 4 carbon atoms, for example in the presence of an acid catalyst, in particular paratoluenesulfonic acid, optionally in the presence of a suitable inert organic solvent, such as tetrahydrofuran or dioxane, at the reflux temperature of the reaction mixture.

The reaction can be carried out in the presence of a lower alkanol, for example methanol or ethanol, optionally in the presence of a mineral acid, for example hydrochloric or sulfuric acid, at a temperature from ambient to reflux of the reaction mixture.

The compounds of formula I, in which R1 and R2 form, with the nitrogen atom to which they are linked, a group of formula XXXII, in which Rp represents an amino substituted by one or two alkyls, identical or different, of 1 with 4 carbon atoms (that is to say compounds of annexed formula IW in which R * represents an alkyl of 1 to 4 carbon atoms) can be prepared by reaction of a compound of formula IU with a mono- or dial-coylamine in which the alkyl part or parts, identical or different, have from 1 to 4 carbon atoms. The reaction can be carried out in a suitable inert organic solvent, for example tetrahydrofuran, at a temperature from ambient to reflux of the reaction mixture, in the presence of an excess of mono- or di-alkyl amine.

The compounds of formula I, in which R1 represents R5 which is an alkyl of 2 to 8 carbon atoms optionally substituted in alpha by an alkoxy of 1 to 6 carbon atoms and R2 represents a hydrogen atom (i.e. - say the compounds of the appended formula IY, in which Ry represents a hydrogen atom or an alkyl of 1 to 7 carbon atoms and T2 represents a hydrogen atom or an alkoxy of 1 to 6 carbon atoms) can be prepared by reduction of the minimal double bond of a compound of formula XXXVII. This reduction can be carried out with an alkali boro or cyanoborohydride, for example sodium, in the presence of a suitable inert organic solvent, for example a lower alkanol such as methanol or ethanol, or tetrahydrofuran, at a temperature of 0 ° C. to 60 ° C. When the reduction is carried out under mild conditions, a compound of formula IY is obtained, in which R2 represents an alkoxy, while a more vigorous reduction leads to a compound of formula IY in which T2 represents an atom of hydrogen. In the presence of an alkanol, the reduction may be accompanied by an alcoholysis of the T2 alkoxy of the formula

XXXVII, which gives a compound in which R1 is substituted in alpha by the alkoxy corresponding to the alkanol.

The compounds of general formula I, in which R1 represents R5 which is an alkyl of 2 to 8 carbon atoms substituted by a carboxy, an alkoxycarbonyl of 2 to 9 carbon atoms or an aminocarbonyl optionally substituted by one or two (identical or different ) alkyls of 1 to 8 carbon atoms, or substituted by one or two (identical or different) alkenyls or alkynyls of 2 to 8 carbon atoms, and R2 represents a hydrogen atom (i.e. the compounds of formula IZ appended, in which R3 represents an alkylene of 2 to 8 carbon atoms and T3 represents a hydroxy, an alkoxy of 1 to 8 carbon atoms or an amino optionally substituted by one or two (identical or different) alkyls of 1 with 8 carbon atoms, one or two (identical or different) alkenyls or alkynyls of 2 to 8 carbon atoms), can be prepared by treatment of a compound of formula I, in which R, R2 form with the atom d which carries them a group of formula II of 2 to 8 carbon atoms (that of carbonyl being excluded), to effect the fusion of the amide group of this compound with, respectively, an aqueous solution of an alkali hydroxide, for example sodium or potassium, optionally in the presence of a lower alkanol, for example methanol, or with an alkanol of 1 to 8 carbon atoms in the presence of an alkaline lower alcoholate, for example methanolate, or ethanolic hydrogen chloride, optionally in the presence of water, or with l ammonia or a mono- or di-alkyl (identical or different) amino of 1 to 8 carbon atoms, mono- or di-alkenyl (identical or different) amino or alkynyl (identical or different) amino of 2 to 8 atoms carbon, optionally in the presence of an inert organic solvent, for example toluene, tetrahydrofuran or dioxane. at a temperature from ambient to reflux of the reaction mixture.

The compounds of formula XXXVI1 can be prepared by reacting a compound of formula IA with a compound of formula

XXXVIII, to give a compound of formula XXXVII in which T2 is a hydrogen atom, or with a compound of formula XXXVI to give a compound of formula XXXVII in which T2 is alkoxy. The reaction can be carried out under the conditions described above for the reaction of the compound of formula IA with that of formula XVII.

The compounds of formula XXXV, in which T1 represents a hydrogen atom can be prepared by methods described for the preparation of the compounds of formula I, in which R1 represents R5 which is an alkyl, alkenyl, alkynyl, substituted by a carboxy or an alkoxycarbonyl and R2 represents a hydrogen atom. The compounds of formula XXXV, in which T1 represents a group R25C (= O) can be prepared according to the process described for the preparation of the compounds of formula XV.

The compounds of formula I in which R1 and R2. together with the nitrogen atom to which they are linked, represent a group of formula II, are prepared by treatment with a soft base of a compound of formula XXVIII. This reaction can be carried out with sodium hydride in dichloromethane or dimethylsulfoxide, potassium bicarbonate in ethanol and, optionally, water, triethylamine in ethanol and, optionally,

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water, Triton B in ethanol and, optionally, water, at a temperature from ambient to reflux of the reaction mixture.

The compounds of formula XXVIII are prepared by reaction of a compound of formula IA with a compound of annexed formula XXIX, in which X2 represents a chlorine or bromine atom, X and X2 may be identical or different, optionally in the presence of a suitable inert organic solvent, for example a ketone, such as acetone, an aromatic hydrocarbon, such as benzene or toluene, chloroform, dichloromethane or dimethylformamide, optionally in the presence of an acid-fixing agent, for example pyridine, triethylamine or an alkali carbonate or bicarbonate, for example of sodium or potassium, at a temperature from 0 ° C. until the reaction mixture refluxes.

