as mentioned above , according to a first aspect of the present invention , the thiadiazole derivatives represented by the formula [ i ] are provided . it should be noted that the term &# 34 ; lower &# 34 ; means c 1 - c 6 in this specification and claims unless otherwise specified . the thiadiazole derivatives represented by the formula [ i ] may be prepared by reacting a corresponding amino acid amide or a hydrogen halide salt thereof represented by the formula [ x ] with sulfur monochloride or thionyl chloride according to the method described in journal of organic chemistry , p . 2823 ( 1967 ). ## str14 ## ( wherein x , v and z represent the same meaning as in formula [ i ], and q represents halogen ). this reaction may usually be carried out in a solvent at 20 °- 100 ° c . for 1 - 24 hours . preferred examples of the solvent which may be used in this reaction may include aromatic hydrocarbons such as benzene and toluene ; ethers such as tetrahydrofuran ; halogenated hydrocarbons such as chloroform ; and polar solvents such as nitromethane , acetonitrile and n , n - dimethylformamide . the ratio of the reactants may usually be one equivalent of the amino acid amide to 3 - 4 equivalents of the sulfur monochloride or thionyl chloride . the thiadiazole derivatives of the formula [ i ] may also be prepared by reacting a thiadiazole derivative represented by the formula [ xi ] with a -- q ( wherein a represents the same meaning as in formula [ i ] and q &# 39 ; represents halogen ), r 9 oc (═ o ) r 9 ( wherein r 9 represents the same meaning as in formula [ i ], or with r 10 c (═ o ) oc (═ o ) r 10 ( wherein r 10 represents the same meaning as in formula [ ii ]). ## str15 ## ( wherein x , y , z and v represent the same meaning as in formula [ i ]). this reaction may usually be carried out in a solvent and in the presence of a base at 0 °- 150 ° c . for several minutes to 48 hours . preferred examples of the solvent which may be used in this reaction may include ketones such as acetone and methylethyl ketone ; aromatic hydrocarbons such as benzene , toluene and xylene ; ethers such as diethyl ether , tetrahydrofuran and dioxane ; halogenated hydrocarbons such as dichloromethane , chloroform , carbon tetrachloride , dichloroethane and chlorobenzene ; tertially amines such as pyridine , triethylamine and n , n - dimethylaniline ; polar solvents such as acetonitrile , n , n - dimethylformamide , dimethylsulfoxide , 1 , 3 - dimethyl - 2 - imidazolidinone and hexamethyl phosphoric triamide . preferred examples of the base which may be used in the reaction may include , organic bases such as pyridine , triethylamine and n , n - dimethylaniline ; inorganic bases such as sodium hydroxide , potassium hydroxide , sodium carbonate , potassium carbonate and sodium hydride ; and alkaline metal alkoxides such as sodium methoxide and sodium ethoxide . usually , 1 - 2 equivalents of a -- q , r 9 oc (═ o ) or 9 or r 10 c (═ o ) oc (═ o ) r 10 and 1 - 5 equivalents of bases are used for one equivalent of the thiadiazole derivative . the thiadiazole derivatives represented by the formula [ i ] wherein a represents -- coor 9 or cwnr 11 r 12 may be prepared as follows : that is , the thiadiazole derivative of the formula [ xi ] is reacted with phosgene , thiophosgene , trichloromethyl chloroformate or bis ( trichloromethyl ) carbonate in the presence or absence of a solvent in the presence or absence of a base at 0 °- 100 ° c . for several minutes to 48 hours . preferred examples of the solvent which may be used in this reaction may include aromatic hydrocarbons such as benzene and toluene ; and halogenated hydrocarbons such as dichloromethane , chloroform and carbon tetrachloride . preferred examples of the base which may be used in this reaction may include organic bases such as pyridine , triethylamine and n , n - dimethylaniline ; and inorganic bases such as sodium hydrogen carbonate and sodium carbonate . then the resultant is reacted with a corresponding alcohol or amine in the presence or absence of a solvent and in the presence or absence of a base at 0 °- 150 ° c . for several minutes to 48 hours , thereby the desired thiadiazole derivative may be obtained . preferred examples of the solvent which may be used in this reaction may include ketones such as acetone and methylethyl ketone , aromatic hydrocarbons such as benzene , toluene and xylene ; ethers such as diethyl ether , tetrahydrofuran and dioxane , halogenated hydrocarbons such as dichloromethane , chloroform , dichloroethane and carbon tetrachloride ; tertiary amines such as pyridine , triethylamine and n , n - dimethylaniline ; polar solvents such as acetonitrile , n , n - dimethylformamide , acetonitrile , dimethylsulfoxide and 1 , 3 - dimethyl - 2 - imidazolidinone . preferred examples of the base which may be used in this reaction may include organic bases such as pyridine and triethylamine ; and inorganic bases such as sodium hydroxide , potassium carbonate and sodium hydrogen carbonate . the thiadiazole derivatives represented by the formula [ i ] wherein a represents -- cwnr 11 r 12 may be prepared by reacting the thiadiazole derivative of the above - described formula [ xi ] with a corresponding isocyanate in the presence or absence of a solvent in the presence or absence of a base at 0 °- 150 ° c . for several minutes to 48 hours . preferred examples of the solvent which may be used in this reaction may include aromatic hydrocarbons such as benzene , toluene and xylene ; ethers such as diethyl ether , tetrahydrofuran and dioxane ; halogenated hydrocarbons such as dichloromethane , chloroform and carbon tetrachloride ; and polar solvents such as pyridine , triethylamine , n , n - dimethylformamide , dimethylsulfoxide , 1 , 3 - dimethyl - 2 - imidazolidinone and hexamethyl phosphoric triamide . preferred examples of the base which may be used in this reaction may include organic bases such as pyridine , triethylamine and n , n - dimethylaniline ; inorganic bases such as sodium hydroxide , potassium hydroxide , sodium carbonate , potassium carbonate and sodium hydride . the thiadiazole derivatives represented by the formula [ i ] wherein y represents sulfur and a represents hydrogen may be prepared by thermally converting a corresponding thionocarbamate to the corresponding thiolcarbamate and by subsequent hydrolysis . this reaction may be carried out under nitrogen atmosphere in the absence of a solvent at 130 °- 200 ° c . for several minutes to 24 hours , followed by the hydrolysis . further , in cases where at least one of x , v and z in formula [ i ] is nitro , the thiadiazole derivative of the formula [ i ] may be prepared by reacting the thiadiazole derivative represented by the formula [ xii ] with conc . sulfuric acid / conc . nitric acid at - 10 ° c . to 100 ° c . for several minutes to 24 hours . ## str16 ## ( wherein x and v represent the same meaning as in formula [ i ]) usually , 4 parts by weight of the thiadiazole derivative of the formula [ xii ] may be reacted with 10 - 100 parts by weight of conc . sulfuric acid and 1 - 100 parts by weight of conc . nitric acid . in a second aspect of the present invention , thiadiazole derivatives represented by the above - described formula [ ii ] are provided . among the groups designated by r 17 and r 18 in the formula [ ii ], those preferred are c 1 - c 6 linear or branched lower alkyl groups such as methyl , ethyl , propyl , butyl , pentyl and hexyl ; c 1 - c 7 cycloalkyl groups such as cyclopentyl , cyclohexyl and cyloheptyl ; and alkoxyalkyl groups in which an alkyl group is substituted with c 1 - c 6 linear or branched lower alkoxy group such as methoxyethyl , methoxypropyl , ethoxyethyl , ethoxypropyl , propoxyethyl , propoxypropyl and isopropoxypropyl . r 17 and r 18 may also cooperatively form a cyclic amine . preferred examples of the cyclic amine may include pyrrolidine , piperidine , hexamethyleneamine , morpholine and piperazine which may be substituted with c 1 - c 4 linear or branched lower alkyl . r 17 and r 18 in the formula [ ii ] most preferably represent lower alkyl , cycloalkyl or alkyleneamine . the thiadiazole derivatives represented by the formula [ ii ] may be prepared by reacting a corresponding amine , carbonyl sulfide and 3 - chloromethyl - 1 , 2 , 5 - thiadiazole in a solvent in the presence or absence of a base according to the method described below ( japanese laid open patent application ( kokai ) no . 