2-Phenoxy-6-thienylmethyloxypyridine derivative, process for producing the same, and herbicidal composition

Abstract: A 2-phenoxy-6-thienylmethyloxypyridine derivative of formula (I) : wherein: R represents hydrogen, a halogen, cyano, C₁-C₄ alkyl, C₁-C₄ alkoxy, C₁-C₄ alkylthio, C₁-C₄ haloalkyl, C₁-C₄ alkylamino, or di(C₁-C₄ alkyl)amino; each X, which may be identical or different if n is greater than 1, represents a halogen, C₁-C₄ alkyl, C₁-C₄ alkoxy, C₁-C₄ alkylthio, or C₁-C₄ haloalkyl; each Y, which may be identical or different if m is greater than 1, represents a halogen, C₁-C₄ alkyl, C₁-C₄ alkoxy, C₁-C₄ alkylthio, C₁-C₄ haloalkyl, C₁-C₄ haloalkoxy, or C₁-C₄ haloalkylthio; m represents an integer of 0 to 5; and n represents an integer of 0 to 3.

Description: The present invention relates to a 2-phenoxy-6-thienylmethyloxypyridine derivative, a process for producing the derivative, a herbicidal composition containing the derivative as an active ingredient and a method of controlling the growth of weeds at a locus using the derivative. A herbicide having superior herbicidal activity, such as a reliable herbicidal effect at a low application dose such that the residual amount in the environment advantageously decreases, good selectivity between crops and weeds regardless of environmental condition changes, and low phytotoxicity to the succeeding crop cultivated in a double cropping system, has been demanded. The present invention seeks to provide a compound having such herbicidal activity. EP-A-573093 describes herbicidal 2,6-substituted pyridines such as 2-(3-trifluoromethyl(phenoxy)-6-benzyloxypyridine. This compound causes more damage to wheat than 2-(2-thienylmethyloxy)-6-metatrifluoromethylphenoxy) pyridine of the present invention. The present invention provides a 2-phenoxy-6-thienylmethyloxypyridine derivative of formula (I) : wherein: R represents hydrogen, a halogen, cyano, C 1 -C 4 alkyl, C 1 -C 4 alkoxy, C 1 -C 4 alkylthio, C 1 -C 4 haloalkyl, C 1 -C 4 alkylamino, or di(C 1 -C 4 alkyl)amino; each X, which may be identical or different if n is greater than 1, represents a halogen, C 1 -C 4 alkyl, C 1 -C 4 alkoxy, C 1 -C 4 alkylthio, or C 1 -C 4 haloalkyl; each Y, which may be identical or different if m is greater than 1, represents a halogen, C 1 -C 4 alkyl, C 1 -C 4 alkoxy, C 1 -C 4 alkylthio, C 1 -C 4 haloalkyl, C 1 -C 4 haloalkoxy, or C 1 -C 4 haloalkylthio; m represents an integer of 0 to 5; and n represents an integer of 0 to 3. The present invention also provides a process for producing derivative of formula (I) which process comprises reacting a 2-halogeno-6-thienylmethyloxypyridine derivative of formula (II): wherein R, X, and n are as defined above and Z represents a halogen, with an unsubstituted or substituted phenol of formula (III): wherein Y and m are as defined above. The present invention additionally provides a herbicidal composition containing as an active ingredient a 2-phenoxy-6-thienylmethyloxypyridine derivative of formula (I) and an adjuvant. The present invention further provides a method of controlling the growth of weeds at a locus which comprises administering thereto a derivative of formula (I) as defined above. In the definition of each substituent in the derivative of formula (I), the substituents defined by the generic terms include preferred substituents as set forth below. With respect to R, a halogen includes fluorine, chlorine, and bromine; C 1 -C 4 alkyl includes methyl, ethyl, and 1-methylethyl; C 1 -C 4 alkoxy includes methoxy, ethoxy, and (1-methylethyl)oxy; C 1 -C 4 alkylthio includes methylthio and ethylthio; C 1 -C 4 haloalkyl includes trifluoromethyl; C 1 -C 4 alkylamino includes methylamino; and di(C 1 -C 4 alkyl)amino includes dimethylamino. With respect to X, a halogen includes fluorine, chlorine, and bromine; C 1 -C 4 alkyl includes methyl, ethyl, and 1-methylethyl; C 1 -C 4 alkoxy includes methoxy, ethoxy, and (1-methylethyl)oxy; C 1 -C 4 alkylthio includes methylthio, ethylthio, and (1-methylethyl)thio; and C 1 -C 4 haloalkyl includes trifluoromethyl. With respect to Y, a halogen includes fluorine, chlorine, and bromine; C 1 -C 4 alkyl includes methyl, ethyl, and 1-methylethyl; C 1 -C 4 alkoxy includes methoxy, ethoxy, and (1-methylethyl)oxy; C 1 -C 4 alkylthio includes methylthio, ethylthio, and (1-methylethyl)thio; C 1 -C 4 haloalkyl includes trifluoromethyl; C 1 -C 4 haloalkoxy includes difluoromethoxy and trifluoromethoxy; and C 1 -C 4 haloalkylthio includes trifluoromethylthio. Preferably, the substituents R, X and Y are as follows. R preferably represents methoxy, cyano, dimethylamino, methylamino, chlorine, or methyl. X preferably represents 'unsubstituted' (n=0), methyl, bromine, or chlorine. Y preferably represents trifluoromethyl, trifluoromethoxy, trifluoromethylthio, or difluoromethoxy. As for the preferred range of integers m and n, m is 0 to 3 and n is 0 to 2. Examples of the derivative of formula (I) are shown in the Table 1: The derivative of formula (I) (Compound (I)) may be synthesized in accordance with the following Reaction Scheme: wherein R, X, Y, n, and m are as defined above and Z represent a halogen. The derivative of formula (II) may be synthesized in accordance with the following Reaction scheme II: wherein R, X, and n are as defined above and Z represents a halogen, and each Z in formula (IV) may be identical or different. Examples of the unsubstituted or substituted phenol of formula (III) are phenol, meta-cresol, meta-chlorophenol, 