Abstract:
A novel process for the preparation of benzonitrile compounds useful for herbicides or their intermediates is provided. A process for the preparation of compounds of the formula (1), characterized in comprising reacting a compound of the formula (1 a ) with one or more cyanides selected from potassium cyanide, sodium cyanide and zinc cyanide in the presence of a metallic catalyst.                            
     In the scheme, X is hydrogen, fluorine or chlorine atom; Z is nitro, amino or C 1 -C 4  alkylsulfonylamino group or the like; Y is fluorine, chlorine or bromine atom or the like; and Q is hydrogen atom, or nitro or amino group or the like.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a process for the preparation of benzonitrile compounds as described in U.S. Pat. No. 5,127,935 and JP-5-186436A, which are useful as herbicides and their intermediates. 
     2. Description of the Background 
     A process for the preparation of benzonitrile compounds is described in JP-9-48761A. Since the process includes the use of copper cyanide as a cyanizing agent, the industrial application thereof has the following problems. The treatment of a waste fluid is troublesome since the waste fluid contains copper which is one of the metals designated in Water Pollution Control Law. In addition, copper cyanide is expensive. Accordingly, the improvement of the above process has been demanded. 
     SUMMARY OF THE INVENTION 
     The present inventors concentrated on developing another process for the preparation of benzonitrile compounds useful as herbicides and their intermediates so as to solve the above problems. As the result, it was found that the benzonitrile compound can be obtained with a high yield by synthesizing it in the presence of a metallic catalyst even if potassium, sodium or zinc cyanide, which has a reactivity lower than that of copper cyanide, is used as a cyanizing agent. Thus, the present invention relates to the process for the preparation set forth below. 
     [1] A process for the preparation of benzonitrile compounds represented by the formula (1):                           
      wherein 
     X is hydrogen, fluorine or chlorine atom; 
     Z is nitro, amino, C 1 -C 4  alkylsulfonylamino, bis(C 1 -C 4  alkylsulfonyl)amino, (C 2 -C 5  alkoxycarbonyl)amino, (C 2 -C 5  alkylcarbonyl)amino, (optionally substituted benzoyl)amino, (C 2 -C 5  alkylcarbonyl)(C 1 -C 4  alkylsulfonyl)amino or (optionally substituted benzoyl)(C 1 -C 4  alkylsulfonyl)amino group; and 
     Q is hydrogen atom, or nitro, amino, (C 2 -C 5  alkoxycarbonyl)amino, 6-trifluoromethyl-2,4(1H,3H)-pyrimidinedione-3-yl, 1-methyl-6-trifluoromethyl-2,4(1H,3H)pyrimidinedione-3-yl or 1-amino-6-trifluoromethyl-2,4(1H,3H)pyrimidinedione-3-yl group, provided that if Z is nitro or amino group, then Q is (C 2 -C 5  alkoxycarbonyl)amino, 6-trifluoromethyl-2,4(1H,3H)pyrimidinedione-3-yl, 1-methyl-6-trifluoromethyl-2,4(1H,3H)pyrimidinedione-3-yl or 1-amino-6-trifluoromethyl-2,4(1H,3H)pyrimidinedione-3-yl group, characterized in that the process comprises reacting a halogenated benzene compound represented by the formula (1a):                           
     wherein X, Z and Q are as defined above, and Y is fluorine, chlorine, bromine or iodine atom, provided that if X is fluorine atom, then Y is chlorine, bromine or iodine atom, and if X is chlorine atom, then Y is bromine or iodine atom, 
      with one or more cyanides selected from potassium cyanide, sodium cyanide and zinc cyanide in the presence of a metallic catalyst. 
     [2] A process as described in the above item [1] wherein Z is C 1 -C 4  alkylsulfonylamino, bis(C 1 -C 4  alkylsulfonyl)amino, (C 2 -C 5  alkylcarbonyl)(C 1 -C 4  alkylsulfonyl)amino or (optionally substituted benzoyl)(C 1 -C 4  alkylsulfonyl)amino group. 
     [3] A process as described in the above item [1] wherein Z is C 1 -C 4  alkylsulfonylamino group. 
     [4] A process as described in the above item [1] wherein Q is 6-trifluoromethyl-2,4(1H,3H)pyrimidinedione-3-yl, 1-methyl-6-trifluoromethyl-2,4(1H,3H)pyrimidinedione-3-yl or 1-amino-6-trifluoromethyl-2,4(1H,3H)pyrimidinedione-3-yl group. 