73732 / 79 ). the dithiol carbamates may also be prepared in the similar manner by reacting a corresponding amine , carbon disulfide and 3 - chloromethyl - 1 , 2 , 5 - thiadiazole in a solvent in the presence or absence of a base . these reactions may be carried out by reacting the above - described reactants in a solvent at 0 °- 100 ° c . for 1 - 24 hours . preferred examples of the solvent which may be employed in these reactions may include water ; alcohols such as methanol and ethanol ; aromatic hydrocarbons such as benzene and toluene ; and pyridine . among these , most preferred are water , ethanol , toluene and pyridine . preferred examples of the base which may be employed in these reactions may include organic bases such as pyridine , triethylamine and n , n - dimethylaniline , and inorganic bases such as sodium hydroxide , potassium hydroxide , sodium carbonate , potassium carbonate and sodium hydride . among these , most preferred is sodium hydroxide . the amount of the amine subjected to the reaction may be not less than 2 equivalents with respect to 1 equivalent of 3 - chloromethyl - 1 , 2 , 5 - thiadiazole in the absence of the base , or not less than 1 equivalent with respect to 1 equivalent of 3 - chloromethyl - 1 , 2 , 5 - thiadiazole in the presence of the base . the amount of the base may be not less than 1 equivalent with respect to 1 equivalent of 3 - chloromethyl - 1 , 2 , 5 - thiadiazole . in a third aspect of the present invention , the thiadiazole derivatives represented by the above - described formula [ iii ] are provided . in the formula [ iii ], r 23 represents phenyl group which is substituted with c 1 - c 6 alkyl such as 2 , 6 - dimethylphenyl , 2 , 6 - diethylphenyl , 2 - methyl - 6 - ethylphenyl , 2 , 6 - dipropylphenyl , 2 - methyl - 6 - propylphenyl and 2 , 4 , 6 - trimethylphenyl ; c 1 - c 8 alkenyl such as 1 - propenyl , 1 - methyl - 1 - propenyl and 1 , 3 - dimethylbutenyl ; or cycloalkenyl which may be substituted with c 1 - c 6 linear or branched alkyl such as 1 - cyclohexyl , 1 - cyclopentyl , 2 , 6 - dimethyl - 1 - cyclohexynyl and 2 , 6 - dimethyl - 1 - cyclopentenyl . the thiadiazole derivative of the formula [ iii ] may be prepared according to one of the following reactions [ a ] to [ c ]. ## str17 ## ( wherein ar represents phenyl group which is substituted with c 1 - c 6 linear or branched alkyl ) ## str18 ## ( wherein ar represents the same meaning as in formula [ xiii ]) ## str19 ## ( wherein r 30 and r 31 , the same or different , represent c 1 - c 6 linear or branched alkyl or r 30 and r 31 cooperatively form c 1 - c 18 alicyclic group ). in the reaction [ a ], the amine represented by the formula [ xiii ] and chloroacetyl chloride represented by the formula [ xiv ] are reacted in the presence or absence of a solvent in the presence of a base at 0 °- 150 ° c . for several minutes to 48 hours . the reaction may preferably be carried out in the presence of a solvent . preferred examples of the solvent which may be employed in the reaction may include aliphatic hydrocarbons such as hexane , heptane , ligroin and petroleum ether ; aromatic hydrocarbons such as benzene , toluene and xylene ; ethers such as diethyl ether , diisopropyl ether , dioxane , tetrahydrofuran and diethyleneglycoldimethyl ether ; ketones such as acetone , methylethyl ketone , methylisobutyl ketone and cyclohexanone ; halogenated hydrocarbons such as dichloromethane , chloroform , carbon tetrachloride , dichloroethane , chlorobenzene and dichlorobenzene ; esters such as ethyl acetate and butyl acetate ; nitriles such as acetonitrile and isobutylonitrile ; dimethylforamide ; and dimethylsulfoxide . preferred examples of the base which may be used in reaction [ a ] may include organic bases such as pyridine , triethylamine and n , n - diethylaniline ; alkaline metal hydroxides such as sodium hydroxide and potassium hydroxide ; and alkaline metal carbonates such as sodium carbonate and potassium carbonate . in reaction [ a ], 1 - 10 equivalents of the compound of the formula [ xiv ] and 1 - 10 equivalents of the base may usually be used per one equivalent of the compound of the formula [ xiii ]. the reaction [ b ] may be carried out by reacting the amide represented by the formula [ xv ] with 3 - chloromethyl - 1 , 2 , 5 - thiadiazole of the formula [ xvi ] in a solvent in the presence of a base at 0 °- 150 ° c . for several minutes to 48 hours . the reaction may preferably be carried out in a solvent . preferred examples of the solvent may include aromatic hydrocarbons such as benzene , toluene and xylene ; ethers such as diisopropyl ether , dioxane , tetrahydrofuran , diethyleneglycol dimethylether ; ketones such as acetone , methylethyl ketone , methylisobutyl ketone and cyclohexanone ; halogenated hydrocarbons such as dichloromethane , chloroform , carbon tetrachloride , dichloroethane , chlorobenzene and dichlorobenzene ; esters such as ethyl acetate and butyl acetate ; nitriles such as acetonitrile and isobutylonitrile ; dimethylformamide ; and dimethylsulfoxide . preferred examples of the base which may be used in reaction [ b ] are the same as those preferred in reaction [ a ]. in reaction [ b ], 1 - 10 equivalents of the compound of the formula [ xvi ] and 1 - 10 equivalents of the base may usually be used per one equivalent of the compound of the formula [ xv ]. the reaction [ c ] may be carried out by reacting the amine of the formula [ xvii ] with chloroacetyl chloride of the formula [ xiv ] in the presence or absence of a solvent in the presence or absence of a base at 0 °- 150 ° c . for several minutes to 48 hours . the reaction [ c ] may preferably be carried out in a solvent in the absence of a base . preferred examples of the solvent which may be employed in reaction [ c ] may include those preferred in reaction [ b ]. examples of the base which may be employed in reaction [ c ] may include those preferred in reaction [ a ]. in reaction [ c ], 1 - 10 equivalents of the compound of the formula [ xiv ] and 1 - 10 equivalents of the base may usually be used per one equivalent of the compound of the formula [ xvii ]. in a fourth aspect of the present invention , a thiadiazole derivative of the above - described formula [ iv ] is provided . in the formula [ iv ], r 24 and r 25 , the same or different , represents hydrogen or halogen such as fluorine , chlorine , bromine and iodine ; r 26 and r 27 , the same or different , represents hydrogen , lower alkyl preferably c 1 - c 6 linear or branched alkyl such as methyl , ethyl , n - propyl , isopropyl , n - butyl , isobutyl , sec - butyl , tert - butyl , n - pentyl , isopentyl , n - hexyl and isohexyl , or -- cor 28 ( wherein r 28 represents lower alkyl or amino group which may be substituted with lower alkyl ), or r 26 and r 27 cooperatively form phthaloyl group . among the compounds represented by the formula [ iv ], those represented by the above - described formula [ v ] may be prepared by reacting the thiadiazole derivative of the above - described formula [ vi ] with the amine of the above - described formula [ vii ]. this reaction may be carried out in a solvent in the presence or absence of copper and / or cuprous chloride at 60 °- 150 ° c . for several minutes to 48 hours . in the formula [ vii ], preferred examples of the lower alkyl groups represented by r 28 and r 29 may be c 1 - c 6 linear or branched alkyl such as methyl , ethyl , n - propyl , isopropyl , n - butyl , isobutyl , sec - butyl , tert - butyl , n - pentyl , isopentyl , n - hexyl and isohexyl . preferred examples of the solvent which may be employed in this reaction may include alcohols such as methanol and ethanol ; polar solvents such as n , n - dimethylformamide , dimethylsulfoxide , 1 , 3 - dimethyl - 2 - imidazolidinone and hexamethyl phosphoric triamide ; and water . in this reaction , 1 - 100 equivalents of the amine of the formula [ viii ], 1 - 10 equivalents of copper and 1 - 10 equivalents of cuprous chloride may be used per 1 equivalent of the thiadiazole derivative of the formula [ xiii ]. among the thiadiazole derivatives represented by the formula [ iv ], those represented by the above - described formula [ viii ] may be prepared by reacting the thiadiazole derivative of the above - described formula [ vi ] with potassium phthalimide . this reaction may be carried out in a solvent at 80 °- 150 ° c . for several minutes to 48 hours . preferred examples of the solvent which may be used in this reaction may include alcohols such as methanol and ethanol ; polar solvents such as n , n - dimethylformamide , dimethylsulfoxide , 1 , 3 - dimethyl - 2 - imidazolidinone and hexamethyl phosphoric triamide ; and water . in this reaction , 1 - 10 equivalents of potassium phthalimide may be used per one equivalent of the thiadiazole derivative of the formula [ vi ]. among the thiadiazole derivatives represented by the formula [ iv ], those represented by the above - described formula [ ix ] may be prepared by hydrolyzing the thiadiazole derivative of the above - described formula [ viii ]. this hydrolysis may be carried out by treating the thiadiazole derivative of the formula [ viii ] with an acid such as hydrochloric acid and sulfuric acid or hydrazine in a solvent at 50 °- 100 ° c . for several minutes to 24 hours . preferred examples of the solvent which may be used in this reaction may include alcohols such as methanol and ethanol ; and water . in this reaction , 1 - 100 equivalents of the acid or hydrazine is used for one equivalent of the thiadiazole derivative of the formula [ viii ]. among the thiadiazole derivatives of the formula [ iv ], those wherein r 26 and r 27 represent -- cor 28 may be prepared by reacting the thiadiazole derivative of the above - described formula [ ix ] with x &# 39 ;-- cor 28 ( wherein x &# 39 ; represents halogen and r 28 represents the same meaning as in formula [ iv ]). this reaction may be carried out in the presence of a base and a solvent at 40 °- 150 ° c . for several minutes to 24 hours . preferred examples of the solvent which may be employed in this reaction may include ketones such as acetone and methylethyl ketone ; aromatic hydrocarbons such as benzene , toluene and xylene ; ethers such as diethyl ether , tetrahydrofuran and dioxane ; halogenated hydrocarbons such as dichloromethane , chloroform , carbon tetrachloride , dichloroethane and chlorobenzene ; tertiary amines such as pyridine , triethylamine and n , n - dimethylaniline ; and polar solvents such as acetonitrile , n , n - dimethylformamide , dimethylsulfoxide , 1 , 3 - dimethyl - 2 - imidazolidinone and hexamethyl phosphoric triamide . preferred examples of the base which may be employed in this reaction may include organic bases such as pyridine , triethylamine and n , n - dimethylaniline ; inorganic bases such as sodium hydroxide , potassium hydroxide , sodium carbonate , potassium carbonate and sodium hydride ; and alkaline earth metal alkoxide such as sodium methoxide and sodium ethoxide . in this reaction , 1 - 5 equivalents of x &# 39 ;-- cor 28 and 1 - 10 equivalents of the base are used for one equivalent of thiadiazole derivative of the formula [ ix ]. in still another aspect of the present invention , a herbicide composition comprising the thiadiazole derivative of the present invention represented by the formula [ i ], [ ii ], [ iii ] or [ iv ] in an agriculturally acceptable carrier is provided . the herbicide composition of the present invention has excellent herbicidal effectiveness while it does not substantially damage the useful crops . more particularly , the herbicide composition of the present invention can inhibit the growth of weeds in fields such as slender rush , purslane , cocklebur , coreopsis species , ragweed , common lambsquarters , pale smartweed , chickweed , shepherd &# 39 ; s purse , chickweed , jimsonweed , morningglory , nightshade , honblt , plaintain , velvetleaf , woodsorrel , catchweed badstraw , buckwheat , fleabane , horseweed , daisy fleabane , barnyardgrass , green foxtail , large crabgrass , annual bluegrass , water foxtail , oats and johnsongrass , as well as the weeds in paddy fields such as barnyardgrass , falsepinpernel , spindle - flowered rotala , small flower umbrellaplant , bulrush , slender spikerush , water mutgrass , monochoria and arrowhead species . the herbicidal effect is exhibited either before the germination of the weeds or during the growth of the weeds . on the other hand , the herbicide composition of the present invention does not substantially damage the useful crops such as corn , wheat , rice , soybean , cotton and beat . the herbicide composition of the present invention may contain other agricultural chemicals such as pesticides , fungicides , herbicides and plant growth regulators , as well as fertilizers and soil improvers . in particular , by blending one or more herbicides , the labor of application of the herbicides is reduced and the range of the weeds which can be controlled by the composition may be widen . examples of such herbicides may include triazine - based herbicides such as 2 , 4 - bis ( ethylamino )- 6 - ethylthio - 1 , 3 , 5 - triazine ( common name : simetryne ), 2 , 4 - bis ( isopropylamino )- 6 - methylthio - 1 , 3 , 5 - triazine ( common name : prometryne ) and 2 -( 1 , 2 - dimethylpropylamino )- 4 - ethylamino - 6 - methylthio - 1 , 3 , 5 - triazine ( common name : dimethametryn ); carbamate - based herbicides such as s - 4 - chlorobenzyl n , n - diethylthiocarbamate ( common name : benthiocarb ), s - α , α - dimethylbenzyl n , n - pentamethylenethio carbamate ( common name : dimepiperate ), s - benzyl n - ethyl - n -( 1 , 2 - dimethylpropyl ) thiocarbamate ( common name : esprocarb ), s - ethylhexahydro - 1h - azepine - 1 - carbothioate ( common name : molinate ), and o - 3 - tert - butylphenyl n -( 6 - methoxy - 2 - pyridyl )- n - methylthiocarbamate ( common name : piributycarb ); phenoxy - based herbicides such as 2 , 4 - d , mcpb , 2 -( 2 - naphthyloxy ) propionanilide ( common name : naproanilide ), and 2 -( 2 , 4 - dichloro - 3 - methylphenoxy ) propionanilide ( common name : clomeprop ); diphenyl ether - based herbicides such as 2 , 4 , 6 - trichlorophenyl 4 - nitrophenyl ether ( common name : chloronitrofen ), 2 , 4 - dichlorophenyl 3 - methoxy - 4 - nitrophenyl ether ( common name : chloromethoxynil ), 2 , 4 - dichlorophenyl 3 - methoxycarbonyl - 4 - nitrophenyl ether ( common name : bifenox ) and 2 - chloro - 4 - trifluoromethylphenyl 4 - nitro - 3 -( tetrahydropyrane - 3 - yloxy ) phenyl ether ( test code : mt - 124 ); amide - based herbicides such as n - butoxymethyl - 2 - chloro - 2 &# 39 ;, 6 &# 39 ;- diethylacetoanilide ( common name : butachlor ), n - propoxyethyl - 2 - chloro2 &# 39 ;, 6 &# 39 ;- diethylacetoanilide ( common name : pretilachlor ), n - methyl - 2 -( 2 - benzothiazolyloxy ) acetoanilide ( common name : mefenacet ), 2 &# 39 ;, 3 &# 39 ;- dichloro - 4 - ethoxymathoxybenzanilide ( test code : hw - 52 ), n -( α , α - dimethylbenzyl )- 2 - bromo - 3 , 3 - dimethylbutylamide ( common name : bromobutide ), and 3 &# 39 ;, 4 &# 39 ;- dichloropropionanilide ( common name : propanil ); urea - based herbicides such as 1 -( α , α - dimethylbenzyl )- 3 -( 4 - methylphenyl ) urea ( common name : dymron ) and 1 -( 2 - chlorobenzyl )- 3 -( α , α - dimethylbenzyl ) urea ( test code : jc - 940 ); quinone - based herbicides such as 2 - amino - 3 - chloro - 1 , 4 - naphthoquinone ( common name : acn ); heterocycle - based herbicides such as 4 -( 2 , 4 - dichlorobenzoyl )- 1 , 3 - dimethyl - 5 - pyrazolyl p - toluenesulfonate ( common name : pyrazolate ), 4 -( 2 , 4 - dichlorobenzoyl )- 1 , 3 - dimethyl - 5 - phenasyloxypirazole ( common name : pyrazoxyfen ), 4 -( 2 , 4 - dichloro - 3 - methylbenzoyl )- 1 , 3 - dimethyl - 5 -( 4 - methylphenasyloxy ) pyrazole ( common name : benzofenap ), 5 - benzyloxy - 4 -( 2 , 4 - dichlorobenzoyl )- 1 - methylpirazole ( test name : nc - 310 ), 5 - tert - butyl - 3 -( 2 , 4 - dichloro - 5 - isopropoxyphenyl )- 1 , 3 , 4 - oxadiazole - 2 -( 3h )- one ( common name : oxadiazone ), 3 , 7 - dichloro - 8 - quinoline carboxylic acid ( common name : quinolorac ), 3 - chloro - 2 -[ 2 - fluoro - 4 - chloro - 5 -( 1 - propynyloxy ) phenyl ]- 4 , 5 , 6 , 7 - tetrahydro - 2h - imidazole ( test code : s - 275 ), 3 - isopropyl - 2 , 1 , 3 - benzothiaziadinone - 4 )- 2 , 2 - dioxide ( common name : bentazone ), and 1 -( 3 - methylphenyl )- 5 - phenyl - 1h - 1 , 2 , 4 - triazole - 3 - carboxamide ( test code : knw - 242 ); organic phosphur - based herbicides such as o , o - diisopropyl - 2 -( benzenesulfonamide ) ethylenedithiophosphate ( common code : sap ); and sulfonylurea - based herbicides such as methyl 2 -[[[[[( 4 , 6 - dimethoxypyrimidine - 2 - yl ) amino ] carbonyl ] amino ] sulfonyl ] methyl ] benzoate ( common name : londax ) and ethyl 5 -[ 3 -( 4 , 6 - dimethoxypyrimidine - 2 - yl ) ureidosulfonyl ]- 1 - methylpirazole - 4 - carboxylate ( common name : pyrazosulfuron ethyl ). the herbicide composition of the present invention may be in the form of an emulsifiable concentrate , wettable powder , flowable powder , granules or powder . these formulations may be prepared by formulating the effective ingredient of the present invention with an agriculturally acceptable carrier such as a solid carrier , solvent , surfactant and a formulation aid . examples of the solid carrier include kaolin , clay , bentonite , diatomaceous earth , acidic terra abla , white carbon and pumice powder . examples of the solvent include aromatic hydrocarbons such as xylene and methylnaphthalene , alcohols such as isopropanol , ethyleneglycol and cellosolve ; ketones such as acetone and cyclohexanone ; mineral oil ; dimethylsulfoxide ; n , n - dimethylformamide ; acetonitrile and water . examples of the surfactants include anion surfactants such as salts of alkyl sulfate , alkyl sulfonate and aryl sulfonate ; and non - ion surfactants such as polyoxyethyleneglycol ethers , polyoxyethyleneglycol esters and polyol esters . examples of other formulation aids include polyvinyl alcohol , lignin sulfonate and acacia . the herbicide composition of the present invention usually contains 0 . 1 - 90 % by weight , preferably 1 - 80 % by weight of the effective ingredient of the present invention . the amount of the compound of the present invention to be applied to the field varies depending on the weather conditions , formulation of the composition , timing of application , method of application , field conditions , species and stage of growth of the weeds and on the crops . usually , the amount to be applied may be 1 - 1000 g / 10 a , preferably 2 - 500 g / 10 a in terms of the weight of the effective ingredient of the present invention . the herbicide composition of the present invention may directly be applied to the leaves or stems of weeds or to the field before the germination of the weeds . the invention will now be described by way of examples thereof . the examples are presented for the illustration purpose only and should not be interpreted in any restrictive way . in n , n - dimethylformamide , 14 . 5 g of 2 , 6 - dichlorophenyl glycine amide hydrobromic acid salt was dissolved and 19 . 5 g of sulfur monochloride was added thereto . the mixture was stirred for 12 hours at room temperature . the mixture was then poured into water and was converted to alkaline with sodium hydroxide , followed by removal of insoluble materials by filtration . the filtrate was converted to acidic with hydrochloric acid and the generated precipitates were extracted with ether . the ether layer was washed twice with dilute hydrochloric acid and then twice with saturated sodium chloride solution , followed by drying over anhydrous sodium sulfate . the solvent was evaporated off and the obtained crystals were recrystallized from chloroform to obtain 9 . 5 g of 3 -( 2 , 6 - dichlorophenyl )- 4 - hydroxy - 1 , 2 , 5 - thiadiazole . m . p . : 194 °- 195 ° c . 1 h - nmr ( cdcl 3 , δ ppm ) 7 . 3 - 7 . 6 ( m ) ir ( kbr , cm - 1 ) 3200 - 2400 , 1540 , 1505 , 1435 , 1230 , 880 , 790 , 775 elemental analysis for c 8 h 4 n 2 oscl 2 calcd . : c ; 38 . 88 , h ; 1 . 63 , n ; 11 . 33 found : c ; 39 . 00 , h ; 1 . 48 , n ; 11 . 53 in acetonitrile , 0 . 25 g of 3 -( 2 , 6 - dichlorophenyl )- 4 - hydroxy - 1 , 2 , 5 - thiadiazole and 0 . 15 g of potassium carbonate were suspended and 0 . 12 g of dimethylcarbamoyl chloride was added thereto . the mixture was heated to reflux for 12 hours . after allowing to cool , the mixture was poured into water and extracted with ether . the ether layer was washed twice with dilute sodium hydroxide solution , twice with water and twice with aqueous saturated sodium chloride solution . the extract was dried over anhydrous sodium sulfate and the resultant was condensed , followed by silica gel column chromatography to obtain 0 . 25 g of 4 -( 2 , 6 - dichlorophenyl )- 1 , 2 , 5 - thiadiazol - 3 - yl n , n - dimethyl carbamate . m . p . : 115 °- 116 ° c . 1 h - nmr ( cdcl 3 , δ ppm ) 2 . 87 ( s , 3h ), 2 . 93 ( s , 3h ), 7 . 2 - 7 . 45 ( m , 3h ) ir ( kbr , cm - 1 ) 1735 , 1365 , 1235 , 1150 , 785 elemental analysis for c 11 h 9 n 3 oscl 2 calcd . : c ; 41 . 52 , h ; 2 . 85 , n ; 13 . 20 found : c ; 41 . 58 , h ; 2 . 86 , n ; 13 . 04 in ether , 0 . 5 g of 3 -( 2 , 6 - dichlorophenyl )- 4 - hydroxy - 1 , 2 , 5 - thiadiazole and 0 . 18 g of pyridine were dissolved and 0 . 23 g of acetic anhydride was added thereto . the mixture was stirred for 3 hours at room temperature . the reaction mixture was poured into water and extracted with ether . the ether layer was washed twice with aqueous dilute sodium hydroxide solution , twice with water and twice with aqueous saturated sodium chloride solution . the resultant was dried over anhydrous sodium sulfate and concentrated , followed by silica gel column chromatography to obtain 0 . 41 g of 4 -( 2 , 6 - dichlorophenyl )- 1 , 2 , 5 - thiadiazol - 3 - yl acetate . m . p . : 56 °- 59 ° c . 1 h - nmr ( cdcl 3 , δ ppm ) 2 . 17 ( s , 3h ), 7 . 15 - 7 . 4 ( m , 3h ) ir ( kbr , cm - 1 ) 1795 , 1430 , 1175 , 780 elemental analysis for c 10 h 6 n 2 o 2 scl 2 calcd . : c ; 41 . 54 , h ; 2 . 09 , n ; 9 . 68 found : c ; 41 . 23 , h ; 2 . 27 , n ; 9 . 84 in benzene , 0 . 49 g of 3 -( 2 , 6 - dichlorophenyl )- 4 - hydroxy - 1 , 2 , 5 - thiadiazole and 0 . 21 g of bis ( trichloromethyl ) carbonate were dissolved . to the mixture , 0 . 2 g of pyridine was added and the mixture was stirred at room temperature for 12 hours . then 0 . 41 g of n - methyl - n -( 3 - methoxypropyl ) amine was added to the mixture and the resulting mixture was stirred at room temperature for 12 hours . the reaction mixture was poured into water and was extracted with ether . the ether layer was washed three times with dilute aqueous sodium hydroxide solution , three times with dilute hydrochloric acid , twice with water and then twice with aqueous saturated sodium chloride solution . the resultant was dried over anhydrous sodium sulfate and condensed , followed by silica gel column chromatography to obtain 0 . 38 g of 4 -( 2 , 6 - dichlorophenyl )- 1 , 2 , 5 - thiadiazol - 3 - yl n -( 3 - methoxypropyl )- n - methyl carbamate . n d 25 . 0 : 1 . 5638 1 h - nmr ( cdcl 3 , δ ppm ): 1 . 4 - 2 . 0 ( m , 2h ), 2 . 92 ( broad s , 3h ), 3 . 1 - 3 . 6 ( m , 7h ), 7 . 25 - 7 . 5 ( m , 3h ) ir ( nacl , cm - 1 ) 1745 , 1430 , 1385 , 1230 , 1120 , 790 elemental analysis for c 14 h 15 n 3 o 3 scl 2 calcd . : c ; 44 . 69 , h ; 4 . 01 , n ; 11 . 16 found : c ; 44 . 34 , h ; 4 . 05 , n ; 10 . 92 under nitrogen atmosphere , 1 . 34 g of 4 -( 2 , 6 - dichlorophenyl )- 1 , 2 , 5 - thiadiazol - 3 - yl n , n - dimethylthiono carbamate was heated to 180 ° c . after allowing to cool , the reaction mixture was purified by silica gel column chromatography to obtain 0 . 8 g of 4 -( 2 , 6 - dichlorophenyl )- 1 , 2 , 5 - thiadiazol - 3 - yl n , n - dimethylthiol carbamate m . p . : 168 °- 170 ° c . 