3,4-dichlorophenol, meta-trifluoromethylphenol, 3,5-di(trifluoromethyl)phenol, 3-(difluoromethoxy)phenol, meta-triluoromethoxyphenol, and 3-(trifluoromethylthio)phenol. Examples of the unsubstituted or substituted thiophenemethanol of formula (V) are 2-thiophenemethanol, 3-thiophenemethanol, 4-bromo-2-thiophenemethanol, 5-bromo-2-thiophenemethanol, 2,5-dibromo-3-thiophenemethanol, 3-methyl-2-thiophenemethanol, 5-methyl-2-thiophenemethanol, 5-methyl-3-thiophenemethanol, 2,5-dimethyl-3-thiophenemethanol, 5-methylthio-3-thiophenemethanol, and 5-trifluoromethyl-3-thiophenemethanol. The unsubstituted or substituted thiophenemethanol of formula (V) and the unsubstituted or substituted phenol of formula (III) may be commercially available or may be easily obtained in accordance with existing techniques. The 2,6-dihalogeno-4-substituted-pyridine of formula (IV) may also be commercially available or may be easily obtained in accordance with existing techniques. For example, 2,6-dichloro-4-cyanopyridine is described in Roczniki Chem. 1959, 33 , 387 and others. 2,6-Dichloro-4-methoxypyridine and 2,6-dibromo-4-methoxypyridine are described respectively in J. Chem. Soc. B 1967, (8), 758 and Chem. Ber. 1989, 122 (3), 589. Further, the 2,6-dihalogeno-4-substituted-pyridine of formula (IV) may be obtained by substituting a suitable group for the nitro group of 2,6-dichloro-4-nitropyridine disclosed in EP-A-53,306 through nucleophilic displacement using a C 1 -C 4 alkanol such as methyl alcohol, ethyl alcohol, and 1-methylethyl alcohol. 2,6-Dichloro-4-(C 1 -C 4 alkylthio) pyridine may be obtained by substituting a suitable group for the nitro group of 2,6-dichloro-4-nitropyridine through nucleophilic displacement using a C 1 -C 4 alkanethiol such as methanethiol and ethanethiol. 2,6-Dichloro-4-(C 1 -C 4 alkylamino)pyridine may be obtained by substituting a suitable group for the nitro group of 2,6-dichloro-4-nitropyridine through nucleophilic displacement using a C 1 -C 4 alkylamine such as methylamine and ethylamine. 2,6-Dichloro-4-[di(C 1 -C 4 alkyl)amino]pyridine may be obtained by substituting a suitable group for the nitro group of 2,6-dichloro-4-nitropyridine through nucleophilic displacement using a di(C 1 -C 4 alkyl)amine such as dimethylamine and diethylamine. The 2,6-dichloro-4-[di(C 1 -C 4 alkyl)amino)pyridine may be also obtained by alkylating the nitrogen of the C 1 -C 4 alkylamino group of 2,6-dichloro-4-(C 1 -C 4 alkylamino)pyridine with a C 1 -C 4 alkyl halide such as methyl iodide, ethyl iodide, and propyl bromide. The method is suited to the production of a compound having a dialkylamino group wherein each alkyl is different. Further, the 2,6-dichloro-4-[di(C 1 -C 4 alkyl)amino]pyridine may be obtained by dialkylating the amino group of 4-amino-2,6-dichloropyridine. This method is suited to the production of a compound having a dialkylamino group wherein each alkyl is identical. The 2,6-dihalogeno-4-substituted-pyridine of formula (IV) wherein the halogen represented by Z is chlorine, bromine, or iodine is preferably used. According to the production process of the present invention, every reaction may be advantageously conducted in a solvent or a mixture of solvents. Examples of the solvents are set forth below: aromatic hydrocarbons such as benzene, toluene, xylene, and methylnaphthalene; aliphatic hydrocarbons such as petroleum ether, pentane, hexane, heptane, and methylcyclohexane; halogenated hydrocarbons such as methylene chloride, chloroform, carbon tetrachloride, and chlorobenzene; amides such as dimethylformamide, dimethylacetamide, and N-methyl-2-pyrrolidinone; ethers such as diethyl ether, dimethoxyethane, diisopropyl ether, tetrahydrofuran, diglyme, and dioxane; as well as others including carbon disulfide, acetonitrile, ethyl acetate, pyridine, dimethyl sulfoxide, and hexamethylphosphoric amide. When the production process of the present invention is carried out in a solvent, the solvent may be used alone or in a combination of two or more. A mixture of the solvents incapable of forming a homogeneous phase may also be used. In this case, the reaction may preferably be conducted in the presence of a phase transfer catalyst such as a conventional quaternary ammonium salt or crown ether. Since the production process of the present invention is based on nucleophilic displacement at the carbon atom on the pyridine ring, the reaction may preferably be conducted in the presence of a base. Further, copper(I) chloride, copper(I) bromide, and copper(I) iodide are preferably used together with the base. Examples of the base are basic compounds such as: alkaline metal hydrogen carbonates such as potassium hydrogen carbonate and sodium hydrogen carbonate; alkaline metal carbonates such as potassium carbonate and sodium carbonate; alkaline metal hydroxides such as potassium hydroxide and sodium hydroxide; alkaline metals such as lithium, sodium and potassium, and alkaline earth metals such as magnesium; alkaline metal alkoxides such as sodium methoxide, sodium ethoxide, and potassium t-butoxide; alkaline metal hydrides such as sodium hydride and potassium hydride; alkaline earth metal hydrides such as calcium hydride; organic alkaline metal compounds such as methyl lithium, ethyl lithium, n-butyl lithium, and phenyl lithium; Grignard reagents such as methylmagnesium iodide, ethylmagnesium bromide, and n-butylmagnesium bromide; organic copper compounds prepared from organic alkaline metal compounds