HERBICIDAL 1,5-DIPHENYL-1H-1, 2,4-TRIAZOLE-3-CARBOXAMIDE DERIVATIVES

Abstract: Herbicidal 1,5-diphenyl-1H-1,2,4-triazole-3-­ carboxamide derivatives are represented by the formula (I): wherein R¹ represents a straight-chain alkyl group of from 2 to 10 carbon atoms, a branched-chain alkyl group or a cycloalkyl group of from 3 to 10 carbon atoms, a (cycloalkyl)-alkyl group of from 4 to 10 carbon atoms, an unsubstituted or halogen-substituted phenyl group, an aralkyl group of from 7 to 9 carbon atoms, an alkenyl group of from 3 to 6 carbon atoms or an alkyl group of from 2 to 10 carbon atoms substituted by 1 to 19 fluorine atoms; and R² represents a fluorine atom, a chlorine atom, a methyl group or a methoxy group.

Description: The present invention relates to 1,5-diphenyl-1H-1,2,4-triazole-3-carboxamide derivatives, their preparation, herbidical compositions containing them and their use as herbicides. Rice plants, wheat and corn are important crop plants. In order to protect these crop plants from weeds and for yielding a good harvest of the crops, the use of herbicide(s) is indispensable. The development of a compound, which has an excellent selective herbidical activity in killing only weeds without damaging the useful crop plants such as rice plants, wheat or corn, has been strongly demanded. Derivatives of 1,5-diphenyl-1H-1,2,4-triazole-3-carboxamide and their herbicidal activity have been hitherto reported in, for example, FR-A-2 526 271 and Japanese Patent Applications Laying-Open (KOKAI) Nos. 57-193406 (1982), 57-193466 (1982) and 58-185572 (1983). However, the herbicidal activity of each of these derivatives of 1,5-diphenyl-1H-1,2,4-triazole-3-carboxamide is not fully satisfactory. Their selectivity cannot be said to be excellent. The present invention provides 1,5-diphenyl-1H-1, 2,4-triazole-3-carboxamide derivatives represented by the following formula (I): wherein R¹ represents a straight-chain alkyl group of from 2 to 10 carbon atoms, a branched alkyl group or a cycloalkyl group of from 3 to 10 carbon atoms, a (cycloalkyl)-alkyl group of from 4 to 10 carbon atoms, an unsubstituted or halogen-substituted phenyl group, an aralkyl group of from 7 to 9 carbon atoms, an alkenyl group of from 3 to 6 carbon atoms or an alkyl group of from 2 to 10 carbon atoms substituted by 1 to 19 fluorine atoms; and R² represents a fluorine atom, a chlorine atom, a methyl group or a methoxy group. It is thus possible to provide derivatives of 1,5-diphenyl-1H-1,2,4-triazole-3-carboxamide which show an excellent herbicidal activity to graminous weeds and broad-leaved weeds, particularly to broad-leaved weeds. On the other hand, the derivatives of formula (I) can show practically no phytotoxicity to crop plants such as rice plant, wheat and corn. Preferably, R¹ represents a straight-chain alkyl group of from 3 to 6 carbon atoms, a branched-chain alkyl group or cycloalkyl group of from 3 to 7 carbon atoms, an alkyl group of from 1 to 3 carbon atoms substituted by an alicyclic structure of from 3 to 7 carbon atoms, an unsubstituted phenyl group, a phenyl group substituted by from 1 to 3 chlorine atom(s) and/or fluorine atom(s), an aralkyl group of from 7 to 9 carbon atoms, an alkenyl group of from 3 to 6 carbon atoms or an alkyl group of from 2 to 7 carbon atoms substituted by from 3 to 12 fluorine atoms. More preferably R¹ represents a straight-chain or branched chain alkyl of from 4 to 6 carbon atoms, an alkyl group of from 1 to 3 carbon atoms substituted by cyclohexyl or a group of formula CH₂(CF₂) m (CHF) n CF₂X wherein X represents a hydrogen or fluorine atom, m is 0 or an integer of from 1 to 5, n is 0 or 1 and m + n is not greater than 5, and R² is a fluorine atom. R² may be a fluorine atom in the 2-position of the 5-phenyl ring of the derivatives of formula (I). The compounds represented by the formula (I) according to the present invention are exemplified in the following Table 1. Table 2 below shows the melting points, the results of spectroscopic analysis and elementary analysis of the thus exemplified compounds. Since each of the compounds represented by the formula (I), preferably compound Nos. 1-3, 6-9, 15-17, 20, 21, 24 and 25, has an excellent selective herbicidal activity, it can be utilized in crop fields and paddy fields as an active ingredient of a herbicidal composition. The compound represented by the formula (I) according to the present invention can be manufactured by the process shown in the following reaction scheme 1. Reaction scheme 1, wherein R¹ and R² respectively represent the same meaning as that described before. Namely, a derivative of 2-phenyl-4-phenylhydrazono-2-oxazolin-5-one represented by the formula (II) is reacted with ammonia in organic solvent such as toluene and acetone at a temperature of preferably -10 to 50°C, more preferably 0 to 30°C, and preferably for 0.1 to 10 hours. Then, after the reaction mixture is acidified with acid such as hydrochloric acid and acetic acid, dehydrating ring closure is carried out with stirring at a temperature of preferably 0 to 150°C, more preferably 20 to 80°C, and preferably for 0.1 to 10 hours, thereby manufacturing the compound represented by the formula (I) in a high yield. The compound represented by the formula (II) can be synthesized according to the process shown in the following reaction scheme 2. Reaction scheme 2, wherein R¹ and R² respectively represent the same meaning as that described before. Namely, 3-chloromethyl-1-nitrobenzene (III) is reacted with a compound represented by the formula: R¹OH wherein R¹ has the same meaning as above, in a solvent such as dimethylformamide, hexamethylphosphoramide, etc. preferably for 0.1 to 20 hours, more preferably for 0.5 to 10 hours, at a temperature of -10 to 150°C, preferably 0 to 80°C, in the presence of an acceptor for hydrogen chloride formed such as KOH or NaH, to obtain a nitrobenzyl ether (IV). The thus obtained nitrobenzyl ether (IV) is reduced by various well known methods. For instance, the nitrobenzyl ether (IV) is heated under reflux after adding hydrazine hydrate in alcohol for 1 to 10 hours in the presence of palladium-charcoal, to convert the compound to an aniline compound (V). Then the aniline compound is diazotized by, for example, sodium nitrite in hydrochloric acid at a temperature of preferably -10 to 15°C to obtain diazonium salt. Separately, a derivative of 2-phenyl-2-oxazolin-5-one (VI) is synthesized by subjecting a derivative of hippuric acid to dehydrating-cyclization in acetic anhydride at a temperature of 20 to 100°C, preferably 50 to 90°C, for 0.1 to 30 hours, preferably 0.1 to 3 hours. Then the diazonium salt is reacted with the derivative of 2-phenyl-2-oxazolin-5-one at a temperature of -50 to 100°C, preferably -30 to 40°C, for 0.01 to 20 hours, preferably 0.1 to 10 hours to obtain the compound represented by the formula (II). The derivative of 1,5-diphenyl-1H-1,2,4-triazole-3-carboxamide according to the present invention is used singly as a herbicide, or used as a herbicidal composition such as wettable powders, emulsions, granules and powders while using a carrier (diluent) and/or an adjuvant, which have (has) been hitherto used for the preparation of agricultural chemicals. The content of the derivative of 1,5-diphenyl-1H-1,2,4-triazole-3-carboxamide according to the present invention in a herbicidal composition is 0.1 to 50% by weight. The derivative of 1,5-diphenyl-1H-1,2,4-triazole-3-carboxamide according to the present invention or a herbicidal composition containing the derivative as an active ingredient is applied onto the soil of a paddy field and a crop field and/or weeds so that 0.1 to 500 g of the derivative is applied per 10 ares. The