FR2660308A1 - New sulphur-containing derivatives of 5,6-dihydro-2-methyl-4-[3-(trifluoromethyl)phenyl]-2H-1,2,4-oxadiazin- 3(4H)-one, process for their preparation and the intermediates in this process, their application as herbicides and the compositions containing them - Google Patents

Abstract

The invention relates to the products of formula (I): in which n is equal to 0, 1 or 2 and R represents a substituted or unsubstituted, saturated or unsaturated, cyclic or acyclic hydrocarbon radical containing from 1 to 14 carbon atoms, it being understood that when n is equal to 0, R cannot represent an unsubstituted, saturated, acyclic hydrocarbon radical containing from 1 to 4 carbon atoms, to the process for their preparation and to their use as herbicides.

Description

 The present invention relates to novel 5,6-dihydro-2-methyl-4- [3- (trifluoromethyl) phenyl) -2H-1,2,4-oxadiazin-3 (4H) -one derivatives having a radical -S in the 4-position of phenyl. (O) -R their process of preparation and the intermediates of this process, their application as herbicides and the compositions containing them.

dans laquelle n est égal à 0, 1 ou 2 et R représente un radical hydrocarboné cyclique ou acyclique, saturé ou insaturé, substitué ou non substitué et renfermant de un à quatorze atomes de carbone, étant entendu que lorsque n est égal à O, R ne peut pas représenter un radical hydrocarboné acyclique, saturé et non substitué renfermant de un à quatre atomes de carbone.The subject of the invention is the products of formula (I)

in which n is 0, 1 or 2 and R is a saturated or unsaturated, substituted or unsubstituted, cyclic or acyclic hydrocarbon radical containing from one to fourteen carbon atoms, it being understood that when n is 0, R can not represent a saturated and unsubstituted acyclic hydrocarbon radical containing one to four carbon atoms.

 By cyclic hydrocarbon radical, saturated or unsaturated, substituted or unsubstituted, is meant mainly cycloalkyl, cycloalkenyl, cycloalkadienyl or aryl optionally substituted by one or more alkyl radicals, haloalkyl, polyhaloalkyl, alkyloxy, (haloalkyl) oxy, (polyhaloalkyl) ) oxy, alkylthio, (haloalkyl) thio, (polyhaloalkyl) thio or alkoxycarbonyl.It is preferentially cyclopropyl, cyclopentyl, cyclohexyl, 2-isopropyl 5-methylcyclohexyl, 1-cyclopentenyl, 2 -cyclopentenyl, 1-cyclohexenyl radicals. 2-cyclohexenyl, 1,3-cyclopentadienyl, 1,3-cyclohexadienyl, 1,4-cyclohexadienyl, phenyl, 2-bromo phenyl, 4-bromo phenyl, 2-chloro-phenyl, 4-chloro-phenyl, 2-fluoro-phenyl, 4-Fluoro phenyl, 2-methylphenyl, 4-methylphenyl, 3-methylphenyl, 2,4-dichlorophenyl, 2,6-dichlorophenyl, 3,4-dichlorophenyl, 2,4-dibromo phenyl, 2,4, 5-trichlorophenyl, 3,5-dimethyl phenyl, 2-methyl-4-chlorophenyl, 3-methyl-4-chlorophenyl, 4-methyl-3- (trifluoromethyl) phenyl, 3- (trifluoromethyl) phenyl, 4-methoxyphenyl, 4-difluoromethoxy) phenyl, 4-chloro 3 , 5-dimethoxyphenyl, 2-chloro-5-methoxyphenyl, 4- (methylthio) phenyl, 3-methyl-4- (methylthio) phenyl or 3-ethoxycarbonylphenyl.

 When R represents a saturated or unsaturated, substituted or unsubstituted acyclic hydrocarbon radical, it may be linear or branched; it is in particular an alkyl radical containing from one to eight carbon atoms, an alkenyl radical containing from two to eight carbon atoms, an alkynyl radical containing from two to eight carbon atoms or a alkadienyl radical containing from three to eight carbon atoms.

 When it is an alkyl radical containing from one to four carbon atoms, R is necessarily substituted when n is equal to zero; in other cases, R may be unsubstituted or substituted.

 The substituent or substituents R may carry are preferably chosen, independently of one another, from fluorine, bromine, chlorine or iodine atoms, or hydroxy, carboxy, methylsulfonyloxy, phenylsulfonyloxy, ortho, meta or para tolylsulfonyloxy groups. alkyloxy containing one to three carbon atoms linear or branched and optionally substituted by one or more atoms selected from chlorine, bromine or iodine fluorine atoms, alkylthio containing from one to three carbon atoms, linear or branched and optionally substituted by one or more atoms chosen from fluorine, chlorine, bromine or iodine atoms, alkoxycarbonyl containing from two to five carbon atoms, cycloalkyl containing from three to eight carbon atoms and optionally substituted with one or several groups chosen from fluorine, bromine or chlorine atoms or linear or branched alkyl radicals containing from one to three carbon atoms and optionally substituted by one or more chlorine, fluorine, bromine or iodine atoms, cycloalkenyl containing from five to eight carbon atoms and optionally substituted by one or more groups selected from halogen atoms or alkyl radicals, linear or branched and containing one to three carbon atoms, cycloalkadienyl containing from five to eight carbon atoms and optionally substituted by one or more groups selected from halogen atoms or linear or branched alkyl radicals and containing from one to three carbon atoms, phenyl optionally substituted by one or more groups chosen from fluorine, chlorine, bromine or iodine atoms or alkyl radicals containing from one to four linear or branched carbon atoms and optionally substituted with one or more fluorine, chlorine, bromine or iodine atoms, hydroxy, carboxy, methylsulfonyloxy, phenylsulfonyloxy, ortho, meta or para tolylsulfonyloxy, alkyloxy containing from one to three carbon atoms linear or branched and optionally substituted by one or more atoms chosen from chlorine, bromine or iodine fluorine atoms, alkylthio containing from one to three carbon atoms , linear or branched and optionally substituted by one or more atoms chosen from fluorine, chlorine, bromine or iodine atoms, alkoxycarbonyl containing from two to five carbon atoms, or isolated, fused or bridged heterocyclic groups, comprising from one to four heteroatoms selected from sulfur, oxygen or nitrogen atoms and optionally substituted, such as 2-pyridyl, 3-pyridyl, 4-pyridyl, 5-ethyl-2-pyridyl, 4-methyl-2-methyl, pyridyl, 6-methyl-2-pyridyl, 4,6-dimethyl-2-pyridyl, 2-ethyl-1-oxaspiro (4.5] dec-2-yl, 2-ethyl-1,7-dioxaspiro [4. 5] dec-2-yl or 2,3-dihydro-1,4-benzodioxin-2-yl.

dans laquelle R1 représente un radical hydrocarboné acyclique saturé ou insaturé, renfermant de un à quatre atomes de carbone, pouvant être substitué par un radical phényle, lui-même éventuellement substitué par un ou plusieurs atomes d'halogène, étant entendu que, lorsque n est égale à 0, R1 ne peut pas représenter un radical hydrocarboné acyclique, saturé et non substitué renfermant de un à quatre atomes de carbone.The subject of the invention is particularly the products of formula (I) as defined above and corresponding to formula (I1)

in which R 1 represents a saturated or unsaturated acyclic hydrocarbon radical containing from one to four carbon atoms, which may be substituted by a phenyl radical, itself optionally substituted by one or more halogen atoms, it being understood that when n is equal to 0, R1 can not represent a saturated and unsubstituted acyclic hydrocarbon radical containing from one to four carbon atoms.

 When n is 0, R 1 represents in particular an alkenyl radical such as vinyl, 1-propenyl or 2-propenyl, alkynyl such as 2-propynyl or 2-butynyl, or phenylalkyl such as benzyl or phenethyl, these radicals being optionally substituted by one or more halogen atoms.

 When n is 1 or 2, R 1 represents in particular an alkyl radical such as the methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, isobutyl or tert-butyl radical, an alkenyl radical such as the vinyl radical, propenyl or 2-propenyl, alkynyl such as 2-propynyl or phenylalkyl such as benzyl or phenethyl, these radicals may be optionally substituted with one or more halogen atoms.

 The subject of the invention is more particularly the products of formula (I) as defined above in which n is equal to 1 or 2 and especially those whose names follow - 4- [4- (tert-butylsulfonyl) 3- ( trifluoromethyl) phenyl] 5,6-dihydro-2-methyl-2H-1,2,4-oxadiazin-3 (4H) -one - 5,6-dihydro-2-methyl 4- (4- (propylsulfonyl) -3- (trifluoromethyl) ) phenyl] 2H-1,2,4-oxadiazin-3 (4H) -one - 4- [4- (butylsulfinyl) -3- (trifluoromethyl) phenyl] 5,6-dihydro-2-methyl-2H-1,2,4- oxadiazin-3 (4H) -one - 5,6-dihydro-2-methyl-4- [4- (propylsulphinyl) -3- (trifluoromethyl) phenyl] -2H-1,2,4-oxadiazin-3 (4H) -one - 5,6-dihydro-2-methyl-4- [4 - [(1-methylethyl) sulfonyl] -3 (trifluoromethyl) phenyl] -2H-1,2,4-oxadiazin-3 (4H) -one - 4- [ 4- (Cyclohexylsulfonyl) 3- (trifluoromethyl) phenyl] 5,6-dihydro-2-methyl-2H-1,2,4-oxadiazin-3 (4H) -one - 5,6-dihydro-2-methyl-4- [4- - [(1-methylpropyl) sulfonyl] 3 (trifluoromethyl) phenyl] 2H-1,2,4-oxadiazin-3 (4H) -one - 5,6-dihydro 2-methyl 4- [4 - [(2-propenyl) sulfonyl] 3- (trifluoromethyl) phenyl] 2H-1,2,4-oxadiazin-3 (4H) -one - 5,6-dihydro-2-methyl 4- (4 - ((phenylmethyl) sulfinyl] 3 (trifluoromethyl) phenyl] 2H-1,2,4-oxadiazin-3 (4H) -one.