or Grignard reagents and copper(I) salts; and alkaline metal amides such as lithium diisopropylamide. The reaction conditions for each of Reaction Schemes I and II may be suitably selected. These reactions are usually conducted at a temperature of 1 to 200°C for 0.5 to 30 hours and at a temperature of 1 to 200°C for 0.5 to 10 hours respectively, if necessary, under pressurization. Although the derivative of formula (I) of the present invention may be applied as it is, it is generally applied after having been formulated with an adjuvant into various composition forms such as powders, wettable powders, granules or emulsifiable concentrates. If formulated, the composition contains one or more derivatives of formula (I) in an amount of 0.1 to 95 % by weight, preferably 0.5 to 90 % by weight, more preferably 2 to 70 % by weight. Among adjuvants including carriers(diluents) and surface active agents, suitable solid carriers are talc, kaolin, bentonite, diatomaceous earth, white carbon, and clay. Suitable liquid diluents are water, xylene, toluene, chlorobenzene, cyclohexane, cyclohexanone, acetone, dimethylsulfoxide, dimethylformamide, and alcohol. Surface active agents may be properly selected depending upon their effects, and suitable emulsifying agents include polyoxyethylene alkylaryl ether, and polyoxyethylene sorbitan monolaurate. Suitable dispersing agents include lignin sulfonate, and dibutylnaphthalene sulfonate. Suitable wetting agents are alkyl sulfonates, and alkylphenyl sulfonates. The above mentioned compositions include those which are to be applied as such and those which are to be applied after having been diluted to a proper concentration by using a diluent such as water. When diluted, the derivative of formula (I) is preferably contained at a concentration of 0.001 to 1.0% by weight. The application dose of the derivative of formula (I) of the present invention is usually 0.01 to 10 kg/ha, preferably 0.05 to 5 kg/ha. The concentrations and the application doses described above are varied depending on, for example, the dosage forms, time of application, way of application, application sites, and crops to be treated. Thus, modifications thereof are possible without being limited to the above defined ranges. Further, the derivative of formula (I) of the present invention may be used in combination with other active ingredients such as fungicides, insecticides, acaricides and herbicides. EXAMPLES The derivative of the present invention, the production process and the use thereof will be more specifically described in the following Synthesis Examples, Formulation Examples and Test Examples. Synthesis Example 1 Synthesis of 2-(2-thienylmethyloxy)-6-(meta-trifluoromethylphenoxy) pyridine (I-3) (1) Synthesis of an intermediate, 2-chloro-6-(2-thienylmethyloxy) pyridine To a solution containing 2-thiophenemethanol (1.5 g, 0.0135 × 1.0 mol) and sodium hydride (0.58 g, (ca.60% in mineral oil), 0.0135 × 1.1 mol) in tetrahydrofuran, 2,6-dichloropyridine (2.0 g, 0.0135 mol) was added and the resultant solution was refluxed for about 2 hours. The reaction solution was partitioned between ethyl acetate and aqueous saturated sodium hydrogen carbonate. The obtained organic layer was washed with aqueous saturated sodium chloride, dried over anhydrous sodium sulfate and thereafter, concentrated and purified on a silica gel column to obtain the end product. Yield: 2.69 g (89%). Oily product. 1 H-NMR (60 MHz, CDCl 3 , δ): 5.45(2H,s), 7.3-7.6(6H, complex). (2) Synthesis of 2-(2-thienylmethyloxy)-6-(meta-trifluoromethylphenoxy)pyridine from the intermediate To a solution containing meta-trifluoromethylphenol (3.62 g, 0.0045 × 5.0 mol), sodium hydride (0.36 g, (Ca.60% in mineral oil), 0.0045 × 2.0 mol) and CuI (0.42 g, 0.0045 × 0.5 mol) in dimethylformamide, 2-chloro-6-(2-thienylmethyloxy)pyridine (1.0 g, 0.0045 mol) was added and the resultant solution was refluxed for about 3 hours. Additional sodium hydride (0.36 g, (60% in mineral oil), 0.0045 × 2.0 mol) was added thereto and the resultant solution was refluxed for another about 1 hour, thereafter the reaction solution was partitioned between ethyl acetate and aqueous saturated sodium hydrogen carbonate. The obtained organic layer was washed with aqueous saturated sodium chloride, dried over anhydrous sodium sulfate and thereafter, concentrated and purified on a silica gel column to obtain the end product. Yield: 0.60 g (42%). Oily product. 1 H-NMR (60 MHz, CDCl 3 , δ): 5.20(2H,s), 6.40(2H,d,J=7.9 Hz), 6.7-7.7(8H, complex). Synthesis Example 2 Synthesis of 2-(3-thienylmethyloxy)-6-(meta-trifluoromethylphenoxy)pyridine (I-4) (1) Synthesis of an intermediate, 2-chloro-6-(3-thienylmethyloxy)pyridine To a solution containing 3-thiophenemethanol (1.17 g, 0.010 × 1.0 mol) and sodium hydride (0.39 g, (ca.60% in mineral oil), 0.010 × 1.0 mol) in tetrahydrofuran, 2,6-dichloropyridine (1.5 g, 0.010 mol) was added and the resultant solution was refluxed for about 2 hours. The reaction solution was partitioned between ethyl acetate and aqueous saturated sodium hydrogen carbonate. The obtained organic layer was washed with aqueous saturated sodium chloride, dried over anhydrous sodium sulfate and thereafter, concentrated and purified on a silica gel column to obtain the end product. Yield: 1.94 g (87%). Oily product. 