present invention will be explained more precisely while referring to the following non-limitative examples. SYNTHETIC EXAMPLE 1 : Synthesis of 1-(3-methylbutoxy)methyl-3-nitrobenzene Into a mixture of 500 ml (4.59 mol) of 3-methyl-1-butanol and 140 ml of dimethylformamide, 158.1 g (0.92 mol) of 3-chloromethylnitrobenzene was dissolved, and 78 g (1.39 mol) of potassium hydroxide pellets was added to the thus formed solution while cooling with water under a vigorous stirring. The temperature of the reaction mixture rised to 43°C and then dropped slowly to room temperature. Thereafter, the reaction mixture was stirred for 7 hours at room temperature to complete the reaction. After removing the solid matters in the liquid reaction mixture by filtration and adjusting the filtrate to pH 2 by hydrochloric acid, the excess alcohol and dimethylformamide were distilled off from the thus adjusted filtrate. After dissolving the residue into a mixture of 450 ml of n-hexane and 50 ml of ethyl acetate, and washing the solution with 1N HCl and an aqueous saturated solution of sodium chloride successively, the thus washed solution was dried over anhydrous magnesium sulfate. After distilling the solvent off from the thus dried solution, the residual liquid was subjected to fractional distillation to collect 182.2 g of a fraction at 116 - 117°C (0.08 mmHg) to obtain 1-(3-methylbutoxy)methyl-3-nitrobenzene in a yield of 90.1 %. SYNTHETIC EXAMPLE 2 : Synthesis of 3-[(3-methylbutoxy)methyl]aniline Into 150 ml of ethanol, 130 g (0.58 mol) of 1-(3-methylbutoxy)methyl-3-nitrobenzene obtained in Synthetic Example 1 was dissolved, and 0.6 g of 10 % palladium-charcoal was added to the thus formed solution. Into the thus treated solution, 89 ml (1.84 mol) of hydrazine hydrate was dropped such a speed that violent foaming is not caused. After ending the dropping, the reaction mixture was refluxed for 3 hours on a hot water bath to complete the reaction. After cooling the liquid reaction product by allowing to stand, the catalyst was removed from the reaction mixture by filtration, and the thus removed catalyst was washed with ethanol. After condensing the filtrate together with the ethanol washings, the condensate was dissolved into 300 ml of dichloromethane and after washing the thus formed solution with an aqueous 10 % sodium carbonate solution, then with an aqueous saturated sodium chloride solution, the thus washed solution was dried over anhydrous potassium carbonate. By distilling the solvent off from the thus dried solution and fractionally distilling the residue, 109.2 g of a fraction boiling at 105 to 106°C (0.19 mmHg) were collected to obtain 3-[(3-methylbutoxy)methyl]aniline in a yield of 97.1%. SYNTHETIC EXAMPLE 3 : Synthesis of 2-(2-fluorophenyl)-4-[3-[(3-methylbutoxy)methyl]phenyl]hydrazono-2-oxazolin-5-one After preparing 2-(2-fluorophenyl)-2-oxazolin-5-one by stirring the mixture of 3.94 g of 2-fluorohippuric acid, 3.28 g of sodium acetate and 17.4 ml of acetic anhydride for 20 min at 60°C, the mixture was rapidly cooled in iced water. Separately, a solution of a diazonium salt was prepared by adding 2.8 ml of isopentyl nitrite to a mixture of 3.48 g (18 mmol) of 3-[(3-methylbutoxy)methyl]aniline, 3.4 ml of 35 % hydrochloric acid and 12 ml of acetic acid under cooling with iced water and under agitation for 10 min. Into the mixture of 2-(2-fluorophenyl)-2-oxazolin-5-one, the thus prepared solution of the diazonium salt was added within 2 min while stirring the mixture under cooling with iced water, and the thus formed mixture was stirred for 2 hours. Thereafter, 40 ml of iced water and 20 ml of petroleum ether were added to the reaction mixture and the mixture was stirred for 2 hours. The precipitated orange-coloured substance was collected by filtration of the reaction mixture to obtain 2.45 g of 