dans laquelle X représente un atome d'halogène est traité par un thiolate de métal alcalin de formule (III')
R'-S M+ (III') dans lequel M+ représente un cation de métal alcalin et R' a la signification de R telle que définie précédemment lorsque n est égal à un ou deux, pour conduire au produit de formule (IV')

dont soit on oxyde la fonction thioéther pour obtenir selon l'oxydant choisi1 le produit de formule (IVb) ou le produit de formule (IVC) ::

dans lesquelles R a la signification telle que définie précédemment, produit de formule (IVb) ou (IVC) que l'on réduit en amine respectivement, de formule (Vb) ou (Vc)

et transforme après salification, en isocyanate, respectivement de formule (VIb) ou (VIC) :

produit de formule (VIb) ou (VIC) qui par réaction en présence d'une base avec un sel de N-méthyl hydroxylamine de formule (VII)
CH3-NH-OH (VII) conduit respectivement au produit de formule (VIIIb) ou (VIIIC)

produit de formule (VIIIb) ou (VIIIc) qui, traité en présence d'une base et de préférence dans un solvant polaire avec un 1,2-dihalo éthane de formule (IX) ::
Y-CH2 -CH2 -Y (IX) dans laquelle Y représente un atome de chlore ou de brome) conduit respectivement au produit de formule (Ib), correspondant à la formule (I) dans laquelle n est égal à 1, ou au produit de formule (Ic), correspondant à la formule (I) dans laquelle n est égal à 2

soit en réduit la fonction nitro pour obtenir l'amine de formule (V')::

produit de formule (V') qui, en utilisant le procédé de préparation des produits de formule (Ib) ou (Ic) à partir respectivement des amines de formules (Vb) ou (Vc) décrit plus haut conduit successivement aux produits de formule (VI')

The subject of the invention is also a process for the preparation of the products of formula (I), characterized in that the product of formula (II):

in which X represents a halogen atom is treated with an alkali metal thiolate of formula (III ')
R'-S M + (III ') in which M + represents an alkali metal cation and R' has the meaning of R as defined above when n is equal to one or two, to yield the product of formula (IV ')

wherein the thioether function is oxidized to obtain, depending on the chosen oxidant, the product of formula (IVb) or the product of formula (IVC):

in which R has the meaning as defined above, product of formula (IVb) or (IVC) which is reduced to amine respectively, of formula (Vb) or (Vc)

and after salification, isocyanate, respectively of formula (VIb) or (VIC):

product of formula (VIb) or (VIC) which by reaction in the presence of a base with an N-methyl hydroxylamine salt of formula (VII)
CH3-NH-OH (VII) leads to the product of formula (VIIIb) or (VIIIC) respectively

product of formula (VIIIb) or (VIIIc) which, treated in the presence of a base and preferably in a polar solvent with a 1,2-dihaloethane of formula (IX) ::
Y-CH 2 -CH 2 -Y (IX) in which Y represents a chlorine or bromine atom) respectively leads to the product of formula (Ib), corresponding to formula (I) in which n is equal to 1, or to the product of formula (Ic), corresponding to formula (I) in which n is equal to 2

or reduce the nitro function to obtain the amine of formula (V ') ::

product of formula (V ') which, using the method of preparation of the products of formula (Ib) or (Ic) from amines of formulas (Vb) or (Vc) described above respectively, leads successively to the products of formula ( VI ')

produit de formule (I') qui, lorsque R' ne représente pas un radical hydrocarboné acyclique, saturé et non substitué renfermant de un à quatre atomes de carbone, correspond au produit de formule (Ia) et produit de formule (I') qui, si nécessaire est oxydé en sa fonction thioéther pour donner selon l'oxydant utilisé, le produit de formule (I (Ib) ou le produit de formule
L'invention a aussi pour objet des variantes du procédé décrit ci-dessus, caractérisées en ce que soit l'amine de formule (X)

est salifiée puis transformée successivement en produit de formules (XI), (XII) puis (XIII)

et le produit de formule (XIII) est soumis à l'action du thiolate alcalin de formule (III') telle que définie ci-dessus pour obtenir le produit de formule (I') telle que définie précédemment qui si nécessaire, est oxydé en produit de for mule (Ib) ou (Ic), i soit le produit de formule (XIV)

est cyclisé par action d'un dihalo éthane de formule (IX) dans un solvant polaire et en présence d'une base en produit de formule (XV)

produit de formule (XV) quivsoumis à l'action d'un thiol de formule (XVI')
R'SH (XVI') dans laquelle R' a la signification définie précédemment, en présence d'un sel cuivreux, conduit au produit de formule (I') telle que définie précédemment qui, si nécessaire, est oxydé en produit de formule (Ib) ou
Dans un mode d'exécution préféré de ce procédé ou de ses variantes a) le thiolate alcalin de formule (III') est préparé "in situ" ; b) la réduction des dérivés nitrés est opérée soit par hydrogénation catalytique, soit par action du fer en présence d'acide chlorhydrique ou de fer en présence de chlorure d'ammonium et d'eau c) les amines sont salifiés en chlorhydrates d) le réactif de transformation des sels d'amine en isocyanate peut être le phosgène ou le chloroformiate de trichlorométhyle e) les dérivés de l'urée sont préparés par réaction du chlorhydrate de N-méthyl hydroxylamine sur les isocyanates dans un solvant tel que le diméthylformamide ou le chloroforme en présence d'une base azotée comme la triéthylamine ou la diméthylamino pyridine ; f) la réaction de cyclisation en 5,6-dihydro 2H-1,2,4oxadiazine substituée a lieu dans un solvant polaire comme le diméthyl sulfoxyde avec du 1,2-dichloro éthane en présence d'une base comme le carbonate de potassium g) le réactif d'oxydation des thioéthers en sulfoxydes est le périodate de potassium dans le méthanol aqueux h) le réactif d'oxydation des thioéthers en sulfones est un peracide organique comme l'acide 3-chloro perbenzoïque ou le mono peroxyphtalate de magnésium.

product of formula (I ') which, when R' does not represent a saturated and unsubstituted acyclic hydrocarbon radical containing from one to four carbon atoms, corresponds to the product of formula (Ia) and product of formula (I ') which if necessary is oxidized to its thioether function to give, according to the oxidant used, the product of formula (I (Ib) or the product of formula
The subject of the invention is also variants of the process described above, characterized in that either the amine of formula (X)

is salified and then successively transformed into a product of formulas (XI), (XII) then (XIII)

and the product of formula (XIII) is subjected to the action of the alkali thiolate of formula (III ') as defined above to obtain the product of formula (I') as defined previously which, if necessary, is oxidized in product of formula (Ib) or (Ic), i is the product of formula (XIV)

is cyclized by the action of a dihalo ethane of formula (IX) in a polar solvent and in the presence of a base product of formula (XV)

product of formula (XV) quivsubmitted to the action of a thiol of formula (XVI ')
R'SH (XVI ') in which R' has the meaning defined above, in the presence of a cuprous salt, leads to the product of formula (I ') as defined above which, if necessary, is oxidized to a product of formula ( Ib) or
In a preferred embodiment of this process or its variants a) the alkali thiolate of formula (III ') is prepared "in situ"; b) the reduction of the nitrated derivatives is carried out either by catalytic hydrogenation, by the action of iron in the presence of hydrochloric acid or iron in the presence of ammonium chloride and water; c) the amines are salified with hydrochlorides; d) the transformation reagent of the amine salts to isocyanate may be phosgene or trichloromethyl chloroformate e) the urea derivatives are prepared by reaction of N-methylhydroxylamine hydrochloride on isocyanates in a solvent such as dimethylformamide or chloroform in the presence of a nitrogen base such as triethylamine or dimethylamino pyridine; f) the cyclization reaction to substituted 5,6-dihydro-2H-1,2,4-oxadiazine takes place in a polar solvent such as dimethyl sulfoxide with 1,2-dichloroethane in the presence of a base such as potassium carbonate g ) the oxidation reagent of thioethers to sulfoxides is potassium periodate in aqueous methanol; (h) the thioether oxidation reagent to sulfones is an organic peracid such as 3-chloro-perbenzoic acid or magnesium mono-peroxyphthalate.

 Nitrates of formula (II) are commercial products; it is the same for the amine of formula (X), the 1,2-dihalo ethanes of formula (IX), certain thiolates of formula (III ') and certain mercaptans of formula (XVI').

The non-commercial mercaptans of formula (XVI ') can be prepared conventionally by reaction of hydrocarbon halides with sodium hydrogen sulfide (NaSH) ("The
Chemistry of the Thiol Group pt. 1, pp 179-211 and pt. 2, pp. 735-74, John Willey and Sons New York 1974) or by disulfide reduction; (Overman and Coll Synthesis (1974) 59
OSII, 580, OSIV, 295).

 Products of formulas VIa, VIb, VIC, VIIIa, VIIIb, XI, XII, XIII, XIV and XV, it being understood that formulas (VIa) and (VIIIa) respectively correspond to the products of formulas (VI ') and (VIII') in which R 'does not represent a saturated and unsubstituted acyclic hydrocarbon radical containing from one to four carbon atoms, are new and therefore also object of the present invention, as industrial products.

 The subject of the invention is also the use as herbicides of the products of formula (I) as defined above, particularly the use as herbicides of the products of formulas (I1), (I2), (I3) and (I4) and especially the use as herbicides of the following products - 4- (4- (tert-butylsulfonyl) 3- (trifluoromethyl) phenyl] 5,6-dihydro-2-methyl-2H-1,2,4-oxadiazine 3 (4H) -one - 5,6-dihydro-2-methyl-4- [4- (propylsulfonyl) -3- (trifluoromethyl) phenyl] -2H-1,2,4-oxadiazin-3 (4H) -one - 4 - (4- (Butylsulphinyl) -3- (trifluoromethyl) phenyl) -5,6-dihydro-2-methyl-2H-1,2,4-oxadiazin-3 (4H) -one - 5,6-dihydro-2-methyl-4- [4- (propylsulphinyl) 3- (trifluoromethyl) phenyl] 2H-1,2,4-oxadiazin-3 (4H) -one - 5,6-dihydro-2-methyl-4- (4 - ((1-methylethyl) sulfonyl] 3 (Trifluoromethyl) phenyl] 2H-1,2,4-oxadiazin-3 (4H) -one - 4- (4- (cyclohexylsulfonyl) 3- (trifluoromethyl) phenyl] 5,6-dihydro-2-methyl-2H-1 , 2,4-oxadiazin-3 (4H) -one - 5,6-dihydroxy 2-methyl 4- (4 - ((1-methylpropyl) sulfonyl] 3 (trifluoromethyl) phenyl] 2H-1,2,4-oxadiazin-3 (4H) -one - 5,6-dihydro-2-methyl 4- (4 - ((2-propenyl) sulfonyl] -3- (trifluoromethyl) phenyl] -2H-1,2,4-oxadiazin-3 (4H) -one - 5,6-dihydro-2-methyl-4- - ((phenylmethyl) sulfinyl) 3 (trifluoromethyl) phenyl) 2H-1,2,4-oxadiazin-3 (4H) -one.

the framework of use as herbicides of products of formula (I) is in particular the cultivation of cereals such as wheat, barley, oats, rye or corn, or the cultivation of rice, cotton, soybean or sunflower.

