CH635324A5 - Compounds having agronomic use - Google Patents

Description

635,324

CLAIMS 1. Compounds for agricultural use corresponding to the formula

* 3

The present invention relates to compounds for agricultural use which exhibit activity as regulators of plant growth, in particular as chemical gametocides, to compositions for regulating the growth of plants containing these compounds as as active substances and to methods making it possible to act on the growth of plants with these compounds and compositions.

The licensee has found a new class of chemical compounds that can be used as plant growth regulators and in particular as chemical gametocides in cereal seeds. These compounds are 2-pyridones corresponding to the formula

* 3

(i)

in which

R1 represents an alkyl group,

R2 represents a carboxy group optionally in the form of a salt acceptable for agronomic use, or a carbalkoxy group, R3 represents a hydrogen atom or an alkyl group, R4 represents a hydrogen atom, an alkyl group or an atom halogen, and R5 represents an optionally substituted aryl group.

2. Compounds according to claim 1, characterized in that: R1 represents a C1-C4 alkyl group,

R2 represents a carboxy group optionally in the form of a salt acceptable for agronomic or carbohydrate use (C1-C4 alkoxy), R3 represents a hydrogen atom or a C1-C4 alkyl group, R4 represents a hydrogen, a C1-C4 alkyl group or a halogen atom, and R5 represents a phenyl group, a naphthyl group or a phenyl group carrying one or two identical or different substituents chosen from halogen atoms, alkyl groups containing Cl-C4, C1-C4 alkoxy, trifluoromethyl and nitro.

3. Compounds according to claim 2, characterized in that R2 represents a carboxy group optionally in the form of a salt acceptable for agronomic use.

4. Compounds according to claim 3, characterized in that R1 is a methyl group and R4 is a hydrogen atom.

5. Compounds according to claim 4, characterized in that R3 is a methyl group.

6. Compounds according to claim 5, characterized in that R5 is a phenyl group substituted by a halogen.

7. Compounds according to claim 6, characterized in that R5 is a halophenyl group in position 4.

8. Compounds according to claim 4, characterized in that R3 represents a hydrogen atom.

9. Compounds according to claim 3, characterized in that R1 represents a methyl group and R4 a halogen atom.

10. Compounds according to claim 9, characterized in that R3 represents a methyl group.

11. Compounds according to claim 10, characterized in that R4 represents bromine.

12. Composition for regulating plant growth, characterized in that it contains a compound according to one of claims 1 to 11 and a vehicle acceptable for agricultural use.

13. Process for inhibiting the growth of plants, the process being characterized in that an effective amount of a compound according to one of claims 1 is applied to plants, to seeds of plants or to plant habitat. 11.

14. Method according to claim 13, characterized in that the plants are cereals.

15. The method of claim 14, characterized in that the compound is applied to plants before meiosis in an amount effective to cause sterility of males in plants.

25 in which

R1 represents an alkyl group, preferably C1-C4, R2 represents a carboxy group (—COOH) optionally in the form of a salt acceptable for agronomic use, or a carbalkoxy group (—COOR, R being an alkyl group of preferably in Cl-30 C12 or better still in C1-C4),

R3 represents a hydrogen atom or an alkyl group, preferably C1-C4,

R4 represents a hydrogen atom, a preferably C1-C4 alkyl group or a halogen atom, preferably a bromine or choler atom, and

R5 represents an optionally substituted aryl group, preferably an optionally substituted phenyl group or an optionally substituted naphthyl group.

In a preferred embodiment of the invention, R1 represents a methyl group, R2 represents a carboxy group optionally in the salt state, R3 represents a hydrogen atom or a methyl group, R4 represents a hydrogen atom or halogen and R5 represents a substituted phenyl group.

