Method for preparing pyrazolecarboxylic acid and derivatives

Abstract: There is disclosed a process for preparing a pyrazolecarbo­ xylic acid derivative represented by the formula (II): wherein Y and Z each represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, COOR₁, NR₁R₂, CONR₁R₂, SR₁, SO₂NR₁R₂, SO₂R₃, R₃CO, OR₄, CHX₂ or CX₃; A represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a substituted or unsubsti­ tuted phenyl group, a substituted or unsubstituted pyridyl group or OR₅; where R₁ and R₂ each represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; R₃ represents an alkyl group having 1 to 10 carbon atoms; R₄ represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a substi­ tuted or unsubstituted phenyl group, CHF₂, CF₃ or CF₃CH₂; R₅ represents an alkyl group having 1 to 10 carbon atoms; and X represents a halogen atom, which comprises oxidizing a pyrazole compound represented by the formula (I): wherein Y, Z and A have the same meanings as defined above, with an oxygen-containing gas in the presence of a metal compound catalyst.

Description: BACKGROUND OF THE INVENTION This invention relates to a novel method for preparing pyrazolecarboxylic acid derivatives which are useful as an intermediate of a herbicide, etc. Heretofore, as the method for preparing pyrazolecarboxylic acid from alkylpyrasole derivatives, it has been known the permanganic acid oxidation method. However, this method uses excessive amount of permanganate and the yield is extremely bad as 40 % or lower. Also, it is required to process a large amount of waste water and waste material containing manganese so that it is difficult to employ the method as an industrial scale preparation. Also, as the preparative method of heterocyclic carboxylic acid due to the liquid phase autoxidation method, the following has been known. (1) Japanese Patent Publication No. 9869/1959 (2) Japanese Patent Publication No. 17068/1975 In the aforesaid (1), oxidation of a compound having pyridine or quinoline nucleus has been carried out in the presence of a heavy metal compound such as manganese, cobalt, etc. and a bromine compound. In the aforesaid (2), oxidation of alkylpyridine derivatives have been carried out in the presence of a compound selected from zirconium, cobalt and manganese and a bromine compound to prepare pyridinecarboxylic acids. However, none of the above-mentioned processes provides a method in which only a methyl group of a pyrazole compound having simultaneously a methyl group bonded to the pyrazole ring and a substituent bonded to a nitrogen atom is selectively oxidized to give pyrazolecarboxylic acid derivatives. SU-A-453404 [Chem. Abs. 82 (1975), 140122] describes the preparation of 3-carboxy pyrazole, and analogous 4-nitro and 4-sulpho compounds, by oxidizing the corresponding 3-methyl compounds with ozone in the presence of sulphuric acid. EP-A-0224094 describes a process for converting 5-methyl-4-nitro-1-aryl pyrazoles into the corresponding 5-carboxy compounds by oxidation with potassium permanganate and atmospheric oxygen, generally in alkaline solution. The effective oxidizing agent appears to be the potassium permanganate, in view of its preferred use in molar to 10-molar amounts. US-A-3801584 discloses the production of pyridine carboxylic acids by oxidizing alkyl pyridines with molecular oxygen, in the presence of (a) zirconium compounds with (b) bromine on a bromine compound, and (c) a soluble salt of a transition metal, such as cobalt and/or manganese. The present inventors have intensively studied concerning the method of obtaining a pyrazolecarboxylic acid derivative from a pyrazole compound having simultaneously a methyl group bonded to the pyrazole ring and a substituent bonded to a nitrogen atom, and as the result, accomplished the present