     [5] A process as described in the above item [2] wherein Q is 6-trifluoromethyl-2,4(1H,3H)pyrimidinedione-3-yl, 1-methyl-6-trifluoromethyl-2,4(1H,3H)pyrimidinedione-3-yl or 1-amino-6-trifluoromethyl-2,4(1H,3H)pyrimidinedione-3-yl group. 
     [6] A process as described in the above item [3] wherein Q is 6-trifluoromethyl-2,4(1H,3H)pyrimidinedione-3-yl, 1-methyl-6-trifluoromethyl-2,4(1H,3H)pyrimidinedione-3-yl or 1-amino-6-trifluoromethyl-2,4(1H,3H)pyrimidinedione-3-yl group. 
     [7] A process as described in the above items [1] to [6] wherein palladium, nickel or platinum is used as the metallic catalyst. 
     [8] A process as described in the above items [1] to [6] wherein palladium is used as the metallic catalyst. 
     [9] A process as described in the above items [7] and [8] wherein a metal selected from zinc, iron, manganese, tin, copper, magnesium, chromium, titanium and aluminum or a halide of the metal is used as a co-catalyst. 
     [10] A process as described in the above items [7] and [8] wherein a halide of a metal selected from zinc, tin and copper is used as a co-catalyst. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The process of the present invention will be described in more detail. Scheme of the process of the present invention is as follows:                           
     wherein X, Y, Z and Q are as defined above. 
     In the process of the present invention, examples of Z include nitro, amino, methylsulfonylamino, ethylsulfonylamino, n-propylsulfonylamino, i-propylsulfonylamino, n-butylsulfonylamino, i-butylsulfonylamino, s-butylsulfonylamino, tert-butylsulfonylamino, bis(methylsulfonyl)amino, bis(ethylsulfonyl)amino, bis(n-propylsulfonyl)amino, bis(i-propylsulfonyl)amino, bis(n-butylsulfonyl)amino, bis(i-butylsulfonyl)amino, bis(s-butylsulfononyl)amino, bis(tert-butylsulfonyl)amino, methoxycarbonylamino, ethoxycarbonylamino, n-propoxycarbonylamino, i-propoxycarbonylamino, n-butoxycarbonylamino, i-butoxycarbonylamino, s-butoxycarbonylamino, tert-butoxycarbonylamino, acetylamino, propionylamino, n-butyrylamino, i-butyrylamino, benzoylamino, 2-bromobenzoylamino, 3-bromobenzoylamino, 4-bromobenzoylamino, 2-chlorobenzoylamino, 3-chlorobenzoylamino, 4-chlorobenzoylamino, 2-fluorobenzoylamino, 3-fluorobenzoylamino, 4-fluorobenzoylamino, 2-toluoylamino, 3-toluoylamino, 4-toluoylamino, 2-ethylbenzoylamino, 4-ethylbenzoylamino, 2-i-propylbenzoylamino, 4-i-propylbenzoylamino, 2-tert-butylbenzoylamino, 4-tert-butylbenzoylamino, 2-methoxybenzoylamino, 3-methoxybenzoylamino, 4-methoxybenzoylamino, 2-ethoxybenzoylamino, 3-ethoxybenzoylamino, 4-ethoxybenzoylamino, 2-i-propyloxybenzoylamino, 3-i-propyloxybenzoylamino, 4-i-propyloxybenzoylamino, 2-n-butoxybenzoylamino, 3-n-butoxybenzoylamino, 4-n-butoxybenzoylamino, acetyl(methylsulfonyl)amino, propionyl(methylsulfonyl)amino, n-butyryl(methylsulfonyl)amino, i-butyryl(methylsulfonyl)amino, acetyl(ethylsulfonyl)amino, propionyl(ethylsulfonyl)amino, n-butyryl(ethylsulfonyl)amino, i-butyryl(ethylsulfonyl)amino, acetyl(n-propylsulfonyl)amino, propionyl(n-propylsulfonyl)amino, n-butyryl(n-propylsulfonyl)amino, i-butyryl(n-propylsulfonyl)amino, benzoyl(methylsulfonyl)amino, 2-bromobenzoyl(methylsulfonyl)amino, 3-bromobenzoyl(methylsulfonyl)amino, 4-bromobenzoyl(methylsulfonyl)amino, 2-chlorobenzoyl(methylsulfonyl)amino, 3-chlorobenzoyl(methylsulfonyl)amino, 4-chlorobenzoyl(methylsulfonyl)amino, 2-fluorobenzoyl(methylsulfonyl)amino, 3-fluorobenzoyl-(methylsulfonyl)amino, 4-fluorobenzoyl(methylsulfonyl)amino, 2-toluoyl(methylsulfonyl)amino, 3-toluoyl(methylsulfonyl)amino, 4-toluoyl(methylsulfonyl)amino, 2-ethylbenzoyl(methylsulfonyl)amino, 4-ethylbenzoyl(methylsulfonyl)amino, 2-i-propylbenzoyl(methylsulfonyl)amino, 4-i-propylbenzoyl(methylsulfonyl)amino, 2-tert-butylbenzoyl(methylsulfonyl)amino, 4-tert-butylbenzoyl(methylsulfonyl)amino, 2-methoxybenzoyl(methylsulfonyl)amino, 3-methoxybenzoyl (methylsulfonyl)amino, 4-methoxybenzoyl(methylsulfonyl)amino, 2-ethoxybenzoyl(methylsulfonyl)amino, 3-ethoxybenzoyl(methylsulfonyl)amino, 4-ethoxybenzoyl(methylsulfonyl)amino, 2-i-propyloxybenzoyl(methylsulfonyl)amino, 3-i-propyloxybenzoyl(methylsulfonyl)amino, 4-i-propyloxybenzoyl(methylsulfonyl)amino, 2-n-butoxybenzoyl(methylsulfonyl)amino, 