1 h - nmr ( cdcl 3 , δ ppm ) 2 . 93 ( s , 6h ), 7 . 2 - 7 . 45 ( m , 3h ) ir ( kbr , cm - 1 ) 1690 , 1430 , 1090 , 785 elemental analysis for c 11 h 9 n 3 os 2 cl 2 calcd . : c ; 39 . 52 , h ; 2 . 71 , n ; 12 . 57 found : c ; 39 . 38 , h ; 2 . 83 , n ; 12 . 79 to a mixed solvent of 15 ml of ethanol and 0 . 3 ml of water , 0 . 6 g of 4 -( 2 , 6 - dichlorophenyl )- 1 , 2 , 5 - thiadiazol - 3 - yl n , n - dimethylthiol carbamate and 0 . 28 g of potassium hydroxide were added and the mixture was heated to reflux for 15 hours . ethanol was removed from the reaction mixture and aqueous dilute sodium hydroxide solution was added to the resulting mixture , followed by extraction with ether . the aqueous layer was extracted with ether after converting it to acidic with hydrochloric acid . the ether layers were washed twice with dilute hydrochloric acid and twice with saturated aqueous sodium chloride solution , and the resultant was dried over anhydrous sodium sulfate , followed by removal of the solvent to obtain 0 . 4 g of 3 -( 2 , 6 - dichlorophenyl )- 4 - mercapto - 1 , 2 , 5 - thiadiazole . m . p . : 91 °- 94 ° c . 1 h - nmr ( cdcl 3 , δ ppm ) 3 . 09 ( broad s , 1h ), 7 . 53 ( s , 3h ) ir ( kbr , cm - 1 ) 550 , 1430 , 1345 , 1175 , 820 , 790 , 785 elemental analysis for c 8 h 4 n 2 s 2 cl 2 calcd . : c ; 36 . 51 , h ; 1 . 53 , n ; 10 . 64 found : c ; 36 . 82 , h ; 1 . 38 , n ; 10 . 58 in pyridine , 0 . 25 g of 3 -( 2 , 6 - dichlorophenyl )- 4 - hydroxy - 1 , 2 , 5 - thiadiazole was dissolved and 0 . 17 g of methyl isocyanate was added to the solution . the mixture was stirred at room temperature for 19 hours . the reaction mixture was then poured into water and extracted with ether . the ether layer was washed twice with dilute hydrochloric acid and twice with saturated aqueous sodium chloride solution , and the resultant was dried over anhydrous sodium sulfate . the resultant was condensed and purified by silica gel chromatography to obtain 0 . 24 g of 4 -( 2 , 6 - dichlorophenyl )- 1 , 2 , 5 - thiadiazol - 3 - yl n - methyl carbamate . m . p . : 118 °- 122 ° c . 1 h - nmr ( cdcl 3 , δ ppm ) 2 . 75 ( d , j = 5hz , 3h ), 5 . 3 ( broad s , 1h ), 7 . 2 - 7 . 5 ( m 3h ) ir ( kbr , cm - 1 ) 3290 , 1760 , 1730 , 1400 , 1225 elemental analysis for c 10 h 7 n 3 o 2 scl 2 calcd . : c ; 39 . 49 , h ; 2 . 31 , n ; 13 . 81 found : c ; 39 . 66 , h ; 2 . 48 , n ; 14 . 13 in the similar manner , various compounds represented by the formula [ i ] were prepared . the structures thereof as well as the physical properties are shown in table 1 . to mixed acid ( mixture of 9 ml of concentrated sulfuric acid and 9 ml of concentrated nitric acid ), 2 . 75 g of 3 -( 2 , 6 - dichlorophenyl )- 4 - hydroxy - 1 , 2 , 5 - thiadiazole was added and the resulting mixture was stirred for 4 hours at room temperature . the resulting reactin mixture was poured into water and the resultant was extracted with ether . the ether layer was washed twice with water and twice with saturated aqueous sodium chloride solution . the resultant was dried over anhydrous sodium sulfate and the solvent was distilled off to obtain 3 . 15 g of 4 -( 2 , 6 - dichloro - 3 - nitrophenyl )- 3 - yl methyl carbonate . 1 h - nmr ( solvent : cdcl 3 , δ ppm ) 3 . 93 ( s , 3h ), 7 . 62 ( d , j = 8 . 5hz , 1h ), 7 . 59 ( d , j = 8 . 5hz , 1h ) ir ( nacl , cm - 1 ): 1785 , 1540 , 1530 , 1250 , 1220 elementary analysis (%): calcd . : c ; 34 . 30 , h ; 1 . 43 , n ; 12 . 00 found : c ; 34 . 30 , h : 1 . 56 , n ; 11 . 97 in the similar manner , various compounds represented by the formula [ i ] were prepared . the structures thereof as well as the physical properties are shown in table ten parts of the compound of the present invention , 86 . 5 parts by weight of zeaklite ( commercially available from zeaklite kagaku kogyo ), 2 parts by weight of new cargen nv - 406 ( commercially available from takemoto oil ) and 1 . 5 parts by weight of disksol wa ( commercially available from daiichi kogyo seiyaku ) were mixed and the mixture was pulverized to obtain wettable powder . five parts by weight of the compound of the present invention , 75 parts by weight of xylene and 20 parts by weight of solpol 2806b ( a surfactant commercially available from toho kagaku kogyo ) were mixed and the mixture was uniformly stirred to obtain emulsifiable concentrate . ten parts by weight of the compound of the present invention , 50 parts by weight of bentonite , 35 parts by weight of kunilite ( commercially available from kunimine kogyo ) and 5 parts by weight of solpol 800a ( a surfactant commercially available from toho kagaku kogyo ) were mixed and the mixture was pulverized . water was added to the resulting mixture and the mixture was stirred . the mixture was then formed into granules and dried to obtain granules . test for evaluation of effectiveness in growth inhibition of weeds by treatment of water in paddy field in a plastic pot of 100 cm 2 , plowed soil of paddy field was packed and the seeds of weeds shown in table 2 were sown . two two - leaves stage seedlings of paddy rice were planted per 1 pot and the soil was covered with water of 2 cm thickness . in the germination period of the weeds , the herbicide composition in the form of wettable powder formulated as in example 9 was dropped on the water in the amount shown in table 2 . the pots were placed in a green house and water was appropriately supplied to the pots . after 20 days from the treatment with the herbicide , the herbicidal effectiveness and damage of the rice were examined . the results are shown in table 2 . the herbicide effectiveness as well as the damage of the crops is classified into 6 ranks according to the following criteria : ______________________________________herbicidal effectiveness rate of growth inhibition______________________________________0 0 - 9 % 1 10 - 29 % 2 30 - 49 % 3 50 - 69 % 4 70 - 89 % 5 90 - 100 % ______________________________________ in a 50 ml pear - shaped flask , 1 . 08 g of diethylamine and 1 . 08 g of water were placed and 0 . 89 g of carbonyl sulfide was bubbled at 15 °- 20 ° c . with stirring and cooling with water . to the mixture , 1 g of 3 - chloromethyl - 1 . 2 . 5 - thiadiazole was added dropwise . after completion of the addition , the mixture was heated at 50 ° c . for 3 hours under stirring . after allowing to cool , the mixture was extracted with ether . the organic layer was washed with 1n hydrochloric acid and water , and the resultant was dried over anhydrous magnesium sulfate . the solvent was evaporated under reduced pressure and the residue was distilled to obtain 1 . 05 g of s - 3 - 1 , 2 , 5 - thiadiazolyl methyl n , n - diethylthiol carbamate ( compound no . 131 ). b . p . : 106 ° c ./ 0 . 5 mmhg 1 h - nmr ( cdcl 3 , δ ppm ) 1 . 0 ( 6h , t , d = 7hz ), 3 . 28 ( 4h , q , j = 7hz ), 4 . 30 ( 2h , s ), 8 . 5 ( 1h , s ) ir ( nacl , cm - 1 ) 1650 elemental analysis for c 8 h 13 n 3 os 2 calcd . : c ; 41 . 53 , h ; 5 . 66 , n ; 18 . 16 found : c ; 41 . 10 , h ; 5 . 46 , n ; 17 . 99 to a solution composed of 1 . 34 g of dimethylamine and 1 . 34 g of water , carbonyl sulfide was bubbled to saturation under cooling with water , and 1 g of 3 - chloromethyl - 1 , 2 , 5 - thiadiazole was added dropwise thereto . thereafter , the procedure in example 13 was followed to obtain 0 . 73 g of s - 3 - 1 , 2 , 5 - thiadiazolylmethyl n , n - dimethylthiol carbamate ( compound no . 132 ). b . p . : 99 ° c ./ 0 . 4 mmhg 1 h - nmr ( ccl 4 , δ ppm ) 2 . 95 ( 6h , s ), 4 . 32 ( 2h , s ), 8 . 5 ( 1h , s ) ir ( nacl , cm - 1 ) 1650 elemental analysis for c 6 h 9 n 3 os 2 calcd . : c ; 35 . 45 , h ; 4 . 46 , n ; 20 . 78 found : c ; 35 . 78 , h ; 4 . 47 , n ; 20 . 78 to a solution composed of 1 . 50 g of diisopropylamine and 1 . 5 g of water , carbonyl sulfide was bubbled to saturation and then 1 g of 3 - chloromethyl - 1 , 2 , 5 - thiadiazole was dropped into the mixture . the mixture was heated at 50 ° c . for 3 hours under stirring . after allowing to cool , the mixture was extracted with ether . the organic layer was washed with 1n hydrochloric acid and water , and the resultant was dried over anhydrous magnesium sulfate . the solvent was evaporated under reduced pressure and the residue was purified by silica gel column chromatography ( eluant : benzene / ethyl acetate = 10 / 1 ) to obtain 1 . 