invention. That is, the present invention concerns a method for preparing a pyrazolecarboxylic acid derivative represented by the formula (II): wherein Y and Z each represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, COOR₁, NR₁R₂, CONR₁R₂, SO₂NR₁R₂, SO₂R₃, R₃CO, OR₄, CHX₂ or CX₃; A represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group, a pyridyl group or OR₅; where R₁ and R₂ each represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; R₃ represents an alkyl group having 1 to 10 carbon atoms; R₄ represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a phenyl group, CHF₂, CF₃ or CF₃CH₂; R₅ represents an alkyl group having 1 to 10 carbon atoms; and X represents a halogen atom, which comprises oxidizing a pyrazole compound represented by the formula (I): wherein Y, Z and A have the same meanings as defined above, with an O₂-containing gas in the presence of a metal compound catalyst, which catalyst is more precisely defined below, and a bromine compound as reaction promotor. DESCRIPTION OF THE PREFERRED EMBODIMENTS In the above formula (II), as the halogen atoms for Y, Z and Z (that is, X in CHX₂ or CX₃), there may be mentioned a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. As the alkyl group having 1 to 10 carbon atoms for R₁, R₂, R₃, R₄ and R₅, there may be mentioned a methyl group, an ethyl group, a n-propyl group, an i-propyl group, a n-butyl group, an i-butyl group, a t-butyl group, a n-pentyl group, an i-pentyl group, a n-hexyl group, an i hexyl group, a n-heptyl group, an i-heptyl group, a n-octyl group, an i-octyl group, a n-nonyl group, an i-nonyl group, a n-decyl group or an i-decyl group. Among these, as R₁ to R₅, a methyl group or an ethyl group is particularly preferred. As the alkyl group having 1 to 4 carbon atoms for A, there may be mentioned a methyl group, an ethyl group, a n-propyl group, an i-propyl group, a n-butyl group, an i-butyl group or a t-butyl group. As A, a methyl group or an ethyl group is particularly preferred. In the above, n means normal, i means iso and t means tertiary. As the O₂-containing gas, a pure oxygen gas or air may be used. Oxygen partial pressure may be 0.1 to 9.3 MPa (atmospheric pressure to 80 kg/cm²), preferably 0.1 to 6.3 MPa (atmospheric pressure to 50 kg/cm²). As the metal compound catalyst, there may also be mentioned aliphatic acid iron salts such as iron formate, iron acetate, iron lacate, iron oxalate or iron octylate; chelate compounds such as iron acetylacetonate; iron salts such as iron chloride, iron bromide, iron iodide, iron carbonate, iron sulfate or iron nitrate; aliphatic acid cobalt salts such as cobalt formate, cobalt acetate or cobalt octylate; chelate compounds such as cobalt acetylacetonate; cobalt salts such as cobalt chloride, cobalt bromide, cobalt iodide, or cobalt carbonate; aliphatic acid nickel salts such as nickel formate, nickel acetate or nickel octylate; chelate compounds such as nickel acetylacetonate; nickel salts such as nickel chloride, nickel bromide, nickel iodide or nickel carbonate; aliphatic acid manganese salts such as manganese formate, manganese acetate or manganese octylate, chelate compounds such as manganese acetylacetonate; manganese salts such as manganese chloride, manganese bromide, manganese iodide or manganese carbonate; aliphatic acid cerium salts such as cerium formate, cerium acetate or cerium octylate, chelate compounds such as cerium acetylacetonate; cerium salts such as cerium chloride, cerium bromide, cerium iodide or cerium carbonate; aliphatic acid zirconium salts such as zirconium formate, zirconium acetate or zirconium octylate, chelate compounds such as zirconium acetylacetonate; zirconium salts such as zirconium chloride, zirconium bromide, zirconium iodide or zirconium carbonate; copper compounds such as cupric