 The herbicidal activity of the products of formula (I) has been demonstrated according to a methodology described below. The results show the advantage of using these products either as a total weed killer or as a selective weed killer in the pre- or post-emergence period.

 The present invention finally relates to herbicidal compositions characterized in that they contain as active ingredient, at least one of the products of formula (I) as defined above.

 The compositions according to the invention can be prepared by mixing the active ingredient with an inert filler, and thus be easily applicable by means of usual apparatus.

 It is thus possible to prepare solid compositions in powder form by grinding the active material with finely divided inert fillers such as talcs and clays, bentonite, pumice stone, fulling earth, pyrophillite, silicates, kieselguhr and other solid inert materials customarily used or by impregnating a solid support with a solution of the active ingredient followed by evaporation of the solvent.

 These solid compositions may thus be in the form of dusting powder, wettable powder or granules. The compositions according to the invention may also be in the form of a suspension, an emulsion or a solution, by mixing the active ingredient with a liquid vehicle and / or an anionic, non-ionic or non-ionic surfactant agent ensuring, among other things, uniform dispersion of the substances of compositions. The liquid vehicle may be water, alcohol, hydrocarbons or other organic solvents such as aromatic or ketonic solvents. The proportion of solvent varies from 1 to 90% depending on the solubility of the active ingredient.

 The examples and the biological study described below illustrate the invention without however limiting it.

EXAMPLE 1: 5,6-Dihydro-2-methyl-4- [4 - [(1-methylethyl) sulfonyl] -2- (trifluororethyl) -phenyl-2H-1,2,4-oxadiazin-3 (4H) -one
STAGE A: 1- (Isopropylthio) 4-nitro 3- (trifluoromethyl) benzene
100 g of 1-chloro-4-nitro 2- (trifluoromethyl) benzene are mixed with 300 cm 3 of dimethylformamide and 53 g of isopropyl mercapton; the solution is cooled to -5 ° C. and 31 g of potassium hydroxide, 20 cm3 of water and 200 cm3 of dimethylformamide are added. The medium is stirred for 1 hour at 0 ° C., poured on ice, extracted with isopropyl ether, the organic phase washed, dried and filtered and the filtrate brought to dryness. After chromatography, eluting with a hexane-methylene chloride mixture ( 8-2), 110 g of the desired product are obtained: Rf = 0.2.

STAGE B: 1- (Isopropylsulfonyl) 4-nitro-3- (trifluoromethyl) benzene
110 g of the product prepared in the preceding stage, 1 liter of methylene chloride and then, per portion, 320 g of 3-chloroperbenzoic acid at 55% are mixed at 0.degree. C., the temperature is maintained at 30.degree. The mixture is cooled, poured into 2 liters of a 0.5N aqueous solution of sodium thiosulphate, extracted with methylene chloride, the organic phase washed, dried and filtered and the filtrate brought to dryness.

 After recrystallization from ethyl acetate, 22 g of the desired product are obtained. Rf = 0.32 (eluent: methylene hexanechloride (8-2)).

STAGE C: 4- (Isopropylsulfonyl) 3- (trifluoromethyl) aniline
2 g of the product prepared in the preceding stage are mixed at 20 ° C. with 50 cm 3 of methanol and 200 mg of 10% palladium hydroxide on charcoal and hydrogenated.

 After absorption of 440 ml of hydrogen, the solution is filtered and the filtrate brought to dryness and 1.76 g of the desired product are collected. Rf = 0.30 (eluent: methyleneacetate ethyl chloride (95-5)).

STAGE D: 1-hydroxy-3- (4- (isopropylsulfonyl) 3- (trifluoromethyl) phenyl] 1-methyl urea a) Preparation of 4- (isopropylsulfonyl) 3 (trifluoromethyl) aniline hydrochloride.

 94 g of the aniline prepared in the preceding stage are mixed with 1 liter of ethanol and 200 cm3 of a 15N ethanolic solution of hydrochloric acid, then the reaction medium is brought to dryness under vacuum at 40 ° C.

b) Preparation of 4- (isopropylsulfonyl) 3 (trifluoromethyl) phenyl isocyanate.

 The dry extract obtained in paragraph a) is taken up in 1.5 l of dioxane and 50 cm3 of trichloromethyl chloroformate are then added and the whole is brought to reflux for 17 hours. After cooling, the solution is filtered and the filtrate brought to dryness. 103 g of isocyanate are thus collected and used as such.

c) 1-hydroxy 3- [4- (isopropylsulfonyl) -3- (trifluoromethyl) phenyl] 1-methyl urea.

 50 g of N-methyl hydroxylamine hydrochloride in 1 liter of chloroform are added under nitrogen at 20 ° C., cooled to -10 ° C., 80 cm 3 of triethylamine are added, the mixture is stirred for 1 hour at 20 ° C., cooled to 0 ° C. and a solution is added. containing the 103 g of isocyanate prepared in the preceding stage in 800 cm3 of chloroform. After stirring for 17 hours at 20 ° C., the mixture is poured into water and extracted with chloroform, the organic phase is dried and filtered and the filtrate is brought to dryness After chromatography and recrystallization from acetane, 93 g of desired product Rf = 0.35 (eluent: methylene chloride-ethyl acetate (7-3)).

Microanalysis: C12H15F3N2SO4 = 340.324 g
CHFNS% calculated 42.35 4.44 16.75 8.23 9.42% found 42.5 4.4 17.1 8.1 9.6
STAGE E: 5,6-Dihydro-2-methyl-4- (4 - ((1-methylethyl) sulfonyl] 3- (trifluoromethyl) phenyl] -2H-1,2,4-oxadiazin-3 (4H) one
20 g of the product prepared in the preceding stage are mixed with dimethylsulfoxide (200 cc), potassium carbonate (73 g) and 1,2-dichloroethane (17.35 g), the mixture stirred at 20 ° C. for 7 hours and poured into the water. and extracted with methylene chloride. The organic phase is washed, dried and filtered, the filtrate brought to dryness.

 After chromatography on silica, eluting with a mixture of methylene chloride and isopropyl ether and then recrystallization from methanol, 20.3 g of the desired product are collected. Rf = 0.4 (eluent: methylene chloride-isopropyl ether (7-3)).

Microanalysis: C14H17F3N2SO4 = 366.361 g
CHFNS% calculated 45.90 4.68 15.55 7.64 8.75% found 45.8 4.7 15.7 7.6 8.3
Infra red 1144 - 1329 cm -1: -SO 2 - 1665: C = O
Spectrum mass peak at 366.

NMR (CDCl3 250 MHz ppm) 1.26 - 1.36: hydrogen bonded to the primary carbons of the isopropyl group 3.24: hydrogen bonded to the tertiary carbon of the isopropyl group 3.79 to 3.95: hydrogen at the 5-position of ring 4 , 26 to 4.44: hydrogen at position 6 of the 7,6 to 8,20 ring: aromatic hydrogens.

EXAMPLE 2 4- [4- (tert-Butylsulfonyl) -3- (trifluoromethyl) phenyl] -5,6-dihydro-2-methyl-2H-1,2,4-oxadiazin-3 (4H) -one
STAGE A: 1- (tert-butylthio) 4-nitro 3- (trifluoromethyl) benzene
A solution of 6.8 g of sodium tert-butylthiolate in 30 cm3 of dimethylformamide is added at 0 ° C. to 9 g of 1-chloro-4-nitro 2- (trifluoromethyl) benzene in 30 cm 3 of dimethylformamide, heated at 800 ° C. for 1 hour. hour, cool, pour on ice and extract with methylene chloride. The organic phase is washed, dried and filtered and the filtrate brought to dryness.

 After chromatography on silica, 6.6 g of the desired product are obtained. Rf = 0.15 (eluent: hexane-methylene chloride (8-2)).

STAGE B: 4- (tert-butylthio) 3- (trifluoromethyl) aniline
58 g of the product prepared in the preceding stage, 200 cm3 of ethanol and 5 cm3 of concentrated hydrochloric acid are stirred under nitrogen at 20 ° C. and then added with 190 g of hematite cast iron 100; the mixture is refluxed 17 hours, cooled and filtered, washed with ethanol and methylene chloride and the filtrate brought to dryness. After chromatography, 30 g of the desired aniline are collected. Rf = 0.4 (eluent: hexane-methylene chloride).

STAGE C: 4- (tert-butylthio) 3- (trifluoromethyl) phenyl isocyanate
30 g of the aniline prepared in the preceding stage are mixed with 300 cm 3 of ethanol; an ethanolic solution of hydrochloric acid is then added until the pH is equal to 1. The mixture is brought to dryness and the residue is taken up in dioxane.

 100 cm3 of dioxane are added again with stirring and under nitrogen 10 cm3 of trichloromethyl chloroformate. After stirring for 17 hours at 50 ° C., the solution is brought to dryness and 34.48 g of crude product are collected which is used for the next stage.

STAGE D: 3- (4- (tert-butylthio) 3- (trifluoromethyl) phenyl) 1-hydroxy-1-methyl urea
A solution of 12 g of N-methylhydroxylamine hydrochloride in 120 cm.sup.3 of dimethylformamide is prepared at 20.degree. C. and then at 0.degree. C., 19.9 cm.sup.3 of triethylamine is added, the mixture is stirred for 1 hour at 20.degree. C. and washed with 60 cm.sup.3. The dimethylformamide, filtered, cooled the filtrate to 0 ° C and added under nitrogen 35 g of the crude isocyanate prepared in the preceding stage.

 After stirring for 48 hours at 20 ° C., the mixture is poured into water. It is filtered, washed and dried and collected 34.38 g of the desired product. Rf = 0.4 (eluent: methylene chloride tetrahydrofuran (95-5)).