3-n-butoxybenzoyl(methylsulfonyl)amino, 4-n-butoxybenzoyl(methylsulfonyl)amino, benzoyl(ethylsulfonyl)amino, 2-bromobenzoyl(ethylsulfonyl)amino, 3-bromobenzoyl(ethylsulfonyl)amino, 4-bromobenzoyl(ethylsulfonyl)amino, 2-chlorobenzoyl(ethylsulfonyl)amino, 3-chlorobenzoyl(ethylsulfonyl)amino, 4-chlorobenzoyl(ethylsulfonyl)amino, 2-fluorobenzoyl(ethylsulfonyl)amino, 3-fluorobenzoyl(ethylsulfonyl)amino, 4-fluorobenzoyl(ethylsulfonyl)amino, 2-toluoyl(ethylsulfonyl)amino, 3-toluoyl(ethylsulfonyl)amino, 4-toluoyl(ethylsulfonyl)amino, 2-ethylbenzoyl(ethylsulfonyl)amino, 4-ethylbenzoyl(ethylsulfonyl)amino, 2-i-propylbenzoyl(ethylsulfonyl)amino, 4-i-propylbenzoyl(ethylsulfonyl)amino, 2-tert-butylbenzoyl(ethylsulfonyl)amino, 4-tert-butylbenzoyl(ethylsulfonyl)amino, 2-methoxybenzoyl(ethylsulfonyl)amino, 3-methoxybenzoyl(ethylsulfonyl)amino, 4-methoxybenzoyl(ethylsulfonyl)amino, 2-ethoxybenzoyl(ethylsulfonyl)amino, 3-ethoxybenzoyl(ethylsulfonyl)amino, 4-ethoxybenzoyl(ethylsulfonyl)amino, 2-i-propyloxybenzoyl(ethylsulfonyl)amino, 3-i-propyloxybenzoyl(ethylsulfonyl)amino, 4-i-propyloxybenzoyl(ethylsulfonyl)amino, 2-n-butoxybenzoyl(ethylsulfonyl)amino, 3-n-butoxybenzoyl(ethylsulfonyl)amino, 4-n-butoxybenzoyl(ethylsulfonyl)amino, benzoyl(n-propylsulfonyl)amino, 2-bromobenzoyl(n-propylsulfonyl)amino, 3-bromobenzoyl(n-propylsulfonyl)amino, 4-bromobenzoyl(n-propylsulfonyl)amino, 2-chlorobenzoyl(n-propylsulfonyl)amino, 3-chlorobenzoyl(n-propylsulfonyl)amino, 4-chlorobenzoyl(n-propylsulfonyl)amino, 2-fluorobenzoyl(n-propylsulfonyl)amino, 3-fluorobenzoyl(n-propylsulfonyl)amino, 4-fluorobenzoyl(n-propylsulfonyl)amino, 2-toluoyl(n-propylsulfonyl)amino, 3-toluoyl(n-propylsulfonyl)amino, 4-toluoyl(n-propylsulfonyl)amino, 2-ethylbenzoyl(n-propylsulfonyl)amino, 4-ethylbenzoyl(n-propylsulfonyl)amino, 2-i-propylbenzoyl(n-propylsulfonyl)amino, 4-i-propylbenzoyl(n-propylsulfonyl)amino, 2-tert-butylbenzoyl(n-propylsulfonyl)amino, 4-tert-butylbenzoyl(n-propylsulfonyl)amino, 2-methoxybenzoyl(n-propylsulfonyl)amino, 3-methoxybenzoyl(n-propylsulfonyl)amino, 4-methoxybenzoyl(n-propylsulfonyl)amino, 2-ethoxybenzoyl(n-propylsulfonyl)amino, 3-ethoxybenzoyl(n-propylsulfonyl)amino, 4-ethoxybenzoyl(n-propylsulfonyl)amino, 2-i-propyloxybenzoyl(n-propylsulfonyl)amino, 3-i-propyloxybenzoyl(n-propylsulfonyl)amino, 4-i-propyloxybenzoyl(n-propylsulfonyl)amino, 2-n-butoxybenzoyl(n-propylsulfonyl)amino, 3-n-butoxybenzoyl(n-propylsulfonyl)amino and 4-n-butoxybenzoyl(n-propylsulfonyl)amino groups and the like. Among them, C 1 -C 4  alkylsulfonylamino, bis(C 1 -C 4  alkylsulfonyl)amino, (C 2 -C 5  alkylcarbonyl)(C 1 -C 4  alkylsulfonyl)amino and (optionally substituted benzoyl)(C 1 -C 4  alkylsulfonyl)amino groups are preferable, C 1 -C 4  alkylsulfonylamino group being more preferable. 
     Examples of Q include hydrogen atom, and nitro, amino, methoxycarbonylamino, ethoxycarbonylamino, n-propoxycarbonylamino, i-propoxycarbonylamino, n-butoxycarbonylamino, i-butoxycarbonylamino, s-butoxycarbonylamino, tert-butoxycarbonylamino, 6-trifluoromethyl-2,4(1H,3H)pyrimidinedione-3-yl, 1-methyl-6-trifluoromethyl-2,4(1H,3H)pyrimidinedione-3-yl and 1-amino-6-trifluoromethyl-2,4(1H,3H)pyrimidinedione-3-yl groups and the like. Among them, 6-trifluoromethyl-2,4(1H,3H)pyrimidinedione-3-yl, 1-methyl-6-trifluoromethyl-2,4(1H,3H)pyrimidinedione-3-yl and 1-amino-6-trifluoromethyl-2,4(1H,3H)pyrimidinedione-3-yl groups are preferable. 
     With respect to one mole of the halogenated benzene compound (1a) as a starting substance, potassium or sodium cyanide is generally used in an amount of 0.5 to 10 moles, preferably 0.8 to 3 moles and zinc cyanide is generally used in an amount of 0.25 to 10 moles, preferably 0.4 to 1.5 moles. These metal cyanides may be used in combination. 