acetate, cupric chloride or cupric carbonate; palladium compounds such as palladium acetate, palladium chloride or palladium iodide; osmium compounds such as osmium tetrachloride; and lead compounds such as lead tetraacetate. The amount of the metal compound catalyst is 0.1 to 20 gram-atom, preferably 1 to 10 gram-atom, in terms of a metal based on 100 moles of the compound of the formula (I). Also, the above metal compound catalysts are used in combination, for example, when 1 to 1/50 gram-atom, preferably 1 to 1/10 gram-atom of manganese is used to cobalt, good results can be obtained. A bromine compound is used as a reaction promotor. The bromine compound is not particularly limited and, for example, there may be mentioned ammonium bromide, sodium bromide, potassium bromide, bromine, hydrogen bromide, etc. Sodium bromide or ammonium bromide is particularly preferred. An amount of the bromine compound is not particularly limited, but generally 0.5 to 20 moles, preferably 1 to 10 moles based on 100 moles of the compound of the formula (I). The reaction temperature is preferably 20 to 200 °C, most preferably 60 to 180 °C. The reaction of the present invention may be possible without any solvent but a solvent may be used. If a solvent is used, operability, safty, and the like are improved. The solvent is not particularly limited so long as it is stable, and may include a lower aliphatic acid such as acetic acid, propionic acid, a butyric acid, etc.; a lower aliphatic acid anhydride such as acetic anhydride, propionic anhydride, etc., and acetic acid is particularly preferred. An amount of the solvent is not particularly limited, but it is preferred to use 2-fold to 100-fold based on 1 part by weight of the substrate since good results can be obtained. According to the present invention, the pyrazolecarboxylic acid represented by the formula (II) can be prepared from the pyrazole compound represented by the formula (I) with ease and high yield. Particularly, the present invention is effective as the method for preparing 3,5-dichloro-1-methylpyrazole-4-carboxylic acid from 3,5-dichloro-1,4-dimethylpyrazole. The compound is an available compound as an intermediate of a herbicide for corn field. EXAMPLES In the following, the present invention will be explained by referring to Examples, but the present invention is not limited by these. Example 1 In a 100 ml of an autoclave made of Hastelloy C-276 were charged 50 ml of acetic acid, 8.25 g (50 mmole) of 3,5-dichloro-1,4-dimethylpyrazole, 0.498 g (2 mmole) of cobalt acetate, 0.123 g (0.5 mmole) of manganese acetate and 0.408 g (4 mmole) of sodium bromide. After supplying an oxygen gas in the autoclave to make 5.3 MPa (40 kg/cm²), the mixture was heated under stirring and reaction was carried out at 140 °C for 2 hours. After the reaction, the products were taken out and analyzed by a gas chromatography, and as the result, a conversion ratio of the starting 3,5-dichloro-1,4-dimethylpyrazole was 100 %. After removing acetic acid, the residue was esterified by diazomethane and the products were analyzed by a gas chromatography-mass spectrograph to obtain the result of M/e being 208 whereby it could be confirmed to be a methyl ester of the objective compound. As the result of the gas chromatography analysis, a yield of 3,5-dichloro-1-methylpyrazole-4-carboxylic acid was 88.7 %. Example 2 In the same manner as in Example 1 except for changing an oxygen pressure to 2.4 MPa (10 kg/cm²), the reaction and operation were carried out. A conversion ratio of the starting 3,5-dichloro-1,4-dimethylpyrazole was 90.5 % and a yield of 3,5-dichloro-1-methylpyrazole-4-carboxylic acid was 79.9 %. Example 3 In the same manner as in Example 1 except for changing the reaction temperature to 130 °C, the reaction and operation were carried