When the carboxy group represented by R2 is in the salt state, the cation may consist of an alkali metal, an alkaline earth metal or a transition metal. However, it can also be an optionally substituted ammonium cation. Among the metal cations which are suitable, mention will be made of alkali metal cations such as sodium, potassium, lithium and the like, cations of alkaline earth metals such as calcium, magnesium, barium, strontium and analogous metals, and heavy metal cations such as zinc, manganese, copper in the cuprous or cupric state, iron in the ferrous or ferric state, titanium, aluminum and the like cations. Among the ammonium salts, mention will be made of those 55 in which the ammonium cation corresponds to the formula NZ * Z2Z3Z4, each of the symbols Z1, Z2, Z3 and Z4 representing, independently of the others, a hydrogen atom, a hydroxy group, a C1-C4 alkoxy group, a C1-C20 alkyl group, a C3-C8 alkenyl group, a C3-C8 alkynyl group, a C2-C8 hydroxyalkyl group, a C2-C8 alkoxyalkyl group, a C2-C6 aminoalkyl group, C2-C6 haloalkyl group, optionally substituted phenyl group, optionally substituted phenylalkyl group containing up to 4 carbon atoms in the alkyl moiety, amino group optionally bearing alkyl-65 substituents the, or alternatively any two of the symbols Z1, Z2, Z3 and Z4, taken together, can form, with the nitrogen atom, a 5- or 6-membered heterocyclic ring containing, where appropriate, another hetero atom oxygen, nitrogen or sulfur in the cycle, and preferably

3

635,324

saturated resin, for example a piperidine ring, morpholine, Pyrrolidine, piperazine or the like; or alternatively any three of the symbols Z1, Z2, Z3 and Z4, taken together, can form with the nitrogen atom a heteroaromatic ring with 5 or 6 members, for example a pyrazole or pyridine ring. When the ammonium group bears a substituted alkyl, substituted phenyl or substituted phenylalkyl group, the substituents are generally chosen from halogen atoms, C1-C8 alkyl, C1-C4 alkoxy, hydroxy, nitro, trifluoromethyl , cyano, amino, C1-C4 alkylthio and the like. These substituted phenyl groups preferably contain up to two such substituents. As particular examples of ammonium cations, mention will be made of unsubstituted ammonium cations, dimethylammonium, 2-ethylhexylammonium, bis (2-hydroxyethyl) -ammonium, tris- (2-hydroxyethyl) ammonium, dicyclohexylammonium, t-octylammonium, 2-hydroxyethylammonium , morpholinium, piperidinium, 2-phenethylammonium, 2-methylbenzylammonium, n-hexylammonium, triethylammonium, trimethylammonium, tri (n-butyl) ammonium, methoxyethylammonium, diisopropylammonium, pyridinium, diallylammonium, pyrazolium, propargylammonium, dimethylammonium ammonium , octadecylammonium, 4-dichlorophenylammonium, 4-nitrobenzylammonium, benzyltrimethylammonium, 2-hydroxyethyldimethyloctadecylammonium, 2-hydroxyethyldiethyl-octylammonium, decyltrimethylammonium, hexyltriethylammo-nium, 4-methylbenzyl.

Among the substituents which are identical or different from the aryl group represented by R5, mention may be made of alkyl groups, preferably of C 1 -C 4 groups, aryl groups, preferably of optionally substituted phenyl groups, preferably of C 1 -C 4 alkyloxy groups, groups optionally substituted phenoxy, halogen atoms, for example fluorine, chlorine, bromine and iodine, nitro, perhaloalkyl groups such as trifluoromethyl, alkoxyalkyl, preferably C1-C6, alkoxyalkoxy, preferably C1- C6, amino, alky-lamino or dialkylamino preferably containing up to 4 carbon atoms in each of the alkyl, cyano, carboxy, car-balcoxy substituents preferably containing up to 4 carbon atoms in the alkoxy, carbamoyl, alkyl part - or dialkylcarbamoyles preferably containing up to 4 carbon atoms in each of the alkyl, sulfo, sulfonamido, alkylcarbonyl or carboxyalky substituents, preferably containing them up to 4 carbon atoms in the alkyl, alkanoyloxy part preferably containing up to 4 carbon atoms, haloalkyls, alkanoylamido, preferably C1-C4, alkylthio, preferably C1-C4, alkylsulfinyls, preferably C1-C4, alkylsulfonyles, preferably in C1-C4 and the like. Generally, R5 will carry up to two substituents. The most preferred substituents are halogen atoms, at least one in position 4, C1-C4 alkyl groups, preferably a methyl group in position 4, C1-C4 alkoxy groups, preferably a methoxy group. position 4, trifluoromethyl groups, preferably in position 4 and nitro groups, preferably in position 4.