If desired, the compound of formula XXVIII can be prepared in situ by reacting a compound of formula IA with a compound of formula XXIX and treated with a soft base to give the compound of formula I, in which R1 and R2 form together with the nitrogen atom to which they are linked a group of formula II, without isolating the compound of formula XXVIII.

When, in a compound of formula XXVIII, one of the two groups Re and Rr represents a hydrogen atom and one of the two or both Rs and R "represent an alkyl containing a hydrogen atom in alpha, the treatment of the compounds of formula XXVIII with a base may, depending on the conditions used, give rise, in addition to the compound of formula I, to a compound in which the pyrazole nucleus carries, in position 5, an open chain alkenylcarbonylamino, by elimination of chloride or hydrogen bromide with the formation of an ethylenic double bond. For example,

when, in the compound of formula XXVIII, Rf is a hydrogen atom, one can obtain, in addition to the compound of formula I, a compound of annexed formula XXX, while, when, in the compound of formula XXVIII, Rs represents an alkyl containing a hydrogen atom in alpha, and Rh represents a hydrogen atom or an alkyl not containing a hydrogen atom in alpha, it is possible to obtain, in addition to the compound of formula I, a compound of formula XXXI annexed in which RJ and Rk, identical or different, each represent a hydrogen atom or an alkyl, linear or branched, from 1 to 3 carbon atoms, the combined total number of carbon atoms of RJ and Rk not exceeding three. Compounds of similar structure can be formed by elimination of chloride or hydrogen bromide with the formation of an ethylenic double bond, for example when, in the compound of formula XXVIII, Rh represents an alkyl containing a hydrogen atom in alpha and Rg represents a hydrogen atom or an alkyl without hydrogen atom in alpha. The mixtures thus obtained of compounds of formula I and of compounds in which the pyrazole nucleus carries, in position 5, an open chain alkenylcarbonylamino, for example the compounds of formulas XXX and XXXI can be easily separated into their constituents in a manner known per se , for example by chromatography on silica, selective solvent extraction or fractional crystallization.

The compounds obtained from the compounds of formula XXVIII in which the pyrazole nucleus carries, in position 5, an open chain alkenylcarbonylamino, for example the compounds of formulas XXX and XXXI, have herbicidal properties similar to those of the compounds of formula I.

The base salts acceptable in agriculture for the compounds of formula I in which R1 represents a group Rs, itself alkyl, alkenyl or alkynyl substituted by a carboxy, can be prepared in a manner known per se, for example by reaction of compounds of general formula I with a stoichiometric amount of a suitable base, for example an alkali hydroxide, carbonate or bicarbonate, an alkaline earth hydroxide or carbonate, ammonia or an amine (for example, diethanolamine, triethanolamine, octylamine, morpholine or dioctylamine ) in a suitable solvent. The salts can be, if necessary, purified by recrystallization from one, two or more solvents.

These salts, useful in themselves as herbicidal active materials, can also be used in the purification of the corresponding compounds of formula I for example by using the difference in solubility between the salts and the corresponding parent products in water or organic solvents, by techniques known per se.

The compounds of formula V can be prepared by methods known per se, for example by reaction of 2-chloro-5-trifiuoro-methylpyridine or 2,3-dichloro-5-trifluoromethylpyridine with hydrogen hydrate in ethanol . the compounds of formulas VI, XII, XIII, XVII, XIX, XX, XXI, XXII, XXIII, XXIX, XXXIV, XXXVI and XXXVIII can also be prepared by methods known per se.

2-chloro-5-trifluoromethylpiridine and 2,3-dichloro-5-trifluo-romethylpyridine can be prepared as described in the published British patent application No. 2,002,368 A.

The following examples and the reference example illustrate the preparation of the compounds of formula I. Chromatography was carried out on a silica column (Merck 0.040-0.063 mm) at a pressure of 6.6 Nm ~ 2.

EXAMPLE 3 Preparation of Compound No. 1

Ethoxymethylenemalonitrile [2.68 g; described by Huber, J. Amer. Chem. Soc., 65.2224 (1943)] and 3-chloro-2-hydrazino-5-trifluoromethylpyridine (4.65 g) to a solution, with magnetic stirring, of a sodium acetate solution (0, 91 g) in glacial acetic acid (20 ml) at room temperature. After stirring for 2 hours, a yellow solid precipitates from the brown solution obtained and stirring is continued for 15 hours. The mixture is filtered. The solid obtained is washed successively with acetic acid, water, sodium bicarbonate in aqueous solution and with water, to give 3-chloro-5-trifluoromethylpyrid-2-yl-hydrazinomethylenemalonitrile (1.68 g ), melting point 212-215 ° C, in the form of a yellow solid.

This product is then heated at reflux for 2 hours in ethoxyethanol (20 ml). The hot solution is filtered and the filtrate cooled, diluted with water (100 ml) and filtered to give a brown solid which, by crystallization from toluene (50 ml) gives 5-amino-1- (3-chloro- 5-trifluoromethylpyrid-2-yl) -4-cyanopyrazole (1.58 g), melting point 199-200 ° C, in the form of a cream-colored solid.

Example 4; Preparation of compounds N 2 and 3

Acetyl chloride (0.95 ml) is added to a suspension, with stirring of 5-amino-1- (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyanopyrazole (prepared as in the example 3; 1.0 g) in chloroform (10 ml) at 0 ° C. A solution of pyridine (0.56 ml) in chloroform (5 ml) is then added as a reaction mixture at 0-5 ° C. the latter is then warmed to room temperature and left to stand overnight. The solution is then diluted with dichloromethane (50 ml) and washed with hydrochloric acid (2N; 50 ml) and twice with water (2 x 50 ml) and dried over anhydrous magnesium sulfate and evaporated to give a solid yellow. This is chromatographed on a silica column, elected with dichloromethane and with increasing amounts (from 0 to 10% by volume) of ethyl acetate. Evaporation of the eluate containing the fastest product gives 1 - (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyano-5-diacé-tylaminopyrazole (0.40 g), melting point : 134-136 ° C, in the form of a solid cream color.