     Examples of the metallic catalyst include iron, cobalt, nickel, ruthenium, rhodium, palladium, iridium, platinum, osmium and the like. Nickel, palladium and platinum are preferable, palladium being more preferable. Specifically, the nickel catalyst is a supported catalyst such as nickel supported on silica, nickel supported on alumina and nickel supported on carbon; a complex catalyst such as dichloro-bis(triphenylphosphine)nickel, dichloro[1,2-bis(diphenylphosphino)ethane]nickel, dichloro[1,3-bis(diphenylphosphino)propane]nickel, dichlorobis[1,4-bis(diphenylphosphino)butane]nickel, dichlorobis[1,1′-(diphenylphosphino)ferrocene]nickel, dibromobis(triphenylphosphine)nickel, dibromo[1,2-bis(diphenylphosphino)ethane]nickel, dibromo[1,3-bis(diphenylphosphino)propane]nickel, dibromobis[1,4-bis(diphenylphosphino)butane]nickel, dibromobis[1,′-(diphenylphosphino)ferrocene]nickel, bromobis(triphenylphosphine)nickel, chlorobis(triphenylphosphine)nickel, tris(triphenylphosphine)nickel, bis(triphenylphosphine)dicarbonylnickel, tetrakis(triphenylphosphine)nickel, tetrakis(triphenylphosphite)nickel, bis(cyclooctadiene)nickel and acetylacetonato nickel; and nickel chloride, nickel bromide, nickel iodide, nickel nitrate, nickel acetate, nickel oxide, nickel cyanide, and the like. 
     The palladium catalyst is a supported catalyst such as palladium supported on silica, palladium supported on alumina and palladium supported on carbon; a complex catalyst such as (2,2-bipyridine)dichloropalladium, bis(acetonitrile)palladium chloride, bis(benzonitrile)palladium chloride, bis[1,2-(diphenylphosphino)ethane]palladium, bis[1,2-bis(diphenylphosphino)ethane]palladium chloride, dichlorobis(triphenylphosphine)palladium, dichlorobis(trimethylphosphine)palladium, dichlorobis(tributylphosphine)palladium, tetrakis(triethylphosphite)palladium, bis(cycloocta-1,5-diene)palladium, tetrakis(triphenylphosphine)palladium, dicarbonylbis(triphenylphosphine)palladium, carbonyltris(triphenylphosphine)palladium, acetylacetonato palladium, dichloro(1,5-cyclooctadiene)palladium and tris(dibenzylideneacetone)dipalladium; and palladium chloride, palladium bromide, palladium nitrate, palladium oxide, palladium acetate, palladium cyanide, and the like. 
     The platinum catalyst is a supported catalyst such as platinum supported on silica, platinum supported on alumina and platinum supported on carbon; a complex catalyst such as bis(acetonitrile)dichloroplatinum, bis(benzonitrile)dichloroplatinum, dichlorobis(triphenylphosphine)platinum, dichlorobis(trimethylphosphine)platinum, dichlorobis(tributylphosphine)platinum, tetrakis(triphenylphosphine)platinum, tetrakis(triphenylphosphite)platinum, tris(triphenylphosphine)platinum, dicarbonylbis(triphenylphosphine)platinum, bis(triphenylphosphine)(ethylene)platinum, carbonyltris(triphenylphosphine)platinum, bis(1,5-cyclooctadiene)platinum, (1,5-cyclooctadiene)dichloroplatinum and (1,5-cyclooctadiene)dibromoplatinum; and platinum chloride, platinum bromide, platinum iodide, platinum oxide and the like. 
     The above catalysts may be used singly or in combination. 
     The catalyst is generally used in an amount of 0.0001 to 100 molar %, preferably 0.01 to 50 molar % with respect to the compound of the general formula (1a). 
     If necessary, a ligand may be added to the metallic catalyst in order to stabilize and activate the catalyst. 
     The ligand is exemplified below. As mono- or multi-dentate tertiary phosphines, bis(dialkylphosphino)alkanes such as 1,1-bis(dimethylphosphino)methane, 1,1-bis(diethylphosphino)methane, 1,2-bis(dimethylphosphino)ethane, 1,2-(diethylphosphino)ethane, 1,3-bis(dimethylphosphino)propane and 1,4-bis(dimethylphosphino)butane; bis(diphenylphosphino)alkanes such as 1,1-bis(diphenylphosphino)methane, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,5-bis(diphenylphosphino)pentane and 1,6-bis(diphenylphosphino)hexane; and. 1,1′-bis(diphenylphosphino)ferrocene, tris(3-sulfonatophenyl)phosphine sodium salt, bis(diphenylphosphino)binaphthyl, trimethylphosphine, triethylphosphine, tributylphosphine, triphenylphosphine, tris(para-tolyl)phosphine, tris(parafluorophenyl)phosphine, tris(2,6-dimethylphenyl)phosphine, sodium diphenylphosphinobenzene-3-sulfonate, bis(3-sulfonatophenyl)phosphinobenzene sodium salt, 17-diphenylphosphino-2,5,8,11,14-pentaoxabicyclo-[13.4.0]-nonadeca-15,17,19-triene and 20-diphenylphosphino-2,5,8,11,14,17-hexaoxabicyclo-[16.4.0]-docosa-18,20,22-triene, and the like are mentioned. 