As specific examples of compounds corresponding to formula I, the following will be cited:

N- (4-chlorophenyl) -5-carboxy-4,6-dimethylpyrido-2-one

N- (3-chlorophenyl) -5-carboxy-4,6-dimethylpyrido-2-one

N- (4-bromophenyl) -5-carboxy-4,6-dimethylpyrido-2-one

N- (2-chlorophenyl) -5-carboxy-4,6-dimethylpyrido-2-one

N- (4-iodophenyl) -5-carboxy-4,6-dimethylpyrido-2-one

N- (2-fluorophenyl) -5-carboxy-4,6-dimethylpyrido-2-one

N- (4-trifluoromethylphenyl) -5-carboxy-4,6-dimethylpyrido-2-one

N- (4-methoxyphenyl) -5-carboxy-4,6-dimethylpyrido-2-one

N- (3-nitrophenyl) -5-carboxy-4,6-dimethylpyrido-2-one

N- (4-cyanophenyl) -5-carboxy-4,6-dimethylpyrido-2-one

N- (4-chlorophenyl) -5-carboxy-6-methylpyrido-2-one

N- (4-nitrophenyl) -5-carboxy-6-methylpyrido-2-one

N- (4-cyanophenyl) -5-carboxy-4,6-dimethylpyrido-2-one

N- (3-ethoxyphenyl) -5-carboxy-6-methylpyrido-2-one

N- (4-methylphenyl) -5-carboxy-6-methylpyrido-2-one

N- (3,4-dichlorophenyl) -5-carboxy-6-methylpyrido-2-one N- (4-methyl-3-chlorophenyl) -5-carboxy-6-methylpyrido-2-one N- (4-chlorophenyl ) -5-carboxy-3,4,6-trimethylpyrido-2-one N- (4-bromophenyl) -5-carboxy-4,6-diethylpyrido-2-one 5 N- (4-chlorophenyl) -5-carboxy -4,6-diethylpyrido-2-one N- (4-bromophényI) -5-carboxy-4,6-dipropylpyrido-2-one N- (4-chlorophenyl) -5-carboxy-4-ethyl-6-methylpyrido -2-one N- (4-trifluoromethylphenyl) -5-carboxy-6-ethyl-4-methylpyrido-2-one io N- (4-chlorophenyl) -5-carboxy-6-ethylpyrido-2-one N- ( 4-bromophenyl) -5-carboxy-6-propylpyrido-2-one N- (4-chlorophenyl) -5-carboxy-3,6-dimethylpyrido-2-one N- (4-trifluoromethylphenyl) -5-carboxy-3 , 6-dimethylpyrido-2-one N- (4-bromophenyl) -5-carboxy-6-methylpyrido-2-one 15 N- (3,4-dichlorophenyl) -5-carboxy-4,6-dimethylpyrido-2- one N- (2-chloro-4-methylphenyl) -5-carboxy-4,6-dimethylpyrido-2-one 3-bromo-N- (4-chlorophenyl) -5-carboxy-4,6-dimethylpyrido-2- one 3-bromo-N- (4-fluorophenyl) -5-carboxy-4,6-dimethylpyrido-2-one 3-chloro-N- (2,4-dichlorophenyl ) -5-carboxy-4,6-dimethylpyrido-2-20 one

3-fluoro-N- (3-chlorophenyl) -5-carboxy-4,6-dimethylpyrido-2-one

3-bromo-N- (4-trifluoromethylphenyl) -5-carboxy-6-methylpyrido-2-

one and the salts of these acids acceptable for agronomic use, 25 N- (4-chlorophenyl) -5-carbomethoxy-4,6-dimethylpyrido-2-one N- (4-fluorophenyl) -5-carbethoxy-4, 6-dimethylpyrido-2-one N- (3-methylphenyl) -5-carbobutoxy-4,6-dimethylpyrido-2-one N- (3,4-dichlorophenyl) -5-carbethoxy-6-methylpyrido-2-one N -phenyl-5-carbomethoxy-6-methylpyrido-2-one. The compounds of formula I can be prepared by methods known and described in the prior art literature for the preparation of analogous compounds. Suitable preparation methods are given below: in the first method, an acid chloride corresponding to the formula is condensed