Evaporation of the eluate containing the slowest product gives 5-acetamido-1- (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyanopy-razole (0.30 g), melting point: 171-173 ° C, as a colorless solid.

Example 5 Preparation of Compound No. 4

A mixture of 5-amino-1- (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyanopyrazole (1.0 g) and sodium hydride powder is heated at reflux for 16 hours. 0.17 g) in dry dioxane (25 ml). The reaction mixture is cooled, supplemented with iodide

5

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662,564

of ethyl (1.13 ml), refluxed for 2 hours then left for 24 hours at room temperature and added with ethyl iodide (1 ml). The reaction mixture is kept at room temperature for 24 hours and then evaporated to dryness. The residue is taken up with a mixture of dichloromethane (25 ml) and water (25 ml). The organic layer is washed with aqueous hydrochloric acid (2N; 25 ml), dried over anhydrous magnesium sulfate and evaporated to give a brown residue.

The residue is treated by chromatography with a dieth-ylether-hexane mixture as eluent. Evaporation of the eluate containing the main compound gives 1- (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyano-5-ethylaminopyrazole (0.17 g), melting point 82-84 ° C, in the form of a pale yellow solid, after trituration with a mixture of diethyl ether and hexane.

Example 6 Preparation of Compound No. 5

A mixture of 5-amino-1- (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyanopyrazole (1.0 g) and paratoluene sulfonic acid hydrate (0.02 g) in trimethylorthoformate (10 ml) is heated at reflux for 1 hour. After cooling, the reaction mixture is evaporated to dryness and the residue treated by chromatography with dichloromethane as eluent.

Evaporation of the eluate containing the main compound gives a yellow semi-solid (0.9 g) which is recrystallized from a mixture of diethyl ether and hexane to give l- (3-chloro-5-trifluoromé-thylpyrid -2-yl) -4-cyano-5-methoxymethylene-aminopyrazole (0.7 g), melting point 73-74 ° C, as a colorless solid.

EXAMPLE 7 Preparation of Compounds Nos. 6 and 15

Propionyl chloride (1.14 g) is added with stirring to a suspension of 5-amino-1- (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyanopyrazole (1.0 g) in chloroform (10 ml) at 0 ° C. To the suspension thus obtained is added, over 10 minutes, with stirring, at 0-2 ° C by external cooling, a solution of pyridine (0.55 g) in chloroform (5 ml ). The reaction mixture is then kept stirring at room temperature for 16 hours and the resulting solution is evaporated to dryness. The residue is taken up in ethanol (10 ml) made basic by adding ammonia (d = 0.88; 10 ml). The basic solution is heated at reflux for 3 hours and then evaporated to dryness.

The residue is taken up in dichloromethane (100 ml), washed successively once with water, twice with 2N hydrochloric acid and twice with water, dried over anhydrous magnesium sulfate and then evaporated. The brown solid obtained is crystallized from toluene (10 ml) to give 1- (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyano-5-propionamidopyrazole (0.46 g), melting point 130 -132 ° C, in the form of a sand-colored powder.

By operating in the same manner, but replacing propionyl chloride by valeryl chloride and by alkalizing the reaction mixture with aqueous potassium bicarbonate, instead of ammonia, the 1- (3-chloro-5) is prepared. -trifluoromethyl-pyrid-2-yl) -4-cyano-5-pentanamidopyrazole (5.0 g), melting point 89-90 ° C, in the form of a brown solid, by crystallization from a toluene-hexane mixture .

Example 8 Preparation of Compound N "9

Phenylchloroformate (5.44 g) is added with stirring to a suspension of 5-amino-1- (3-chloro-5-trifiuoromethylpyrid-2-yl) -4-cyanopyrazole (5.0 g) in dry chloroform ( 75 ml), at -10 ° C. Pyridine (3.46 g) is added dropwise over 5 minutes to the reaction mixture maintained at -10 ° C by external cooling. Stirring is continued for 16 hours at room temperature. The reaction mixture is then cooled to -10 ° C and added with phenylchloroformate (2.72 g) then pyridine (1.73 g). The reaction mixture is maintained again for 16 hours with stirring, at room temperature.

The clear reaction mixture is evaporated to dryness and the residue taken up in diethyl ether (200 ml). This solution is washed with water (3 x

200 ml), dried over sodium sulfate and evaporated to give a yellow oily solid which, after trituration with toluene, gives the

1- (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyano-5-di (phenoxycarbonyl) aminopyrazole (7.9 g), melting point 191-193 ° C, in the form of colorless crystals .

Example 9 Preparation of Compounds N '"11, 10 and 14

1- (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyano-5-di (phenoxycarbonyl) aminopyrazole (prepared in Example 7; 2.4 g) is added to a methanolic solution of methanolate. sodium [prepared from powdered sodium hydride (0.11 g) and anhydrous methanol (50 ml)], and the reaction mixture is heated at reflux for 1 hour.

It is then evaporated to dryness and the residue is taken up in dichloromethane (150 ml) and in water (150 ml). The organic layer is separated and evaporated to give a yellow oil (1.4 g), which, after crystallization from a mixture of diethyl ether (5 ml) and hexane (15 ml), gives 1- (3-chloro- 5-trifluoromethylpyrid-2-yl) -4-cyano-5-meth-oxycarbonylaminopyrazole (0.68 g), melting point 128-129 "C,

in the form of colorless crystals.