Infra red (CHCl3) 3530 cm 1: -OH 3418 cm-1: = C-NH1663 cm 1: C = O
STAGE E: 4- (4- (tert-butylthio) 3- (trifluoromethyl) phenyl] 5,6-dihydro-2-methyl-2H-1,2,4-oxadiazin-3 (4H) -one
30 g of the product prepared in the preceding stage are mixed under nitrogen with 160 cm3 of. dimethylsulfoxide and 138 g of potassium carbonate.

 25 cm3 of 1,2-dichloroethane are then added, the mixture is stirred for 17 hours at 20-25 ° C. and the mixture is then poured into water and extracted with isopropyl ether, the organic phase is dried, filtered and the filtrate is brought to room temperature. After chromatography and recrystallization from isopropyl ether, 18.56 g of the desired product are collected, R.sub.f = 0.2 (eluent: hexane-tetrahydrofuran (8-2)).

Microanalysis: C15H19F3N2SO2 = 348.389 g
CHFNS% calculated 51.71 5.50 16.36 8.04 9.20% found 51.7 5.6 16.8 8.0 9.3
STAGE F: 4- (4- (tert-butylsulfonyl) 3- (trifluoromethyl) phenyl] 5,6-dihydro-2-methyl-2H-1,2,4-oxadiazin-3 (4H) -one
50 g of the product prepared in the preceding stage are mixed in 50 cm 3 of ethanol, then 18 g of magnesium monoperoxyphatalate, brought to 50 ° C. for 3 hours, cooled to 20 ° C., poured onto an aqueous solution of thiosulphate of sodium and extracted with methylene chloride. The organic phase is washed, dried, filtered and the filtrate brought to dryness. After chromatography, the fraction is impasted in pentane, drained, washed and dried to collect 3.04 g of the desired product.

Rf = 0.2 (eluent: methylene chloride-isopropyl ether (95-5)).

Microanalysis: C15H19F3N2SO4 = 380.388 g
CHFNS% calculated 47.37 5.03 14.98 7.36 8.43% found 47.2 5.0 15.1 7.3 8.3
Infra red (CHCl 3) 1326-1164 cm -1: -SO 2 - 1666 cm -1: C = O
NMR (CDCl 3 250 MHz ppm) 1.39: tert-butyl radical hydrogens 3.27: methyl substituents at the 2-position of ring 3.92: hydrogen at position 5 of ring 4.38: hydrogens at ring position 6 7.79 to 8.07: aromatic hydrogens.

EXAMPLE 3 4- [4- (tert-Butylsulfinyl) -3- (trifluoromethyl) phenyl] 5,6-dihydro-2-methyl-2H-1,2,4-oxadiazin-3 (4H) -one
3 g of the product prepared in Stage E of Example 2 are mixed with 200C to 15 cm3 of water, 40 cm3 of methanol and 2 g of sodium periodate. After stirring for 17 hours at 20 ° C., the mixture is poured into an aqueous solution of sodium thiosulfate and then extracted with methylene chloride. The organic phase is washed, dried and filtered, and the filtrate brought to dryness.

The residue is slurried in pentane, drained, washed with pentane and dried under vacuum at 20 ° C. Thus 2.99 g of the desired product are collected. Rf = 0.28 (eluent: methylene chloride tetrahydrofuran (90-10)).

Microanalysis: C15H19F3N2SO3 = 364.388 g
CHFNS% calculated 49.44 5.25 15.64 7.69 8.80% found 49.30 5.2 15.4 7.7 8.8
Infra red (CHCl3) 1043 cm: -SO1665 cm-1: C = O
NMR (CDCl3 250 MHz ppm) 1.22: hydrogens of the tert-butyl radical 3.25: hydrogen of the methyl substituent at the 2-position of the 3.89 ring: hydrogen at the 5-position of the 4.36 ring: hydrogen at position 6 of the ring 7.75 to 8.10: aromatic hydrogens.

EXAMPLE 4: 5,6-Dihydro-2-methyl-4- [4- (methylsulfonyl) -3 (trifluoromethyl) phenyl] -2H-1,2,4-oxadiazin-3 (4H) -one
2 g of 5,6-dihydro-2-methyl-4- [4- (methylthio) -3- (trifluoromethyl) phenyl] -2H-1,2,4-oxadiazin-3 (4H) -one are prepared (prepared in the French patent No. 2327788), 20 cm3 of ethanol and 8 g of magnesium monoperoxyphthalate hexahydrate, stirred for 3 hours at 20 ° C., poured into water and extracted with methylene chloride. The organic phase is washed, dried and filtered and the filtrate brought to dryness. After chromatography, a fraction is collected which is pasted in pentane and thus obtains 690 mg of the desired product. Rf = 0.18 (eluent: methylene chloride-isopropyl ether (95-5)).

Microanalysis: C12H13F3N2SO4 = 338.308 g
CHFNS% calculated 42.60 3.87 16.85 8.28 9.48% found 42.6 4.0 16.8 8.2 9.5
Spectrum mass peak at 338.

Infra red (CHC13, cm-1) 1332, 1160 cm: -SO2-
NMR (CDCl3 250 MHz ppm) 3.18: methylsulfonyl radicals 3.27: methyl substituents at the 2-position
EXAMPLE 5: 5,6-Dihydro-2-methyl-4- [4- (methylsulfinyl) -3 (trifluoromethyl) phenyl] -2H-1,2,4-oxadiazin-3 (4H) -one
By operating as in Example 3 starting from 5,6-dihydro-2-methyl-4- [4- (methylthio) -3- (trifluoromethyl) phenyl] -2H, 2,2,4-oxadiazin-3 (4H) -one (prepared in French Patent No. 2327788, the desired product is obtained.

Yield 75%. Rf = 025 (eluent: methylene chloride tetrahydrofuran (9-1))
Microanalysis: C12H13F3N2SO3 = 322.308 g
CHFNS% calculated 44.72 4.06 17.68 8.69 9.95% found 44.9 4.0 17.4 8.6 9.8
Infra red (CHCl3) 1055 cm-1: -SO
NMR (CDCl3 250 MHz ppm) 2.75: methylsulphinyl radicals 3.26: hydrogen of the methyl substituent at the 2-position of the 3.90 ring: hydrogen at the 5-position of the 4.37 ring: hydrogens at the 6-position of ring 7, 80 to 8.28: aromatic hydrogens.

EXAMPLE 6: 5,6-Dihydro-2-methyl-4- [4 - [(1-methylpropyl) sulfonyl] -3- (trifluoromethyl) phenyl] -2H-1,2,4-oxadiazine (4H) -one
STAGE A: 1 - [(1-methylpropyl) thio) 4-niro 3- (trifluoromethyl) benzene
30 cm3 of 1-chloro-4-nitro-2- (trifluoromethyl) benzene, 38 cm 3 of sec-butyl mercapon and 150 cm 3 of dimethylformamide are cooled under nitrogen, cooled to -10 ° C., an emulsion is added dropwise over 1 hour. 15.5 g of potassium hydroxide in 46.5 cm3 of dimethylformamide. The mixture is then poured into 500 cm3 of ice and extracted with methylene chloride. The organic phase is dried and evaporated. 59.7 g of the desired product are obtained. Rf = 0.35 (eluent: hexane-methylene chloride (8-2)).

STAGE B: 4 - [(1-methylpropyl) thio] 3- (trifluoromethyl) aniline hydrochloride a) 4-t (1-methylpropyl) thio] 3- (trifluoromethyl) aniline
5 g of the product prepared in the preceding stage are dissolved in 40 cm3 of ethanol and 40 cm3 of water, then 3.65 g of iron and 2.4 g of ammonium chloride are added. After 1 hour at reflux, the solution is filtered, the filtrate brought to dryness, the residue taken up in 50 cm3 of methylene chloride and washed with water. The organic phase is dried and concentrated to yield 899 g of the desired product. Rf = 0.15 (eluent hexane-methylene chloride (8-2)).

b) 4 - [(1-methylpropyl) thio] 3- (trifluoromethyl) aniline hydrochloride
The 3.89 g of aniline obtained in paragraph a) above are mixed with 20 cm3 of ethyl ether; then 6.5 cm3 of a standard ethanolic solution of hydrochloric acid 2.7 is added and then evaporated. The crystals obtained are taken up in isopropyl ether; after filtration, 2.11 g of the desired salt are obtained in the form of white crystals.

STAGE C: 4-t (1-methylpropyl) thio] 3- (trifluoromethyl) phenylisocyanate
2.11 g of the hydrochloride prepared in the preceding stage are mixed under nitrogen with 20 cm3 of dioxane and then 1 cm3 of trichloromethyl chloroformate is added. After 24 hours at 50-55 ° C, the solution is concentrated and taken to 2 g of the desired product (yellow oil).

STAGE D: 1-hydroxy-methyl-3-t - [(1-methylpropyl) thio] 3 (trifluoromethyl) phenyl] urea
Working as in Step D of Example 2, from 2 g of the isocyanate prepared in the preceding stage, allowing the reaction to proceed for 24 hours, 1.73 g of the expected product are obtained. Rf = 0.2 glutant: methylene chloride isopropyl ether (9-1)).

Infra red (CHCl 3) 3530 cm -1: -OH 3420 cm -1: = C-NH 1667 cm -1: C = O 1526-1580-1608 cm -1: aromatic + secondary amide
STAGE E: 5,6-Dihydro-2-methyl-4-t4 - [(1-methylpropyl) thio] 3- (trifluoromethyl) phenyl] -2H-1,2,4-oxadiazin-3 (4H) -one
Working as in Step E of Example 2, from 1.73 g of the product of the preceding stage, 0.82 g of the expected product is obtained. Rf = 0.35 (eluent: methylene chloride-isopropyl ether (95-5)).

Microanalysis: C15H19F3N2SO2 = 348.4 g
CHFNS% calculated 51.7 5.5 16.4 8.0 9.2% found 51.5 5.4 16.1 8.0 9.4
STAGE F: 5,6-dihydro-2-methyl-4- [4- (1-methylpropyl) sulfonyl) -3- (trifluoromethyl) phenyl] -2H-1,2,4-oxadiazin-3 (4H) -one
5.23 g of the product prepared in the preceding stage are mixed with 11.65 g of 55% 3-chloro-perbenzoic acid and 150 cm 3 of methylene chloride. After 5 hours at 40-45 ° C., the reaction mixture is cooled and poured into a 0.5 N solution of sodium thiosulfate and extracted with methylene chloride. The organic phase is washed, dried and filtered and the filtrate brought to dryness. After chromatography, 2.7 g of the expected product are obtained. Rf = 0.15 (eluent: methylene chloride-isopropyl ether (95-5)).

