JP5885620B2 - 2- (2-Furyl) imidazole compound and antioxidant - Google Patents

Description

  The present invention relates to a novel 2- (2-furyl) imidazole compound and a copper or copper alloy antioxidant containing the imidazole compound.

  As an imidazole compound similar to the present invention, for example, Non-Patent Document 1 discloses 2- (2-furyl) -4-phenylimidazole represented by the chemical formula (III). However, this document does not disclose the imidazole compound of the present invention.

Bioorganic & Medicinal Chemistry Letters, 18 (20), 5460-5462 (2008).

  An object of the present invention is to provide a novel 2- (2-furyl) imidazole compound and an antioxidant for copper or a copper alloy containing the imidazole compound.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have been able to synthesize a novel 2- (2-furyl) imidazole compound represented by the chemical formula (I) or the chemical formula (II). The inventors have found that the imidazole compound exhibits an antioxidant effect on the surface of copper or a copper alloy, and completed the present invention.
That is, the first invention is a 2- (2-furyl) imidazole compound represented by the chemical formula (I) or the chemical formula (II), and the second invention is copper or copper characterized by containing the imidazole compound. It is an antioxidant for alloys.

（式中、ｎは０、１又は２を表す。）

(In the formula, n represents 0, 1 or 2.)

  The 2- (2-furyl) imidazole compound of the present invention is an antioxidant for the surface of a metal, particularly copper or a copper alloy (hereinafter simply referred to as copper), a curing agent or curing accelerator for an epoxy resin. It is also useful as an intermediate material in the medical and agrochemical field. Moreover, the antioxidant of copper containing the 2- (2-furyl) imidazole compound of the present invention can improve the solderability when soldering the copper surface.

Hereinafter, the present invention will be described in detail.
The 2- (2-furyl) imidazole compound of the present invention is
2- (2-furyl) -5-methyl-4-phenylimidazole,
4- (2-chlorophenyl) -2- (2-furyl) -5-methylimidazole,
4- (3-chlorophenyl) -2- (2-furyl) -5-methylimidazole,
4- (4-chlorophenyl) -2- (2-furyl) -5-methylimidazole,
4- (2,3-dichlorophenyl) -2- (2-furyl) -5-methylimidazole,
4- (2,4-dichlorophenyl) -2- (2-furyl) -5-methylimidazole,
4- (2,5-dichlorophenyl) -2- (2-furyl) -5-methylimidazole,
4- (2,6-dichlorophenyl) -2- (2-furyl) -5-methylimidazole,
4- (3,4-dichlorophenyl) -2- (2-furyl) -5-methylimidazole,
4- (3,5-dichlorophenyl) -2- (2-furyl) -5-methylimidazole,
2- (2-furyl) -4- (1-naphthyl) imidazole and 2- (2-furyl) -4- (2-naphthyl) imidazole.

  The 2- (2-furyl) imidazole compound of the present invention can be synthesized according to a known method. For example, as shown in the reaction formula (A), a 2-position halogenated alkylaryl ketone compound and 2-furancarboxamidine are synthesized by heating in an organic solvent in the presence of a dehydrohalogenating agent. be able to.

  In the above reaction, the amount of 2-furancarboxamidine to be used is preferably 0.8 to 1.5 times, more preferably 0.9 to 1.1 times the mol of the 2-position halogenated alkylaryl ketone compound. A mole ratio may be used. The amount of the dehydrohalogenating agent used is preferably a ratio of 1 to 10 times equivalent to the 2-position halogenated alkyl aryl ketone compound.

  Examples of the 2-position halogenated alkyl aryl ketone compound include 2-chloropropiophenone, 2-bromopropiophenone, 2-iodopropiophenone, 2-bromo-2′-chloropropiophenone, 2,3 ′. -Dichloropropiophenone, 2-bromo-3'-chloropropiophenone, 2,4'-dichloropropiophenone, 2-bromo-4'-chloropropiophenone, 2-bromo-2 ', 3'- Dichloropropiophenone, 2-bromo-2 ', 4'-dichloropropiophenone, 2-bromo-2', 5'-dichloropropiophenone, 2 ', 6'-dichloro-2-iodopropiophenone, 2-bromo-3 ', 4'-dichloropropiophenone, 2,3', 5'-trichloropropiophenone, 2-chloro-1'-acetonaphthone 2-bromo-1'-acetonaphthone, 2-iodo-1'-acetonaphthone, 2-chloro-2'-acetonaphthone, 2-bromo-2'-acetonaphthone and 2-iodo-2'-acetonaphthone and the like.