35

R-

R

H

\

(he)

COC1

in which R6 represents a hydrogen atom or an alkyl group and R3 has the meanings indicated above, with an enamine 45 corresponding to the formula

R1

^ (ni)

R0oC

d ■

H

NHR-

in which R, R1 and R5 have the meanings indicated above; a dihydropyridone corresponding to the formula is obtained

R

0

(IV)

in which R, R1, R3, R5 and R6 have the meanings indicated above.

635324

4

This reaction is generally carried out in an inert solvent such as ethyl ether, methylene chloride, benzene or toluene, at a temperature of 0 to 100 ° C. The dihy-dropyridone is then subjected to dehydrogenation in the presence of a dehydrogenating agent such as 2,3-dichloro-5,6-dicyano-1,4-benzoquinone or a similar quinone, palladium on carbon or N -bromosuccinimide. The dehydrogenation reaction is generally carried out in an inert solvent such as benzene, xylene or chlorobenzene and at a temperature of 50 to 250 ° C; it gives a pyridone corresponding to the formula

> 3

, 6 COpR

(V)

in which R, R1, R3, Rs and R6 have the meanings already indicated. The ester can then be converted to the corresponding acid or to a salt of this acid by hydrolysis of the conventional type, for example using sodium or potassium hydroxide or a similar base, at room temperature or at a temperature of up to 100 ° C.

In a second process for preparing the compounds according to the invention, a pyrone corresponding to the formula r3 is reacted

0

(VI)

in which R, R1 and R3 have the meanings indicated above, with an amine corresponding to the formula

NH2 — Rs

(VII)

in which Rs has the meanings already indicated.

This reaction is generally carried out in the presence of an acid catalyst such as p-toluenesulfonic acid, methanesulfonic acid, hydrochloric acid or sulfuric acid in an inert solvent such as chlorobenzene, toluene, xylene or eumene, or in a reaction medium consisting of 50% aqueous acetic acid; we obtain a pyridone corresponding to the formula

R "

20

co2r

(VIII)

In which R, R1, R3 and Rs have the meanings indicated above. The reaction is generally carried out at a temperature of 50 to 250 ° C. The free acid and its salts can then be prepared by conventional techniques.

The compounds corresponding to formula I in which R4 represents a halogen atom can be prepared by reaction of the corresponding 4-pyridones in which R4 is a hydrogen atom with a halogenating agent such as bromine, chlorine, sulfuryl bromide or sulfuryl chloride. This reaction is generally carried out in a suitable inert solvent such as methylene chloride or methanol and at a temperature of 0 to 100 ° C.

A list of illustrative compounds corresponding to formula I can be found in Table I, with their melting points and the results of the elementary analyzes.

Table 1

4-C1 4-C1 H

Elementary analysis (calculated: higher figures;

found: lower numbers)

Y

R

mp (° C)

VS

H

NOT

X

H

H

358-9

60.55

4.36

5.06

12.77

60.85

4.42

4.99

13.07

H

N / A

> 300

56.10

3.70

4.67

11.83

55.29

3.78

4.73

11.65

H

H

250-1

69.12

5.39

5.76

-

69.57

5.40

5.61

-

5

Table 1 (continued)

635324

Elementary analysis (calculated: higher figures;

found: lower numbers)

Compound No.