09 g of s - 3 - 1 , 2 , 5 - thiadiazolylmethyl n , n - diisopropylthiol carbamate ( compound no . 133 ). refractive index : n d 25 = 1 . 5470 1 h - nmr ( ccl 4 , δ ppm ) 1 . 32 ( 6h , d , j = 7hz ), 3 . 4 - 4 . 2 ( 2h , m ), 4 . 38 ( 2h , s ), 8 . 50 ( 1h , s ) ir ( nacl , cm - 1 ) 1635 elemental analysis for c 10 h 17 n 3 os 2 calcd . : c ; 46 . 30 , h ; 6 . 60 , n ; 16 . 19 found : c ; 46 . 40 , h ; 6 . 69 , n ; 16 . 29 to 1 ml of aqueous solution containing 0 . 67 g of dimethylamine , 0 . 57 g of carbon disulfide was added dropwise under cooling in ice . after stirring in ice for 30 minutes , 1 g of 3 - chloromethyl - 1 , 2 , 5 - thiadiazole was added to the mixture . thereafter , the procedure in example 15 was followed to obtain 1 . 28 g of s - 3 - 1 , 2 , 5 - thiadiazolyl n , n - dimethyldithio carbamate ( compound no . 136 ). refractive index : n d 25 = 1 . 6508 1 h - nmr ( ccl 4 , δ ppm ) 3 . 40 ( 6h , s ), 4 . 75 ( 2h , s ), 8 . 52 ( 1h , s ) elemental analysis for c 6 h 9 n 3 os 2 calcd . : c ; 32 . 85 , h ; 4 . 13 , n ; 19 . 15 found : c ; 32 . 48 , h ; 4 . 04 , n ; 19 . 03 in the similar manner , various compounds represented by the formula [ ii ] were prepared . the structures thereof as well as the physical properties are shown in table 3 . test for evaluation of effectiveness in growth inhibition of weeds by treatment of water in paddy field the compounds shown in table 4 formulated into wettable powder according to example 9 were tested for their effectiveness in growth inhibition of weeds in the same manner as in example 12 . the results are shown in table 4 . to a 100 ml three - necked flask , 30 ml of anhydrous dimethylsulfoxide , 0 . 7 g of pulverized potassium hydroxide powder and 2 g of n - 2 , 6 - diethylphenyl - α - chloroacetamide were placed . under nitrogen atmosphere , the mixture was stirred at room temperature until the mixture became a uniform solution . to the thus obtained uniform solution , 1 . 2 g of 3 - chloromethyl - 1 , 2 , 5 - thiadiazole was added under cooling in ice . after the addition , the mixture was stirred at room temperature for one hour and 30 ml of iced water was added to the reaction mixture . the resulting mixture was then extracted with ether and the organic layer was dried over anhydrous magnesium sulfate , followed by evaporation of the solvent . the residue was purified by silica gel column chromatography to obtain 0 . 55 g of the desired product . m . p . : 77 . 5 °- 78 ° c . ir ( kbr , cm - 1 ) 1650 1 h - nmr ( cdcl 3 , δ ppm ) 1 . 08 ( 6h , d , j = 7hz ), 2 . 22 ( 4h , q , j = 7hz ), 3 . 68 ( 2h , s ), 5 . 00 ( 2h , s ), 6 . 95 - 7 . 32 ( 3h , m ), 8 . 77 ( 1h , s ) the same procedure as in example 18 was repeated except that 30 ml of dimethylsulfoxide , 0 . 5 g of potassium hydroxide and 1 . 58 g of n -( 2 , 6 - dimethylphenyl )- α - chloroacetamide were used to obtain 0 . 9 g of the desired product . m . p . : 75 °- 76 ° c . ir ( kbr , cm - 1 ) 1650 1 h - nmr ( cdcl 3 , δ ppm ) 1 . 65 ( 6h , s ), 3 . 70 ( 2h , s ), 5 . 02 ( 2h , s ), 7 . 0 - 7 . 3 ( 3h , m ), 8 . 76 ( 1h , s ) the same procedure as in example 18 was repeated except that 10 ml of dimethylsulfoxide , 20 ml of tetrahydrofuran , 0 . 5 g of potassium hydroxide and 1 . 47 g of n - 2 , 6 - diethylphenyl - α - chloroacetamide were used to obtain 0 . 49 g of the desired product . m . p . : 66 °- 67 ° c . ir ( kbr , cm - 1 ) 1680 1 h - nmr ( cdcl 3 , δ ppm ) 1 . 05 ( 3h , t , j = 7hz ), 1 . 92 ( 3h , s ), 2 . 27 ( 2h , q , j = 7hz ), 3 . 80 ( 2h , s ), 5 . 00 ( 2h , s ), 6 . 82 - 7 . 44 ( 3h , m ), 8 . 72 ( 2h , s ) to 10 ml of a solution in toluene containing 0 . 7 g of 3 -( n - 2 , 6 - dimethylcyclohexylideneaminomethyl )- 1 , 2 , 5 - thiadiazole obtained by the condensation of 2 , 6 - dimethylcyclohexanone and 3 - aminomethyl 1 , 2 , 5 - thiadiazole , 0 . 4 g of chloro - α - chloroacetyl was added and the resulting mixture was stirred for 8 hours under heat . after allowing the mixture to cool , the solvent was evaporated under reduced pressure and the residue was purified by silica gel column chromatography to obtain 0 . 48 g of the desired product in the form of oil . refractive index : n d 25 = 1 . 5489 ir ( nacl , cm - 1 ) 1665 1 h - nmr ( cdcl 3 , δ ppm ) 0 . 72 - 2 . 75 ( 13h , m ), 3 . 92 ( 2h , s ), 4 . 71 , 4 . 87 ( 2h , s ), 8 . 65 ( 1h , s ) the same procedure as in example 21 was repeated except that 1 g of a condensate of methylisopropyl ketone and 3 - aminomethyl - 1 , 2 , 5 - thiadiazole , and 0 . 68 g of chloro - α - chloroacetyl was used to obtain 0 . 9 g of the desired product in the form of oil . refractive index : n d 25 = 1 . 5263 ir ( nacl , cm - 1 ) 1665 1 h - nmr ( cdcl 3 , δ ppm ) 0 . 95 ( 6h , d , j = 6 . 2hz ), 1 . 89 ( 3h , s ), 2 . 08 - 2 . 82 ( 1h , m ), 4 . 08 ( 2h , s ), 4 . 82 ( 2h , s ), 5 . 11 ( 1h , s ), 8 . 55 ( 1h , s ) test for evaluation of effectiveness in growth inhibition of weeds by treatment of water in paddy field the compounds of compound nos . 178 - 182 formulated into wettable powder according to example 9 were tested for their effectiveness in growth inhibition of weeds in the same manner as in example 12 . the results are shown in table 5 . a solution in methanol containing 5 . 31 g of 3 - chloro - 4 -( 2 , 6 - dichlorophenyl )- 1 , 2 , 5 - thiadiazole , 1 . 91 g of copper powder and 1 . 97 g of cuprous chloride saturated with ammonia gas was placed in a stainless steel vessel . after sealing the vessel , the solution was stirred at 120 ° c . for 24 hours . after allowing the mixture to cool , insoluble materials were removed by filtration . the filtrate was concentrated and the residue was purified by silica gel column chromatography to obtain 2 . 19 g of 3 - amino - 4 -( 2 , 6 - dichlorophenyl )- 1 , 2 , 5 - thiadiazole . m . p . : 95 °- 97 ° c . 1 h - nmr ( cdcl 3 , δ ppm ) 4 . 52 ( s , 2h ), 7 . 2 - 7 . 5 ( m , 3h ) ir ( kbr , cm - 1 ) 3425 , 3325 , 3210 , 1620 , 1535 , 1490 , 1430 , 1420 , 790 , 780 ms ( m / z ): 245 ( m + ) to a solution of 1 . 16 g of 3 - chloro - 4 -( 4 - chlorophenyl )- 1 , 2 , 5 - thiadiazole in n , n - dimethylformamide , 1 . 11 g of potassium phthalimide was added and the mixture was heated to reflux at 110 ° c . for 12 hours . after allowing to cool , the mixture was poured into water and the resultant was extracted with ether . the ether layer was washed twice with dilute aqueous sodium hydroxide solution , twice with water , and twice with saturated aqueous sodium chloride solution . the resultant was then dried over anhydrous sodium sulfate and concentrated . the residue was purified by silica gel column chromatography to obtain 0 . 85 g of 3 -( 4 - chlorophenyl )- 4 - phthalimide - 1 , 2 , 5 - thiadiazole . m . p . : 152 °- 153 ° c . 1 h - nmr ( cdcl 3 , δ ppm ) 7 . 1 - 7 . 4 ( m , 2h ), 7 . 4 - 7 . 7 ( m , 2h ), 7 . 7 - 8 . 0 ( m , 4h ) ir ( kbr , cm - 1 ) 1790 , 1725 , 1440 , 1180 , 885 , 715 ms ( m / z ): 341 ( m + ) to a solution of 0 . 41 g of 3 -( 4 - chlorophenyl )- 4 - phthalimide - 1 , 2 , 5 - thiadiazole in ethanol , 0 . 05 g of 80 % aqueous hydrazine solution was added and the mixture was heated to reflux for one hour . after allowing to cool , the mixture was poured into water and extracted with ether . the ether layer was washed twice with water and twice with saturated aqueous sodium chloride solution . the resultant was dried over anhydrous sodium sulfate and the resultant was concentrated , followed by purification by silica gel column chromatography to obtain 0 . 21 g of 3 - amino - 4 -( 4 - chlorophenyl )- 1 , 2 , 5 - thiadiazole . m . p . : 132 °- 133 ° c . 1 h - nmr ( acetone - d 6 , δ ppm ) 5 . 40 ( bs , 2h ), 7 . 2 - 7 . 5 ( m , 2h ), 7 . 5 - 7 . 8 ( m , 2h ) ir ( kbr , cm - 1 ) 3410 , 3310 , 3190 , 1620 , 1515 , 1495 , 1435 , 1400 , 1090 , 830 ms ( m / z ): 211 ( m + ) in a stainless steel vessel , 5 . 