MXPA97008398A

MXPA97008398A - Procedure for the obtaining of ariluracilos substitui

Info

Publication number: MXPA97008398A
Application number: MXPA/A/1997/008398A
Authority: MX
Inventors: Wilhelm Drewes Mark; Gallenkamp Bernd; Andree Roland
Original assignee: Bayer Aktiengesellschaft
Priority date: 1995-05-03
Filing date: 1997-10-31
Publication date: 1998-02-01

Abstract

The invention relates to a new process for the preparation of substituted aryluracils, in which aminoalkenoic acid reactants are made with arylurethanes and, subsequently, with sulfonamides, and, in addition, refers to the new 4- (alkoxycarbonylamino) -2,5 -di-fluorobenzonitrile

Description

PROCEDURE FOR THE OBTAINING OF SUBSTITUTE ARILURACILES DESCRIPTION OF THE INVENTION The invention relates to a new process for the preparation of substituted aryluracils, which are known as compounds with herbicidal activity. It is known that certain substituted aryluracils are obtained, such as, for example, 1- (4-cyano-2-fluoro-5-ethylsulfonylamino-phenyl) -3,6-dihydro-2,6-dioxo-4-tri -fluoromethyl-1 (2H) -pyrimidine, if the 3-amino-4,4,4-trifluoromethyl crotonate is reacted with sodium hydride in dimethylformamide / toluene and, afterwards, with 4-cyano-2 , 5-difluorophenylisocyanate and 1- (4-cyano-2,5-di-fluoro-phenyl) -3,6-dihydro-2,6-dioxo-4-trifluoromethyl-l (2H) -pyrimidine, thus obtained, it is reacted with ethanesulfonamide (see DE 4412079). In this way of obtaining sodium hydride, which is unsuitable for industrial purposes, is used as an acid acceptor and the reaction is carried out in several stages. It has now been found that substituted aryluracils of the general formula (I) are obtained, REF: 25872 where R 1 signifies hydrogen or halogen, R 2 signifies cyano, halogen, thiocarbamoyl or 1-quilo, optionally substituted, R 3 signifies alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, aryl or arylalkyl, optionally substituted, R 4 is hydrogen, halogen or alkyl, optionally substituted and R 5 is alkyl, optionally substituted, with good yields, if aminoalkenoic acid esters of the general formula (II) are reacted wherein R 4 and R 5 have the meanings given above and R means alkyl, aryl or arylalkyl, with aryl urethanes (arylcarbamates) of the general formula (III) wherein R1 and R2 have the meanings indicated above, R means alkyl, aryl or arylalkyl and X signifies halogen, in the presence of an alkali metal alcoholate or a metal carbonate as the acid accepting agent and in the presence of an aprotic solvent. at temperatures between -20 and +150 ° C ("first stage") and, if necessary after intermediate isolation, the intermediate-formed aryluracils of the general formula (Ia) are reacted wherein R1, R2, R4, R5 and X have the meanings given above, with sulfonamides of the general formula (IV) H2N-S02-R- (IV) wherein R 3 has the meaning indicated above, in the presence of a metal carbonate as an acid-accepting agent and in the presence of an aprotic-polar solvent, if appropriate under an inert gas atmosphere, at temperatures between 20 ° C and 200 ° C ("second stage"). Surprisingly, the substituted aryluracils of the general formula (I) can be prepared more easily than in the case of the prior art, in good yields and with high purity, according to the process of the invention. The method according to the invention thus represents a valuable enrichment of the state of the art. The process according to the invention preferably relates to the preparation of compounds of the formula (I), in which R 1 is hydrogen, fluorine, chlorine or bromine, R 2 is cyano, fluorine, chlorine, bromine, thiocarbamoyl or alkyl. with 1 to 4 carbon atoms substituted, if appropriate, by fluorine and / or by chlorine, R3 means alkyl, alkenyl or alkynyl with respectively up to 6 carbon atoms, respectively substituted, if appropriate by cyano, by fluorine, by chlorine, by bromine or by alkoxy with 1 to 4 carbon atoms, means cycloalkyl or cycloalkylalkyl, with 3 to 8 carbon atoms in the cycloalkyl part and, optionally, 