DD299059A5 - PROCESS FOR PREPARING 2- (2'-HYDROXYARYL-) 1H-IMIDAZOLE DERIVATIVES - Google Patents

Abstract

The invention relates to a process for the preparation of * the general formula {hydrometallurgy; selective extractant; * * aromatic aldehydes; a-oximinoketones}

Description

For this 1 page formulas

Field of application of the invention

The invention relates to a process for the preparation of 2- (2'-hydroxyaryl) -1H-imidazole derivatives, which can be used in hydrometallurgy in the liquid-liquid extraction as an extractant for the 3d metals, preferably copper.

Characteristic of the known state of the art

1 H-imidazole-N (3) oxides have been prepared by Diels and co-workers (Berisch., Ges. Ges. 51 [1918] 965) by condensation of a-oximinoketonen with aldehydes in the presence of ammonia or with aldimines. This synthesis principle was described by Allen, F.J., and Allen, G.G. (Chem. Ind., London 44 (1964) 1837) and Lettau, H. (Z. Chem., 10 [1970] 338), where the preparation of 2- (2'-hydroxyaryl) -1H-imidazole N-oxides are not known according to the abovementioned synthesis principle, but also the conversion of these 2- (2'-hydroxyaryl) -1H-imidazole N-oxides into the 2- (2'-hydroxyaryl) -1H-imidazoles Reduction is unknown.

Ziol of the invention

The aim of the invention is to develop easily producible and therefore cheap new extractant for copper.

Explanation of the essence of the invention

The invention has for its object to develop a process for the preparation of chelates forming copper ions, readily soluble in organic solvents using the technicch easily accessible α-oximinoketones.

According to the invention the technical object is achieved in that α-Oximinoketone with a 2-Hydroxyaryla! Dehyde in an equimolar ratio in a suitable solvent, preferably ethanol, in the presence of A ^ nonia. "At temperatures of 60-100 ⁰ C and reaction times of 0 , 25-2 hours to 2- (2'-hydroxyaryl) -1H-imidazole N-oxides of the general formula (X = N ⁺ -O-)

R ¹ = alkyl, phenyl, subst. Phenyl, such as alkyl phenyl. Alkoxy phenyl

R ² = H, alkyl, phenyl

R = H, hydroxy, nitro, alkyl, alkoxy, halogen

X = N ₁ N ⁺ -O-

and the 2- (2'-hydroxyaryl) -1H-imidazole N-oxides are optionally reduced to the corresponding 2- (2'-hydroxyaryl) -1H-imidazole (X = N).

The α-oximinoketones can be used in the form of the isolated pure products, but also in the form of the product mixtures of the a-oximation (isonitrogenation) of phenylalkyl ketones or nuclear-substituted phenylalkyl ketones. For example, the product mixtures or isolated α-oximinoketones can be prepared from the reaction of ketones such as phenylmethylketone, phenylethylketone, phenylpropylketone, phenylpentylketone, etc., or 4-methylphenylpentylketone, 4-ethylphenylpentylketone, 4-isopropylphenylketone, etc., with alkylnitrites in the presence of hydrogen chloride or other a-Oximierungsreagenzien be used. Suitable aldehydes are 2-hydroxy-substituted aromatic aldehydes, such as. Salicylaldehyde (2-hydroxybenzaldehyde), 2-hydroxy-1-naphthaldehyde, o-vanillin (2-hydroxy-3-methoxybenzaldehyde) and others. The ammonia is advantageously used in the form of organic ammonium salts, preferably ammonium acetate. The precipitated from the hot reaction solution or after cooling or after removal of the solvent crude product is purified by recrystallization.

The 2- (2'-hydroxyaryl) -1H-imidazole N-oxides can be converted by reduction into the corresponding 2- (2'-hydroxyaryl-) -1H-imidazoles. In this case, the 2- (2'-hydroxyaryl) -1-imidazole N-oxides in the form of the purified compound or as a crude product with the system Fe / glacial acetic acid (acetic acid) or Zn / glacial acetic acid at room temperature to 100 ⁰ C. The reduction can also be done with other conventional reduction systems. After separation of the inorganic constituents, the reaction mixture is diluted with water and the resulting 2- (2'-hydroxyaryl) -1 H-imidazole purified by recrystallization.

The 2- (2'-hydroxyaryl) -1H-imidazoles have better solubility than the corresponding 2- (2'-hydroxyaryl) -1H-imidazole N-oxides in common organic solvents, such as benzene, toluene and chloroform, on.

The 2- (2'-hydroxyaryl) -1H-imidazole derivatives prepared by the process according to the invention are well suited for the liquid-liquid extraction of the 3d metals, in particular copper. They show z. B. in the pH range of 4-6.5 a strong selectivity of extraction for copper over cobalt, nickel and zinc.

embodiment

By the process of the invention, the compounds listed in Table 1 were prepared analogously to Example 1,2,3 or 4. The values of the elemental analysis agree with the calculated values within the usual tolerances of ± 0.3%

 The invention will be explained in more detail with reference to the following β examples:

Example 1 (route A)

2- (2'-hydroxy-3'-methoxyphenyl) -4-methyl-5-phenyl-1H-imidazole N-oxide is prepared by dissolving 0.1 mol of 1-phenylpropane-1,2-dione-2 oxime, 0.1 mol of ortho-vanillin and 20 g of ammonium acetate dissolved in 100 ml of ethanol and heated to boiling for 2 hours at reflux. After cooling, the solvent is removed and the resulting solid is recrystallized from ethyl acetate. Based on analytically pure substance was 2- (2'-hydroxy-3'-methoxyphenyl) -4-methyl-5-phenyl-1 H-imidazole N-oxide in a yield of 80% d. Th. Obtained with a melting point of 190-195 ⁰ C.