     As other ligands, phosphonic esters such as triethyl phosphite, tributyl phosphite, triphenyl phosphite and tris(2,6-dimethylphenyl)phosphite; phosphonium salts such as triphenylmethylphosphonium iodide, triphenylmethylphosphonium bromide, triphenylmethylphosphonium chloride, triphenylallylphosphonium iodide, triphenylallylphosphonium bromide, triphenylallylphosphonium chloride, tetraphenylphosphonium iodide, tetraphenylphosphoniuim bromide and tetraphenylphosphonium chloride; phosphoric esters such as triphenyl phosphate, trimethyl phosphate, triethyl phosphate and triallyl phosphate; phosphine oxides such as triphenylphosphine oxide and diphenylmethylphosphine oxide; phosphine sulfides such as triphenylphosphine sulfide and diphenylmethylphosphine sulfide; unsaturated hydrocarbons such as cyclooctadiene and cyclopentadiene; nitriles such as benzonitrile and acetonitrile; pyridine alanogs such as 2,2′-bipyridine, 1,10-phenanthroline and 8-hydroxyquinoline; acetylacetone, and the like are mentioned. 
     The ligand is generally used in an amount of 0 to 10,000 molar %, preferably 0 to 1,000 molar % with respect to the metallic catalyst. 
     According to the present invention, the metallic catalysts and the phosphines may be added to a reaction system in combination or separately, or alternatively they may be used as a complex previously formed. 
     For reducing a divalent metallic complex to a corresponding zero-valent complex, zinc powder, tin powder, manganese powder, magnesium powder, cobalt powder and iron powder, iron(II) salt, tin(II) salt, manganese(III) salt, cobalt (II) salt, formic acid and oxalic acid, and a mixture thereof, and an alloy powder thereof, and, a Grignard reagent such as ethyl magnesium bromide, an alkyl lithium reagent such as butyl lithium, a metallic reagent for hydrogenation such as sodium borohydride, and an electrolytic reduction may be used. 
     Examples of an organic solvent used in the process of the present invention include aromatic hydrocarbons such as benzene, toluene, xylene and chlorobenzene; halogenated hydrocarbons such as chloroform and methylene chloride; nitrites such as acetonitrile and propionitrile; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; ethers such as diethyl ether, dioxane, tetrahydrofuran and dimethoxyethane; tertiary amines such as pyridine, 5-ethyl-2-methylpyridine, quinoline and N,N′-dimethylaniline; acid amides such as N,N′-dimethylacetamide, N,N′-dimethylformamide, N-methylpyrrolidone and tetramethylurea; sulfur-containing compounds such as dimethylsulfoxide and sulfolane; phosphoric compounds such as hexamethylphosphoric triamide; and the like. Two or more of them may be mixed to use. 
     In order to proceed the reaction more smoothly, the use of a co-catalyst is effective. Examples of the co-catalyst include metal salts such as copper(I) chloride, copper(I) bromide, copper(I) iodide, copper(II) chloride, copper(II) oxide, copper(II) sulfate, copper(I) cyanide, copper powder, zinc(II) chloride, zinc(II) bromide, zinc(II) iodide, zinc(II) cyanide, zinc powder, tin(II) chloride, tin(II) bromide, tin(II) iodide, tin powder, aluminum oxide, aluminum chloride, iron(II) chloride, iron(III) chloride, iron powder, magnesium(II) chloride, chromium(II) chloride, manganese (II) chloride, lead(IV) acetate, titanium(IV) chloride, potassium hexachloroplatinate(IV) and potassium hexacyanoferrate(III); crown ethers such as 18-crown-6-ether, 15-crown-5-ether and dicyclohexyl-18-crown-6-ether; and silicon tetrachloride. Optionally, sodium iodide, sodium bromide, potassium iodide, potassium bromide or the like may be added to the reaction system. Among the co-catalysts mentioned above, the halides of the metal selected from zinc, iron, manganese, tin, copper, magnesium, chromium, titanium and aluminum are the preferable co-catalysts. The more preferable co-catalysts are the halides of the metal selected from zinc, tin and copper. The amount of the co-catalyst to be added is generally 0 to 10,000 molar %, preferably 0 to 500 molar % with respect to the metal catalyst. 
     Generally, the reaction is carried out at a temperature of from room temperature to 300° C., preferably 50 to 200° C. Alternatively, it may be carried out at a reflux temperature of the solvent to be used. Generally, reaction time ranges from 30 minutes to 72 hours, preferably 1 to 24 hours. 
    