X

Y

R

m.p. CC)

VS

H

NOT

X

4

H

H

N / A

> 300

63.39 61.54

4.56 4.78

5.28 5.18

-

5

4-CH3

H

H

238-40

70.02 70.14

5.88 6.02

5.45 5.29

-

6

4-CH3

H

N / A

> 300

64.51 63.45

5.05 5.18

5.02 5.09

-

7

3,4-diCl

H

H

276-7

53.87 54.02

3.55 3.54

4.49 4.32

22.72 22.68

8

3,4-diCl

H

N / A

296-7

50.32 45.25

3.02 3.17

4.19 4.05

21.22 21.40

9

4-F

H

H

260-1

64.36 63.89

4.63 4.59

5.36 5.53

7.27 7.07

IO

4-F

H

N / A

> 300

59.36 58.83

3.92 3.88

4.95 5.03

6.71 4.95

11

3-C1

H

H

254-5

60.55

4.36

5.04

12.77

60.03

4.31

5.05

13.63

12

3-C1

H

N / A

> 300

56.10

3.70

4.67

11.83

53.57

3.75

4.46

11.45

13

4-CH3, 3-C1

H

H

247-51

61.75 61.61

4.84 4.88

4.80 5.27

12.16 12.24

14

4-CH3, 3-C1

H

N / A

> 300

54.29 54.88

4.56 4.28

4.22 4.39

10.66 11.05

15

4-OCH3

H

H

219-21

65.92 65.52

5.53 5.39

5.13 5.18

-

16

4-OCH3

H

N / A

295-8

-

-

-

-

17

4-CF3

H

H

230-2

57.88

3.89

4.50

18.31

58.31

3.93

4.66

18.04

18

4-CF3

H

N / A

> 300

-

-

-

19

4-Br

H

H

244-6

52.19 52.67

3.76 3.85

4.35 4.60

24. IF

24.84

20

4-Br

H

N / A

> 300

-

-

-

-

21

4-C1 naphthyle

H

H

264-6

65.96 65.68

4.31 4.27

4.27 4.41

10.82 11.03

22

4-C1 naphthyle

H

N / A

> 300

-

-

-

-

23

4-C1

Br

H

243-6

47.14 47.65

3.11 3.13

3.93 4.29

24

4-C1

Br

N / A

> 220

-

-

-

25

4-Br

Br.

H

248-50

41.92 42.06

2.77 2.72

3.49 3.91

39.85 40.33

26

4-Br

Br

N / A

290

-

-

-

-

27

4-Br

H

C2H5

129-30

H

54.87 54.97

4.61 4.69

4.00 3.98

22.82 23.33

0 ^

1 5

28

4-C1

H

H

271-73

59.21 59.17

3.82 3.76

5.31 5.71

13.45 '13.49

635324

6

The following examples illustrate the invention without, however, limiting it; in these examples, the parts and percent indications are by weight unless otherwise stated.

Example 1:

Preparation of N- (4-chlorophenyl) -5-carboxy-4,6-dimethylpyrido-2-one.

(Compound 1 table).

a) 48.4 g of 4-chloraniline, 4.7 g of p-toluenesulfonic acid and 65 g of ethyl isodehydracetate are suspended in 260 ml of eumene. It is brought to reflux by collecting the water in a Dean-Stark trap. 18 h later, the reaction mixture is cooled and washed with dilute hydrochloric acid which removes excess 4-chloraniline. The eumene is removed under vacuum; the residue obtained is crude 5-carbethoxy-N- (4-chlorophenyl) -4,6-dimethylpyrido-2-one in the form of a dark brown oil.

b) The crude ester obtained in a above is suspended in a solution obtained by mixing 500 ml of methanol, 500 ml of water and 50 g of 50% sodium hydroxide solution. The suspension is brought to reflux for 6 h. The solvent is removed in vacuo and replaced with 11 of water. The insoluble substance is filtered and discarded. The clear aqueous layer is acidified with hydrochloric acid; the precipitate is filtered and dried; 55 g of the desired compound are obtained after recrystallization from acetone, which can also be called N- (4-chlorophenyl) -4,6-dimethylpyrido-2-one-5-carboxylic acid, melting at 258-259 ° C (dec.).

Example 2:

Preparation of N- (4-bromophenyl) -5-carboxy-4,6-dimethylpyrido-2-one.

(Compound 19 of Table 1).

20 g (0.102 mol) of ethyl dehydracetate and 19.3 g (0.112 mol) of 4-bromaniline are dissolved in 100 ml of 50% aqueous acetic acid. The mixture is refluxed for 12 h, the solvent is removed and the crude ester is isolated in the form of a brownish oil.