  These 2-position halogenated alkyl aryl ketone compounds can be synthesized by halogenating the 2-position of the alkyl aryl ketone compound. Among the 2-position halogenations, 2-position chlorination and 2-position iodination are possible, but 2-position bromination in which 1 mole of bromine is reacted with 1 mole of alkyl aryl ketone compound is the simplest.

  Examples of the alkyl aryl ketone compound include propiophenone, 2'-chloropropiophenone, 3'-chloropropiophenone, 4'-chloropropiophenone, 2 ', 3'-dichloropropiophenone, 2' 4,4'-dichloropropiophenone, 2 ', 5'-dichloropropiophenone, 2', 6'-dichloropropiophenone, 3 ', 4'-dichloropropiophenone, 3', 5'-dichloropro Piophenone, 1-acetonaphthone and 2-acetonaphthone are mentioned. These are known compounds, and those commercially available as reagents can be used.

  As for the above-mentioned 2-furancarboxamidine, various synthetic methods are known. As shown in the reaction formula (B), 2-furonitrile is reacted with methanol using sodium methoxide as a catalyst, The method of synthesizing 2-furancarboxamidine as hydrochloride by reacting with ammonium chloride is the simplest.

For synthesis of 2- (2-furyl) imidazole compound, 2-furancarboxamidine hydrochloride obtained by the above reaction can be used, but the free form (2-furancarboxamidine) is used. Inorganic acid salts such as hydrobromide and organic acid salts such as acetate can also be used.
Moreover, the said 2-furonitrile is a well-known substance, and what is marketed as a reagent can be used.

  As the dehydrohalogenating agent, known ones can be used without limitation. Examples of such a dehydrohalogenating agent include inorganic alkalis such as sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, triethylamine, 1,8 -Organic bases such as diazabicyclo [5,4,0] -7-undecene (DBU), metal alkoxides such as sodium methoxide and potassium tert-butoxide, and the like.

  As said organic solvent, a well-known thing can be used without a restriction | limiting, if a 2-position halogenated alkyl aryl ketone compound and 2-furan carboxamidine can be melt | dissolved and it does not participate in reaction. Examples of such solvents include alcohols such as isopropyl alcohol and tert-butanol, hydrocarbons such as hexane and toluene, halogenated hydrocarbons such as chloroform and chlorobenzene, esters such as ethyl acetate, and nitriles such as acetonitrile. , Ethers such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, amides such as N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAC), dimethyl sulfoxide (DMSO), and the like. A combination of solvents may be used.

  The reaction temperature is preferably room temperature to reflux temperature, and the reaction time is preferably 1 to 10 hours. The reaction may be usually performed under atmospheric pressure.

The 2- (2-furyl) imidazole compound produced under the above reaction conditions can be isolated by ordinary post-treatment.
For example, the reaction mixture after completion of the reaction can be divided into an aqueous layer and an organic solvent layer, and a crude 2- (2-furyl) imidazole compound that precipitates as crystals can be obtained by washing the organic solvent layer with water. It can be purified by a recrystallization operation or the like.

  This 2- (2-furyl) imidazole compound is used as an active ingredient of a copper antioxidant prepared by dissolving in water. This antioxidant prevents oxidation of the copper surface by forming a chemical conversion film on the surface of copper. The imidazole compound is contained in the antioxidant in a proportion of 0.01 to 10% by weight, preferably in a proportion of 0.1 to 5% by weight. When the content ratio of the imidazole compound is less than 0.01% by weight, the film thickness of the chemical conversion film formed on the copper surface becomes thin, and oxidation of the copper surface cannot be sufficiently prevented. On the other hand, when the amount is more than 10% by weight, the imidazole compound may remain undissolved in the antioxidant or may be reprecipitated even if it is completely dissolved.