    
     EXAMPLES 
     The process of the present invention will be described in more detail by referring to the following Examples which are not intended to limit the invention. 
     Reaction scheme according to the Examples is set forth below.                           
     Example 1 
     Preparation of 3-(4-cyano-5-ethylsulfonylamino-2-fluorophenyl)-1-methyl-6-trifluoromethyl-2,4(1H,3H)-pyrimidinedione (Compound No. 1) 
     1.2 g (2.5 mmol) of 3-(4-bromo-5-ethylsulfonylamino-2-fluorophenyl)-1-methyl-6-trifluoromethyl-2,4(1H,3H)pyrimidinedione, 0.15 g of sodium cyanide and 0.04 g of zinc chloride were added to 5 ml of 5-ethyl-2-picoline and the mixture was stirred at 120° C. under an argon atmosphere for 1 hour. Next, 0.6 g of tetrakis(triphenylphosphine)palladium was added to the mixture, which was then heated with stirring for 10 hours. After the reaction was completed, the title compound was obtained with a yield of 90% as determined by the internal standard method in liquid chromatography. 
     Example 6 
     Preparation of 3-(4-cyano-5-ethylsulfonylamino-2-fluorophenyl)-1-methyl-6-trifluoromethyl-2,4(1H,3H)-pyrimidinedione (Compound No. 1) 
     1.2 g (2.5 mmol) of 3-(4-bromo-5-ethylsulfonylamino-2-fluorophenyl)-1-methyl-6-trifluoromethyl-2,4(1H,3H)pyrimidinedione and 0.11 g of 55% sodium hydride in oil were added to 20 g of 5-ethyl-2-picoline and the mixture was stirred at room temperature for 30 minutes. Next, 0.07 g of copper(II) chloride and 0.15 g of sodium cyanide were added to the mixture, which was then stirred at 140° C. under an argon atmosphere for 1 hour. Further, 0.3 g of tetrakis(triphenylphosphine)palladium was added to the mixture, which was then heated with stirring for 3 hours. After the reaction was completed, 79% of the title compound was detected as the relative area value in liquid chromatography. 
     Example 7 
     Preparation of 3-(4-cyano-5-ethylsulfonylamino-2-fluorophenyl)-1-methyl-6-trifluoromethyl-2,4(1H,3H)-pyrimidinedione (Compound No. 1) 
     0.5 g (1.0 mmol) of 3-(4-bromo-5-ethylsulfonylamino-2-fluorophenyl)-1-methyl-6-trifluoromethyl-2,4(1H,3H)pyrimidinedione was dissolved in 10 ml of 5-ethyl-2-picoline, to which 0.04 g of sodium hydride was added under cooling with ice, and the mixture was stirred for 5 minutes. Next, 0.04 g of palladium acetate and 0.16 g of 1,4-bis(diphenylphosphino)ethane were added to the mixture, which was then stirred at 90° C. under an argon atmosphere for 1 hour. After the mixture was allowed to cool, 0.03 g of zinc chloride and 0.06 g of sodium cyanide were added to the mixture, which was then stirred for further 4 hours. After the reaction was completed, 61% of the title compound was detected as the relative area value in liquid chromatography. 
     Example 9 
     Preparation of 3-(4-cyano-5-ethylsulfonylamino-2-fluorophenyl)-1-methyl-6-trifluoromethyl-2,4(1H,3H)-pyrimidinedione (Compound No. 1) 
     2.0 g (4.2 mmol) of 3-(4-bromo-5-ethylsulfonylamino-2-fluorophenyl)-1-methyl-6-trifluoromethyl-2,4(1H,3H)pyrimidinedione, 0.3 g of zinc cyanide and 0.5 g of tetrakis(triphenylphosphine)palladium were added to 10 g of 5-ethyl-2-picoline and the mixture was stirred at 80° C. under an argon atmosphere for 3.5 hours. After the reaction was completed, 94% of the title compound was detected as the relative area value in liquid chromatography. 
     Other Examples together with the above Examples were shown in Table 2. Any compound wherein the benzene ring was cyanized at 2-position was hardly detected in all of Examples 1 to 9. 
     Abbreviations and terms used in Table 2 have meanings as described in Table 1. 
     