This crude ester is heated for 6 h with 300 g of 5% sodium hydroxide in a methanol / water mixture in equal parts. It is cooled, diluted with 100 ml of water and the insolubles are filtered. Part of the methanol is removed in vacuo and water is added. The clear basic solution is acidified, the precipitate is filtered and dried. Recrystallization from acetonitrile gives pure N- (4-bromophenyl) -5-carboxy-4,6-dimethylpyrido-2-one with a yield of 5.3 g, or 16.1%, and a melting point from 244-246 ° C (dec.).

Example 3:

Preparation of N- (4-bromophenyl) -3-bromo-5-carboxy-4,6-dimethylpyrido-2-one.

(Compound 25 in Table 1).

285 g (0.00828 mol) of N- (4-bromophenyl) -4,6-dimethylpyrido-2-one-5-carboxylate are dissolved in 50 ml of dry methanol. Furthermore, 1.59 g (0.00994 mol, 1.2 Eq) of bromine is dissolved in 50 ml of methanol and added slowly, drop by drop, to the salt solution, with vigorous stirring, in 15 to 20 min. The solvent is removed and the residue is taken up in a dilute base.

After filtration of the insoluble material, the clear basic aqueous solution is acidified with hydrochloric acid. The precipitate is filtered, dried and recrystallized from acetonitrile; 2.25 g, or 67.8%, of N- (4-bromophenyl) -3-bromo-5-carboxy-4,6-dimethylpyrido-2-one are obtained, melting at 248-250 ° C.

Example 4:

Preparation of N- (4-chlorophenyl) -5-carboxy-6-methylpyrido-2-one.

(Compound 28 in Table 1).

a) 23.9 g of ethyl β-anilinocrotonate are dissolved in 200 ml of dry benzene and placed in a flask in a nitrogen atmosphere. 10 g of acryloyl chloride are further dissolved in 200 ml of dry benzene and the solution is added dropwise using a dropping funnel at 1% h. It is left to stand for 1 hour at approximately 25 ° C., then it is poured into water and extracted with methylene chloride. Evaporation of the solvent gives 23.3 g of 5-carbethoxy-N- (4-chlorophenyl) -6-methyl-3,4-dihydropyrido-2-one, melting at 124-126 ° C after recrystallization from a mixture hexane / ether.

b) 15 g of the ester obtained in a above are dissolved in 500 ml of chlorobenzene. 23.2 g of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) are added and the mixture is brought to reflux for 3 h. The mixture is cooled, filtered and diluted with an equal volume of methylene chloride and washed until exhaustion with a dilute aqueous solution of sodium bicarbonate. The solvent is removed in vacuo and the crude product residue is recrystallized from a hexane / ether mixture; we obtain

8.3 g of 5-carbethoxy-N- (4-chlorophenyl) -6-methylpyrido-2-one, melting at 53-54 ° C.

c) 7.0 g of the pyridone obtained in b above is suspended in 200 ml of 5% sodium hydroxide solution. The mixture is heated in a water bath for 1 h, cooled and acidified with aqueous hydrochloric acid; 4.0 g of N- (4-chlorophenyl) -5-carboxy-6-methylpyrido-2-one are obtained which, after recrystallization from acetonitrile, melts at 271-273 ° C (dec.).

The compounds corresponding to formula I are of particular interest as chemical gametocides of cultivated cereals such as wheat, barley, corn, rice, sorghum, millet, oats, rye and similar cereals . When used as chemical gametocides, the compounds effectively cause high sterility of the treated plants without appreciable inhibition of their growth. The compounds of formula I also elicit growth-regulating responses in other plants; thus, for example, they inhibit the formation of seeds of undesirable monocotyledonous species, which makes it possible to fight against weeds, to control flowering, to control the formation of fruits and to inhibit the formation of seeds of species other than the cereals; they also control maturation and cause other related growth-regulating responses.