Microanalysis: C15H19F3N2SO4 = 380.49 g
CHFNS% calculated 47.36 5.03 14.98 7.36 8.4:% found 47.6 5.1 14.9 7.3 8.5
NMR (CDCl3 250 MHz ppm) 1: hydrogen at the 3-position of the 1-methylpropyl radical 1.29: hydrogen of the methyl substituent at the 1-position of the 1-methylpropyl radical 1.6: hydrogen at the 2-position of the 1-methylpropyl radical 3.23: hydrogen at the 1-position of the 1-methylpropyl radical 3.27: hydrogen of the methyl substituent at the 2-position of the 3.92 ring: hydrogen at the 5-position of the 4.38 ring: hydrogen at the 6-position of the 7.73 ring at 8.17: aromatic hydrogens.

EXAMPLE 7: 5,6-Dihydro-2-methyl-4-E4- (i-methylpropyl) sulfinyl] -3- (trifluoromethyl) phenyl] -2H-1,2,4-oxadiazin-3 (4H) -one (isomers A and B) )
By operating as in Example 3 starting from 5.4 g of product prepared in stage E of example 6, after chromatography under pressure, 2.25 g of isomer A were collected, 1.55 g of isomer B and 1 g of an isomeric mixture A + isomer B.

(eluent: methylene chloride-tetrahydrofuran (95-5)).

Isomer A: Rf = 0.15
Isomer B: Rf = 0.10
Microanalysis: C15H19F3N2SO3 = 364.4 g
CHFNS% calculated 49.44 5.25 15.64 7.7 8.8% found
Isomer A 49.6 5.3 15.7 7.6 8.5
Isomere B 49.2 5.3 15.9 7.6 8.9
Infra-red 1029-1064 cm-1: -SO
EXAMPLE 8: 5,6-Dihydro-2-methyl-4- [4 - [(2-propenyl) thiol-3 (trifluoromethyl) phenyl] -2H-1,2,4-oxadiazin-3 (4H) -one
STAGE A: 1-nitro 4- (2-propenylthio) 3- (trifluoromethyl) benzene
By operating in the same manner as in Step A of Example 6 starting from 9 g of 1-chloro-4-nitro 2- (trifluoromethyl) benzene and 8 cm 3 of 70% allyl mercaptan, 8.19 g is obtained. expected thioether.

Rf = 0.38 (eluent: hexane-methylene chloride (5-5)).

STAGE B: 4- (2-propenylthio) 3- (trifluoromethyl) aniline hydrochloride a) 4- (2-propenylthio) 3- (trifluoromethyl) aniline
Working as in Step B (a) of Example 6, starting from 1.20 g of the product prepared in the preceding stage, 1.04 g of the desired aniline is obtained.

NMR (CDCl 3 ppm) 3.40: hydrogen at the 1-position of the 2-propenylthio radical 3.89: hydrogen of the amino group 4.90: hydrogen at the 3-position of the 2-propenylthio radical 5.83: hydrogen at the 2-position of the radical 2 propenylthio 6,73 - 6,93 - 7,35: aromatic hydrogens.

b) 4- (2-propenylthio) 3- (trifluoromethyl) aniline hydrochloride
The 1.04 g of the aniline obtained are dissolved in isopropyl ether; 1.4 cm3 of a 3.8 M ethanolic solution of hydrochloric acid is added, concentrated, washed, drained and dried at 40 ° C. to give 0.92 g of the desired hydrochloride. Rf = 0.24 (eluent: methylene chloride-hexane (7-3)).

STAGE C: 4- (2-propenylthio) 3- (trifluoromethyl) phenylisocyanate
By operating as in Step C of Example 6 from 4.33 g of hydrochloride prepared in the preceding stage, 4.96 g of the expected product are obtained.

STAGE D: 1-methyl-3- [4- (2-propenylthio) 3- (trifluoromethyl) phenyl] urea hydroxy
A solution of 4.96 g of isocyanate in 5 cm 3 of chloroform is added under nitrogen at 7 ° C. to a mixture containing 1.91 g of N-methylhydroxylamine hydrochloride, 53 cm 3 of chloroform and 3.3 cm 3 of triethylamine. leave at room temperature for 5 hours 30, concentrate, wash, filter and concentrate the filtrate. After chromatography, 1.17 g of the expected product is obtained. Rf = 0.1 (eluent: hexane-tetrahydrofuran (8-2)).

Infra-red (CHCl3 cm-1) 3530: -OH 3415: = C-NH1666: C = O924-1648: CH = CH2 1482-1526-1580-1608: aromatic + secondary amide
STAGE E: 5,6-dihydro-2-methyl-4- (4 - ((2-propenyl) thio] 3 (trifluoromethyl) phenyl] 2H-1,2,4-oxadiazin-3 (4H) -one
Working as in Step E of Example 2 starting from 4.01 g of the product prepared in the preceding stage, allowing 19 hours of reaction and extracting with methylene chloride, 3.79 g of the desired product are obtained.

Rf = 0.1 (eluent: methylene chloride-hexane (8-2)).

Microanalysis: C14H15F3N2SO2 = 322.344 g
CHFNS% calculated 50.6 4.55 17.15 8.43 9.65% found 50.7 4.4 17.5 8.4 9.8
NMR (CDCl3 ppm) 3.18: hydrogen of the methyl substituent at the 2-position of the 3.50 ring: hydrogen at the 1-position of the 2-propenylthio radical 3.65 - 3.88: hydrogen at the 5-position of the 4, 17 and 4 ring , 42: hydrogenes at position 6 of the 4.88 to 5.30 ring: hydrogens at the 3-position of the 2-propenylthio radical 5.5 to 6.2: hydrogens at the 2-position of the 2-propenylthio radical 7.42 - 7.45 - 7.60: aromatic hydrogens.

EXAMPLE 9 5,6-Dihydro-2-methyl-4-E4-E (2-propenyl) sulfinyl] -3- (trifluoromethyl) phenyl] -2H-1,2,4-oxadiazin-3 (4H) -one
3 g of the product prepared in Stage E of Example 8 are dissolved in 60 cm 3 of methylene chloride at 20 ° C., the solution is cooled to 0 ° C. and 4.65 g of 3% chloro-perbenzoic acid are introduced therein. After 17 hours at 20-25 ° C., the mixture is poured into a solution of 0.5 N sodium thiosulfate and extracted with methylene chloride; the organic phase is washed, dried and filtered and the filtrate brought to dryness; the residue obtained is chromatographed and led to 2.1 g of the desired product. Rf = 0.33 (eluent: methylene chloride isopropyl ether (95-5)).

Microanalysis: C14H15F3N2S 4 = 364.346 g
CHFNS% calculated 46,15 4.15 15.64 7.69 8.8% found 46.2 4.2 16.0 7.6 9.1
Mass spectrum: peak at 364
Infra-red (CHCl3 cm-1) 1334 - 1148 -SO2
NMR (CDCl 3 ppm) 3.31: methyl substituents at the 2-position of the 3.93 - 4.08 ring: hydrogen at the 1-position of the 2-propenylsulphonyl radical 3.87 - 3.95 - 4.05: hydrogen at position 5 of the 4.35 - 4.44-4.53 cycle: hydrogen at position 6 of the ring 5.13 to 6.28: hydrogen at position 2 and 3 of the 2-group propenyl sulphonyl e 7.73-8 , 31: aromatic hydrocarbons.

EXAMPLE 10: 5,6-Dihydro-2-methyl-4- (4 - ((2-propenyl) sulfinyl] -3- (trifluoromethyl) phenyl] -2H-1,2,4-oxadiazin-3 (4H) -one
By operating as in Example 3, starting from 3 g of the product prepared in Stage E of Example 8, 2 g of the desired product are obtained. Rf = 0.2 (eluent: methylene chloride tetrahydrofuran (95-5)).

Microanalysis: C14H15F3N2S 3 = 348.346 g
CHFNS% calculated 48.27 4.34 16.36 8.04 9.2% found 48.6 4.6 16.1 7.7 9.0
EXAMPLE 11 4- (4- (Cyclohexylthio) -3- (trifluoromethyl) phenyl-5,6-dihydro-2-methyl-2H-1,2,4-oxadiazin-3 (4H) -one
STAGE A: 1- (cyclohexylthio) 4-nitro 2- (trifluoromethyl) benzene
A solution containing 30 cm3 of 1-chloro-4-nitro 2- (trifluoromethyl) benzene, 43 cm 3 of cyclohexylmercapton and 150 cm 3 of dimethylformamide is prepared under nitrogen, cooled to -10 ° C. and an emulsion of 15.5 g of potash in 15.5 cm3 of water and 46.5 cm3 of dimethylformamide. The mixture is poured into 500 cm3 of ice, filtered and extracted with isopropyl ether.

 The filtered product is dissolved in 500 cm3 of isopropyl ether and the organic phases are combined, dried and concentrated in vacuo. 7.2 g of the expected product are obtained.

Rf = 0.2 (eluent: hexane-methylene chloride (8-2)).

STAGE B: 4- (cyclohexylthio) 3- (trifluoromethyl) aniline
Operating as in Step B paragraph a) of Example 6, from 5 g of the product prepared in the preceding stage, 3.77 g of the expected aniline are obtained after chromatography.

Rf = 0.07 (eluent: hexane-methylene chloride (8-2)).

STAGE C: 4- (cyclohexylthio) 3- (trifluoromethyl) phenyl isocyanate
By operating as in Stage C of Example 2, from 3.77 g of aniline prepared in the preceding stage and by intermediating its hydrochloride, 3.48 g of the expected isocyanate are obtained.

Infra-red (CHC13 on Nicolet) 2270 cm 1: N = C = O
STAGE D: 3- [4- (cyclohexylthio) 3- (trifluoromethyl) phenyl] 1-hydroxy-1-methyl urea
Working as in Step D of Example 2, from 3.48 g of the isocyanate prepared in the preceding stage and allowing 4 hours to react, 2.62 g of the desired product are obtained after chromatography. Rf = 0.2 (eluent: methylene chloride-isopropyl ether (9-1)).

STAGE E: 4- [4- (cyclohexylthio) 3- (trifluoromethyl) phenyl] 5,6-dihydro-2-methyl-2H-1,2,4-oxadiazin-3 (4H) -one
Working as in Step E of Example 2, from 2.6 g of the product of Step D of Example 11, 1.85 g of the expected product are obtained. Rf = 0.15 (eluent toluene-isopropyl ether (95-5)).