1 to 4 carbon atoms in the alkyl part, substi tuted respectively In the case given by cyano, by fluorine, by chlorine, by bromine or by alkyl with 1 to 4 carbon atoms, it means aryl or arylalkyl with 6 or 10 carbon atoms in the aryl part and, if appropriate, 1 to 4 atoms of carbon in the alkyl part, respectively substituted, if appropriate, by fluorine, chlorine, bromine, cyano, nitro, carboxy, carbamoyl, thiocarbamoyl, alkyl with 1 to 4 carbon atoms, alkoxy with 1 to 4 carbon atoms, by alkylthio with 1 to 4 carbon atoms, by alkylsulfinyl with 1 to 4 carbon atoms or by alkylsulfonyl with 1 to 4 carbon atoms (which are respectively substituted, if appropriate, by fluorine and / or by chlorine), by dimethylamino -sulfonyl or diethylaminosulfonyl, by alkoxycarbonyl having 1 to 4 carbon atoms (which is optionally substituted by fluorine, by chlorine, by bromine, by cyano, by methoxy or by ethoxy), by phenyl, by phenyloxy or by phenylthio (which are respectively substituted, if appropriate, by fluorine, chlorine, bromine, cyano, methyl, methoxy, trifluoromethyl and / or trifluoromethoxy), means hydrogen, fluorine, chlorine, bromine or alkyl with 1 to 6 carbon atoms substituted if necessary by fluorine and / or by chlorine and R5 means alkyl having 1 to 6 carbon atoms, optionally substituted by fluorine, chlorine, bromine, methoxy or ethoxy. The process according to the invention relates in particular to the preparation of compounds of the formula (I), wherein R 1 signifies hydrogen, fluorine or chlorine, "R 2 signifies cyano, fluorine, chlorine, bromine, thiocarbamoyl, methyl or trifluoromethyl, R 3 signifies methyl, ethyl, n- or i-propyl, n-, i-, s- or t-butyl, ethenyl, propenyl, butenyl, ethynyl, propynyl or butynyl substituted, where appropriate, by cyano, fluorine, chlorine, methoxy or ethoxy, means cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, cyclobutylmethyl, cyclopentylmethyl or cyclohexylmethyl respectively substituted, where appropriate, by cyano, by fluorine, by chlorine, by bromine, by ethyl, by n- or i-propyl, means phenyl, naphthyl, benzyl or phenylethyl substituted respectively, where appropriate fluorine, chlorine, bromine, cyano, nitro, carboxy, carbamoyl, thiocarbamoyl, methyl, ethyl, n- or i-propyl, trifluoromethyl, methoxy, by ethoxy, by n- or i-propoxy, by difluoromethoxy, by trifluoromethoxy, by methylthio, by ethyl thio, by n- or i-propylthio, by ethylsulphinyl, by ethylsulfinyl, by n- or i-propylsulfinyl, by methylsulfonyl, by ethylsulfonyl, by n- or i-propylsulfonyl, by dimethylaminosulfonyl or by diethylaminosulfonyl, by methoxycarbonyl, ethoxycarbonyl, by n- or i-propoxycarbonyl, R 4 is hydrogen, fluorine, chlorine, bromine, methyl, ethyl or trifluoromethyl and R 5 is methyl, ethyl, trifluoromethyl, chlorodifluoromethyl, fluoride-chloromethyl or pentafluoroethylene. If they are used, for example, the methyl 3-amino-crotonate and the N- (4-cyano-2, 5-difluoro-phenyl) -O-methyl-urethane as well as the methanesulfonamide as starting products and the potassium carbonate as an acid acceptor, the development of the reaction in the process according to the invention can be schematized by means of the following formula scheme: The esters of the aminoalkenoic acids, to be used as starting materials in the process according to the invention for the preparation of the compounds of the formula (I), are generally defined by the formula (II). In formula (II), R4 and R5 preferably have or especially those meanings which have already been indicated in a preferred manner or, more particularly, for R4 and R5 in connection with the description of the compounds to be obtained according to the invention. expiration of formula (II); R preferably means alkyl having 1 to 4 carbon atoms, phenyl or benzyl, especially means methyl, ethyl or phenyl. The starting materials of the formula (II) are known and / or can be prepared according to known procedures (see J. Heterocycl, Chem. 9 (1972), 513-522). The aryl urethanes to be further used as