By operating in an analogous manner, but replacing the methanol with the alcohol indicated below, one prepares:

- from isopropanol: 1- (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyano-5-isopropoxycarbonylaminopyrazole, melting point 119-120 ° C, as colorless crystals, by crystallization in a mixture of diethyl ether and hexane;

- from allyly alcohol: 1- (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyano-5-propenyloxycarbonylaminopyrazole, melting point 105-106 ° C, in the form of colorless crystals, by chromatography with a dichloromethane / ethyl acetate mixture (5-1 by volume) as eluent, followed by crystallization from a diethyl ether-hexane mixture.

Example 10 Preparation of Compound No. 12

A mixture of 5-amino-1- (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyanopyrazole (3.0 g) and (±) 3- chloride is heated at reflux for 5 hours. chloro-2-methylpropionyl (7.3 g) in dry acetonitrile (15 ml). The reaction mixture is evaporated under reduced pressure to give a solid which, after decolorization with carbon black and recrystallization from toluene, gives the (±) 5- (3-chloro-

2-methylpropionamido) -l- (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyanopyrazole (1.57 g), melting point 151-151.5 C, as a solid tawny color .

Example 11 Preparation of Compounds N ™ 13, 7 and 8

A solution of 5- (3-chloro-2-methylpropionamido) -l- (3-chloro-5-trifluoromethylpyrid-2-yl) -4-cyanopyrazole is added dropwise over 1 hour, with rapid stirring. 1.40 g) in a mixture of dimethylformamide (10 ml) and dichloromethane (40 ml), to a suspension of powdered sodium hydride (0.21 g) in a mixture of dimethylformamide (10 ml) and dichloromethane (40 ml), at room temperature. The reaction mixture is kept for 2 hours and an aqueous solution of ammonium chloride is added to it. The organic layer is then separated, washed with water, dried over anhydrous magnesium sulfate and evaporated to dryness. The residue is treated by chromatography with a diethyl ether-hexane mixture (1-2 by volume) as eluent. Evaporation of the eluate containing the fastest constituent gives the (±) l- (3-chlo-ro-5-trifluoromethylpyrid-2-yl) -4-cyano-5- (3-methyl-2-oxo -azetidin-1-yl) pyraz ° le (0.33 g), melting point 123-124 C, in the form of colorless crystals.

By operating as described in Example 4, but replacing the acetyl chloride with the acid chloride indicated below, the following are prepared:

- from diacetyl chloride, 1- (3-chloro-5-trifluorome-thylpyrid-2-yl) -4-cyano-5-dichloroacetamidopyrazole, melting point 165-166 ° C, in the form of a solid buff color, by crystallization from a toluene-hexane mixture;

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662,564

16

from succinyl chloride, 1- (3-chloro-5-trifluoromé-thylpyrid-2-yl) -4-cyano-5-succinimidopyrazole, melting point 200-201 ° C, in the form of a solid buff color, by crystallization from a toluene-hexane mixture.

R

15

NC_ N -

R

12

R

NC N-

15

17

Reference example 1:

The 3-chloro-2-hydrazino-5-trifluoromethylpyridine, starting material used in Example 3, is prepared as follows:

2,3-dichloro-5-trifluoromethylpyridine (10.37 g) is added

(described in published English patent application 2,002,368 A) to a solution of hydrazine hydrate (99-100% by weight; 7.5 ml) in ethanol (50 ml) and the mixture is heated to reflux for 24 hours.

The mixture is then cooled and evaporated to dryness and the residue is recrystallized from ethanol (25 ml) to give 3-chloro-2-hydrazino-5-trifluoromethylpyridine (4.85 g), melting point 88- 90 ° C, under 15 ^

form of a solid gray. A sample of this product is recrystallized y from n-hexane to give 3-chloro-2-hydrazino-5-triftuoro- (CRaRb) „. .O methylpyridine, melting point; 87 ° C, in the form of colorless crystals.

The various formulas mentioned in the description are the following:

R

V

NC-

R '

NOT

1

ß (1)

R

N N '

(IG)

R14OH

(IX)

N (1H) N '

R '

XOG— (CRa Rb) „, - COX (X)

(XI)

RC

•NOT

17

R

\

R I

(VS)

CV

2. "V

(II)

Nxr

R5 — N —C = 0

I

R17

\ (XII) H

R NC

R5 — N-

R

5a

Vi

N N '

(M)

N N '

(IK)

NC

NC NC,

\ /

(III)

; C = CHNHNHR3 (IV)

\

/ ° \

NC H

(VI)

R '

R8COX

(VII)

R

NC

h2N

'/ \

N ^

L

R ^

R3NHNH,

NC-N-

(IA)

R

10

not

NOT /

R '

NC-

RSX '(XIII) r

18

CH-

•NOT.

, 18

(V)

<IB) R5_

, 19

NC N

N (IM) H ^

L

RP

(R8C0), 0 (VIII)

L I

, 19

H

NC N -

AT

N>, T /

R-

R-

NC

NOT-

AT

NOT

(HE)

(XIV)

D1

N (XV)

CO

l20

Nc — J ~ \ NC — 7— \ 55 NC — 7 / - ^

OCHN ^ N (IQ OCHN () (ID) r2L_CH2 — N ^ N (IN)

! I I, I Ì

H '5 R11 l3 H I

K R 60 R?

ITC NC

„7) ^ NC-

N (IE) R1 "5 N Il N

/ d

H '3 H i -a; 'X

R R5 R

NC -, ^

N / (IF) 65H21 CONH N (XVI) R, 8R10CO (XVII)

17

662,564

NC HN

NOT /

CO

i20

R '

(XVIII)

R *

Rk — C

Rc R

NC

R - C— C— (C) —COHN-i. not

Rf Rd

N (XXX1)

NOT/

L

R5X1

R20COX

(R20CO) 2O

(XIX)

(XX)

(XXI)

Rp —C = N-

I

R "

NC

R24 — C-Rr-N

V \

N N ^

(XXXII)

(IP)

R21COX

(R2IC0) 20

NC H —N

CO

I

22

AT

N N /

I,

R "'

R

NC

E25 — co—:

Rb R

I I

CC-

NC.