       
         
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 Abbreviation or Term 
                 Meaning 
               
               
                   
               
             
             
               
                 Sub. 1 
                 3-(4-bromo-5-ethylsulfonyl- 
               
               
                 (Substrate 1) 
                 amino-2-fluorophenyl)-1-methyl- 
               
               
                   
                 6-trifluoromethyl- 
               
               
                   
                 2,4(1H, 3H)pyrimidinedione 
               
               
                 Sub. 1-Na 
                 3-(4-bromo-5-ethylsulfonyl- 
               
               
                 (Substrate 1-Na) 
                 amino-2-fluorophenyl)-1-methyl- 
               
               
                   
                 6-trifluoromethyl- 
               
               
                   
                 2,4(1H, 3H)pyrimidinedione sodium 
               
               
                   
                 salt 
               
               
                 dppe 
                 1,2- 
               
               
                   
                 bis(diphenylphosphino)ethane 
               
               
                 MEP 
                 5-ethyl-2-picoline 
               
               
                 DMF 
                 N,N-dimethylformamide 
               
               
                 amount of cyanizing agent 
                 equivalent of the cyanizing agent 
               
               
                   
                 with respect to the substrate 
               
               
                 amount of catalyst 
                 equivalent of the catalyst with 
               
               
                   
                 respect to the substrate 
               
               
                 amount of co-catalyst 
                 equivalent of the co-catalyst 
               
               
                   
                 with respect to the substrate 
               
               
                 amount of solvent 
                 parts by weight of the solvent per 
               
               
                   