starting materials for the process according to the invention, for the preparation of the compounds of the formula (I), are generally defined by the formula (III). In the formula (III), R1 and R2 preferably have or especially those meanings which have already been indicated preferably or particularly preferably for R1 and R2 in relation to the description of the compounds to be obtained according to the invention of the formula (I); R preferably means alkyl having 1 to 4 carbon atoms, phenyl or benzyl, especially means methyl, ethyl or phenyl, X preferably means fluorine, chlorine or bromine, especially fluorine or chlorine. The starting materials of the formula (III) are known and / or can be prepared according to known processes (see DE 4412079, examples of preparation). The sulfonamides to be further employed as starting materials in the process according to the invention for the preparation of the compounds of the formula (I) are generally defined by the formula (IV). In formula (IV), R 3 preferably has, in particular, those meanings which have already been indicated as being preferred or, more particularly, R 3 in relation to the description of the compounds to be obtained according to the invention of the formula ( I). The starting materials of formula (IV) without chemical products for known synthesis. The process according to the invention is carried out in the first step with the use of a metal alcoholate or a metal carbonate as the acid-accepting agent. Preference is given to using alkali metal alcoholates as acid-binding agents., such as lithium, sodium, potassium alcoholates with 1 to 5 carbon atoms, especially methylate, ethylate, n- or i-propylate, n-, i-, s- or sodium t-butylate or of potassium, or carbonates of alkali metals or alkaline-earth metals, such as lithium, sodium, potassium, magnesium and calcium carbonate, especially potassium carbonate. The process according to the invention is carried out in the second stage with the use of a metal carbonate as acid-accepting agent. The alkali metal and alkaline earth metal carbonates, such as lithium carbonate, sodium carbonate, potassium carbonate, magnesium carbonate and calcium carbonate, are preferably used as acid-binding agents. Potassium carbonate will be especially preferred as acid accepting agent. The process according to the invention is carried out - in both steps - in the presence of an aprotic-polar solvent. Examples of these solvents which may be mentioned are ketones such as methyl ethyl ketone, methyl-i-propyl ketone and methyl-i-butyl ketone, esters such as ethyl acetate, n- or i-propyl acetate and n-acetate, i- or s-butyl, nitriles, such as acetonitrile, propionitrile or butyronitrile, amides such as dimethylformamide and dimethylacetamide, furthermore dimethylsulfoxide, tetramethylene sulfone (sulfolane), N-methyl-pyrrolidone and hexa-methylphosphorotriamide. In the process according to the invention, N-methyl-pyrrolidone in the form of a solvent will be very particularly preferred. The reaction temperatures in carrying out the first step of the process according to the invention can vary within wide limits. In general, work is carried out at temperatures between -20 ° C and 100 ° C, preferably between 0 ° C and 80 ° C, especially between 0 ° C and 60 ° C. The reaction temperatures in the embodiment of the second stage of the process according to the invention can also vary within wide limits. In general, work is carried out at temperatures between 20 ° C and 200 ° C, preferably between 50 ° C and 180 ° C, especially between 80 ° C and 160 ° C. The process according to the invention will be carried out - in both stages - in general under normal pressure. However, it is also possible to carry out the process according to the invention under higher pressure or at a lower pressure - generally between 0.1 bar and 10 bar To carry out the process according to the invention for the preparation of the substituted aryluracils of the formula (I), generally between 0.5 and 1.5 are