X R

(C) n— COHN

R

X R Rd Rg Re RC

CO N (i N

NOT'

CO

! "

R22OH R23COX

R8 Re Rc h 1 1 1

R - C — C— (C) „- COX2

NC.

(XXII) 20

(XXIII)

25

(XXIV)

(XXV)

(XXVI) 45

(XXVII)

N (XXVIII) N x

(XXIX)

Rh — C = C - (C) —COHN

R

N (XXX) 65

N y

R ^

R "

NC

Cl— c— Rr — N

0

H

R24 —H

N N '

I,

RJ

NC

T ° —C - Rr — N

II I

OH

V \

N N /

R-

NC

HO— R - N

I

H

NOT

NOT /

NC-

R ^ -O-C R - N

N N /

NC.

Cl— R - N _ I

H

NC

N y

R "

RV— S — N

H

N R /

R ^

(XXXIII)

(XXXIV)

(IQ)

(1R)

(XXXV)

(IS)

(IT)

662,564

18

NC

RV— 0 - C = N ^

N N /

RU— N

R4-

RW-C (ORV) 3 NC

- C = - N

| I

RX Rq

R

// N ■ S '

L

(IU)

(XXXVI)

(IW)

NC-

Ry— C = N

1.2

NC

C- R— N

11

0 h

not\

N N /

- NOT //

N N /

R '

(XXXVII)

(IZ)

NC

Ry-CH-N - (/ N I 1 NN ^

T2 H

!

• 3

R '

20

(IY)

RyCHO

(XXXVIII)

R

Claims (39)