1 H-NMR (60 MHz, CDCl 3 , δ): 5.29(2H,s), 6.57(1H,d,J=7.9 Hz), 6.79(1H,d,J=7.5 Hz),7.0-7.6(4H, complex). (2) Synthesis of 2-(3-thienylmethyloxy)-6-(meta-trifluoromethylphenoxy)pyridine from the intermediate To a solution containing meta-trifluoromethylphenol (3.62 g, 0.0045 × 5.0 mol), sodium hydride (0.89 g, (Ca.60% in mineral oil), 0.0045 × 5.0 mol) and CuI (0.42 g, 0.0045 × 0.5 mol) in dimethylformamide, 2-chloro-6-(3-thienylmethyloxy)pyridine (1.0 g, 0.0045 mol) was added and the resultant solution was refluxed for about 3 hours. Then, the reaction solution was partitioned between ethyl acetate and aqueous saturated sodium hydrogen carbonate. The obtained organic layer was washed with aqueous saturated sodium chloride, dried over anhydrous sodium sulfate and thereafter, concentrated and purified on a silica gel column to obtain the end product. Yield: 0.71 g (50%). Oily product. 1 H-NMR (60 MHz, CDCl 3 , δ): 5.06(2H,s), 6.39(1H,d,J=7.9 Hz), 6.43(1H,d,J=7.9 Hz), 6.8-7.7(8H, complex). Synthesis Example 3 Synthesis of 4-chloro-2-(3-thienylmethyloxy)-6-(meta-trifluoromethylphenoxy)pyridine (I-8) (1) Synthesis of an intermediate, 2,4-dichloro-6-(3-thienylmethyloxy)pyridine: To a solution of 3-thiophenemethanol (0.32 g, 0.0027 × 1.05 mol) in 10 ml of dry tetrahydrofuran, sodium hydride (0.13 g, (ca.60% in mineral oil), 0.0027 × 1.2 mol) was added. After the bubbling ceased, a solution of 2,4,6-trichloropyridine (0.49 g, 0.0027 mol) in 10 ml of dry tetrahydrofuran was added dropwise at room temperature. Thereafter, the resultant solution was stirred for about 15 hours under reflux. Then, the solvent was distilled off and the residue was partitioned between ethyl acetate and water. The obtained organic layer was washed with aqueous saturated sodium chloride and dried over anhydrous sodium sulfate. After the solvent was distilled off, the residue was purified on a silica gel column to obtain the end product. Yield: 0.58 g (84%). Oily product. 1 H-NMR (60 MHz, CDCl 3 , δ): 5.26(2H,s), 6.57(1H,d,J=2 Hz), 6.8(1H,d,J=2 Hz), 6.9-7.3(3H, complex). (2) Synthesis of 4-chloro-2-(3-thienylmethyloxy)-6-(meta-trifluoromethylphenoxy)pyridine from the intermediate To a solution of meta-trifluoromethylphenol (0.28 g, 0.0018 × 1.0 mol) in 10 ml of dry N,N-dimethylacetamide, sodium hydride (0.077 g, (ca. 60% in mineral oil), 0.0018 × 1.1 mol) was added. After the bubbling ceased, a solution of 2,4-dichloro-6-(3-thienylmethyloxy)pyridine (0.46 g, 0.0018 mol) in 10 ml of dry N,N-dimethylacetamide was added dropwise and the resultant solution was stirred for about 7 hours at a temperature of 160 to 170°C. After being allowed to cool, water was added to the reaction solution, then the mixture was partitioned by using ethyl acetate. The obtained organic layer was washed with aqueous saturated sodium chloride and dried over anhydrous sodium sulfate. The solvent was distilled off, then the residue was purified successively on silica gel column chromatography and on reversed phase column chromatography (Lobar column, Lichroprep RP-18, 40-63 µm, elution solvent: CH 3 CN/H 2 O = 7/3(v/v)), whereby the end product was obtained. Yield: 0.10 g (15%). Oily product. 1 H-NMR (60 MHz, CDCl 3 , δ): 5.00(2H,s), 6.42(2H,s), 6.7-7.5(7H, complex). Synthesis Example 4 Synthesis of 4-cyano-2-(3-thienylmethyloxy)-6-(meta-trifluoromethylphenoxy)pyridine (I-9) (1) Synthesis of an intermediate, 2-chloro-4-cyano-6-(3-thienylmethyloxy)pyridine Sodium hydride (0.24 g (ca.60% in mineral oil), 0.006 × 1.0 mol) was suspended in 20 ml of N-methyl-2-pyrrolidinone, and 3-thiophenemethanol (0.69 g, 0.006 × 1.0 mol) was added thereto and the resultant solution was stirred for about 30 minutes at room temperature. The resultant mixture was cooled to 4°C with iced water, then 4-cyano-2,6-dichloropyridine (1.04 g, 0.006 mol) was added thereto and stirred for about 1.5 hour while cooling with iced water. After stirred for about another 1.5 hours, the reaction solution was partitioned between ethyl acetate and water. The obtained organic layer was washed with aqueous saturated sodium chloride, dried over anhydrous sodium sulfate and thereafter, concentrated and purified on a silica gel column to obtain the end product. Yield: 0.94 g (63%). Oily product. 1 H-NMR (60 MHz, CDCl 3 , δ): 5.30(2H,s), 6.78(1H,s), 6.97(1H,s), 6.9-7.4(3H, complex). (2) Synthesis of 4-cyano-2-(3-thienylmethyloxy)-6-(meta-trifluoromethylphenoxy)pyridine from the intermediate 2-Chloro-4-cyano-6-(3-thienylmethyloxy)pyridine (0.79 g, 0.00315 mol) and meta-trifluoromethylphenol (0.57 g, 0.00315 × 1.1 mol) were dissolved in 20 ml of N-methyl-2-pyrrolidinone, and anhydrous potassium carbonate (0.48 g, 0.00315 × 1.1 mol) was added thereto, and the resultant solution was stirred for about 4 hours at about 100°C. Then, the reaction solution was partitioned between ethyl acetate and water. The obtained organic layer was washed with aqueous saturated sodium chloride, dried over anhydrous sodium sulfate and thereafter, concentrated and purified on silica gel column. Then the end product was obtained by recrystallization from a small amount of n-hexane. Yield: 0.71 g (47%). Solid. Melting point 67-68°C. 1 H-NMR (60 MHz, CDCl 3 , δ): 5.03(2H,s), 6.60(2H,s), 6.6-7.6(7H, complex). Synthesis Example 5 Synthesis of 4-methyl-2-(3-thienylmethyloxy)-6-(meta-trifluoromethylphenoxy)pyridine (I-10) (1) Synthesis of an intermediate, 2-chloro-4-methyl-6-(3-thienylmethyloxy)pyridine To a solution containing 3-thiophenemethanol (0.78 g, 0.0062 × 1.1 mol) and sodium hydride (0.26 g, (ca.60% in mineral oil), 0.0062 × 1.05 mol) in tetrahydrofuran, 2,6-dichloro-4-methylpyridine (1.0 g, 0.0062 mol) was added, and the resultant solution was refluxed for about 1 hour. Then, the reaction solution was partitioned between ethyl acetate and aqueous saturated sodium hydrogen carbonate. The obtained organic layer was washed with aqueous saturated sodium chloride, dried over anhydrous sodium sulfate and thereafter, concentrated and purified on silica gel column to obtain the end product. Yield: 1.21 g (82%). Oily product. 