used per mole of the aminoalkenoic acid ester of the formula (II). moles, preferably between 0.7 and 1.3 moles of arylurethane of the formula (III) and between 0.5 and 2.0 moles, preferably between 0.8 and 1.5 moles of the sulfonamide of the formula (IV). In a preferred embodiment of the process according to the invention, the aminoalkenoic acid ester of the formula (II) is heated with an alkali metal or alkaline earth metal carbonate in an aprotic-polar solvent with stirring to approximately 100 ° C. The aryl urethane of the formula (III) is then added and the mixture is heated for some time at a somewhat elevated temperature - approximately at 120 ° C to 150 ° C -, whereby the alcohol, released during the reaction, is distilled off . Next, a sulfonamide of the formula (IV) and, if appropriate, an alkali metal or alkaline earth metal carbonate are added and the mixture is stirred, at the above-mentioned elevated temperature, until the end of the reaction. It is then diluted with water, washed with an organic solvent practically immiscible with water, such as, for example, methylene chloride, the aqueous phase is acidified with a strong acid, such as, for example, hydrochloric acid, extracted with an organic solvent practically immiscible with water, such as, for example, methylene chloride, the extraction solution is washed with water and concentrated by vacuum evaporation of the water tube. The residue is digested with water and the precipitated crystalline product is isolated by suction filtration. The substituted aryluracils prepared according to the process of the invention are already known as compounds with herbicidal activity (see DE 4412079). Preparation examples; Example 1 A mixture consisting of 27.6 g (0.15 mol) of ethyl 3-amino-4,4,4-trifluoro-crotonate, 27.6 g (0.20 mol) of potassium carbonate (powder) is stirred. and 100 ml of N-methyl-pyrrolidone, under nitrogen atmosphere, for one hour at 100 ° C. Then 22.8 g (0.10 mol) of N- (4-cyano-2,5-difluoro-phenyl) -O-ethyl-urethane are added and the mixture is stirred for approximately 4 hours at 13'0 ° C. in the water separator, removing ethanol by distillation. Subsequently, 16.4 g (0.12 mole) of ethanesulfonamide (80% strength) and 13.8 g (0.10 mole) of potassium carbonate (powder) are added at 130 ° C and the mixture is stirred for 2 hours at 130 ° C and another 16 hours at 140 ° C. After the reaction is complete, pour the mixture into 750 ml of water and wash three times with 250 ml of methylene chloride each time. The aqueous phase is acidified with approximately 10% hydrochloric acid and extracted three times with 300 ml of methylene chloride each time. The combined organic phases are washed twice with 250 ml each time of water and concentrated by evaporation under vacuum of the water pump. The residue is stirred with 250 ml of water and the crystalline product, precipitated, is isolated by suction filtration. 28.3 g (70% of theory) of 1- (4-cyano-5-ethylsulfonylamino-2-fluoro-phenyl) -3,6-dihydro-2,6-dioxo-4-trifluoromethyl-1 (2H) are obtained. ) -pyrimidine with a melting point of 228 ° C. Example 2 (first stage) 184 g of sodium methylate (97%, 3.3 moles) in 2000 ml of N-methyl-pyrrolidone (NMP) and combine, at 0 ° C to 5 ° C, with a solution of 617 g of 3-amino-4,4,4-trifluoro-crotonate of ethyl (98%, 3.3 moles) in 100 ml of NPM over the course of about 90 minutes. The mixture is stirred for about 60 minutes at room temperature (about 20 ° C) and then heated to about 125 ° C, whereby methanol is removed by distillation and the internal temperature increases in this case, slowly, until about -With 120 ° C. After approximately 90 minutes, 632 g of N- (4-cyano-2) are added to the mixture., 5-difluoro-phenyl) -0-ethylurethane (98%, 2.75 mol) and the reaction mixture is then stirred for approximately 5 hours at 135 ° C to 140 ° C, the alcohol released being largely distilled off . The NMP is then thoroughly distilled off, the residue is taken up in 14 liters of water and, after the addition of 1 liter of i-propanol, it is slowly acidified with 10% hydrochloric acid (approximately 750 ml). The mixture is stirred for two hours at 20 ° C, allowed to stand for about 15 hours and then separated by filtration by suction. The solid crude product is suspended in 2750 ml of i-propanol, the mixture is stirred for two hours under reflux and for a further 15 hours at 20 ° C. The purified product is then isolated by suction filtration. 