662,564 2 CLAIMS 1. N-pyridylpyrazole derivatives of general formula NC- R 1 R £ NOT 1 NOT / (I) R® R \ / R> c / 0Xx Rf "\ r / Wnr-% I 0 Rd (II) in which: - R1 represents: a) either a hydrogen atom b) or a group R4 C (= 0) -, in which R4 represents: - either a hydrogen atom, - either an alkyl, linear or branched, from 1 to 7 carbon atoms, or an alkoxy, linear or branched, from 1 to 4 carbon atoms, - either an alkenyloxy, linear or branched, of 3 or 4 carbon atoms, either the alkyl or alkoxy above, substituted by an alkoxy group, linear or branched, of 1 to 4 carbon atoms, an alkoxycarbonyl group of 2 to 8 carbon atoms, or at least 1 halogen atom, - either a cycloalkyl of 3 to 6 carbon atoms optionally substituted by methyl or ethyl, - either a phenoxy group, c) or an R5 group, which represents: - either a linear or branched alkyl group, from 1 to 8 carbon atoms, - either an alkenyl or alkynyl group, linear or branched, of 2 to 8 carbon atoms, - either the alkyls, alkenyls or alkinyls of Rs substituted by a cyano, hydroxy, linear or branched alkoxy containing from 1 to 6 carbon atoms, a carboxy, an alkoxycarbonyl containing from 2 to 9 carbon atoms, an aminocarbonyl group substituted or not by one or two alkyl, linear or branched, containing from 1 to 8 carbon atoms and which, when the aminocarbonyl group is substituted by two alkyls, can be identical or different, or substituted by one or two alkenyls or alkynyls, linear or branched, containing from 2 to 8 carbon atoms and which, when the aminocarbonyl group is substituted by two alkenyls or alkynyls, can be the same or different, an al-coxyaminocarbonyl in which the alkoxy part contains from 1 to 8 carbon atoms and can be linear or branched, an alkanesulfona-midocarbonyl, in which the alkane part contains from 1 to 8 carbon atoms and can be linear or branched, a group —C (= 0) Het in which Het represents a heterocylated, saturated nitrogen group having from 3 to 7 atoms in the ring, including up to two additional heteroatoms chosen by rmi oxygen, nitrogen and sulfur, and linked to the group - C = 0 of the group —C (= 0) Het by the nitrogen atom, or at least one halogen atom, or R5 represents a cycloalkyl of 3 to 6 carbon atoms optionally substituted by at least one alkyl of 1 to 4 carbon atoms, - R2 represents: d) or a hydrogen atom, when R1 represents a hydrogen atom, e) either a hydrogen atom or the R4C group (= O) - when R1 represents the R4C group (= 0) -, f) or a hydrogen atom or R5, when R1 represents R5; - R1 and R2 can also form together: - or the group —CO— (CRaRb) mCO—, in which Ra and Rb, identical or different, each represent a hydrogen atom or an alkyl, linear or branched, from 1 to 4 carbon atoms and m represents 2 or 3, - either, with the nitrogen atom to which they are attached, on the one hand, a group of formula in which Rc, Rd, Re, Rr, Rs and Rh, identical or different, each represent a hydrogen atom or an alkyl, linear or branched from 1 to 6 carbon atoms, and n represents 0.1 or 2, - on the other hand, when n represents 1 or 2, the parts - [(Rc—) C (—Rd)] - and _ [(RC—) C (—Rd)] 2- of the group of formula II may be the same or different or - R1 and R2 can also form together with the nitrogen atom with which they are linked a group of formula 20 Rp — C = N- I R " (XXXII) in which: 25 - Rp represents a linear or branched alkoxy of 1 to 4 carbon atoms, or an amino substituted by one or two linear or branched alkyls, identical or different, of 1 to 4 carbon atoms, - Rq represents a hydrogen atom or an alkyl, linear or branched, from 1 to 4 carbon atoms, - or R1 also represents, when R2 is a hydrogen atom, a linear or branched alkylthio, from 1 to 4 carbon atoms, or an alkenylcarbonyl group, - R3 represents a group of formula 35, 40 (HI) in which: - R6 represents a hydrogen or chlorine atom and, when Rs 45 represents an alkyl, alkenyl or alkynyl substituted by a carboxy, the corresponding salts with bases acceptable in agriculture. 2. N-pyridylpyrazole derivatives according to claim 1, in which R1 represents a group R4C (= 0) -, in which R4 is a 50 alkyl, linear or branched, from 1 to 7 carbon atoms or an alkoxy from 1 to 4 carbon atoms, substituted by at least one chlorine atom. 3. N-pyridylpyrazole derivatives according to claim 1, in which R1 is an Rs group which represents an alkyl of 1 to 8, of 55 preferably 1 to 4 carbon atoms, or an alkenyl or alkynyl of 2 to 8, preferably 2 to 4 carbon atoms optionally substituted by at least one chlorine atom, or by an alkoxycarbonyl containing 2 to 7 carbon atoms or by an aminocarbonyl group, substituted by one or two alkyls, or by an alkanesulfonamide with “o a part of alkane with 1 to 4 carbon atoms. 4. N-pyridylpyrazole derivatives according to claim 3, characterized in that, in Rs, the alkyl contains from 1 to 4 carbon atoms and the alkenyl or alkynyl contains from 2 to 4 carbon atoms. 5. N-pyridylpyrazole derivatives according to claim 1, carac-65 terized in that, in formula III, R6 is a chlorine atom. 6. N-pyridylpyrazole derivatives according to claim 1, in which R1R2N represents an open chain alkenylcarbonylamino group. 3 662,564 7. N-pyridylpyrazole derivatives according to claim 1 of formula Rg Re R ° HC. Rh — C = C - (C) —COHN- R V \ NOT / I N (XXX) wherein Rc, Rd, Re, Rf, R8, Rh and n as well as R3 are defined as in claim 1. 8. N-pyridylpyrazole derivatives according to claim 1 of formula R Rk — C 3 Re RC NC- R - C - C— (C) n — COHN- R R (XXXI) N N / R " in which Rc, Rd, Rc, Rf, Rg, Rh and n as well as R3 are .as defined in claim 1, Rk and R *, identical or different, each represent a hydrogen atom or a linear or branched alkyl, from 1 to 3 carbon atoms, without the total number of carbon atoms of Rk and RJ exceeding 3. 9. Process for the preparation of a compound of formula I according to claim 1, in which Rt and R2 are a hydrogen atom, characterized in that the compound of formula is cyclized 12. Process for the preparation of a compound of formula I according to claim 1, in which R1 is a group R4aC (= 0), in which R4a is a hydrogen atom, R2 is a hydrogen atom, characterized in that that a compound of formula IA is reacted as 5 defined in claim 11 with formic acid. 13. Process for the preparation of a compound of formula I according to claim 1, in which R1 is a group R4aC (= 0) in which R4a is a hydrogen atom, R2 is a hydrogen atom or HC (= O ), characterized in that a compound of 10 formula IA as defined in claim 11 with formylacetic anhydride. 14. Process for the preparation of a compound of formula I according to claim 1, in which R1 is a group R4C (= 0), in which R4 is defined as in claim 1, R2 is an atom 15 of hydrogen, characterized in that selective elimination is carried out by hydrolysis under mild conditions to transform into hydrogen a group R1 or R2 representing R4C (= 0) of the compound of formula I. 15. Process for the preparation of a compound of formula I according to 20 claim 1, in which R1 is a group R4bC (= 0), in which R4b is an alkoxy, linear or branched, of 1 to 4 carbon atoms, R2 is a hydrogen atom, characterized in that react a compound of formula NC NC, NC \ / ' , C = CHNHNHR3 (IV) wherein R3 is defined as in claim 1. 