1 H-NMR (60 MHz, CDCl 3 , δ): 2.20(3H,s), 5.26(2H,s), 6.38(1H,s), 6.64(1H,s), 6.9-7.4(3H, complex). (2) Synthesis of 4-methyl-2-(3-thienylmethyloxy)-6-(meta-trifluoromethylphenoxy)pyridine from the intermediate To a solution containing meta-trifluoromethylphenol (1.70 g, 0.0021 × 5.0 mol) and sodium hydride (0.42 g, (ca.60% in mineral oil), 0.0021 × 5.0 mol) in dimethylformamide, 2-chloro-4-methyl-6-(3-thienylmethyloxy)pyridine (0.5 g, 0.0021 mol) and CuI (0.20 g, 0.0021 × 0.5 mol) were successively added and the resultant solution was refluxed for about 5 hours. Then, the reaction solution was partitioned between ethyl acetate and aqueous saturated sodium hydrogen carbonate. The obtained organic layer was washed with aqueous saturated sodium chloride, dried over anhydrous sodium sulfate and thereafter, concentrated and purified on a silica gel column to obtain the end product. Yield: 0.34 g (45%). Oily product. 1 H-NMR (60 MHz, CDCl 3 , δ): 2.23(3H,s), 5.05(2H,s), 6.25(2H,s), 6.6-7.6(7H, complex). Synthesis Example 6 Synthesis of 4-methoxy-2-(3-thienylmethyloxy)-6-(meta-trifluoromethylphenoxy)pyridine (I-13) (1) Synthesis of an intermediate, 2-chloro-4-methoxy-6-(3-thienylmethyloxy)pyridine To a solution containing 3-thiophenemethanol (0.45 g, 0.0033 × 1.2 mol) and sodium hydride (0.14 g, (ca.60% in mineral oil), 0.033 × 1.05 mol) in tetrahydrofuran, 2,6-dichloro-4-methoxypyridine (0.59 g, 0.0033 mol) was added and the resultant solution was refluxed for about 2 hours. Then, the reaction solution was partitioned between ethyl acetate and aqueous saturated sodium hydrogen carbonate. The obtained organic layer was washed with aqueous saturated sodium chloride, dried over anhydrous sodium sulfate and thereafter, concentrated and purified on a silica gel column to obtain the end product. Yield: 0.64 g (76%). Oily product. 1 H-NMR (60 MHz, CDCl 3 , δ): 3.63(3H,s), 5.17(2H,s), 5.95(1H,d,J=2.0 Hz), 6.30(1H,d,J=2.0 Hz), 6.7-7.2(3H, complex). (2) Synthesis of 4-methoxy-2-(3-thienylmethyloxy)-6-(meta-trifluoromethylphenoxy)pyridine from the intermediate To a solution containing meta-trifluoromethylphenol (1.40 g, 0.0021 × 4.0 mol), sodium hydride (0.25 g, (ca.60% in mineral oil), 0.0021 × 3.0 mol) and CuI (0.20 g, 0.0021 × 0.5 mol) in dimethylformamide, 2-chloro-4-methoxy-6-(3-thienylmethyloxy)pyridine (0.54 g, 0.0021 mol) was added and the resultant solution was refluxed for about 6 hours. Then, the reaction solution was partitioned between ethyl acetate and aqueous saturated sodium hydrogen carbonate. The obtained organic layer was washed with aqueous saturated sodium chloride, dried over anhydrous sodium sulfate and thereafter, concentrated and purified on a silica gel column to obtain the end product. Yield: 0.39 g (49%). Oily product. 1 H-NMR (60 MHz, CDCl 3 , δ): 3.65(3H,s), 4.94(2H,s), 5.85(2H,s), 6.6-7.4(7H, complex). Synthesis Example 7 Synthesis of 4-methylmercapto-2-(3-thienylmethyloxy)-6-(meta-trifluoromethylphenoxy)pyridine (I-26) (1) Synthesis of an intermediate, 2-chloro-4-methylmercapto-6-(3-thienylmethyloxy)pyridine To a solution containing 3-thiophenemethanol (0.56 g, 0.0041 × 1.2 mol) and sodium hydride (0.17 g, (ca.60% in mineral oil), 0.0041 × 1.05 mol) in tetrahydrofuran, 2,6-dichloro-4-methylmercaptopyridine (0.80 g, 0.0041 mol) was added, and the resultant solution was refluxed for about 2 hours. Then, the reaction solution was partitioned between ethyl acetate and aqueous saturated sodium hydrogen carbonate. The obtained organic layer was washed with aqueous saturated sodium chloride, dried over anhydrous sodium sulfate and thereafter, concentrated and purified on a silica gel column to obtain the end product. Yield: 0.74 g (66%). Oily product. 1 H-NMR (60 MHz, CDCl 3 , δ): 2.33(3H,s), 5.17(2H,s), 6.24(1H,d,J=1 Hz), 6.54(1H,d,J=1 Hz), 6.7-7.3(3H, complex). (2) Synthesis of 4-methylmercapto-2-(3-thienylmethyloxy)-6-(meta-trifluoromethylphenoxy)pyridine from the intermediate To a solution containing meta-trifluoromethylphenol (1.60 g, 0.0024 × 4.1 mol), sodium hydride (0.29 g, (ca.60% in mineral oil), 0.0024 × 3.0 mol) and CuI (0.22 g, 0.0024 × 0.5 mol) in dimethylformamide, 2-chloro-4-methylmercapto-6-(3-thienylmethyloxy)pyridine (0.64 g, 0.0024 mol) was added and the resultant solution was refluxed for about 6 hours. Then, the reaction solution was partitioned between ethyl acetate and aqueous saturated sodium hydrogen carbonate. The obtained organic layer was washed with aqueous saturated sodium chloride, dried over anhydrous sodium sulfate and thereafter, concentrated and purified on a silica gel column to obtain the end product. Yield: 0.46 g (49%). Oily product. 