For use as plant growth regulators, the compounds of formula I are applied in any dose to elicit the desired plant response, without undesirable or phytotoxic side effects. Thus, for example, when they are used as chemical gametocides, they are generally applied to the plants to be treated at doses of about 16 g to 22 kg / ha and preferably about 60 g to 11 kg / ha. The application dose varies according to the plant species treated, the compound used for the treatment and other similar factors.

A preferred procedure for applying a compound of formula I as a plant growth regulator is by application to the leaves. With this procedure, gametocidal activity appears under the most effective conditions when the compound is applied before meiosis and preferably after flowering. The compounds of formula I can also be used in the treatment of seeds by soaking the latter in a liquid composition containing the active compound or by applying the coating compound to the seeds. For the treatment of seeds, the compounds are generally applied at a dose of about 0.25 to 10 kg / 100 kg of seeds. The compounds according to the invention can also be used for the treatment of the soil or, in the case of rice fields, on the surface of the water.

The compounds corresponding to formula I can be used as regulators of plant growth individually or in the form of mixtures. Thus, for example, they can be used in combination with other plant growth regulators such as auxins, gibberellins, morphactins, ethylene releasing agents such as Ethephon, pyridones, cytokini- nes, maleic hydrazide, 2,2-dimethylhydrazide of succinic acid, choline and its salts, (2-chlorethyl) trimethyl ammonium chloride, triiodobenzoic acid, tributyl-2 chloride , 4-dichlorobenzylphosphonium, N-vinyl-2-oxazolidinones polymers, trisdimethylaminoethyl phosphate and its salts, N-dimethylamino-l, 2,3,6-tetrahydrophthalamic acid and its salts, 2,3- acid

5

10

15

20

25

30

35

40

45

50

55

60

65

7

635,324

dichlorisobutyric acid and its salts and 3- (4-chlorophenyl) -6-methoxy-s-triazine-2,4- (1H, 3H) -dione. Under certain conditions, the compounds of formula I can be advantageously used with other agricultural chemicals such as herbicides, fungicides, insecticides and bactericides for plants. 5

A compound of formula I can be applied to the culture medium or to the plants to be treated as such or, more generally, as a component of a growth regulation product which also contains an acceptable vehicle for agronomic use. This expression is understood to mean any substance used to dissolve, disperse or cause a compound to diffuse in the composition without reducing its effectiveness, this substance having by itself no disturbing effect on the ground, the equipment, the crops or the agronomic environment. In these compositions, it is also possible to use mixtures of the compounds of formula I. The compositions in question may be in the form of solids, liquids, optionally solutions. Thus, for example, the active compounds can be put in the form of wettable powders, emulsifiable concentrates, dust, granular products, aerosols or concentrates in fluid emulsions. In such compositions, the active compounds are diluted by a liquid or solid vehicle and, if desired, suitable surfactants can be introduced.

Details of suitable compositions for these products and other details valid in the present invention can be found in patent application No. 2512 / 78-8 of 8.3.1978. 25

The compounds of formula I can be applied as a spray by standard techniques, for example in the form of hydraulic sprays, aerial sprays and dust.

For small volume applications, a solution of the active compound is usually used. The dilution and volume applied usually depend on factors such as the type of apparatus used, the mode of application, the area to be treated, the type and stage of development of the crop to be treated.

The results reported in Table 2 illustrate the gamedoxy activity of typical compounds of formula I; these results were obtained by the following procedure:

A beard variety (Fielder) and a beardless variety (Mayo-64) of spring wheat were sown with 6 to 8 seeds per pot of

15 cm containing a sterile medium itself consisting of 3 parts of soil and 1 part of humus. Plants grow during a short daytime period (9 hrs) for the first four weeks to obtain good vegetative growth before flowering. The plants are then cultivated under long day conditions (16 h) carried out using high intensity lamps in the greenhouse. We put fertilizer the 2nd, 4th and 8th week after sowing (fertilizer with 16% of N, 25% of P and 15% of K at the rate of approximately 1.2 ml / l of water) and water is frequently sprayed with the commercial insecticide Isotox to control mites; moreover, sulfur is used to avoid powdery mildew.