Microanalysis: C17H21F3N2So2 = 374.43 g
CHFNS% calculated 54.5 5.6 15.2 7.5 8.6% found 54.3 5.5 15.5 7.4 8.7
NMR (CDCl 3 ppm) 1,2 - 2,2: hydrogens in position 2 to 6 of the cyclohexylthio radical 3,2: hydrogen in position 1 of the cyclohexylthio radical 3,2: hydrogens of the methyl substituent in position 2 of the cycle 3,8: hydrogen at position 5 of the 4,4-ring: hydrogens at position 6 of the 7.5-7.65 ring: aromatic hydrogens.

EXAMPLE 12: 4- (4- (Cyclohexylsulfonyl) -3- (trifluoromethyl) phenyl) -5,6-dihydro-2-methyl-2H-1,2,4-osadiasin-3 (4H) -one
7.5 g of the product prepared in Stage E of Example 11, 25 g of magnesium monoperoxyphthalate and 75 cm 3 of ethanol are heated under a stream of nitrogen, heated for 5 hours at 50 ° C., cooled, poured into 100 cm 3 of water and extracted with ethyl acetate. The organic phase is washed, dried and evaporated.

After chromatography under pressure, 4.1 g of the expected product are obtained. Rf = 0.15 (eluent: methylene chloride, isopropyl ether (95-5)).

Microanalysis: C17H21F3N2S 4 = 406.43 g
CHFNS% calculated 50.24 5.2 14.0 6.9 7.9% found 50.5 5.1 14.3 6.8 8.1
Mass spectrum: peak at 406
Infra-red (CHCl3 on PE 580, cm-1) 1326 - 1148 - 1148: -SO2
NMR (CDCl 3 250 MH 2 ppm) 1.10 to 2.05: hydrogens at the 2- to 6-positions of the cyclohexyl sulphonyl radical 3.17: hydrogen at the 1-position of the cyclohexylsulphonyl radical 3.27: hydrogens of the methyl substituent in the 2-position of the ring 3.91: hydrogens at the 5-position of the 4.37 ring: hydrogens at the 6-ring position of the 7,72-8,04 ring: aromatic hydrogens.

EXAMPLE 13 4- [4- (Cyclohexylsulphinyl) -3- (trifluoromethyl) phenyl 5,6-dihydro-2-methyl-2H-1,2,4-oxadiazin-3 (4H) -one
By operating as in Example 3 starting from 3.74 g of product prepared in Stage E of Example 11, 3.3 g of the expected product are obtained. RF = 0.17 (eluent: methylene chloride tetrahydrofuran (95-5)).

Microanalysis: C17H21F3N2SO3 = 390.43 g
CHFNS% calculated 52.3 5.4 14.6 7.2 8.2% found 52.5 5.4 14.3 7.0 8.2
Mass Spectrum: 390
Infra-red (CHCl3 on Nicolet, cm 1) 1049: -SO
NMR (CDCl 3 250 MHZ ppm) 1.23 to 1.88: hydrogens in positions 2 to 6 of the cyclohexylsulfinyl radical 2.60: hydrogen in position 1 of the cyclohexylsulfinyl radical 3.25: hydrogens of the methyl substituent at the 2-position of ring 3, 89: hydrogens at the 5-position of the 4,36-ring: hydrogens at the 6-position of the 7,76-8,11 ring: aromatic hydrocarbons.

EXAMPLE 14: 5,6-Dihydro-2-methyl-4- [4- [2,4,5-trichloro-phenyl] -thio] -3- (trifluoromethyl) -phenyl] -2H-1,2,4-oxadiazin-3 (4H) -one
STAGE A: 1-hydroxy-methyl-3- (4-bromo-3- (trifluoromethyl) phenyl] urea
Working as described successively in steps C and D of Example 6 from 109.5 g of 4-bromo-3- (trifluoromethyl) aniline hydrochloride (described in Chem Abst.

095-062193) through 4-bromo-3 (trifluoromethyl) phenyl isocyanate, 85 g of the desired urea is obtained. Rf = 0.1 (eluent: methylene chloride tetrahydrofuran (98-2)).

STAGE B: 4- [4-bromo 3- (trifluoromethyl) phenyl] 5,6-dihydro-2-methyl-2H-1,2,4-oxadiazin-3 (4H) -one
Working as in Step E of Example 2 from 85 g of the product of the preceding stage, and extracting with methylene chloride, 44.7 g of the expected product is collected.

Rf = 0.25 (eluent: hexane-tetrahydrofuran (8-2)).

Microanalysis: C11H10BrF3N2O2 = 339.119 g
CH Br FN% calculated 38.96 2.97 23.56 16.81 8.26% found 39.3 2.9 23.6 16.6 8.1
STAGE C: 5,6-dihydro-2-methyl-4- [4 - [(2,4,5-trichloro-phenyl) -thio] -3- (trifluoromethyl) -phenyl-2H-1,2,4-oxadiazin-3 (4H) - one a) Preparation of 2,4,5-trichloro thiophenol
85 g of bis (2,4,5-trichlorophenyl) disulphide are mixed under nitrogen with 750 cm 3 of tetrahydrofuran and then 6 g of 90% sodium borohydride are added, stirred for 1 night at room temperature, poured over a mixture ice water then extracted with methylene chloride. The organic phase is washed, dried and evaporated to yield 83.2 g of the desired product.

Microanalysis: C6H3Cl3S = 213.5 g
CH C1 S% calculated 33.74 1.4 49.8 15.0% found 34.0 1.3 49.5 14.9 b) 5,6-dihydro-2-methyl 4- [4 - [(2, 4,5-trichlorophenyl) thio] 3- (trifluoromethyl) phenyl] 2H-1,2,4-oxadiazin-3 (4H) -one
47.13 g of the product prepared in the preceding stage, 37.26 g of the thiol prepared in paragraph a), 26.5 g of cuprous iodide and 600 cm 3 of pyridine are heated and refluxed overnight.

After cooling, the mixture is poured into water, ammonia is added to 22, and extracted with isopropyl ether. The organic phase is dried and evaporated. After chromatography of the residue, and impaction in pentane, 10.64 g of the expected product are obtained. Rf = 0.17 (eluent: methylene chloride-hexane (80-20)).

Microanalysis: C17H12Cl3F3N2SO2 = 471.7 g
CH C1 FNS% calculated 43.28 2.56 22.55 12.0 5.9 6.8% found 43.1 2.5 22.7 11.8 5.7 7.1
EXAMPLE 15 4- [4- (Benzylthio) -3- (trifluoromethyl) phenyl-5,6-dihydro-2-methyl-2H-1,2,4-oxadiazin-3 (4H) -one
STAGE A: 4-Fluoro-3- (trifluoromethyl) phenyl isocyanate.

A-1) Preparation of 4-fluoro-3- (trifluoromethyl) aniline hydrochloride. About 700 ml of a 2.8N ethanolic solution of hydrochloric acid is added to 300 g of 4-fluoro-3- (trifluoromethyl) aniline in 2 l of isopropyl ether, brought to dryness, the residue is taken up in 2 l of dichloromethane. sulfuric ether, wring and dry the hydrochloride at 20 C under vacuum.

A-2) 4-Fluoro-3- (trifluoromethyl) phenyl isocyanate.

4-Fluoro-3- (trifluoromethyl) aniline hydrochloride is dissolved under nitrogen in 2 lites of dioxane and added with 200 ml of trichloromethyl chloroformate (d = 1.64). The mixture is heated for 17 hours at 40.degree.-45.degree. C. and then brought to dryness, thereby obtaining 343 g of the desired product.

STAGE B: N '- [4-fluoro 3- (trifluoromethyl) phenyl] N-hydroxy
N-methyl urea.

A solution of 240 g of hydrochloride is prepared at 200 ° C.
N-methyl hydroxylamine in 3 liters of chloroform and added at 10 C in 1 hour 279 g of triethylamine. After stirring for 1 hour at 20 ° C., a solution of 343 g of the isocyanate prepared in the preceding stage in 2 liters of chloroform is poured in over 40 minutes. After stirring for 6 hours, 4 liters of water are added and the mixture is extracted with chloroform and then with ethyl acetate.

After drying, filtration and evaporation of the solvent, the residue obtained is slurried in hexane, then drained and dried to obtain 303 g of the desired product. Rf = 0.25 (eluent: methylene chloride - tetrahydrofuran (95-5)).

3.23: hydrogens of the methyl radical 7.09 to 7.72: aromatic hydrogens 8.05: hydrogens of the radical -OH and the group -NH
STAGE C: 4- [4-fluoro-3- (trifluoromethyl) phenyl] -5,6-dihydro-2-methyl-2H-1,2,4-oxadiazin-3 (4H) -one.

 300 g of the product of the preceding stage are dissolved under nitrogen at 20 ° C. in 3 liters of dimethylsulfoxide, then 1200 g of anhydrous potassium carbonate and 300 ml of 1,2-dichloroethane (d = 1,256) are added. hours, poured into water and extracted with isopropyl ether After washing, drying, filtration and evaporation of the solvent a residue is obtained which, after chromatography on silica eluting with the mixture flugene-2-butanone (8-2) yielded 260 g of the desired product Rf = 0.35 (eluent flugene-2-butanone (8-2).

NMR (CDCl3, ppm) 3.18: methyl substituent hydrogens at position 3.63 to 3.86: hydrogen at position 5 of ring 4.16 to 4.41: hydrogen at position 6 of ring 6.9 at 7.7: aromatic hydrogens.

STAGE D: 4- (4- (benzylthio) -3- (trifluoromethyl) phenyl-5,6-dihydro-2-methyl-2H-1,2,4-oxadiazin-3 (4H) -one
Under nitrogen, 1.89 g of 50% sodium hydride in oil and 75 cm 3 of dimethylformamide are added, the suspension is cooled to 0.degree. C., a solution of 5.35 g of benzylmercaptan in 20 to 20 minutes is added in the course of 10 to 15 minutes. cm3 of dimethylformamide, allowed to raise the temperature to 20 C, stirred for 1 hour and added 10 g of the product prepared in the preceding stage. After stirring for 2 hours, the solution is poured into water and extracted with isopropyl ether; the organic phase is washed, dried, filtered and the filtrate brought to dryness. After chromatography and recrystallization from pentane, 11.5 g of the desired product are obtained. Rf = 0.38 (eluent: methylene chloride isopropyl ether (95-5)).