out. A conversion ratio of the starting 3,5-dichloro-1,4-dimethylpyrazole was 95.0 % and a yield of 3,5-dichloro-1-methylpyrazole-4-carboxylic acid was 85.0 %. Example 4 In the same manner as in Example 1 except for charging 0.392 g (4 mmole) of ammonium bromide in place of sodium bromide, the reaction and operation were carried out. A conversion ratio of the starting 3,5-dichloro-1,4-dimethylpyrazole was 100 % and a yield of 3,5-dichloro-1-methylpyrazole-4-carboxylic acid was 90.1 %. Example 5 In the same manner as in Example 1 except for adding 7 mg (0.04 mmole) of ferrous oxalate as an iron compound, the reaction and operation were carried out. A conversion ratio of the starting 3,5-dichloro-1,4-dimethylpyrazole was 95 % and a yield of 3,5-dichloro-1-methylpyrazole-4-carboxylic acid was 93 %. Example 6 In a 100 ml an autoclave made of titanium were charged 50 ml of acetic acid, 6.5 g (50 mmole) of 5-chloro-1,4-dimethylpyrazole, 0.498 g (2 mmole) of cobalt acetate, 0.123 g (0.5 mmole) of manganese acetate and 0.408 g (4 mmole) of sodium bromide, and after supplying air therein to make 11.2 MPa (100 kg/cm²), reaction was carried at 140 °C for 2 hours. A conversion ratio of the starting 5-chloro-1,4-dimethylpyrazole was 100 %. After removing acetic acid, the residue was esterified by diazomethane and the products were analyzed by a gas chromatography-mass spectrograph to obtain the result of M/e being 174 whereby it could be confirmed to be a methyl ester compound of the objective compound. As the result of the gas chromatography analysis, a yield of 5-chloro-1-methylpyrazole-4-carboxylic acid was 86.2 %. Example 7 In a 100 ml of an autoclave made of Hastelloy C-276 were charged 50 ml of acetic acid, 4.8 g (50 mmole) of 1,4-dimethylpyrazole, 0.249 g (1 mmole) of cobalt acetate, 0.123 g (0.5 mmole) of manganese acetate and 0.204 g (2 mmole) of sodium bromide, and reaction and operation were carried out in the same manner as in Example 1. A conversion ratio of the starting 1,4-dimethylpyrazole was 100 % and a yield of 1-methylpyrazole-4-carboxylic acid was 87.7 %. Example 8 In a 100 ml an autoclave made of Hastelloy C-276 were charged 50 ml of acetic acid, 9.6 g (50 mmole) of 1-isopropyl-3-trifluoromethyl-5-methylpyrazole, 0.249 g (1 mmole) of cobalt acetate, 0.123 g (0.5 mmole) of manganese acetate and 0.204 g (2 mmole) of sodium bromide. After supplying an oxygen gas in the autoclave to make 5.8 MPa (45 kg/cm²), the mixture was heated under stirring and reaction was carried out at 160 °C for 2 hours. When the same operations were carried out as in Example 1, a conversion ratio of the starting 1-isoprpoyl-3-trifluromethyl-5-methylpyrazole was 96.8 % and a yield of 1-isopropyl-3-trifluoromethylpyrazole-5-carboxylic acid was 74.2 %. Example 9 In a 100 ml an autoclave made of Hastelloy C-276 were charged 50 ml of acetic acid, 8.2 g (50 mmole) of 1,5-dimethyl-3-trifluoromethylpyrazole, 0.249 g (1 mmole) of cobalt acetate, 0.123 g (0.5 mmole) of manganese acetate and 0.204 g (2 mmole) of sodium bromide, reaction and operation were carried out in the same manner as in Example 1. A conversion ratio of the starting 1,5-dimethyl-3-trifluoromethylpyrazole was 96.8 %, and a yield of 1-methyl-3-trifluoromethylpyrazole-5-carboxylic acid was 52.0 %. Example 10 In a 100 ml an autoclave made of Hastelloy C-276 were charged 50 ml of acetic acid, 10.5 g (50 mmole) of 3-chloro-1,4-dimethylpyrazole-5-sulfonamide, 0.249 g (1 mmole) of cobalt acetate, 0.0615 g (0.25 mmole) of manganese acetate and 0.204 g (2 mmole) of sodium bromide, reaction and operation were carried out in the same manner as in Example 1. A conversion ratio of the starting 3-chloro-1,4-dimethylpyrazole-5-sulfonamide was 90 %, and a yield of 3-chloro-1-methyl-5-sulfonamidopyrazole-4-carboxylic acid was 75.5 %.