1 H-NMR (60 MHz, CDCl 3 , δ): 2.33(3H,s), 4.90(2H,s), 6.12(2H,s), 6.6-7.4(7H, complex). Synthesis Example 8 Synthesis of 2-(3-thienylmethyloxy)-4-trifluoromethyl-6-(meta-trifluoromethylphenoxy)pyridine (I-27) (1) Synthesis of an intermediate, 2-chloro-6-(3-thienylmethyloxy)-4-trifluoromethylpyridine To a mixture prepared by adding to 3-thiophenemethanol (1.27 g, 0.0093 × 1.2 mol) successively tetrahydrofuran and sodium hydride (0.39 g, (ca.60% in mineral oil), 0.0093 × 1.05 mol), 2,6-dichloro-4-trifluoromethylpyridine (2.0 g, 0.0093 mol) was added, and the resultant solution was refluxed for about 1 hour. Then, the reaction solution was partitioned between ethyl acetate and aqueous saturated sodium hydrogen carbonate. The obtained organic layer was washed with aqueous saturated sodium chloride, dried over anhydrous sodium sulfate and thereafter concentrated. The concentrate was purified on a silica gel column and the starting material which was difficult to separate was distilled off by using a tubular oven, whereby the end product was obtained. Yield: 2.42 g (89%). Oily product. 1 H-NMR (60 MHz, CDCl 3 , δ): 5.34(2H,s), 6.83(1H,s), 6.9-7.5(4H, complex). (2) Synthesis of 2-(3-thienylmethyloxy)-4-trifluoromethyl-6-(meta-trifluoromethylphenoxy)pyridine from the intermediate To a mixture prepared by adding to metatrifluoromethylphenol (1.1 g, 0.0034 × 2.0 mol) successively dimethylformamide and sodium hydride (0.20 g, (ca.60% in mineral oil), 0.0034 × 1.5 mol), 2-chloro-6-(3-thienylmethyloxy)-4-trifluoromethylpyridine (1.0 g, 0.0034 mol) was added, and the resultant solution was refluxed for about 2 hours. Then, the reaction solution was partitioned between ethyl acetate and aqueous saturated sodium hydrogen carbonate. The obtained organic layer was washed with aqueous saturated sodium chloride, dried 'over anhydrous sodium sulfate and thereafter concentrated. The concentrate was purified on a silica gel column and the starting material which was difficult to separate was distilled off by using a tubular oven, whereby the end product was obtained. Yield: 1.03 g (72%). Oily product. 1 H-NMR (60 MHz, CDCl 3 , δ): 5.03(2H,s), 6.63(2H,s), 6.7-7.6(7H, complex). Synthesis Example 9 Synthesis of 4-methylamino-2-(3-thienylmethyloxy)-6-(meta-trifluoromethylphenoxy)pyridine (I-28) (1) Synthesis of an intermediate, 2-chloro-4-methylamino-6-(3-thienylmethyloxy)pyridine To a solution of 3-thiophenemethanol (1.42 g, 0.0113 × 1.1 mol) in 20 ml of dry tetrahydrofuran, sodium hydride (1.35 g (ca.60% in mineral oil), 0.0113 × 3.0 mol) was added. After the bubbling ceased, a solution of 2,6-dichloro-4-methylaminopyridine (2.0 g, 0.0113 mol) in 30 ml of dry tetrahydrofuran was added dropwise at room temperature. After the addition, the reaction solution was stirred for about 20 hours under reflux. Then, the solvent was distilled off and the residue was partitioned between ethyl acetate and water. The obtained organic layer was washed successively with aqueous saturated sodium hydrogen carbonate and aqueous saturated sodium chloride, then dried over anhydrous sodium sulfate. After the solvent was distilled off, the residue was purified on a silica gel column to obtain the end product. Yield: 0.45 g (16%). Oily product. 1 H-NMR (60 MHz, CDCl 3 , δ): 2.64(3H,d, J=5 Hz), 4.2(1H,q, J=5 Hz), 5.2(2H,s), 5.6(1H,d, J=2 Hz), 6.0(1H,d,J=2 Hz), 6.9-7.3(3H, complex). (2) Synthesis of 4-methylamino-2-(3-thienylmethyloxy)-6-(meta-trifluoromethylphenoxy)pyridine from the intermediate To a solution of meta-trifluoromethylphenol (0.81 g, 0.00125 × 4.0 mol) in 10 ml of dry N,N-dimethylacetamide, sodium hydride (0.25 g (ca.60% in mineral oil), 0.00125 × 5.0 mol) was added. After the bubbling ceased, a solution of 2-chloro-4-methylamino-6-(3-thienylmethyloxy)pyridine (0.32 g, 0.00125 mol) in 10 ml of dry N,N-dimethylacetamide was added dropwise. Then, CuI (0.12 g, 0.00125 × 0.5 mol) was added thereto and the resultant solution was stirred four 24 hours at a temperature of about 170 to 180°C. After being allowed to cool, the reaction solution was filtered through a glass filter covered with Celite and the filtrate was partitioned between chloroform and water. The obtained organic layer was washed successively with aqueous saturated sodium hydrogen carbonate and aqueous saturated sodium chloride, then dried over anhydrous sodium sulfate. The solvent was distilled off and the residue was purified on column chromatography (elution solvent: acetonitrile/water = 7/3(v/v), Lobar column, Lichroprep RP-18, 40-63 µm), whereby the end product was obtained. Yield: 0.18 g (37%). Oily product. 1 H-NMR (60 MHz, CDCl 3 , δ): 2.7(3H,d,J=5 Hz), 3.9-4.3(1H,s), 5.0(2H,s) 5.6(2H,s), 6.75-7.4(7H, complex). Synthesis Example 10 Synthesis of 4-dimethylamino-2-(3-thienylmethyloxy)-6-(meta-trifluoromethylphenoxy)pyridine (I-29) (1) Synthesis of an intermediate, 2-chloro-4-dimethylamino-6-(3-thienylmethyloxy)pyridine To a solution of 3-thiophenemethanol (0.526 g, 0.0042 × 1.1 mol) in 10 ml of dry tetrahydrofuran, sodium hydride (0.335 g, (ca.60% in mineral oil), 0.0042 × 2.0 mol) was added. After the bubbling ceased, a solution of 2,6-dichloro-4-dimethylaminopyridine (0.8 g, 0.0042 mol) in 20 ml of dry tetrahydrofuran was added dropwise at room temperature. After the addition, the resultant solution was stirred for 24 hours under reflux. Then, the solvent was distilled off and the residue was partitioned between chloroform and water. The obtained organic layer was washed successively with aqueous saturated sodium hydrogen carbonate and aqueous saturated sodium chloride, then dried over anhydrous sodium sulfate. After the solvent was distilled off, the residue was purified on a silica gel column to obtain the end product. Yield: 0.63 g (56%). Solid. Melting point: 78-79°C. 1 H-NMR (60 MHz, CDCl 3 , δ): 2.86(6H,s), 5.20(2H,s), 5.73(1H,d,J=2 Hz), 6.15(1H,d,J=2 Hz), 