31 g of 3 - chloro - 4 -( 2 , 6 - dichlorophenyl )- 1 , 2 , 5 - thiadiazole and 100 ml of 40 % aqueous methylamine solution were placed . after sealing the vessel , the solution was stirred at 120 ° c . for 12 hours . after allowing to cool , the mixture was poured into water and was extracted with ether . the ether layer was washed three times with water and three times with saturated aqueous sodium chloride solution . the resultant was then dried over anhydrous sodium sulfate and then the resultant was concentrated , followed by purification by silica gel column chromatography to obtain 2 . 55 g of 3 -( 2 , 6 - dichlorophenyl )- 4 - methylamino - 1 , 2 , 5 - thiadiazole . m . p . : 145 °- 146 ° c . 1 h - nmr ( cdcl 3 , δ ppm ) 3 . 02 ( s , 3h ), 4 . 10 ( bs , 1h ), 7 . 15 - 7 . 4 ( m , 3h ) ir ( kbr , cm - 1 ) 3320 , 1555 , 1425 , 790 , 775 ms ( m / z ): 259 ( m + ) to a solution containing 0 . 49 g of 3 - amino - 4 -( 2 , 6 - dichlorophenyl )- 1 , 2 , 5 - thiadiazole and 0 . 22 g of triethylamine in n , n - dimethylformamide , 0 . 20 g of acetyl chloride was added and the mixture was stirred at 60 ° c . for 12 hours . after allowing to cool , the mixture was poured into water and was extracted with ether . the ether layer was washed twice with dilute hydrochloric acid , twice with water and twice with saturated aqueous sodium chloride solution . the resultant was dried over anhydrous sodium sulfate , concentrated and purified by silica gel chromatography to obtain 0 . 25 g of 3 - acetylamino - 4 -( 2 , 6 - dichlorophenyl )- 1 , 2 , 5 - thiadiazole . m . p . : 180 °- 185 ° c . 1 h - nmr ( cdcl 3 , δ ppm ) 2 . 1 ( s , 3h ), 7 . 37 ( s , 3h ), 9 . 47 ( bs , 1h ) ir ( kbr , cm - 1 ) 3290 , 1695 , 1540 , 1500 , 1425 , 1230 , 785 ms ( m / z ): 287 ( m + ) to a solution of 2 . 66 g of 3 - chloro - 4 -( 2 , 6 - dichlorophenyl )- 1 , 2 , 5 - thiadiazole in n , n - dimethylformamide , 2 . 22 g of potassium phthalimide was added and the mixture was heated to reflux at 110 ° c . for 12 hours . after allowing to cool , the mixture was poured into water and was extracted with ether . the ether layer was washed twice with dilute aqueous sodium hydroxide solution , twice with water and twice with saturated aqueous sodium chloride solution . the resultant was dried over anhydrous sodium sulfate , concentrated and purified by silica gel column chromatography to obtain 1 . 90 g of 3 -( 2 , 6 - dichlorophenyl )- 4 - phthalimide - 1 , 2 , 5 - thiadiazole . m . p . : 214 °- 215 ° c . 1 h - nmr ( cdcl 3 , δ ppm ) 7 . 15 - 7 . 4 ( m , 3h ), 7 . 55 - 7 . 95 ( m , 4h ) ir ( kbr , cm - 1 ) 1790 , 1745 , 1730 , 1470 , 1465 , 1430 , 1415 , 1310 , 710 ms ( m / z ): 375 ( m + ) to a solution of 0 . 49 g of 3 - amino - 4 -( 2 , 6 - dichlorophenyl )- 1 , 2 , 5 - thiadiazole and 0 . 22 g of triethylamine in n , n - dimethylformamide , 0 . 24 g of dimethylcarbamoyl chloride was added and the mixture was heated at 120 ° c . for 12 hours . after allowing to cool , the mixture was poured into water and was extracted with ether . the ether layer was washed twice with dilute hydrochloric acid , twice with water and twice with saturated aqueous sodium chloride solution . the resultant was dried over anhydrous sodium sulfate , concentrated and purified by silica gel column chromatography to obtain 0 . 19 g of 3 -( 2 , 6 - dichlorophenyl )- 4 ( 3 , 3 - dimethylureido )- 1 , 2 , 5 - thiadiazole . m . p . : 100 °- 103 ° c . 1 h - nmr ( cdcl 3 , δ ppm ) 2 . 83 ( s , 3h ), 3 . 00 ( s , 3h ), 7 . 15 - 7 . 45 ( m , 3h ), 8 . 27 ( s , 1h ) ir ( kbr , cm - 1 ) 1630 , 1460 , 1425 , 1380 , 1115 , 1100 , 790 , 775 ms ( m / z ): 316 ( m + ) to a solution of 0 . 49 g of 3 - amino - 4 -( 2 , 6 - dichlorophenyl )- 1 , 2 , 5 - thiadiazole and 0 . 22 g of triethylamine in n , n - dimethylformamide , 0 . 27 g of isobutyryl chloride was added and the mixture was heated at 60 ° c . for 12 hours . after allowing to cool , the mixture was poured into water and was extracted with ether . the ether layer was washed twice with dilute hydrochloric acid , twice with water and twice with saturated aqueous sodium chloride solution . the resultant was dried over anhydrous sodium sulfate , concentrated and purified by silica gel column chromatography to obtain 0 . 23 g of 3 - isobutyrylamino - 4 -( 2 , 6 - dichlorophenyl )- 1 , 2 , 5 - thiadiazole m . p . : 112 °- 117 ° c . 1 h - nmr ( cdcl 3 , δ ppm ) 1 . 08 ( d , j = 7hz , 6h ), 2 . 68 ( septet , j = 7hz , 1h ) 7 . 2 - 7 . 45 ( m , 3h ), 8 . 10 ( bs , 1h ) ir ( kbr , cm - 1 ) 3290 , 1700 , 1540 , 1495 , 1430 , 1145 ms ( m / z ): 315 ( m + ) test for evaluation of effectiveness in growth inhibition of weeds by treatment of water in paddy field the compounds with compound nos . 183 - 188 formulated into wettable powder according to example 9 were tested for their effectiveness in growth inhibition of weeds in the same manner as in example 12 . the results are shown in table 6 . table 3__________________________________________________________________________com - pound nmr ( 60 mhz ) irno . y r . sup . 15 r . sup . 16 properties ( δ ppm , ccl . sub . 4 ) ( cm . sup .- 1 ) __________________________________________________________________________134 o ( ch . sub . 2 ). sub . 6 n . sub . d . sup . 25 1 . 5699 1 . 58 ( 8h , br , s ), 3 . 18 - 3 . 72 ( 4h , m ), 4 . 34 ( 2h , s ), 1640 8 . 48 ( 1h , s ) 135 o ( ch . sub . 2 ). sub . 5 n . sub . d . sup . 25 1 . 5760 1 . 63 ( 6h , br , s ), 3 . 28 - 3 . 68 ( 4h , 1645 4 . 38 ( 2h , s ), 8 . 50 ( 1h , s ) 137 s c . sub . 2 h . sub . 5 c . sub . 2 h . sub . 5 n . sub . d . sup . 25 1 . 6201 1 . 20 ( 6h , t , j = 7hz ), 3 . 80 ( 4h , q , -- 7hz ), 4 . 8 ( 2h , s ), 8 . 52 ( 1h , s ) 138 s i - c . sub . 3 h . sub . 7 i - c . sub . 3 h . sub . 7 n . sub . d . sup . 25 1 . 5980 1 . 42 ( 12h , d , j = 7hz ), 4 . 22 - 5 . 0 ( 4h , --, 8 . 56 ( 1h , s ) 139 s ( ch . sub . 2 ). sub . 5 n . sub . d . sup . 25 1 . 6453 1 . 65 ( 6h , br . s ), 4 . 00 ( 4h , br . s ), 4 . 82 ( 2h , --, 8 . 57 ( 1h , s ) 140 s ( ch . sub . 2 ). sub . 6 n . sub . d . sup . 25 1 . 6292 1 . 52 ( 8h , br . s ), 3 . 82 ( 2h , t , j = 7hz ), 4 . 11 ( 2h , t , j = 7hz ), -- 4 . 84 ( 2h , s ), 8 . 58 ( 1h , s ) 141 o ## str111 ## n . sub . d . sup . 25 1 . 5625 1 . 21 ( 6h , d , j = 7hz ), 1 . 41 - 1 . 74 ( 6h , m ), 4 . 32 ( 4h , m ), 8 . 48 ( 1h , s ) 1625142 o ch . sub . 2 ch . sub . 2 och . sub . 2 ch . sub . 2 oil 3 . 54 ( 8h , m ), 4 . 35 ( 2h , s ), 8 . 48 ( 1h , 1620143 o ## str112 ## oil 2 . 19 - 2 . 38 ( 7h , m ), 3 . 40 ( 4h , t , j = 7hz ), 4 . 26 ( 2h , s ), 8 . 44 ( 1h , s ) 1630144 o ## str113 ## n . sub . d . sup . 25 1 . 5659 1 . 16 ( 3h , d , j = 8hz ), 1 . 58 ( 6h , br . s ), 2 . 48 - 3 . 21 2h , m ), 3 . 69 - 4 . 68 ( 3h , m ), 8 . 62 ( 1h , 1635145 o ## str114 ## n . sub . d . sup . 25 1 . 5592 1 . 82 ( 3h , t , j = 7hz ), 1 . 56 ( 6h , br . s ), 2 . 76 ( 2h , m ), 3 . 6 - 4 . 5 ( 5h , m ), 8 . 5 ( 1h , 1635146 o ## str115 ## n . sub . d . sup . 25 1 . 5653 0 . 87 ( 3h , d , j = 7hz ,), 1 . 18 - 2 . 00 ( 5h , m ), 2 . 17 - 3 . 10 ( 2h , m ), 3 . 48 - 4 . 25 ( 2h , m ), 4 . 33 ( 2h , s ), 8 . 48 ( 1h , s ) 1640147 o ch . sub . 3 ch . sub . 2 ch . sub . 2 oh n . sub . d . sup . 25 1 . 5819 2 . 98 ( 3h , s ), 3 . 10 - 3 . 70 ( 4h , m ), 4 . 28 ( 2h , 3430 8 . 44 ( 1h , s ) 1640148 o n - c . sub . 4 h . sub . 9 n - c . sub . 4 h . sub . 9 n . sub . d . sup . 25 1 . 5248 0 . 48 - 1 . 80 ( 14h , m ). 2 . 92 - 3 . 40 ( 4h , m ), 4 . 22 ( 2h , s ), 1650 8 . 38 ( 1h , s ) 149 o ch . sub . 2 ch . sub . 2 oh ch . sub . 2 ch . sub . 2 oh n . sub . d . sup . 25 1 . 5931 3 . 00 - 3 . 76 ( 8h , m ), 4 . 10 - 4 . 42 ( 4h , m ), 8 . 72 ( 1h , s ), 3400 ( dmso - d6 ) 1640150 o i - c . sub . 4 h . sub . 9 i - c . sub . 4 h . sub . 9 n . sub . d . sup . 25 1 . 5246 1 . 84 ( 6h , d , j = 7hz ), 1 . 92 ( 2h , h , 1650z ), 3 . 07 ( 4h , d , j = 7hz ), 4 . 28 ( 2h , s ), 8 . 39 ( 1h , s ) 151 o ch . sub . 2 chch . sub . 2 ch . sub . 2 chch . sub . 2 n . sub . d . sup . 25 1 . 5618 3 . 78 - 4 . 05 ( 4h , m ), 4 . 33 ( 2h , s ), 4 . 82 - 6 . 10 ( 6h , m ), 1655 8 . 