  In the practice of the present invention, an organic acid or an inorganic acid is usually used as the acid when the imidazole compound is dissolved (made into an aqueous solution) in water, but a small amount of an organic solvent may be used in combination. Typical organic acids used in this case include formic acid, acetic acid, propionic acid, butyric acid, glyoxylic acid, pyruvic acid, acetoacetic acid, levulinic acid, heptanoic acid, caprylic acid, capric acid, lauric acid, glycolic acid, Glyceric acid, lactic acid, gluconic acid, acrylic acid, methoxyacetic acid, ethoxyacetic acid, propoxyacetic acid, butoxyacetic acid, 2- (2-methoxyethoxy) acetic acid, 2- [2- (2-ethoxyethoxy) ethoxy] acetic acid, 2- {2- [2- (2-Ethoxyethoxy) ethoxy] ethoxy} acetic acid, 3-methoxypropionic acid, 3-ethoxypropionic acid, 3-propoxypropionic acid, 3-butoxypropionic acid, benzoic acid, paranitrobenzoic acid, para Toluenesulfonic acid, salicylic acid, picric acid, succinic acid, succinic acid, maleic acid, fumaric acid, liquor Acid, and adipic acid. Examples of the inorganic acids, hydrochloric acid, phosphoric acid, sulfuric acid, and nitric acid. These acids are contained in the antioxidant in a proportion of 0.1 to 50% by weight, preferably 1 to 30% by weight.

  As the organic solvent, those which are freely miscible with water such as lower alcohols such as methanol, ethanol and isopropyl alcohol or water such as acetone, N, N-dimethylformamide and ethylene glycol are suitable.

To the antioxidant of the present invention, a copper compound can be added in order to increase the formation rate of the chemical conversion film on the surface of copper, and a zinc compound is added to further improve the heat resistance of the formed chemical conversion film. You may do it.
Representative examples of the copper compound include copper acetate, cuprous chloride, cupric chloride, cuprous bromide, cupric bromide, copper iodide, copper hydroxide, copper phosphate, copper sulfate. And copper nitrate.
Representative examples of the zinc compound include zinc oxide, zinc formate, zinc acetate, zinc oxalate, zinc lactate, zinc citrate, zinc sulfate, zinc nitrate, zinc phosphate, etc. What is necessary is just to make it contain in the ratio of 0.01-10 weight% in an agent, Preferably it is a ratio of 0.02-5 weight%.

  In the antioxidant of the present invention, in order to further improve the formation rate of the chemical conversion film and the heat resistance of the film, the halogen compound is added in an amount of 0.001 to 1% by weight, preferably 0.01 to 0% in the antioxidant. .1% by weight can be added. Examples of the halogen compound include sodium fluoride, potassium fluoride, ammonium fluoride, sodium chloride, potassium chloride, ammonium chloride, sodium bromide, potassium bromide, ammonium bromide, sodium iodide, potassium iodide, and ammonium iodide. Etc.

When treating the surface of copper using the antioxidant of the present invention, it is preferable to adjust the pH of the antioxidant. This pH is appropriately set according to the composition (type and content of components) of the antioxidant and the processing temperature and processing time described below.
When lowering the pH, the above-mentioned organic acid or inorganic acid can be used, and when raising the pH, in addition to sodium hydroxide or potassium hydroxide, ammonia or monoethanolamine, diethanolamine, triethanolamine, etc. Substances having a buffering action such as amines can be preferably used.

  As conditions for treating the surface of copper using the antioxidant of the present invention, the liquid temperature of the antioxidant is preferably 10 to 70 ° C., and the contact time is preferably 1 second to 10 minutes. Examples of the contact method include dipping, spraying, and application methods.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. Reference examples 1 and 2 show synthesis examples of 2-bromopropiophenone and 2-furancarboxamidine hydrochloride.

[Reference Example 1]
<Preparation of 2-bromopropiophenone / toluene solution>
To a solution composed of 32.2 g (0.240 mol) of propiophenone and 53 g of methanol, 39.4 g (0.247 mol) of bromine was added dropwise at 50 to 55 ° C. over 50 minutes. Next, the reaction solution was cooled and then concentrated under reduced pressure until the concentrate became 81 g. The concentrate was distributed into 104 g of toluene and 220 g of brine, and the toluene layer was washed with 220 g of brine and dried over sodium sulfate to obtain a colorless and transparent 2-bromopropiophenone (0.240 mol) / toluene solution. It was.

[Reference Example 2]
<Synthesis of 2-furancarboxamidine hydrochloride>
1.7 g (0.074 mol) of metallic sodium was dissolved in 650 ml of dehydrated methanol, and 67.1 g (0.721 mol) of 2-furonitrile was added dropwise over 20 minutes at 24 to 28 ° C. under cooling. After stirring at the same temperature for 2 hours, 42.6 g (0.796 mol) of ammonium chloride was added, followed by stirring at room temperature for 69 hours. Next, insoluble matters in the reaction solution were removed by filtration, the filtrate was concentrated under reduced pressure to 125 g, and the yellow oily concentrate was triturated with hexane three times (150 ml, 100 ml, 100 ml). The resulting solid was dried under reduced pressure to obtain 107.1 g (0.731 mol, yield 101.4%) of 2-furancarboxamidine hydrochloride as a pale yellow green solid.