7.0-7.3(3H, complex). (2) Synthesis of 4-dimethylamino-2-(3-thienylmethyloxy)-6-(meta-trifluoromethylphenoxy)pyridine from the intermediate To a solution of meta-trifluoromethylphenol (1.27 g, 0.0020 × 4.0 mol) in 20 ml of dry N,N-dimethylacetamide, sodium hydride (0.313 g, (ca.60% in mineral oil), 0.0020 × 4.0 mol) was added. After the bubbling ceased, a solution of 2-chloro-4-dimethylamino-6-(3-thienylmethyloxy)pyridine (0.526 g, 0.0020 mol) in 20 ml of dry N,N-dimethylacetamide was added dropwise, then CuI (0.186 g, 0.0020 × 0.5 mol) was added thereto and the resultant solution was stirred for 24 hours at the temperature of 170 to 180°C. After allowed to cool, the reaction solution was filtered through a glass filter covered with Celite and the filtrate was partitioned between chloroform and water. The obtained organic layer was washed successively with aqueous saturated sodium hydrogen carbonate and aqueous saturated sodium chloride, then dried over anhydrous sodium sulfate. The solvent was distilled off and the residue was purified on column chromatography (elution solvent: acetonitrile/water = 7/3(v/v), Lobar column, Lichroprep RP-18, 40-63 µm), whereby the end product was obtained. Yield: 0.26 g (34%). Solid. Melting point 78-80°C. 1 H-NMR (60 MHz, CDCl 3 , δ): 2.9(6H,s), 5.0(2H,s), 5.66(1H,d,J=2 Hz), 5.7(1H,d,J=2 Hz), 6.8-7.4(7H, complex). Reference Synthesis Example 1 Synthesis of 2,6-dichloro-4-methoxypyridine used in the Synthesis example 6 To a tetrahyrofuran solution containing methanol (0.37 g, 0.0104 × 1.1 mol), sodium hydride (0.44 g, (ca.60% in mineral oil), 0.0104 × 1.05 mol) was added. Then 2,6-dichloro-4-nitropyridine (2.00 g, 0.0104 mol) was added thereto and the mixture was stirred for about 2 hours at room temperature. After it was confirmed that there was no bubbling with the addition of methanol (0.5 g), the mixture was stirred for about 1 hour. The reaction solution was partitioned between ethyl acetate and water. The obtained organic layer was washed successively with aqueous saturated sodium hydrogen carbonate and aqueous saturated sodium chloride, then dried over anhydrous sodium sulfate and concentrated to obtain the end product which was almost pure. Yield: 1.63 g (88%). Solid. Melting point: 94-96°C. 1 H-NMR (60 MHz, CDCl 3 , δ): 3.79(3H,s), 6.70(2H,s). Reference Synthesis Example 2 Synthesis of 2,6-dichloro-4-methylmercaptopyridine (used in the Synthesis example 7) To a dimethylformamide solution of 2,6-dichloro-4-nitroprydine (2.0 g, 0.0104 mol), a sodium methanethiol solution (4.84 g, (15% aqueous solution), 0.0104 × 1.0 mol) was added, and the solution was stirred for about 1 hour at room temperature. The reaction solution was partitioned between ethyl acetate and water. The obtained organic layer was washed successively with aqueous saturated sodium hydrogen carbonate and aqueous saturated sodium chloride, then dried over anhydrous sodium sulfate and concentrated. From the concentrate, distillate was collected with a tubular oven at about 170°C under aspiration (2.3-2.4 kPa (17-18 mmHg)) to obtain the end product. Yield: 1.83 g (91%). Solid. Melting point: 69-73°C. 1 H-NMR (60 MHz, CDCl 3 , δ: 2.43(3H,s), 6.82(2H,s). Reference Synthesis Example 3 Synthesis of 2,6-dichloro-4-methylaminopyridine (used in the Synthesis example 9) 2,6-Dichloro-4-nitropyridine (3.0 g, 15.5 mmol) was dissolved in 50 ml of acetonitrile, and an aqueous methylamine solution (3.62 g, (40% aqueous solution), 15.5 × 3 mmol) was added dropwise thereto. The solution was stirred for 1 hour at room temperature, and 100 ml of water was added thereto. The precipitated solid was filtered off, washed with water, and dried. Yield: 2.54 g (92.7%). Yellow solid. Melting point: 194-196°C. 1 H-NMR (60 MHz, CDCl 3 + d 6 DMSO, δ): 2.7(3H,d,J=5Hz), 6.3(2H,s), (NH was indefinite.). Reference Synthesis Example 4 Synthesis of 2,6-dichloro-4-dimethylaminopyridine (used in the Synthesis example 10) To a solution of 4-amino-2,6-dichloropyridine (3.0 g, 18.4 mmol) in 50 ml of dry dimethylformamide, sodium hydride (1.47 g, (ca.60% in mineral oil), 18.4 × 2 mmol) was added at room temperature. After the bubbling ceased, a solution of methyl iodide (5.2 g, 18.4 × 2 mmol) in 5 ml of dry dimethylformamide was added dropwise. The resultant solution was stirred for 4 hours at room temperature and the reaction solution was poured into iced water. The precipitated solid was filtered off, washed with water, and dried. Yield: 3.47 g (99.1%). White solid. Melting point: 137-139°C. 1 H-NMR (60 MHz, CDCl 3 , δ): 2.9(6H,s), 6.28(2H,s). The other compounds shown in the Table 1 were also synthesized in a similar manner to that described in any of the above Examples. Properties and NMR data of the obtained compounds are shown in the Table 2. No. Property 1 H-NMR (60 MHz, CDCl 3 , δ) I-1 Oily 5.05(2H,s), 6.29(1H,d,J=7.9Hz) 6.35(1H,d,J=7.9Hz), 6.6-7.4(7H,complex) 7.41(1H,t,J=7.9Hz) I-2 Oily 2.30(3H,s), 5.10(2H,s), 6.21(1H,d,J=7.9Hz) 6.31(1H,d,J=7.9Hz), 6.6-7.3(7H,complex) 7.37(1H,t,J=7.9Hz) I-6 Oily 5.05(2H,s), 6.34(1H,d,J=7.9Hz) 6.38(1H,d,J=7.9Hz), 6.7-7.5(7H,complex) 7.43(1H,t,J=7.9Hz) I-7 Oily 2.36(3H,s), 5.09(2H,s) 6.2-6.7(4H,complex), 7.0-7.6(5H,complex) I-14 Oily 3.72(3H,s), 4.98(2H,s), 5.8-6.2(2H,complex) 6.6-7.4(3H,complex), 7.57(3H,s) I-16 Oily 3.69(3H,s), 5.04(2H,s) 5.95(2H,s), 6.7-7.6(7H,complex) I-17 Oily 3.66(3H,s), 5.05(2H,s), 5.90(2H,s) 6.36(1H,t,J=73Hz), 6.6-7.5(7H,complex) I-18 Oily 3.70(3H,s), 5.11(2H,s), 5.8-6.2(2H,complex), 6.66(1H,d,J=1.6Hz), 