45 ( 1h , s ) 152 o s - c . sub . 4 h . sub . 9 s - c . sub . 4 h . sub . 9 n . sub . d . sup . 25 1 . 5557 0 . 88 ( 6h , t , j = 7hz ), 1 . 25 ( 6h , d , 1655z ), 1 . 45 - 2 . 00 ( 4h , m ), 2 . 70 - 3 . 75 ( 2h , m ), 4 . 29 ( 2h , s ), 8 . 42 ( 1h , s ) 153 o ## str116 ## n . sub . d . sup . 25 1 . 5572 1 . 15 ( 6h , d , j = 7hz ), 2 . 29 - 2 . 82 ( 2h , m ), 2 . 90 - 4 . 20 ( 4h , m ), 4 . 38 ( 2h , s ), 8 . 48 ( 1h , 1660154 o ## str117 ## n . sub . d . sup . 25 1 . 5658 0 . 90 ( 2h , d , j = 6hz ), 1 . 07 - 1 . 89 ( 5h , m ), 2 . 48 - 3 . 10 ( 2h , m ), 3 . 68 - 4 . 45 ( 4h , m ), 8 . 45 ( 1h , s ) 1650155 o ## str118 ## n . sub . d . sup . 25 1 . 5596 1 . 85 ( 6h , d , j = 7hz ), 1 . 15 - 2 . 56 ( 6h , m ), 2 . 80 - 4 . 50 ( 4h , m ), 8 . 42 ( 1h , s ) 1660156 o n - c . sub . 4 h . sub . 9 n - c . sub . 6 h . sub . 13 n . sub . d . sup . 25 1 . 5269 0 . 67 - 1 . 80 ( 18h , m ), 2 . 92 - 3 . 47 ( 4h , 1655 4 . 30 ( 2h , s ), 8 . 45 ( 1h , s ) 157 o c . sub . 2 h . sub . 5 n - c . sub . 4 h . sub . 9 n . sub . d . sup . 25 1 . 5408 0 . 67 - 1 . 81 ( 10h , m ), 3 . 32 ( 4h , q , j = 7hz ), 4 . 32 ( 2h , s ), 1650 8 . 46 ( 1h , s ) 158 o ## str119 ## n . sub . d . sup . 25 1 . 5612 1 . 62 - 2 . 49 ( 4h , m ), 3 . 07 - 3 . 86 ( 2h , m ), 4 . 21 - 4 . 72 ( 3h , m ), 8 . 52 ( 1h , s ), 9 . 96 ( 1h , 3000 , 1730 , 1650159 o ch . sub . 3 n - c . sub . 4 h . sub . 9 n . sub . d . sup . 25 1 . 5458 0 . 65 - 1 . 80 ( 7h , m ), 2 . 87 ( 3h , s ), 3 . 0 - 3 . 52 ( 2h , m ), 1660 4 . 29 ( 2h , s ), 8 . 43 ( 1h , s ) 160 o ch . sub . 3 n - c . sub . 6 h . sub . 13 n . sub . d . sup . 25 1 . 5336 0 . 6 - 1 . 82 ( 11h , m ), 2 . 90 ( 3h , s ), 3 . 02 - 3 . 48 ( 2h , m ), 1660 8 . 45 ( 1h , s ) 161 o ch . sub . 3 c - c . sub . 7 h . sub . 13 n . sub . d . sup . 25 1 . 5639 1 . 0 - 2 . 0 ( 12h , br . s ), 2 . 79 ( 3h , s ), 3 . 57 - 4 . 22 ( 1h , m ), 1650 4 . 34 ( 1h , s ), 8 . 51 ( 1h , s ) 162 o ch . sub . 3 c - c . sub . 6 h . sub . 11 n . sub . d . sup . 25 1 . 5687 0 . 84 - 2 . 00 ( 10h , m ), 2 . 83 ( 3h , s ), 3 . 62 - 4 . 15 ( 1h , m ), 1630 4 . 32 ( 2h , s ), 8 . 49 ( 1h , s ) 163 o c . sub . 2 h . sub . 5 c - c . sub . 6 h . sub . 11 n . sub . d . sup . 25 1 . 5515 0 . 69 - 2 . 04 ( 13h , m ), 3 . 30 ( 2h , q , 1650z ), 3 . 60 - 4 . 16 ( 1h , m ), 4 . 35 ( 2h , s ), 8 . 48 ( 1h , s ) 164 o n - c . sub . 3 h . sub . 7 n - c . sub . 3 h . sub . 7 n . sub . d . sup . 25 1 . 5362 0 . 77 ( 6h , t , j = 7hz ), 1 . 48 ( 4h , h , 1660z ), 3 . 16 ( 4h , t , j = 7hz ), 4 . 23 ( 2h , s ), 8 . 40 ( 1h , s ) 165 o ch . sub . 3 ( ch . sub . 2 ). sub . 3 och . sub . 3 n . sub . d . sup . 25 1 . 5471 1 . 43 - 2 . 0 ( 2h , m ), 2 . 9 ( 3h , s ), 3 . 07 - 3 . 58 ( 7h , m ), 1660 4 . 31 ( 2h , s ), 8 . 44 ( 1h , s ) 1120166 o ch . sub . 3 ( ch . sub . 2 ). sub . 3 oc . sub . 2 h . sub . 5 n . sub . d . sup . 25 1 . 5379 1 . 10 ( 3h , t , j = 6h ), 1 . 76 ( 2h , q , 1665z ), 2 . 91 ( 3h , s ), 3 . 18 - 3 . 62 ( 6h , m ), 4 . 35 ( 2h , s ), 8 . 49 ( 1h , s ) 1120167 o ch . sub . 3 ( ch . sub . 2 ). sub . 3 opri n . sub . d . sup . 25 1 . 5245 1 . 05 ( 6h , d , j = 7hz ), 1 . 70 ( 2h , q , j = 7hz ), 2 . 90 ( 3h , s ) 1660 3 . 09 - 3 . 63 ( 7h , m ), 4 . 30 ( 2h , s ), 8 . 41 ( 1h , 1080168 o ch . sub . 3 ( ch . sub . 2 ). sub . 2 oet n . sub . d . sup . 25 1 . 5420 1 . 15 ( 3h , t , j = 7hz ), 3 . 02 ( 3h , s ), 3 . 22 - 3 . 65 ( 6h , m ), 1660 4 . 36 ( 2h , s ), 8 . 48 ( 1h , s ) 1120169 o ch . sub . 3 c - c . sub . 5 h . sub . 9 oil 1 . 0 - 2 . 1 ( 8h , br . s ), 2 . 77 ( 3h , s ), 4 . 1 - 4 . 8 ( 3h , m ), 1650 8 . 48 ( 1h , s ), ( cdcl . sub . 3 ) 170 o c . sub . 2 h . sub . 5 i - c . sub . 4 h . sub . 9 oil 0 . 91 ( 6h , d , j = 7hz ), 1 . 18 ( 3h , t , 1660z ), 2 . 00 ( 1h , h , j = 7hz ), 3 . 18 ( 2h , d , j = 7hz ), 3 . 41 ( 2h , q , j = 7hz ), 4 . 45 ( 2h , s ), 8 . 52 ( 1h , s ), ( cdcl . sub . 3 ) 171 o n - c . sub . 3 h . sub . 7 n - c . sub . 4 h . sub . 9 oil 0 . 65 - 1 . 95 ( 12h , m ), 2 . 90 - 3 . 55 ( 4h , m ), 4 . 35 ( 2h , s ), 1660 8 . 49 ( 1h , s ), ( cdcl . sub . 3 ) 172 o i - c . sub . 3 h . sub . 7 n - c . sub . 4 h . sub . 9 oil 0 . 63 - 1 . 85 ( 13h , m ), 2 . 84 - 3 . 40 ( 2h , m ), 3 . 70 - 4 . 5 ( 3h , m ), 1650 8 . 47 ( 1h , s ), ( cdcl . sub . 3 ) 173 o s - c . sub . 4 h . sub . 9 n - c . sub . 4 h . sub . 9 n . sub . d . sup . 25 1 . 5321 0 . 65 - 1 . 90 ( 14h , m ), 2 . 85 - 3 . 37 ( 2h , 1650 3 . 66 - 4 . 21 ( 1h , m ), 4 . 32 ( 2h , s ), 8 . 47 ( 1h , s ) 174 o n - c . sub . 3 h . sub . 7 i - c . sub . 3 h . sub . 7 n . sub . d . sup . 25 1 . 5494 0 . 75 - 1 . 82 ( 11h , m ), 2 . 92 - 3 . 41 ( 2h , 1645 3 . 85 - 4 . 58 ( 3h , m ), 8 . 51 ( 1h , s ) 175 o i - c . sub . 3 h . sub . 7 s - c . sub . 4 h . sub . 9 n . sub . d . sup . 25 1 . 5332 0 . 80 - 2 . 40 ( 15h , m ), 3 . 08 ( 2h , d , 1650z ), 3 . 30 - 4 . 02 ( 1h , m ), 4 . 39 ( 2h , s ), 8 . 50 ( 1h , s ) 176 o n - c . sub . 3 h . sub . 7 s - c . sub . 4 h . sub . 9 oil 0 . 7 - 2 . 0 ( 13h , m ), 2 . 9 - 3 . 35 ( 2h , m ), 3 . 60 - 4 . 30 ( 1h , m ), 1650 4 . 42 ( 2h , s ), 8 . 50 ( 1h , s ), ( cdcl . sub . 3 ) 177 o ch . sub . 3 i - c . sub . 4 h . sub . 9 oil 0 . 85 ( 6h , d , j = 7hz ), 1 . 15 - 2 . 35 ( 1h , 1660 2 . 70 - 3 . 38 ( 5h , m ), 4 . 38 ( 2h , s ), 8 . 48 ( 1h , __________________________________________________________________________ s ) table 4__________________________________________________________________________amount of damage herbicidal effectcompound compound to crop barnyard - small flower broad - no . g / 10 a rice grass umbrellaplant bulrush monochoria leaved__________________________________________________________________________131 250 0 5 5 4 -- 4 125 0 4 5 4 -- 4132 250 0 3 4 4 3 4 125 0 2 4 3 3 4133 125 0 5 5 5 5 5 60 0 5 5 5 5 5134 125 0 5 5 4 5 5 60 0 5 5 4 5 5135 250 0 3 5 3 -- 4 125 0 3 4 2 -- 3138 250 0 4 5 4 -- 4 125 0 3 5 3 -- 4139 250 0 4 5 2 -- 5 125 0 3 5 2 -- 4140 250 0 3 5 2 -- 4 125 0 3 5 2 -- 4141 125 0 5 5 3 5 5 60 0 5 5 3 4 5144 60 0 5 5 4 3 4 30 0 5 5 3 3 4145 125 0 5 5 5 5 5 60 0 5 5 5 5 5146 250 0 4 5 4 4 4 125 0 3 5 3 3 4148 125 0 5 5 5 4 4 60 0 5 5 4 3 4150 250 0 5 5 4 5 4 125 0 5 5 4 4 4151 250 0 5 5 4 5 5 125 0 3 4 3 5 4152 250 0 5 4 4 4 3 125 0 5 4 3 2 2157 125 0 5 5 5 5 5 60 0 5 5 5 5 5159 125 0 5 5 5 4 5 60 0 5 5 5 3 5160 250 0 5 5 5 5 5 125 0 5 5 5 4 5161 250 0 5 5 5 5 5 125 0 5 5 4 5 5162 250 0 5 5 5 5 5 125 0 5 5 5 5 5163 250 0 5 5 5 5 5 125 0 5 5 5 5 5164 125 0 5 5 5 5 5 60 0 5 5 4 4 4170 250 0 5 5 5 5 5 125 0 4 5 4 5 5171 250 0 5 5 5 5 5 125 0 5 5 5 5 5172 250 0 5 5 5 5 5 125 0 5 5 5 5 5173 125 0 5 5 5 4 5 60 0 3 5 5 2 5174 250 0 5 5 5 5 5 125 0 5 5 5 5 5175 125 0 5 4 5 4 4 60 0 5 4 4 4 4176 125 0 5 5 5 5 4 60 0 5 5 5 3 4177 125 0 5 5 5 5 5 60 0 5 5 5 5 5__________________________________________________________________________ table 5__________________________________________________________________________amount of damage herbicidal effectcompound compound to crop barnyard - small flower broad - no . g / 10 a rice grass umbrellaplant bulrush monochoria leaved__________________________________________________________________________178 30 0 5 5 5 5 5 15 0 5 5 5 5 5179 30 0 5 5 5 5 5 15 0 5 5 5 5 5180 30 0 5 5 5 5 5 15 0 5 5 5 5 5181 30 0 5 5 5 5 5 15 0 5 5 5 5 5182 30 0 5 5 5 5 5 15 0 5 5 5 5 5__________________________________________________________________________ table 6__________________________________________________________________________amount of damage herbicidal effectcompound compound to crop barnyard - small flower broad - no . g / 10 a rice grass umbrellaplant bulrush monochoria leaved__________________________________________________________________________183 125 0 4 5 5 5 5 250 0 5 5 5 5 5184 250 0 4 5 5 5 5 500 0 5 5 5 5 5185 125 0 3 5 5 3 5 250 0 4 5 5 4 5186 250 0 4 5 5 4 5 500 0 5 5 5 4 5187 250 0 4 3 5 3 5 500 0 5 5 5 4 5188 250 0 4 5 4 4 5 500 0 5 5 5 4 5__________________________________________________________________________
thiadiazole derivatives with excellent herbicidal effectiveness , wide herbicidal spectrum and excellent selectivity are disclosed . the thiadiazole derivatives are represented by one of the formula 14 . ## str1 ##