549 g (63% of theory) of l- (4-cyano-2,5-difluoro-phenyl) -3,6-dihydro-2,6-dioxo-4-trifluoromethyl-1 (2H) are obtained. ) -pyrimidine with a melting point of 194 ° C. Example 3 (second stage) 333 g of 1- (4-cyano-2,5-difluoro-phenyl) -3,6-dihydro-2,6-dioxo-4-trifluoromethyl-1 (2H) -pyrimidine (1) are dissolved. , 05 moles) and 201 g of ethanesulfonamide (1.47 moles) in 1050 ml of N-methyl-pyrrolidone (NMP) and combined with 435 g of potassium carbonate (3 ', 15 moles). The mixture is then stirred for 16 hours at 135 ° C. The NMP is then thoroughly distilled off, the residue is taken up in 7.5 liters of water, combined with 250 ml of methylene chloride, acidified with 10% hydrochloric acid and stirred for approximately 2 hours at 20 ° C. . The crystalline product, precipitated, is then isolated by suction filtration. 355 g (96.7%, 80.5% of the theory) of 1- (4-cyano-5-ethylsulfonylamino-2-fluoro-phenyl) -3,6-dihydro-2,6 are obtained -dioxo-4-trifluoromethyl-l (2H) -pyrimidine with a melting point of 228 ° C. Example 4 (second stage) 190 g of 1- (4-cyano-2,5-difluoro-phenyl) -3,6-dihydro-2,6-dioxo-4-trifluoromethyl-1 (2H) -pyrimidine is dissolved. (97.2%, 0.58 moles) and 68.5 g of methane sulfone (96.4%, 0.70 moles) in 800 ml of N-methyl-pyrrolidone (NMP) and combine with 328 g of potassium carbonate (2.37 moles). The mixture is stirred for 17 hours at 135 ° C. The NMP is then thoroughly distilled off, the residue is taken up in 2.75 liters of water, combined with 1500 ml of methylene chloride, acidified with 10% hydrochloric acid and stirred for approximately 2 hours at 20 ° C. . The crystalline product, precipitated, is then isolated by suction filtration (first product fraction). 84.5 g (98.9%) of l- (4-cyano-5-methylsulfonylamino-2-fluoro-phenyl) -3,6-dihydro-2,6-dioxo-4-trifluoromethyl-1 are obtained. (2H) -pyrimidine with a melting point of 248 ° C. The filtrate is shaken, the organic phase is separated, the aqueous phase is shaken with methylene chloride, the combined organic phases are washed with water and then concentrated by evaporation. The residue is stirred with 1.5 liters of water and 150 ml of i-propanol for three hours; then the crystalline product, precipitated, is isolated by suction filtration (second product fraction). 178 g (92%) of 1- (4-cyano-5-methylsulfonylamino-2-fluoro-phenyl) -3,6-dihydro-2,6-dioxo-4-trifluoromethyl-1 (2H) are obtained pyrimidine with a melting point of 248 ° C. Total yield: (80 * of the theory). Starting products of the formula (III); Example (III-l) 630 g of 4-amino-2,5-difluoro-benzo-nitrile (97.8%, 4.0 moles) and 475 g of pyridine (6.0 moles) are dissolved in 4000 ml of methylene chloride and combine, at 0 ° C to 10 ° C, over the course of about two hours, with 488 g of ethyl chloroformate (98%, 4.4 moles). The reaction mixture is then stirred for about 15 hours at about 20 ° C. After addition of another 11 g of ethyl chloroformate, the mixture is stirred for a further two hours at 20 ° C, diluted with 5 liters of methylene chloride, washed twice with 1250 ml of 3% hydrochloric acid each time and washed once. once with 1250 ml of water and the organic phase is concentrated by evaporation. The residue is stirred for one hour with 600 ml of methyl-butyl ether (MTBE) and the crystalline product is then isolated by suction filtration. 793 g of 4- (ethoxycarbonylamino) -2,5-difluoro-benzonitrile (98.5%, 86% of theory) are obtained with a melting point of 107 ° C. Analogously, 4- (methoxycarbonylamino) -2,5-difluoro-benzonitrile with a melting point of 129 ° C is also obtained.