[Example 1]
<Synthesis of 2- (2-furyl) -5-methyl-4-phenylimidazole>
To a solution consisting of 35.8 g (0.244 mol) of 2-furancarboxamidine hydrochloride and 100 g of N, N-dimethylacetamide, 86.2 g (0.624 mol) of potassium carbonate was added, and the temperature was raised to 52 ° C. over 20 minutes. did. Then, the 2-bromopropiophenone / toluene solution prepared in Reference Example 1 was added dropwise at 52 to 59 ° C. over 1 hour. After completion of dropping, the mixture was stirred at 67 to 69 ° C./2 hours 30 minutes.
Next, the reaction suspension was cooled and then mixed with 1000 ml of water, and the separated toluene layer was washed twice with 800 ml of water and then allowed to stand at room temperature for 15 hours to precipitate a solid. The solid was collected by filtration, dispersed and washed with toluene, and dried under reduced pressure to obtain 61.2 g of a beige solid. The solid was recrystallized from 295 g of acetonitrile and dried under reduced pressure to obtain 34.1 g of milky white powder.

The melting point of the obtained powder, Rf value of thin layer chromatography, ¹ H NMR and mass spectrum data were as follows.
・ Mp183-185 ℃
・ TLC (silica gel, acetone): Rf = 0.61
¹ H NMR (DMSO-d ₆ ): δ = 2.46 (s, 3H), 6.61-7.76 (m, 8H).
MS (EI): m / z (%) = 224 (M ⁺ , 100), 195 (11), 181 (1), 154 (4), 130 (8), 112 (3), 103 (7) , 94 (2), 77 (6).
From these spectral data, the obtained powder was identified as 2- (2-furyl) -5-methyl-4-phenylimidazole represented by the chemical formula (IV). Yield 62.3%.

[Example 2]
<Synthesis of 4- (2,4-dichlorophenyl) -2- (2-furyl) -5-methylimidazole>
First, the 2-bromo-2 ', 4'-dichloropropiophenone / toluene solution was replaced with 2', 4'-dichloropropiophenone in Reference Example 1 in accordance with the method of Reference Example 1 instead of 2 ', 4'-dichloropropiophenone. Was prepared.
Next, a synthesis test was performed in accordance with the method of Example 1 by replacing the 2-bromopropiophenone / toluene solution of Example 1 with a 2-bromo-2 ′, 4′-dichloropropiophenone / toluene solution. A white powder was obtained.

The melting point of the obtained powder, Rf value of thin layer chromatography, ¹ H NMR and mass spectrum data were as follows.
・ Mp230 ℃ (decomposition)
・ TLC (silica gel, acetone): Rf = 0.70
¹ H NMR (DMSO-d ₆ ): δ = 2.17 (s, 3H), 6.61-7.76 (m, 6H).
MS (EI): m / z (%) = 294 (M + 2, 65), 292 (M ⁺ , 100), 257 (9), 242 (2), 222 (4), 193 (2), 172 (3), 164 (4), 147 (4), 136 (4), 128 (2), 111 (4), 102 (2), 94 (4).
From these spectral data, the obtained powder was identified as 4- (2,4-dichlorophenyl) -2- (2-furyl) -5-methylimidazole represented by the chemical formula (V). Yield 54.9%.

Example 3
<Synthesis of 4- (3,4-dichlorophenyl) -2- (2-furyl) -5-methylimidazole>
First, the 2-bromo-3 ', 4'-dichloropropiophenone / toluene solution was replaced with 3', 4'-dichloropropiophenone in Reference Example 1 in accordance with the method of Reference Example 1 instead of 3 ', 4'-dichloropropiophenone. Was prepared.
Subsequently, a synthesis test was performed in accordance with the method of Example 1 by replacing the 2-bromopropiophenone / toluene solution of Example 1 with a 2-bromo-3 ′, 4′-dichloropropiophenone / toluene solution. A light beige powder was obtained.

The melting point of the obtained powder, Rf value of thin layer chromatography, ¹ H NMR and mass spectrum data were as follows.
・ Mp189-190 ℃
・ TLC (silica gel, acetone): Rf = 0.73
¹ H NMR (DMSO-d ₆ ): δ = 2.46 (s, 3H), 6.63-7.89 (m, 6H).
MS (EI): m / z (%) = 294 (M + 2, 64), 292 (M ⁺ , 100), 263 (6), 222 (4), 198 (2), 172 (3), 164 (3), 147 (4), 136 (3), 128 (2), 111 (4), 102 (3), 94 (4).
From these spectral data, the obtained powder was identified as 4- (3,4-dichlorophenyl) -2- (2-furyl) -5-methylimidazole represented by the chemical formula (VI). Yield 72.5%.