The compounds subjected to the tests are applied to the leaves of female plants with beards when the plants reach the emergence stage of the hanging leaf (stage 8 of the Feeke scale). All the compounds are applied at a vehicle volume of 4001 / ha, at a dose of 30 g / 1001; the vehicle contains a surfactant such as the commercial product Triton X-100.

After emergence of the ear but before meiosis, we enclose 4 to 6 ears per pot in sachets to avoid external crossing. At the first signs of the opening of the flower, we submit two ears per pot to cross-pollination, according to the approach method, with the male parent without beard. As soon as the seeds become clearly visible, measure the length of the ear and count the number of seeds per spicule both in the ears protected by sachets and in the crossed ears. The sterility of the males is then calculated as% inhibition of germination in the ears enclosed in sachets of the treated plants. After maturity, the seed of the crossed ears can be planted for% hybridization determination.

The sterility% is calculated from the following formula:

S - S

Sterility% = - x 100, in which

Se

Sc = seeds / spicule in the ears of the control plants enclosed in sachets.

St = seeds / spicule in the ears of the treated plants enclosed in sachets.

Typical results obtained with the compounds of formula I are shown in Table 2. A dash indicates that a test was not carried out at the dose indicated.

10

15

Table 2

CH3

Y \ ^ \ / - 002H

x r

è: S

X

Dose (kg / ha)

Sterility (%)

X

Y

R

OO OO

4.4

2.2

1.1

0.55

0.27

0.13

4-C1

H

H

100

100

100

96

-

-

-

4-C1

H

N / A

100

100

100

100

92

52

-

H

H

H

22

0

4

6

-

-

-

H

H

N / A

46

0

13

8

-

-

-

4-CH3

H

H

21

0

0

14

13

12

.2

4-CH3

H

N / A

0

0

0

14

11

2

3

3,4-diCl

H

H

98

93

80

12

20

16

12

635,324

8

Table 2 (continued)

Dose (kg / ha)

Sterility (%)

X

Y

R

OO OO

4.4

2.2

1.1

0.55

0.27

0.13

3,4-diCl

H

N / A

96

91

33

22

25

21

4

4-F

H

H

0

0

0

9

0

24

13

4-F

H

N / A

0

0

0

2

7

18

15

3-C1

H

H

4

0

0

0

3

3

2

3-C1

H

N / A

0

2

0

-

-

-

-

4-CH3,3-C1

H

H

6

4

0

19

0

-

-

4-CH3,3-C1

H

N / A

0

2

1

0

1

6

-

4-OCH3

H

H

56

18

2

9

-

-

-

4-OCH3

H

N / A

54

31

0

3

-

-

-

4-CF3

H

H

15

3

-

-

-

-

-

4-CF3

H

N / A

0

3

0

0

1

-

-

4-Br

H

H

100

100

100

-

-

-

-

4-Br

H

N / A

100

100

100

100

100

100

100

4-C1 naphthyle

H

H

2

-

"-

-

-

-

-

4-C1 naphthyle

H

N / A

14

4

0

0

-

-

-

4-C1

Br

H

9

7

9

16

13

-

-

4-C1

Br

N / A

15

13

13

20

13

-

-

4-Br

Br

H

-

-

-

-

-

-

-

4-Br

Br

N / A

100

99

89

43

25

-

-

4-Br

H

C2H5

100

-

100

100

-

100

H

Y

\

O O

R

2

y

"SSsCH_

0 N

3

'x

4-C1

H

H

100

88

49

19

-

-

-

4-C1

H

N / A

100

100

90

39

-

-

-

A particular embodiment of the invention resides in a process for improving, by hybridization, the commercial value of seeds for the production of cereals, this process being characterized in that: 1) a composition is introduced into a mechanical dissemination device of hybridization containing at least one compound of formula I accompanied by a vehicle acceptable for agronomic use, 2) the device is used to apply in the state of dust or of liquid spraying the hybridization composition to the foliage of plants male and female cereals before meiosis, which causes male sterility, 3) the parent treated under these conditions is pollinated using pollen from a male parent of the cereal seed, making it possible to give a hybrid, 4) the pollinated parent is left to mature until the seeds form, and 5) the ripe seeds are harvested.