2-(2-fluorophenyl)-4-[3-[(3-methylbutoxy)methyl]phenyl]hydrazono-2-oxazolin-5-one in a yield of 35.5 %. EXAMPLE 1 : Synthesis of 5-(2-fluorophenyl)-1-[3-(3-methylbutoxy)methyl]phenyl-1H-1,2,4-triazole-3-carboxamide (Compound No. 3) Into 25 ml of acetone, 1.5 g of 4-[3-[(3-methylbutoxy)methyl]phenyl]hydrazono-2-(2-fluorophenyl)-2-oxazolin-5-one obtained in Synthetic Example 3 was dissolved, and while stirring the thus formed solution at room temperature, 0.5 ml of aqueous 28 % solution of ammonia was added thereto, and the mixture was stirred for 10 min to obtain a slurry-like mixture. To the thus obtained slurry-like mixture, 0.5 ml of 35 % hydrochloric acid was added and the mixture was heated for 10 min under reflux. The reaction mixture was added to 200 ml of water, and the precipitated pale brown substances were collected by filtration. On adding the thus collected pale brown material to 20 ml of a 1:5 solvent mixture of ethyl acetate and n-hexane, the colour of the substances transferred to the liquid phase and a colourless solid was obtained. By collecting the solid by filtration and air-drying the thus collected solid, 1.08 g of 5-(2-fluorophenyl)-1-[3-(3-methylbutoxy)methyl]phenyl-1H-1,2,4-triazole-3-carboxamide were obtained in a yield of 72 %. EXAMPLE 2 : Preparation of a herbicidal composition of wettable powder : 50 parts of Compound No. 3, 5 parts of a salt of ligninsulfonic acid, 3 parts of a salt of alkylsulfonic acid and 42 parts of diatomaceous earth. The above substances was pulverized to obtain a herbicidal composition of a wettable powder form. The herbicidal composition is applied after diluting with water. EXAMPLE 3 : Preparation of a herbicidal composition of emulsion : 25 parts of Compound No. 3, 65 parts of xylene and 10 parts of polyoxyethylene alkyl allyl ether. The above substances were uniformly blended to obtain a herbicidal composition of an emulsion. The herbicidal composition is applied after diluting with water. EXAMPLE 4 : Preparation of a herbicidal composition of granule : 8 parts of Compound No. 17, 40 parts of bentonite, 45 parts of clay and 7 parts of ligninsulfonic acid. The above substances were uniformly blended and after adding water to the thus formed blend, the mixture was kneaded and extruded into granules by using an extruding pelletizer. The thus extruded granules were dried to be the herbicidal composition of granule form. TEST EXAMPLE 1 : Effect on the weeds in the crop field (pre-emergence treatment) A planter of the dimensions of 650 × 210 × 220 mm was filled with soil in a state of a crop field, and after sowing a predetermined amount of the seeds of Amaranthus retroflexus , Bidens pilosa var. pilosa , Brassica arvensis , Stellaria media Solanum nigrum , Abutilon theophrasti , Echinochloa Crus-galli var. frumentacea , Digitaria sanguinalis , wheat and corn on the thus filled soil and covering the thus sown seeds with the soil, a dilution (prepared by diluting a wettable powder prepared in the same manner as in Example 2 to a predetermined concentration with water) was uniformly applied onto the soil of the planter in an amount corresponding to 200 g of the active ingredient (the present compound) of the wettable powder per 10 are of the surface of the soil in the planter, and thereafter, the thus treated planter was kept in a glass house at ordinary temperature to observe the growth state of the thus sown seeds. On the 21st day of the treatment, the herbicidal effect of the wettable powder to each of the weeds and the phytotoxicity of the wettable powder to each of the crop plants were observed, and after evaluating the herbicidal effect and the phytotoxicity according to the following ratings, the results shown in Table 3 was obtained. Ratings of evaluation: (1) Herbicidal effect: 0 ..... no herbicidal effect 1 ..... not more than 30 % of herbicidal effect 2 ..... from 