Microanalysis: C18H17F3N2S 2 = 382.405 g
CHFNS% calculated 56.54 4.48 14.9 7.33 8.38% found 56.3 4.3 15.0 7.3 8.5
Mass spectrum: peak at 382
NMR (CDCl 3 ppm) 3.18: methyl substituents at the ring position 2 of the ring 3.65 to 3.83: hydrogen at the 5-position of ring 4.18 to 4.36: hydrogen at position 6 of ring 4.09: benzyl hydrogens 7.16 to 7.58: aromatic hydrogens.

EXAMPLE 16: 4- [4 - [(phenylmethyl) sulfonyl] 3- (trifluoromethyl) phenyl] 5,6-dihydro-2-methyl-2H-1,2,4-oxadiazin-3 (4H) one
3 g of the product prepared in Stage D of Example 15, 60 cm 3 of methylene chloride and then 4 g of 3-chloro-perbenzoic acid at 80% are mixed under nitrogen while maintaining the temperature at 20-25 C. After 17 hours stirring at this temperature, the suspension is poured into a 0.5 N solution of sodium thiosulfate and then extracted with methylene chloride. The organic phase is washed, dried and filtered and the filtrate brought to dryness. After chromatography, 0.81 g of the expected product is collected. Rf = 0.3 (eluent: methylene chloride isopropyl ether (95-5)).

Microanalysis: C18H17F3N2SO4 = 414.04 g
CHFNS% calculated 52.17 4.13 13.75 6.76 7.74% found 52.0 4.1 13.6 6.7 8.0
Mass spectrum: peak at 414
EXAMPLE 17: 5,6-Dihydro-2-methyl-4-L4-E (phenylmethyl) -sulfinyl-3- (trifluoromethyl) -phenyl-2H-1,2,4-oxadiazin-3 (4H) -one
Operating as in Example 3 from 3 g of the product of Step D of Example 15, after chromatography and crystallization in isopropyl ether, 2.85 g of the expected product are obtained. Rf = 0.25 (eluent: methylene chloride tetrahydrofuran (95-5)).

Microanalysis: C18H17F3N2SO3 = 398.404 g
CHFNS% calculated 54.27 4.3 14.31 7.03 8.05% found 54.1 4.2 14.6 6.9 8.2
Mass spectrum: peak at 398
NMR (CDCl 3 ppm) 3.25: methyl substituents at position 2 3.82-4.30: benzyl hydrogens 3.86: hydrogen at position 5 of the 4.35 ring: hydrogens at position 6 of the 7.58 ring at 7.88: aromatic hydrogens
EXAMPLE 18 4- [4 - [[(4-fluorophenyl) methylthiol 3- (trifluoromethyl) phenyl] 5,6-dihydro-2-methyl-2H-1,2,4-oxadiazine 3 (4H) -one
Working as in Step D of Example 15, from 4-fluoro benzylmercapton, the expected product was obtained with a yield of 71%. Rf = 0.45 (eluent: methylene chloride-ethyl acetate (95-5)).

By operating as in Example 3 from the corresponding thioethers, the following products were obtained:
EXAMPLE 19: 4- [4 - [[(4-fluorphenyl) methyl] sulfinyl] -3- (trifluoroethyl) phenyl] 5,6-dihydro-2-methyl-2H-1,2,4-oxadiazine 3 (4H) -one
Yield: 74%. Rf = 0.25 (eluent: methylene chloride tetrahydrofuran (95-5)).

EXAMPLE 20 4- [4- (Butylsulfinyl) -3- (trifluoromethyl) phenyl-5,6-dihydro-2-methyl-2H-1,2,4-oxadiazin-3 (4H) -one
Yield: 92.5%. Rf = 0.3 (eluent: methylene chloride tetrahydrofuran (90-10)).

Microanalysis: C15H19F3N2SO3 = 364.38 g
CHFNS% calculated 49.44 5.25 15.64 7.69 8.80% found 49.4 5.1 15.5 7.5 9.10
Infra-red (CHCl3) 1027 cm-1: -SO
EXAMPLE 21: 5,6-Dihydro 4- [4- (Isopropylsulphinyl) -3- (trifluoromethyl) phenyl] -2-methyl-2H-1,2,4-oxadiazin-3 (4H) -one
Yield: 47%. Rf = 0.3 (ethyl acetate) mp = 82 ° C.

Microanalysis: C14H17F3N2SO3 = 350.361 g
CHFNS% calculated 48.00 4.89 16.27 8.0 9.15% found 48.2 4.9 16.6 7.9 9.20
Mass spectrum: peak at 350.

Infra red 1057 cm: -SO EXAMPLE 22: 5,6-Dihydro-2-methyl-4- (4- (propylsulphinyl) -3 (trifluoromethyl) phenyl] -2H-1,2,4-oxadiazin-3 (4H) -one
Yield: 76%. Rf = 0.12 (ethyl acetate)
Infra-red 1057 cm: -SO
EXAMPLE 23: 4- [4 - [[(4-Fluorophenyl) methyl] sulfonyl] 3- (trifluoromethyl) phenyl] 5,6-dihydro-2-methyl-2H-1,2,4-oxadiazin (4H) -one
By operating as in Example 12 from the product prepared in Step D of Example 17, the expected product is obtained with a 51% yield. Rf = 0.25 (eluent: methylene chloride-ethyl acetate (95-5)).

By operating as in Example 9 from the corresponding thioethers, the following products were prepared
EXAMPLE 24: 5,6-Dihydro-2-methyl-4- [4 - [(1-methylethyl) sulfonyl] -3- (trifluoromethyl) phenyl] -2H-1,2,4-oxadiazine (4H) -one
Rf = 0.18 (hexane ethyl acetate (5-5))
Infra-red 1144-1329 cm-1: -SO2
Mass spectrum: peak at 366.

Microanalysis: C14H17F3N2SO4 3 366.36 g
CHFNS% calculated 45.9 4.68 15.56 7.65 8.76% found 46.0 4.7 15.4 7.5 8.6
EXAMPLE 25 4- (4- (Butylsulfonyl) 3- (trifluoromethyl) phenyl] 5,6-dihydro-2-methyl-2H-1,2,4-oxadiazin-3 (4H) -one
Rf = 0.25 (methylene chloride-isopropyl ether (95-5)).

Infra-red 1154-1332 cm-1: -SO2
Microanalysis: C15H19F3N2SO4 = 380.388 g
CHFNS% calculated 47.36 5.03 14.98 7.36 8.43% found 47.4 5.1 15.0 7.3 8.6
EXAMPLE 26: 5,6-Dihydro-2-methyl-4- (4-propylsulfonyl) (trifluoromethyl) phenyl] -2H-1,2,4-owadiazin-3 (4H) -one
Yield 42%; Rf = 0.28 (eluent: methylene chloride isopropyl ether (95-5)).

Infra-red 1332-1154 cm: -SO, -
Mass spectrum: peak at 366
Microanalysis: C14H17F3N2S 4 '366.31 g
CHFNS% calculated 45.90 4.68 15.56 7.65 8.75% found 46.2 4.8 15.6 7.6 9.0
Study of herbicidal activity 1) Method.

 Horticultural test plant crops containing 5 seedlings per pot in an earthy mixture of clay loam-sandy loam (75%), river sand (12.5%) and potting soil (12.5%) are treated either immediately after sowing (pre-emergence test (H)), or at the two-leaf stage of the seedling (post-emergence test (K)), by spraying a suspension of the active ingredient in a water mixture -acetone at doses of 2.5 kilograms per hectare.

 The controls in the pre-emergence tests are carried out 28 days after treatment and in the post-emergence tests 21 days after treatment.

 This defines an overall efficiency (EF) taking into account, on the one hand, the actual mortality (MR) and, on the other hand, the weight reduction (RP) of the still alive samples, (MR) and (RP) being expressed as a percentage compared to untreated controls.

MR + ((100 - MR) x RP]
EF =
100
The following table summarizes for each product the overall efficacy calculated from the results of the 2.5 kg / ha trials on the following species - Triticum sativum (Winter Soft Wheat Variety Festival) (BTH) - Beta vulgaris (Ceres monogamous beet variety) (BE) - Brassica sp (Winter rapseed variety Jet New) (CH) - Gallium apasine (Cleavers) (G) - Chenopodium album (Goosefoot) (C) - Alopecurus myosuroïdes (Vulpin ) (V).

<Tb>

Product <SEP> of <SEP> I <SEP> I <SEP> I <SEP> I <SEP> I <SEP> I <SEP> I
<tb> the example <SEP> REST <SEP> BTH <SEP> V <SEP> BE <SEP> CH <SEP> C <SEP> G
<tb><SEP> 2 <SEP> H <SEP> 25 <SEP> 100 <SEP> 100 <SEP> 94 <SEP> 100 <SEP> 81
<tb><SEP> K <SEP> 0 <SEP> 88 <SEP> 75 <SEP> 98 <SEP> 95 <SEP> 88
<tb><SEP> 26 <SEP> H <SEP> 0 <SEP> 100 <SEP> 100 <SEP> 88 <SEP> 98 <SEP> 55
<tb><SEP> K <SEP> 44 <SEP> 100 <SEP> 100 <SEP> 100 <SEP> 100 <SEP> 100
<tb><SEP> H <SEP> 0 <SEP> 32 <SEP> 100 <SEP> 98 <SEP> 88 <SEP> 32
<tb><SEP> 20 <SEP> t <SEP>#<SEP><SEP> l <SEP> l <SEP><SEP> l <SEP>
<tb><SEP> K <SEP> 0 <SEP> 0 <SEP> 100 <SEP> 85 <SEP> 65 <SEP> 95
<tb><SEP> I <SEP> H <SEP>#<SEP><SEP> 62 <SEP> 1 <SEP> 100 <SEP> 1 <SEP> 100 <SEP> 1 <SEP> 98 <SEP> 1 <SEP> 100 <SEP> 1 <SEP> 92 # <SEP>
<tb><SEP> 22
<tb><SEP> K <SEP> 55 <SEP> 94 <SEP> 98 <SEP> 100 <SEP> 75 <SEP> 100
<tb><SEP> H <SEP> 62 <SEP> 100 <SEP> 100 <SEP> 100 <SEP> 100 <SEP> 100
<tb><SEP> 1 <SEP> K <SEP> 32 <SEP> 100 <SEP> 100 <SEP> 100 <SEP> 83 <SEP> 100
<tb><SEP> H <SEP> 0 <SEP> 62 <SEP> 100 <SEP> 100 <SEP> 90 <SEP> 88
<tb><SEP> 12 <SEP> K <SEP> 0 <SEP> 40 <SEP> 92 <SEP> 81 <SEP> 0 <SEP> 100
<Tb>

<tb> 6 <SEP> H <SEP> 25 <SEP> 100 <SEP> 98 <SEP> 90 <SEP> 100 <SEP> 100
<tb> K <SEP> 32 <SEP> 94 <SEP> 100 <SEP> 100 <SEP> 0 <SEP> 100
<tb> I <SEP> I <SEP> I <SEP><SEP> I <SEP> I <SEP> I <SEP> I <SEP>
<tb> 9 <SEP> H <SEP> 100 <SEP> 100 <SEP> 100 <SEP> 100 <SEP> 100 <SEP> 98
<tb> K <SEP> 50 <SEP> 100 <SEP> 100 <SEP> 100 <SEP> 75 <SEP> 50
<tb> 17 <SEP> H <SEP> 0 <SEP> 44 <SEP> 81 <SEP> 99 <SEP> 25 <SEP> 25
<tb> K <SEP> 25 <SEP> 25 <SEP> 100 <SEP> 100 <SEP> 100 <SEP> 100
<Tb>
These results show the interest of using the products of formula (I) as herbicides and especially those of Examples 1, 2, 9, and 26.