The compounds prepared according to example (III-1) -4- (methoxycarbonylamino) -2,5-difluoro-benzonitrile and 4- (ethoxycarbonylamino) -2,5-difluoro-benzonitrile - are not yet known in the literature; they are also an object of the present application as new products. It is noted that, in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, the content of the following is claimed as property:

Claims

1.- Procedure for obtaining substituted aryluracils of the general formula (I) wherein R 1 is hydrogen or halogen, R 2 is cyano, halogen, thiocarbamoyl or alkyl, optionally substituted, R 3 is alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, aryl or arylalkyl, optionally substituted, R 4 is hydrogen , halogen or alkyl, optionally substituted and R 5 means alkyl, optionally substituted, characterized in that esters of aminoalkenoic acids of the general formula (II) are reacted (II). wherein R4 and R5 have the meanings indicated above and R means alkyl, aryl or arylalkyl, with aryl urethanes (arylcarbamates) of the general formula (III) wherein R1 and R2 have the meanings indicated above, R means alkyl, aryl or arylalkyl and X means halogen, in the presence of an alkali metal alcoholate or a metal carbonate as the acid accepting agent and in the presence of an aprotic-polar solvent at temperatures between -20 and +150 ° C. ("first stage") and then - if necessary after intermediate isolation - the aryluracils, formed in an intermediate manner, of the general formula (a) are reacted wherein R1, R2, R4, R5 and X have the meanings given above, with sulfonamides of the general formula (IV) H2N-S02-R3 (IV) wherein R 3 has the meaning indicated above, in the presence of a metal carbonate as an acid-accepting agent and in the presence of an aprotic-polar solvent, if appropriate under an inert gas atmosphere, at temperatures between 20 ° C and 200 ° C ("second stage").

2. Process for obtaining substituted aryluracyls of the general formula (I), according to claim 1, characterized in that R1 means hydrogen, fluorine, chlorine or bromine, R2 means cyano, fluorine, chlorine, bromine, thiocarbamoyl or alkyl having 1 to 4 carbon atoms substituted, if appropriate, by fluorine and / or by chlorine, R3 means alkyl, alkenyl or alkynyl with respectively up to 6 carbon atoms, each optionally substituted by cyano, by fluorine, by chlorine, by bromine or by alkoxy with 1 to 4 carbon atoms, means cycloalkyl or cycloalkylalkyl, with 3 a 8 carbon atoms in the cycloalkyl part and, optionally, from 1 to 4 carbon atoms in the alkyl part, each optionally substituted by cyano, by fluorine, by chlorine, by bromine or by alkyl with 1 to 4 atoms of carbon, means aryl or aryl-alkyl having 6 or 10 carbon atoms in the aryl part and, optionally, 1 to 4 carbon atoms in the alkyl part, respectively substituted, if appropriate, by fluorine, by chlorine, by bromine , by cyano, by nitro, by carboxy, by carbamoyl, by thiocarbamoyl, by alkyl with 4 carbon atoms, by alkoxy with 1 to 4 carbon atoms, by alkylthio with 1 to 4 carbon atoms, by alkylsulfinyl with 1 a 4 carbon atoms or by alkylsulfonyl with 1 to 4 carbon atoms (which are respectively substituted, if appropriate, by fluorine and / or by chlorine), by dimethylamine-sulfonyl or by diethylaminosulfonyl, by alkoxy-carbonyl with 1 to 4 carbon atoms (which is substituted in case given by fluorine, chlorine, bromine, cyano, methoxy or ethoxy), phenyl, phenyloxy or phenylthio (substituted respectively by fluorine, chlorine, bromine, cyano, methyl, by methoxy, by trifluoromethyl and / or by tri-fluoro- totoxy), means hydrogen, fluorine, chlorine, bromine or means alkyl having 1 to 6 carbon atoms substituted, if appropriate, by fluorine and / or chlorine and R5 means alkyl having 1 to 6 carbon atoms, optionally substituted by fluorine, chlorine, bromine, methoxy or ethoxy.