31 to 50 % of herbicidal effect 3 ..... from 51 to 70 % of herbicidal effect 4 ..... from 71 to 90 % of herbicidal effect 5 ..... from 91 to 100 % of herbicidal effect. (2) Phytotoxicity: - ..... no damage, ± ..... slight damage, + ..... moderate damage, ++ ..... strong damage, +++ ..... extensive damage. TEST EXAMPLE 2 : Effect on the weeds of the crop field (post-emergence treatment) In the same manner as in Test Example 1, the seeds of the same plants as in Test Example 1 were sown on the soil in a planter, and at the time when each of the plant grew to the first to second leaf-stage, a dilution prepared in the same way as in Test Example 1 from a wettable powder prepared in the same way as in Test Example 1 from a wettable powder prepared in the same way as in Example 2 was uniformly applied on the plants and the surface of the soil in the planter in the same amount as in Test Example 1. The thus treated planter was kept in a glass house at ordinary temperature. On the 21st day of the treatment, the herbicidal activity and the phytotoxicity were observed and evaluated according to the same ratings as in Test Example 1. The results are shown in Table 4. TEST EXAMPLE 3 : Effect on the weeds in the paddy field and phytotoxicity to rice plant in the paddy field After introducing water into a Wagner pot filled with a soil of the ordinary paddy field, thereby covering the soil in the pot with water, the seeds of Echinochloa Crus-galli var. hispidula , Scirpus juncoides subsp. Hotarui , Alisma canaliculatum , Monochoria vaginalis and Cyperus difformis were sown on the soil and the tubers of Sagittaria pygmaea and Cyperus serotinus were planted in the soil. After further transplanting two seedlings of rice plant (variety Sasanishiki) at the two-leaf stage to the pot, the pot was kept in a glass house for 3 days, and then a dilution prepared by diluting an emulsion prepared in the same manner as in Example 3 to a predetermined concentration was uniformly applied onto the surface of water in the pot in the same amount as in Test Example 1 (200 g of the active ingredient per 10 ares). On the 21st day of the treatment, the herbicidal effect on the weeds and the phytotoxicity to the rice plant were observed and evaluated according to the same ratings as in Test Example 1. The results are shown in Table 5.

Claims: A derivative of 1,5-diphenyl-1H-1,2,4-triazole-3-carboxamide represented by the formula (I): wherein R¹ represents a straight-chain alkyl group of from 2 to 10 carbon atoms, a branched-chain alkyl group or a cycloalkyl group of from 3 to 10 carbon atoms, a (cycloalkyl)-alkyl group of from 4 to 10 carbon atoms, an unsubstituted or halogen-substituted phenyl group, an aralkyl group of from 7 to 9 carbon atoms, an alkenyl group of from 3 to 6 carbon atoms or an alkyl group of from 2 to 10 carbon atoms substituted by 1 to 19 fluorine atoms; and R² represents a fluorine atom, a chlorine atom, a methyl group or a methoxy group. A compound according to claim 1, wherein R¹ represents a straight-chain alkyl group of from 3 to 6 carbon atoms, a branched-chain alkyl group or cycloalkyl group of from 3 to 7 carbon atoms, an alkyl group of from 1 to 3 carbon atoms substituted by an alicyclic structure of from 3 to 7 carbon atoms, an unsubstituted phenyl group, a phenyl group substituted by from 1 to 3 chlorine atom(s) and/or fluorine atom(s), an aralkyl group of from 7 to 9 carbon atoms, an alkenyl group of from 3 to 6 carbon atoms or an alkyl group of from 2 to 7 carbon atoms substituted by from 3 to 12 fluorine atoms. A compound according to claim 2, which is 1-(3-butoxymethyl)phenyl-5-(2-fluorophenyl)-1H-1,2,4-triazole-3-carboxamide. A compound according to claim 2, which is 5-(2-fluorophenyl)-1-(3-pentyloxymethyl)-phenyl-1H-1,2,4-triazole-3-carboxamide. A compound according to claim 2, which is 