 The dose of 2.5 kilograms per hectare of use of the products of formula (I) is not limiting and according to the crop, the state of the soil, the climatic conditions and the method of spreading, can vary from 0, 1 to 10 kilograms per hectare.

EXAMPLE 27 Emulsifiable concentrate according to the invention
A composition containing 15% by weight of product of Example 1, 6.4% of atlox 4851 (oxyethylene triglyceride combined with a sulfonate, acid number 1.5) was prepared. 3.2% of atlox 4855 (oxyethylene triglyceride combined with a sulfonate, acid number 3) and 75.4% xylene.

EXAMPLE 28 Wettable Powder According to the Invention
A wettable powder containing 25% of compound of Example 1, 15% of ekapersol (condensation product of sodium naphthalene sulphonate, 0.5% of brecolane) was prepared.
NVA (sodium alkyl naphthalene sulfonate) 34.5% zeozil 39 (synthetic hydrated silica precipitated) and 25% vercoryl "S" (colloidal kaolin).

Claims (9)

1) The products of formula (I)

 in which n is 0, 1 or 2 and R is a saturated or unsaturated, substituted or unsubstituted, cyclic or acyclic hydrocarbon radical containing from one to fourteen carbon atoms, it being understood that when n is 0, R can not represent a saturated and unsubstituted acyclic hydrocarbon radical containing one to four carbon atoms. 2) The products defined according to claim 1 and having the formula (I1):

 in which R 1 represents a saturated or unsaturated acyclic hydrocarbon radical containing from one to four carbon atoms, which radical may be substituted by a phenyl radical itself optionally substituted by one or more halogen atoms, it being understood that when n is equal to 0, R1 can not represent a saturated and unsubstituted acyclic hydrocarbon radical containing from one to four carbon atoms. 3) The products as defined in any one of claims 1 or 2 wherein n is 1 or 2. 4) The products as defined in any one of claims 1 to 3 whose names follow - 4-C4- (tert-butylsulfonyl) 3- (trifluoromethyl) phenyl) 5,6-dihydro-2-methyl 2H-1 2,4-oxadiazin-3 (4H) -one - 5,6-dihydro-2-methyl-4- (4- (propylsulfonyl) -3- (trifluoromethyl) phenyl] -2H-1,2,4-oxadiazin-3 ( 4H) -one - 4- [4- (butylsulfinyl) -3- (trifluoromethyl) phenyl] -5,6-dihydro-2-methyl-2H-1,2,4-oxadiazin-3 (4H) -one 5,6-dihydro-2 methyl 4- [4- (propylsulfinyl) -3- (trifluoromethyl) phenyl) -2H-1,2,4-oxadiazin-3 (4H) -one - 5,6-dihydro-2-methyl-4- (4 - (( 1-methylethylsulfonyl] 3 (trifluoromethyl) phenyl] 2H-1,2,4-oxadiazin-3 (4H) -one - 4- [4- (cyclohexylsulfonyl) -3- (trifluoromethyl) phenyl] 5,6- dihydro-2-methyl-2H-1,2,4-oxadiazin-3 (4H) -one - 5,6-dihydro-2-methyl-4- [4- (1-methylpropyl) sulfonyl] -3 (trifluoromethyl) phenyl] 2H-1,2,4-oxadiazin-3 (4H) -one - 5,6-dihydro-2-methyl-4- (4 - ((2-propenyl) sulfonyl] -3- (trifluoromethyl) phenyl) 2H-1, 2,4-oxadiazin-3 (4H) -one - 5,6-dihydro-2-methyl-4- [4 - ((phenylmethyl) sulfinyl] -3 (trifluoromethyl) phenyl] -2H-1,2,4-oxadiazin-3 (4H) -one. 5) Process for the preparation of the products of formula (I) as defined in claim 1 characterized in that the product of formula (II):

 in which X represents a halogen atom is treated with an alkali metal thiolate of formula (III ')  R'-S M + (III ') in which M + represents an alkali metal cation and R' has the meaning of R as defined in claim 1 when n is one or two, to yield the product of formula (IV ')

 of which the thioether function is oxidized to obtain, according to the chosen oxidant, the product of formula (IVb) or the product of formula (IVc)

 in which R has the meaning as defined in claim 1, product of formula (IVb) or (IVc) which is reduced to amine respectively, of formula (Vb) or (Vc)

 and, after salification, transforming into isocyanate, respectively of formula (VIb) or (VIc)

  product of formula (VIb) or (VIC) which by reaction in the presence of a base with an N-methyl hydroxylamine salt of formula (VII)  CH 3 -NH-OH (VII) respectively leads to the product of formula (VIIIb) or (VIIIc)

 product of formula (VIIIb) or (VIIIc) which, treated in the presence of a base and preferably in a polar solvent with a 1,2-dihaloethane of formula (IX)  Y-CH 2 -CH 2 -Y (IX) in which Y represents a chlorine or bromine atom, respectively leads to the product of formula (Ib), corresponding to formula (I) in which n is equal to 1, or to the product of formula (Ic) corresponding to formula (I) in which n is equal to 2

 (Ib) (Ic) or the nitro function is reduced to obtain the amine of formula (V ')

 product of formula (V ') which, using the method of preparation of the products of formula (Ib) or (Ic) from amines of formulas (Vb) or (Vc) described above respectively, leads successively to the products of formula ( VI ')

 product of formula (I ') which, when R' does not represent a saturated and unsubstituted acyclic hydrocarbon radical containing from one to four carbon atoms, corresponds to the product of formula (Ia) and product of formula (I ') which if necessary is oxidized to its thioether function to give, according to the oxidant used, the product of formula (Ib) or the product of formula 6) Variant of the process according to claim 5 characterized in that the amine of formula (X)

 is salified and then successively transformed into a product of formulas (XI), (XII) then (XIII)

 and the product of formula (XIII) is subjected to the action of the alkali thiolate of formula (III ') as defined in claim 5 to obtain the product of formula (I') as defined in claim 5 which if necessary is oxidized to a product of formula (Ib) or 7) Variant of the process according to claim 5 characterized in that the product of formula (XIV)

  is cyclized by the action of a dihalo ethane of formula (IX) in a polar solvent and in the presence of a base product of formula (XV) ::

 product of formula (XV) which is subjected to the action of a thiol of formula (XVI ')  R'SH (XVI ') in which R' has the meaning defined above, in the presence of a cuprous salt, leads to the product of formula (I ') as defined in claim 5 which, if necessary is oxidized to product of formula (Ib) or 8) The use as herbicides of the products defined in claim 1 or 2. 9) Use as herbicides of the products of formula (I) whose names follow - 4- [4- (tert-butylsulfonyl) 3- (trifluoromethyl) phenyl] 5,6-dihydro-2-methyl-2H-1,2,4 -oxadiazin-3 (4H) -one - 5,6-dihydro-2-methyl-4- (4-propylsulfonyl) -3- (trifluoromethyl) phenyl] -2H-1,2,4-oxadiazin-3 (4H) -one - 4- [4- (Butylsulfinyl) -3- (trifluoromethyl) phenyl] -5,6-dihydro-2-methyl-2H-1,2,4-oxadiazin-3 (4H) -one - 5,6-dihydro-2-methyl-4- (4- (propylsulfinyl) -3- (trifluoromethyl) phenyl] -2H-1,2,4-oxadiazin-3 (4H) -one - 5,6-dihydro-2-methyl-4- [4 - [(1-methylethyl) ) sulfonyl] 3 (trifluoromethyl) phenyl] 2H-1,2,4-oxadiazin-3 (4H) -one - 4- [4- (cyclohexylsulfonyl) 3- (trifluoromethyl) phenyl] 5,6-dihydro-2-methyl 2H-1,2,4-oxadiazin-3 (4H) -one - 5,6-dihydro-2-methyl-4- (4 - [(1-methylpropyl) sulfonyl] -3 (trifluoromethyl) phenyl] 2H-1, 2,4-oxadiazin-3 (4H) -one - 5,6-dihydro-2-methyl-4- [4 - ((2-propenyl) sulfonyl] -3- (trifluoromethyl) phenyl) -2H-1,2,4-diol oxadiazin-3 (4H) -one - l e 5,6-dihydro-2-methyl-4- (4 - [(phenylmethyl) sulfinyl] 3 (trifluoromethyl) phenyl] 2H-1,2,4-oxadiazin-3 (4H) -one. 10) Compositions according to claim 8 characterized in that they contain as active ingredient, at least one of the products of formula (I) as defined in any one of claims 1 or 2. 11) Compositions according to claim 9 characterized in that they contain at least one of the products as defined in claim 3. 12) The intermediate products of the process and its variants, as defined in claims 5 to 7 and corresponding to formulas (VIa), (VIb), (VIC), (VIIIa), (VIIIb), (XI), (XII ), (XIII), (XIV) and (XV), it being understood that the products of formulas (VIa) and (VIlla) respectively correspond to the products of formulas (VI ') and (VIII') in which R 'does not represent a saturated and unsubstituted acyclic hydrocarbon radical containing from one to four carbon atoms.