Example 4
<Synthesis of 2- (2-furyl) -4- (1-naphthyl) imidazole>
First, a 2-bromo-1′-acetonaphthone / toluene solution was prepared according to the method of Reference Example 1 by replacing the propiophenone of Reference Example 1 with 1-acetonaphthone.
Next, the 2-bromopropiophenone / toluene solution of Example 1 was replaced with a 2-bromo-1′-acetonaphthone / toluene solution, and a synthetic test was performed according to the method of Example 1, and beige fine crystals were obtained. Obtained.

The melting point of the obtained crystal, Rf value of thin layer chromatography, ¹ H NMR and mass spectral data were as follows.
・ Mp181-184 ℃
・ TLC (silica gel, acetone): Rf = 0.68
¹ H NMR (DMSO-d ₆ ): δ = 6.66-8.80 (m).
MS (EI): m / z (%) = 260 (M ⁺ , 100), 231 (8), 204 (6), 167 (37), 152 (6), 139 (12), 127 (5) 115 (4), 94 (3).
From these spectral data, the obtained crystal was identified as 2- (2-furyl) -4- (1-naphthyl) imidazole represented by the chemical formula (VII). Yield 48.4%.

Example 5
First, a 2- (2-furyl) imidazole compound synthesized in Examples 1 to 4 and a copper antioxidant containing 2-phenylimidazole (2PZ, manufactured by Shikoku Kasei Kogyo Co., Ltd.) as an active ingredient are prepared separately. did. Next, a chemical conversion film was formed on the surface of copper by bringing the inhibitor into contact with copper. And the wetting time of the molten solder with respect to copper was measured, and the antioxidant performance to the copper surface on which an imidazole compound acts was evaluated. In this case, it is determined that the shorter the wet time of the molten solder, the better the antioxidant performance of the imidazole compound.
The details of the evaluation test are as follows.
(1) Preparation of antioxidant After dissolving an imidazole compound, an acid, a metal salt, and a halogen compound in ion-exchanged water so as to have the composition shown in Table 1, the pH is adjusted with ammonia water to thereby add an antioxidant. Prepared.
(2) Surface treatment method A test piece (copper plate of 5 mm × 50 mm × 0.3 mm) made of metallic copper is degreased, then soft-etched, and immersed in an antioxidant at a predetermined temperature for a predetermined time to obtain a copper surface. After the chemical conversion film was formed on, it was washed with water and dried.
(3) Measurement of wetting time The surface-treated test piece is immersed in post flux (JS-64MSS, manufactured by Hiroki) and solder wetted using a solder wettability tester (SAT-2000, manufactured by Resuka). Time (seconds) was measured. The solder used was tin-lead eutectic solder (H63A-B20, manufactured by Senju Metal Industry), and the measurement conditions were a solder temperature of 240 ° C., an immersion depth of 2 mm, and an immersion speed of 16 mm / second.
In addition, the test piece which measured the solder wetting time includes (A) a sample immediately after the surface treatment, (B) a sample left in a constant temperature and humidity chamber at a temperature of 40 ° C. and a humidity of 90% RH for 96 hours, and (C ) Further heated at 200 ° C. for 10 minutes.
The test results obtained were as shown in Table 1.

  According to the test results shown in Table 1, the antioxidant containing the 2- (2-furyl) imidazole compound of the present invention as an active ingredient forms a chemical conversion film excellent in moisture resistance and heat resistance on the surface of copper. Therefore, it is useful for preventing oxidation of the copper surface.

  According to the present invention, 2- (2) useful as an antioxidant for the surface of metals, particularly copper (including copper alloys), as a curing agent or curing accelerator for epoxy resins, and as an intermediate material in the field of medicine and agrochemicals. -Furyl) imidazole compounds can be provided. Moreover, the antioxidant which makes the solderability at the time of soldering the copper surface favorable can be provided.

Claims (2)

2- (2-furyl) imidazole compound represented by chemical formula (I) or chemical formula (II).

(In the formula, n represents 0, 1 or 2.)

  A copper or copper alloy antioxidant comprising the 2- (2-furyl) imidazole compound according to claim 1.