Claims: A process for preparing a pyrazolecarboxylic acid derivative represented by the formula (II): wherein Y and Z each represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, COOR₁, NR₁R₂, CONR₁R₂, SO₂NR₁R₂, SO₂R₃, R₃CO, OR₄, CHX₂ or CX₃; A represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group, a pyridyl group or OR₅; where R₁ and R₂ each represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; R₃ represents an alkyl group having 1 to 10 carbon atoms; R₄ represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a phenyl group, CHF₂, CF₃ or CF₃CH₂; R₅ represents an alkyl group having 1 to 10 carbon atoms; and X represents a halogen atom, which comprises oxidizing a pyrazole compound represented by the formula (I): wherein Y, Z and A have the same meanings as defined above, with an O₂-containing gas in the presence of a metal compound catalyst, wherein the metal compound catalyst comprises a cobalt compound selected from aliphatic acid cobalt salts, chelate compounds of cobalt and cobalt salts, and a manganese compound selected from aliphatic acid manganese salts, chelate compounds of manganese and manganese salts, wherein the amount of said metal compound catalyst is 0.1 to 20 gram-atom, based on 100 moles of the compound of the formula (I), wherein the amount of manganese in said manganese compound to cobalt in said cobalt compound is 1 to 1/50 gram-atom, and wherein a bromine compound is added in the reaction system as a reaction promoter. A method according to Claim 1, wherein said Y and Z in the formulae (I) and (II) are both chlorine atoms and A in the same is a methyl group. A method according to Claim 1, wherein said O₂-containing gas is pure oxygen gas or air. A method according to Claim 3, wherein a partial pressure of the O₂-containing gas is 0.1 to 9.3 MPa (atmospheric pressure to 80 kg/cm²). A method according to Claim 3, wherein a partial pressure of the O₂-containing gas is 0.1 to 6.3 MPa (atmospheric pressure to 50 kg/cm²). A method according to any one of claims 1 to 5, wherein said cobalt compound and the manganese compound are selected from colalt formate, cobalt acetate, cobalt octylate, cobalt acetylacetonate, cobalt chloride, cobalt bromide, cobalt iodide, cobalt carbonate, manganese formate, manganese acetate, manganese octylate, manganese acetylacetonate, manganese chloride, manganese bromide, manganese iodide and manganese carbonate. A method according to Claim 6, wherein said metal compound catalysts are cobalt acetate and manganese acetate. A method according to any one of claims 1 to 7, wherein said bromine compound is selected from ammonium bromide, sodium bromide, potassium bromide, bromine and hydrobromide. A method according to Claim 8, wherein said bromine compound is sodium bromide. A method according to any one of claims 1 to 9, wherein an amount of said bromine compound is 0.5 to 20 moles based on 100 moles of the compound of the formula (I). A method according to any one of claims 1 to 10, wherein the reaction is carried out at 20 to 200 °C. A method according to any one of claims 1 to 11, wherein the reaction is carried out in the presence of a solvent. A method according to Claim 12, wherein the solvent is selected from a lower aliphatic acid or a lower aliphatic acid anhydride. A method according to Claim 13, wherein the solvent is selected from actic acid, propionic acid, butyric acid, acetic anhydride and propionic anhydride. A method according to Claim 14, wherein the solvent is acetic acid. A method according to any one of claims 1 to 15, wherein the compound of the formula (I) is selected from the group consisting of 3,5-dichloro-1,4-dimethylpyrazole, 5-chloro-1,4-dimethylpyrazole, 1,4-dimethylpyrazole, 1-isopropyl-3-trifluoromethyl-5-methylpyrazole, 1,5-dimethyl-3-trifluoromethylpyrazole, and 3-chloro-1,4-dimethylpyrazole-5-sulfonamide. A method according to any one of claims 1 to 15, wherein the compound of the formula (II) is selected from the group consisting of 3,5-dichloro-1-methylpyrazole-4-carboxylic acid, 5-chloro-1-methylpyrazole-4-carboxylic acid, 1-methylpyrazole-4-carboxylic acid, 1-isopropyl-3-trifluoromethylpyrazole-5-carboxylic acid, 1-methyl-3-trifluoromethylpyrazole-5-carboxylic acid, and 3-chloro-1-methylpyrazole-5-sulfonamidopyrazole-4-carboxylic acid.

Inventors: SHINKE SHUZO C O CENTRAL RESEA, TAKIGAWA SHINICHIRO CENTRAL RE, SHINKE, SHUZO C/O CENTRAL RESEARCH INSTITUTE, TAKIGAWA, SHINICHIRO CENTRAL RESEARCH INSTITUTE
Applicants: NISSAN CHEMICAL IND LTD, NISSAN CHEMICAL INDUSTRIES, LIMITED
Application year: 1989
Main classification: C07D231
IPC codes: B01J27, B01J31, C07B61, C07D231, C07D401