5-(2-fluorophenyl)-1-[3-(3-methylbutoxy)-methyl]phenyl-1H-1,2,4-triazole-3-carboxamide. A compound according to claim 2, which is 5-(2-fluorophenyl)-1-[3-(2-methylbutoxy)-methyl]phenyl-1H-1,2,4-triazole-3-carboxamide. A compound according to claim 2, which is 5-(2-fluorophenyl)-1-[3-(2,2-dimethylpropoxy)-methyl]phenyl-1H-1,2,4-triazole-3-carboxamide. A compound according to claim 2, which is 5-(2-fluorophenyl)-1-(3-hexyloxymethyl)-phenyl-1H-1,2,4-triazole-3-carboxamide. A compound according to claim 2, which is 1-[3-(cyclohexylmethoxy)methyl]phenyl-5-(2-fluorophenyl)-1H-1,2,4-triazole-3-carboxamide. A compound according to claim 2, which is 1-[3-(2,2,2-trifluoroethoxy)methyl]phenyl-5-(2-fluorophenyl)-1H-1,2,4-triazole-3-carboxamide. A compound according to claim 2, which is 5-(2-fluorophenyl)-1-[3-(2,2,3,3-tetrafluoropropoxy) methyl]phenyl-1H-1,2,4-triazole-3-carboxamide. A compound according to claim 2, which is 5-(2-fluorophenyl)-1-[3-(2,2,3,3,3-pentafluoropropoxy) methyl]phenyl-1H-1,2,4-triazole-3-carboxamide. A compound according to claim 2, which is 1-[3-(2,2,3,4,4,4-hexafluorobutoxy)methyl]-phenyl-5-(2-fluorophenyl)-1H-1,2,4-triazole-3-carboxamide. A compound according to claim 2, which is 1-[3-(2,2,3,3,4,4,4-heptafluorobutoxy)-methyl]phenyl-5-(2-fluorophenyl)-1H-1,2,4-triazole-3-carboxamide. A compound according to claim 2, which is 1-[3-(2,2,3,3,4,4,5,5-octafluoropentyloxy)-methyl]phenyl-5-(2-fluorophenyl)-1H-1,2,4-triazole-3-carboxamide. A compound according to claim 2, which is 1-[3-(2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyloxy)methyl]phenyl-5-(2-fluorophenyl)-1H-1,2,4-triazole-3-carboxamide. A process for the preparation of a 1,5-diphenyl-1H-1,2,4-triazole-3-carboxamide derivative represented by the formula (I) as defined in claim 1, which process comprises reacting a compound of formula (II): wherein R¹ and R² are as defined in claim 1, with ammonia in an organic solvent and acidifying the reaction mixture so as to cause ring closure to give a derivative of formula (I). A process for the preparation of a 1,5-diphenyl-1H-1,2,4-triazole-3-carboxamide derivative represented by the formula (I) as defined in claim 1, which process comprises: (1) reacting 3-chloromethyl-1-nitrobenzene represented by the formula (III): with a compound represented by the formula: R¹OH wherein R¹ is as defined in claim 1, at a temperature of from -10 to 150°C in the presence of an acceptor for hydrogen chloride formed; (2) reducing the thus obtained nitrobenzyl ether represented by the formula (IV): wherein R¹ is as defined above; (3) diazotizing the thus obtained aniline compound represented by the formula (V): wherein R¹ is as defined above; and (4) diazocoupling the thus obtained diazonium salt represented by the formula: wherein R¹ is as defined above, with a derivative of 2-phenyl-2-oxazolin-5-one represented by the formula (VI): wherein R² is as defined in claim 1, at a temperature of from -50 to 100°C for from 0.1 to 20 hours. A process according to claim 18, wherein the said derivative of 2-phenyl-2-oxazolin-5-one represented by the formula (VI) is prepared by subjecting a derivative of hippuric acid represented by the formula: wherein R² is as defined in claim 18, to dehydrating-cyclization in acetic anhydride at a temperature of from 20 to 100°C for from 0.1 to 30 hours. A herbicidal composition comprising a 1,5-diphenyl-1H-1,2,4-triazole-3-carboxamide derivative of formula (I) as defined in claim 1 and a herbicidally acceptable carrier or adjuvant. Use as a herbicide of a 1,5-diphenyl-1H-1,2,4-triazole-3-carboxamide derivative of formula (1) as defined in claim 1.

Inventors: ARABORI, HIDEO, KANDA, YOHICHI, SHIDA, TAKAFUMI, SHINKAWA, HIROYASU, WATANABE, TAKEO, YAMAZAKI, SHIRO
Applicants: KUREHA KAGAKU KOGYO KABUSHIKI KAISHA
Application year: 1987
Main classification: C07D249
IPC codes: A01N43, C07D249