3. Process for obtaining substituted aryluracils of the general formula (I), according to claim 1, characterized in that R1 means hydrogen, fluorine or chlorine, R2 means cyano, fluorine, chlorine, bromine, thiocarbamoyl, methyl or trifluoromethyl, R3 means methyl, ethyl, n- or i-propyl, n-, i-, s- or t-butyl, ethenyl , propenyl, butenyl, ethynyl, propynyl or butynyl substituted, where appropriate, by cyano, fluorine, chlorine, methoxy or ethoxy, means cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, cyclobutylmethyl, cyclopentylmethyl or cyclohexylmethyl. substituted respectively by cyano, by fluorine, by chlorine, by bromine, by ethyl, by n- or i-propyl, means phenyl, naphthyl, benzyl or phenylethyl respectively substituted, if appropriate, by fluorine, by chlorine, by bromine, by cyano, by nitro, by carboxy, by carbamoyl, by thiocarbamoyl, by methyl, by ethyl, by n- or i-propyl, by trifluoromethyl, by methoxy, by ethoxy, by n- or i-propoxy, by difluoro ethoxy, by trifluoromethoxy, by methylthio, by ethylthio, by n- or i-propylthio, by ethylsulfi nyl, by ethylsulfinyl, by n- or i-propylsulfinyl, by methylsulfonyl, by ethylsulphonyl, by n- or i-propylsulfonyl, by dimethylaminosulfonyl or by diethylaminosulfonyl, by methoxycarbonyl, by ethoxycarbonyl, by n- or i-propoxycarbonyl, R4 means hydrogen , fluorine, chlorine, bromine, methyl, ethyl or trifluoromethyl and R5 means methyl, ethyl, trifluoromethyl, chlorodifluor ethyl, fluorochloromethyl or pentafluoroethylene.

4. Process for the preparation of 1- (4-cyano-no-5-ethylsulfonylamino-2-fluoro-phenyl) -3,6-dihydro-2,6-dioxo-4-methyl-1 (2H) -pyrimidine according to claim 1, characterized in that methyl 3-amino-crotonate and N- (4-cyano-2,5-difluoro-phenyl) -O-methyl-urethane are reacted as well as methanesulfonamide as starting materials and potassium carbonate as acceptor of acid according to the following is-formulas burn:

5. - Process for obtaining substituted aryluracils according to claims ia 4, characterized in that the reaction temperature in the first stage of the reaction varies in the range between -0 ° C and 80 ° C and in the second stage of the reaction. reaction in the range between 50 ° C and 180 ° C

6. Process for the preparation of substituted aryluracils according to claims 1 to 4, characterized in that this is carried out under normal pressure.

7. Process for the preparation of substituted aryluracils according to claims 1 to 4, characterized in that between 0.5 and 1.5 moles of arylurethane of the formula are used per mole of the aminoalkenoic acid ester of the formula (II). (III) and between 0.5 and 2.0 moles of sulfonamide of the formula (IV).

8.- 4- (Alkoxycarbonylamino) -2,5-difluorobenzoni-tryls of the formula (III) (ip), characterized in that R means methyl or ethyl.