10. A method of preparing a compound of formula I according to claim 1, wherein R! and R2 are a hydrogen atom, characterized in that a compound of formula is reacted R3NHNH2 (V) with a compound of formula NC, \ / \ NC nH (VI) 45 in which R7 is an alkyl, linear or branched from 1 to 4 carbon atoms. 11. A method of preparing a compound of formula I according to claim 1, in which R1 is a group R8C (= 0), in which R8 represents R4 except the hydrogen atom, R2 represents a hydrogen atom or an RsC group (= 0) identical to the previous one, characterized in that a compound of formula is reacted NC j ^ H2N (N / (IA) Ry in which R3 is defined as in claim 1, or one of its alkaline derivatives, with a compound of formula R8COX (VII) in which X represents a chlorine or bromine atom, or with a compound of formula R 15 NOT- R 15 \ V N N ' R ' (IG) in which R15 is a group R16C (= 0), in which R16 is an alkoxy, linear or branched, of 1 to 4 carbon atoms, optionally substituted by an alkoxy of 1 to 4 carbon atoms, an alkoxycarbonyl of 2 to 8 carbon atoms or at least one halogen atom, or a phenoxy, with a compound of formula R140H (IX) in which R14 is as defined in R4b, the replacement of one of the groups represented by R15, by a hydrogen atom and the other R15 by a group R14C (= 0), when R15 is a group R16C (= 0 ), in which R16 is a phenoxy, and if desired the replacement of the other R, s by another R'4C (= 0), when R15 is a group R16C (= 0) as defined for R14. 16. Process for the preparation of a compound of formula 1 according to claim 1, in which R1 and R2, identical or different, represent an R4C (= 0), characterized in that an alkaline derivative of a compound is reacted of formula NC R 12 H N N / R ' (IE) in which R12 is a group R4C (= 0), with formic acid, formylacetic anhydride or a compound of formula VII according to claim 11. 17. Method for preparing a compound of formula I according to claim 1, in which R1 and R2 represent together - CO - (CRaRb) m —CO -, characterized in that a compound of formula IA is reacted as defined in claim 11 with a compound of formula 65 XOC - (CRaRb) m - COX (X) (R8C0) 20 (VIII) or with a compound of formula 662,564 4 (CRaRb) / C ° \ </ .0 (XI) N hT / , 19 R " NC R- T \ ^ N / CO hydroxy, a linear or branched alkoxy of 1 to 6 carbon atoms, or at least one halogen atom, and R2 is a hydrogen atom, characterized in that the carbonyl group of a compound of formula is reduced NC— 18. Process for the preparation of a compound of formula I according to claim 1, in which R1 is R5, as defined in claim 1, R2 is a hydrogen atom or R5, characterized in that a compound is reacted of formula (XII) in which R17 is a hydrogen atom or Rs, R18 is an alkyl, linear or branched, of 1 to 4 carbon atoms, with a compound of formula V as defined in claim 10. 19. Process for the preparation of a compound of formula I according to claim 1, in which R1 is R5 as defined in claim 1, R2 is a hydrogen atom or R5 identical to the previous one, characterized in that the reaction is carried out a compound of formula IA as defined in claim 11 with one or two moles of the compound of formula RSX * (XIII) in which X1 is a chlorine, bromine or iodine atom. 20. Process for the preparation of a compound of formula I according to claim 1, in which R1 is R5 itself being a group R18R19CH—, in which R18 and R19 form, with the carbon atom which carries them, an alkyl , linear or branched from 1 to 8 carbon atoms, optionally substituted by a cyano, hydroxy, linear or branched alkoxy from 1 to 6 carbon atoms, carboxy, a linear or branched alkoxycarbonyl from 2 to 9 carbon atoms or at least one halogen atom, characterized in that the imine double bond of a compound of formula is reduced NC - 30 (XIV) 21. Process for the preparation of a compound of formula I according to claim 1, in which R1 is Rs, as defined in claim 1, R2 is a hydrogen atom, characterized in that removes the R20CO— group from a compound of formula , 21 -CONH- ~ \ V N N x R- (XVI) 24. Process for the preparation of a compound of formula I according to claim 1, in which R1 is R5, itself carrying an alkoxycarbonyl of 2 to 9 carbon atoms and R2 is a hydrogen atom or R5, itself which may be substituted by an alkoxycarbonyl of 2 to 9 carbon atoms, characterized in that each alkoxycarbonyl group of a compound of formula XVI, defined in claim 23, is transested with an alkanol of 1 to 8 carbon atoms the alkoxy part of which differs from the alkoxy groups R5 of R1 and R2. 25. Process for the preparation of a compound of formula I according to claim 1, in which R1 is R3, itself carrying an alkoxycarbonyl of 2 to 9 carbon atoms and R8 is a hydrogen atom or R5, itself can be substituted by an alkoxycarbonyl of 2 to 9 carbon atoms, characterized in that one esterifies a compound of formula I, in which R1 is R5, itself being substituted by a carboxy, and R2 is a hydrogen atom or R5, itself able to be substituted by a carboxy, with an alkanol of 1 to 8 carbon atoms. 26. Process for the preparation of a compound of formula! according to claim 1, in which R1 is R5, itself alkyl, linear or branched, from 1 to 8 carbon atoms or alkenyl or alkynyl from 2 to 8 carbon atoms substituted as defined in claim 1, with the exception substituents included in the group comprising a cyano, a hydroxy, a linear or branched alkoxy of 1 to 6 carbon atoms, a carboxy or at least one halogen atom, and R2 is a hydrogen atom, characterized in that 'we react a compound of formula Cl — C- NC Rr_N H \\ N N ' R- (XXXIII) wherein Rr is a linear or branched alkylene of 1 to 8 carbon atoms or a linear or branched alkenylene or alkynylene of 2 to 8 carbon atoms with a compound of formula R24 — H (XXXIV) (XV) R20 in which R20 is an alkyl or alkoxy, linear or branched, of 1 to 4 carbon atoms. 22. Process for the preparation of a compound of formula I according to claim 1, in which R1 and R2 are each methyl, characterized in that a compound of formula IA as defined in claim 11 is reduced with the acid formic in the presence of acetic acid. 23. Process for the preparation of a compound of formula I according to claim 1, in which R1 is R5, itself being CH2R21, in which R21 represents an alkyl, linear or branched, from 1 to 7 carbon atoms optionally substituted by a cyano, one in which R24 is an amino group substituted or not by one or two alkyls, linear or branched, containing from 1 to 8 carbon atoms and which, when the amino group is substituted by two alkyl-55c, can be identical or different, or substituted by one or two alkenyls or alkynyls, linear or branched, containing from 2 to 8 carbon atoms and which, when the amino group is substituted by two alkenyls or alkynyls, can be identical or different, an alkoxyamino in which the alkoxy part contains from 1 to 8 carbon atoms and can be linear or branched, an alkanesulfonamido, in which the alkane part contains from 1 to 8, and preferably from 1 to 4 carbon atoms and may be linear or branched, a Het group, or, when R24 is an alkanesulfonamido, an alkaline salt of an alkane sulfonamide of formula XXXIV. 