7.00(1H,d,J=1.6Hz) 7.0-7.6(4H,complex) I-19 Oily 3.68(3H,s), 5.06(2H,s), 5.7-6.1(2H,complex), 6.48(1H,d,J=3.4Hz), 6.71(1H,d,J=3.4Hz) 6.9-7.5(4H,complex) I-20 Oily 2.12(3H,s), 3.68(3H,s), 5.12(2H,s) 5.94(2H,s), 6.66(1H,d,J=5Hz), 7.02(1H,d,J=5Hz) 7.0-7.5(4H,complex) I-21 Oily 2.34(3H,s), 3.66(3H,s), 5.07(2H,s) 5.9-6.1(2H,complex), 6.40(1H,d,J=3.6Hz), 6.53(1H,d,J=3.6Hz), 7.1-7.5(4H,complex) I-23 Oily 2.20(3H,s), 2.29(3H,s), 3.69(3H,s), 4.86(2H,s) 5.92(2H,s), 6.39(1H,s), 6.9-7.6(4H,complex) Formulation examples and Test Examples are hereinafter given. The kinds of carriers (diluents) and additives to be used, as well as the mixing ratios thereof and active ingredient contents therein, may be modified in a broad range. In each of the Formulation Examples, the term "parts" is "parts by weight". Formulation Example 1 (wettable powder) The compound of the present invention 50 parts Lignin sulfonate 5 parts Alkyl sulfonate 3 parts Diatomaceous earth 42 parts The above ingredients were mixed together and ground finely to form a wettable powder. It may be applied after being diluted with water. Formulation Example 2 (emulsifiable concentrate) The compound of the present invention 25 parts Xylene 65 parts Polyoxyethylene alkylaryl ether 10 parts The above ingredients were homogeneously mixed to form an emulsifiable concentrate. It may be applied after being diluted with water. Formulation Example 3 (granule) The compound of the present invention 8 parts Bentonite 40 parts Clay 45 parts Lignin sulfonate 7 parts The above ingredients were homogeneously mixed, blended with water and processed into a granular form with an extrusion granulator to give granules. Test Example 1 (Weed control test by foliage and soil treatments A wettable powder of each test compound was prepared as described in Formulation Example 1 and suspended at a predetermined concentration. The thus formed herbicidal solutions were each applied at an active ingredient rate of 100 g/10 a onto both the soil and the foliage of each plant grown to the 1 to 2 leaf stage. The tested plants were pot-cultivated redroot pigweed (Amaranthus retroflexus), wild mustard (Sinapis arvensis), sicklepod (Cassia obtusifolia), black nightshade (Solanum nigrum), velvetleaf (Abutilon theophrasti), cleavers (Galium aparine) and ivyleafspeedwell (Veronica hederaefolia). On the 14th day after the applications, weed control effects were evaluated by the following criteria: Evaluation rating: 1: less than 25% weedkilling 2: 25% to less than 50% weedkilling 3: more than 50% weedkilling The results are shown in Table 3: No. Dose (g ai/10 a) Weed AR SA CO SN AT GA VH I-3 100 3 3 3 3 3 3 3 1-4 100 3 3 3 3 3 3 3 I-7 100 3 3 3 3 3 3 3 I-8 100 3 3 3 3 3 3 3 I-9 100 3 3 3 3 3 3 3 I-10 100 3 3 3 3 3 3 3 I-13 100 3 3 3 3 3 3 3 I-16 100 3 3 3 3 3 3 3 I-17 100 3 3 3 3 3 3 3 I-18 100 3 3 3 3 3 3 3 I-19 100 3 3 3 3 3 3 3 I-20 100 3 3 3 3 3 3 3 I-21 100 3 3 3 3 3 3 3 I-26 100 3 3 3 3 3 3 3 I-28 100 3 3 3 3 3 3 3 I-29 100 3 3 3 3 3 3 3

Claims: A 2-phenoxy-6-thienylmethyloxypyridine derivative of formula (I): wherein: R represents hydrogen, a halogen, cyano, C 1 -C 4 alkyl, C 1 -C 4 alkoxy, C 1 -C 4 alkylthio, C 1 -C 4 haloalkyl, C 1 -C 4 alkylamino, or di(C 1 -C 4 alkyl)amino; each X, which may be identical or different if n is greater than 1, represents a halogen, C 1 -C 4 alkyl, C 1 -C 4 alkoxy, C 1 -C 4 alkylthio, or C 1 -C 4 haloalkyl; each Y, which may be identical or different if m is greater than 1, represents a halogen, C 1 -C 4 alkyl, C 1 -C 4 alkoxy, C 1 -C 4 alkylthio, C 1 -C 4 haloalkyl, C 1 -C 4 haloalkoxy, or C 1 -C 4 haloalkylthio; m represents an integer of 0 to 5; and n represents an integer of 0 to 3. A compound according to claim 1 wherein Y represents trifluoromethyl, difluoromethoxy, trifluoromethoxy, or trifluoromethylthio. A compound according to claim 1 or 2 wherein R represents hydrogen, a halogen, cyano, methyl, methoxy, methylthio, methylamino, dimethylamino, or trifluoromethyl. A compound according to any one of the preceding claims wherein n represents 0. A compound according to any one of claims 1, 2 or 3 wherein X represents methyl, bromine or chlorine. A process for producing a derivative of formula (I) as defined in any one of the preceding claims which process comprises reacting a 2-halogeno-6-thienylmethyloxypyridine derivative of formula (II): wherein R, X, and n are as defined in claim 1 and Z represents a halogen, with an unsubstituted or substituted phenol of formula (III): wherein Y and m are as defined in claim 1. A herbicidal composition containing as an active ingredient a 2-phenoxy-6-thienylmethyloxypyridine derivative of formula (I) as defined in any one of claims 1 to 5 and an adjuvant. A herbicidal composition according to claim 7, wherein Y represents trifluoromethyl, difluoromethoxy, or trifluoromethoxy; R represents hydrogen, a halogen, cyano, methyl, methoxy, methylthio, methylamino, dimethylamino, or trifluoromethyl; and n represents 0. A method of controlling the growth of weeds at a locus which comprises administering thereto a derivative of formula (I) as defined in any one of claims 1 to 5.

Inventors: ARAHIRA MASATO, KANDA YOUICHI, KANNO HISASHI, KUBOTA YOSHIKAZU, SATO TSUTOMU, SHIMIZU SUSUMU, ARAHIRA, MASATO, KANDA, YOUICHI, KANNO, HISASHI, KUBOTA, YOSHIKAZU, SATO, TSUTOMU, SHIMIZU, SUSUMU
Applicants: KUREHA CHEMICAL IND CO LTD, KUREHA KAGAKU KOGYO KABUSHIKI KAISHA
Application year: 1995
Main classification: C07D409
IPC codes: C07D409