                 1 part by weight of the substrate 
               
               
                   
               
             
          
         
       
     
     
       
         
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
             
             
               
                   
                   
               
               
                   
                 Substrate 
                 Cyanizing Agent 
                 Catalyst 
                 Co-catalyst 
                 Solvent 
                 Reaction 
                   
               
             
          
           
               
                   
                   
                 amount 
                   
                 amount 
                   
                 amount 
                   
                 amount 
                   
                 amount 
                 temp. 
                 time 
                 Yield *2   
               
               
                   
                 type 
                 (mmol) 
                 type 
                 (eq) 
                 type 
                 (eq) 
                 type 
                 (eq) 
                 type 
                 (part 
                 (° C.) 
                 (hr) 
                 (%) 
               
               
                   
                   
               
             
          
           
               
                 Ex. 1 
                 Sub. 
                 2.5 
                 NaCN 
                 1.2 
                 Pd(PPh 3 ) 4   
                 0.2 
                 ZnCl 2   
                 0.2 
                 MEP 
                 4.0 
                 120 
                 10.0 
                 90 
               
               
                   
                 1 
               
               
                 Ex. 2 
                 Sub. 
                 2.5 
                 NaCN 
                 1.2 
                 Pd(PPh 3 ) 4   
                 0.2 
                 Zn(CN) 2   
                 0.2 
                 MEP 
                 4.0 
                 100 
                 3.0 
                 62 
               
               
                   
                 1 
               
               
                 Ex. 3 
                 Sub. 
                 2.5 
                 NaCN 
                 1.2 
                 Pd(PPh 3 ) 4   
                 0.1 
                 SnCl 2   
                 0.2 
                 MEP 
                 16.0 
                 140 
                 18.0 
                 (61) 
               
               
                   
                 1-Na 
               
               
                 Ex. 4 
                 Sub. 
                 2.5 
                 NaCN 
                 1.2 
                 Pd(PPh 3 ) 4   
                 0.1 
                 Cu 
                 0.2 
                 MEP 
                 16.0 
                 140 
                 3.0 
                 (56) 
               
               
                   
                 1-Na 
               
               
                 Ex. 5 
                 Sub. 
                 2.5 
                 NaCN 
                 1.2 
                 Pd(PPh 3 ) 4   
                 0.1 
                 CuCl 
                 0.2 
                 MEP 
                 16.0 
                 140 
                 3.0 
                 (75) 
               
               
                   
                 1-Na 
               
               
                 Ex. 6 
                 Sub. 
                 2.5 
                 NaCN 
                 1.2 
                 Pd(PPh 3 ) 4   
                 0.1 
                 CuCl 2   
                 0.2 
                 MEP 
                 16.0 
                 140 
                 3.0 
                 (79) 
               
               
                   
                 1-Na 
                   
                   
                   
                 Pd(OAc) 2   
                 0.2 
               
               
                 Ex. 7 
                 Sub. 
                 1 
                 NaCN 
                 1.2 
                 dppe 
                 0.4 
                 ZnCl 2   
                 0.2 
                 MEP 
                 18.0 
                 140 
                 4.0 
                     (61) *1   
               
               
                   
                 1-Na 
               
               
                 Ex. 8 
                 Sub. 
                 1 
                 NaCN 
                 1.2 
                 Pd(CN) 2   
                 0.1 
                 - 
                 - 
                 DMF 
                 40.0 
                 140 
                 2 
                 (48) 
               
               
                   
                 1-Na 
               
               
                 Ex. 9 
                 Sub. 
                 4.2 
                 Zn(CN) 2   
                 0.6 
                 Pd(PPh 3 ) 4   
                 0.1 
                 - 
                 - 
                 MEP 
                 5.0 
                 80 
                 3.5 
                 (94) 
               
               
                   
                 1 
               
               
                   
               
               
                 Examples 1 to 9 were carried out under an Ar atmosphere.  
               
               
                   *1 : Before the addition of NaCN, stirring was carried out at 90° C. for one hour.  
               
               
                   *2 : Determined by the internal standard method.  
               
               
                 (): relative area value on liquid chromatogram  
               
             
          
         
       
     
     Effect of the Invention 
     According to the process of the present invention, the benzonitrile compounds useful as herbicides and their intermediates can be obtained with a high yield.