65 27. Process for the preparation of a compound of formula I according to claim 1, in which R1 is R5, itself being linear or branched alkyl of 1 to 8 carbon atoms substituted by an alka-nesulfonamidocarbonyl, the alkane part of which, linear or branched, a 5 662,564 from 1 to 8 carbon atoms and R2 is a hydrogen atom, characterized in that a compound of formula I is reacted with R1 being R5, itself being linear or branched alkyl of 1 to 8 substituted carbon atoms by an unsubstituted aminocarbonyl or an alkenyl or alkynyl of 2 to 8 carbon atoms substituted by an unsubstituted aminocarbonyl, and R2 is a hydrogen atom, with a linear or branched alkanesulfonyl chloride of 1 to 8 atoms carbon. 28. Process for the preparation of a compound of formula I according to claim 1, in which R1 is Rs, itself being linear or branched alkyl, from 2 to 8 carbon atoms, substituted by a linear hydroxy or alkenyl or alkynyl or branched, from 3 to 8 carbon atoms substituted by a hydroxy, and R2 represents a hydrogen atom, characterized in that the acid group or carboxylic ester of a compound of formula is reduced XXXII, in which Rp is an alkyl, linear or branched, from 1 to 4 carbon atoms, with a mono- or dialkoylamine in which the alkyl parts, linear or branched, identical or different, contain from 1 to 4 carbon atoms. 33. Process for the preparation of a compound of formula I according to claim 1, in which R1 is R5, itself being alkyl, linear or branched from 2 to 8 carbon atoms, optionally substituted in the alpha position by an alkoxy, linear or branched, from 1 to 6 carbon atoms, and R2 is a hydrogen atom, characterized in that the imine double bond of a compound of formula is reduced NC RÜ0-C — R - N „1 AT NOT N / (XXXV) I R3 wherein R 'is a linear or branched alkylene of 1 to 7 carbon atoms or alkenylene or alkynylene, linear or branched, of 2 to 7 carbon atoms, Ru is a hydrogen atom or a linear or branched alkyl of 1 to 8 carbon atoms and R1 is a hydrogen atom or, when Ru is an alkyl, T1 can also be an R2SC group (= 0) -, in which R25 is an alkyl or alkoxy, linear or branched, from I to 4 carbon atoms. 29. Process for the preparation of a compound of formula I according to claim 1, in which R1 is R5, itself being alkyl, linear or branched, from 1 to 8 carbon atoms substituted by a chlorine or alkenyl or alkynyl atom from 2 to 8 carbon atoms substituted by a chlorine atom and R2 is a hydrogen atom, characterized in that a compound of formula I is reacted in which R1 is an alkyl, linear or branched, from 1 to 8 carbon atoms substituted by hydroxy, alkenyl or alkynyl, linear or branched, from 2 to 8 carbon atoms substituted by hydroxy, and R2 is a hydrogen atom, with thionyl chloride. 30. Process for the preparation of a compound of formula I according to claim 1, in which R1 is R5, itself being a linear or branched alkylthio, of 1 to 4 carbon atoms, and R2 is an atom of hydrogen, characterized in that an alkaline salt of a compound of formula IA indicated in claim 11 is reacted with a linear or branched alkane sulfenyl chloride of 1 to 4 carbon atoms. 31. Process for the preparation of a compound of formula I according to claim 1, in which R1 and R2 form, with the nitrogen atom which carries them, a group of formula XXXII as defined in claim 1, in which Rp is a linear or branched alkoxy of 1 to 4 carbon atoms, characterized in that a compound of formula IA indicated in claim 11 is reacted with a compound of formula Rw — C (OR ") 3 (XXXVI) wherein Rv is a linear or branched alkyl of 1 to 4 carbon atoms, and Rw is a hydrogen atom or a linear or branched alkyl of 1 to 4 carbon atoms. 32. Process for the preparation of a compound of formula I according to claim 1, in which R1 and R2 form together, with the nitrogen atom which carries them, a group of formula XXXII as defined in claim 1, in which Rp is an amino substituted by one or two alkyls, linear or branched, identical or different, from 1 to 4 carbon atoms, characterized in that a compound of formula I is reacted, in which R1 and R2 form, together with the nitrogen atom that carries them, a group of formula NC- Ry— C = r N L 1H * (XXXVII) R in which Ry is a hydrogen atom or a linear or branched alkyl of 1 to 7 carbon atoms and T2 is a hydrogen atom or a linear or branched alkoxy of 1 to 6 carbon atoms. 34. Process for the preparation of a compound of formula I according to claim 1, in which R1 is R5, itself being alkyl, linear or branched from 2 to 8 carbon atoms substituted by a Carboxy, a linear or branched alkoxycarbonyl of 2 to 9 carbon atoms or an aminocarbonyl optionally substituted by one or two alkyls, linear or branched, identical or different, from 1 to 8 carbon atoms, or by one or two alkyls, linear or branched, identical or different, from 2 to 8 carbon atoms, and R2 is a hydrogen atom, characterized in that a compound of formula I is treated, in which R1 and R2 form, together with the atom of nitrogen which carries them, a group of formula II. as defined in claim 1, provided that it contains 2 to 8 carbon atoms, not including that of carbonyl, to effect the fission of the amide group of the group of formula II, with, respectively, an aqueous solution of a alkali hydroxide, a linear or branched alkanol of 1 to 8 carbon atoms in the presence of a lower alkaline alcoholate or ethanolic hydrogen chloride or ammonia or a mono- or dialkoyl- or -alkenyl- or -alkynyl-amine of which respectively the alkyls (identical or different) contain from 1 to 8 carbon atoms, the alkenyls and alkynyls contain from 2 to 8 carbon atoms. 35. Process for the preparation of a compound of formula 1 according to claim 1, in which R1 and R2 form together with 45 the nitrogen atom which carries them a group of formula 11, characterized in that a compound of formula jg is treated R NC. CC- X R (vs). R COHN N (xxvnii N / R- 55 in which X is a chlorine atom, with a base. 36. (3-Chloro-5-trifluoromethyl-pyrid-2-yl) hydrazinomethylene- malonitrile of formula IV as starting material for carrying out the process according to claim 9. 37. Herbicidal composition comprising, as active material, at least one N-pyridylpyrazole derivative of formula I according to claim 1, in combination with at least one diluent or support and / or surfactant, compatible for a herbicide. 38. Composition according to claim 37, characterized in that it contains from 0.05 to 90% by weight of derivative of N-pyridylpyra- 65 zole. 39. Composition according to one of claims 37 and 38, characterized in that it contains at least one other pesticidal active material, including herbicide. 662,564 6 40. A method of weeding, characterized in that a compound is applied according to one of claims 1 to 6. 41. Method according to claim 40, characterized in that weed selectively cereal crops, such as wheat, barley, oats, rice or corn; soy, beans, peas, alfalfa, cotton, peanut, flax, onion, carrots, cabbage, rapeseed, sunflower, beet or permanent or sown meadows.