Example 2 (route B)

2- (2 '• Hydroxyphenyl) -4-butyl-5- (4'-ethylphenyl) -1H-imidazole N-oxide is prepared by dissolving to the product mixture the a-oximation of 0.1 mol of 4-ethylphenyl pentyl ketone in 100 ml of ethanol, 0.1 mol of salicylaldehyde and 20 g of ammonium acetate and heated to reflux for 2 hours. After cooling and removal of the volatiles in vacuo, the residual solid is recrystallized from butyl acetate. Based on the ketone used, the yield of 2- (2'-hydroxyphenyl) -4-butyl-5- (4'-e * .hylphenyl) -1H-imidazole N-oxide is 60% of theory. with a melting point of 199-2Ü1 ° C.

Example 3 (Route C)

2- (2'-Hydroxyphenyl) -4-methyl-5-phenyl-1H-imidazole is prepared by dissolving 10 g of 2- (2'-hydroxyphenyl) -4-methyl-5-phenyl-1H-imidazole-N- oxide dissolved in 100 ml of glacial acetic acid and treated portionwise with 10.5 g of Fe powder, with a stormy gas evolution sets in and the reaction mixture turns red violet. The mixture is then heated for 30 minutes at 100 ⁰ C, filtered from the inorganic constituents of the hot reaction solution and allowed to cool the reaction mixture, wherein a portion of the target product precipitates as a solid. Additional product is obtained after dilution of the reaction mixture with water. The resulting 2- (2'-hydroxyphenyl) -4-methyl-5-phenyl-1 H-imidazole is recrystallized from methanol (melting point 220 to 221 ⁰ C) and in a yield of 90% d. Th. Received.

Example 4 (route D)

2- (2'-Hydroxyphenyl) -4-decyl-5-phenyl-1H-imidazole is prepared by adding to the product mixture of the a-oximation of 0.1 mol Phenylundecylketon dissolved in 100mi of ethanol, 0.1 mol of salicylaldehyde and 20g Ammonium acetate and refluxed for 2 hours to boiling. After cooling and removal of the solvent, the product mixture is dissolved in 100 g of glacial acetic acid, mixed with 33 g of Zn dust and then heated to 100 ° C. After 3 hours, the inorganic constituents are separated by filtration of the hot solution and, after cooling, the reaction mixture is neutralized with aqueous ammonia. This separates a viscous oil, which is then purified by column chromatography on neutral Al ₂ O ₃ with toluene or a mixture of toluene / heptane (50:50) as eluent. The product thus obtained is recrystallized from n-heptane. Based on the ketone used was analytically pure 2- (2'-hydroxyphenyl) -4-decyl-5-phenyl-1 H-imidazole in a yield of 35% d. Th. Obtained with a melting point of 80-81 ⁰ C.

Example 5

A synthetic mixture of copper, cobalt, nickel and zinc sulfate having a total concentration of 0.02 mol / l, with a single concentration of each metal salt of 0.005 mol / l, is mixed with a 0.05 M solution of 2- (2 '-Hydroxyphenyl) -4-butyl-5- (4'-ethylphenyl) -1H-imidazole N-oxide in chloroform in the phase ratio Vw ,, _Mt / V ₀ , _g = 1/1 extracted. In this case, at pH = 5.2Cu to 70% compared to Zn <5%, Co and Ni <3% transferred to the organic phase.

Examples

A synthetic mixture of copper, cobalt, nickel and zinc sulfate having a total kerate concentration of 0.02 mol / l, at a single concentration of each metal salt of 0.005 mol / l each, is mixed with a 0.05 M solution of 2- (2 '-Hydroxyphenyl) -4-decyl-5-phenyl-1H-imidazole in chloroform in the phase ratio Vw «ii (, _t / V ₀ , g. = 1/1 extracted, at pH = 6.2Cu quantitative and Zn <10%, Ni <5%, Co <3% transferred to the organic phase.

Table 1: 2- (2'-Hydroxyaryl) -1H-imidazole derivatives of the general formula

OH

No. (way) R ¹ R ² R X Mp ( ⁰ C) yield (LM) (% D.Th.) KA) me C ₆ H ₆ H N ⁺ -O " 258-261 87 (EtOH) 2 (A) C ₆ H ₆ H H N ⁺ -O " 225-228 25 (MeOH) 3 (A) C ₆ H ₅ me H N ⁺ -O- 234-236 82 (BuOAc) 4 (A) C ₆ H ₅ me 3-OMe N ⁺ -O " 199-201 58 (MeOH) 5 (B) C ₆ H ₅ et H N ⁺ -O " 242-245 50 (MeOH) 6 (B) C ₆ H ₅ C ₄ H ₉ H N ⁺ -O " 258-261 75 (EiOAc) 7 (B) C ₆ H ₆ C ₆ H ₁₃ H N ⁺ -O " 131-133 ' ¹ 30 (Ether) 8 (A) 4-Me-C ₆ H ₄ me H N ⁺ -O " 221-222 83 (MeOH) 9 (B) 4-Me-C ₆ H ₄ C ₄ Hg H N ⁺ -O " 213-215 57 (MeOH) 10 (B) 4-Et-C ₆ H ₄ C ₄ Hg H N ⁺ -O " 199-201 60 (BuOAc) 1KB) 4-1-Pr-C ₆ H ₄ C ₄ H ₉ H N ⁺ -O- 161-165 40 (MeOH) 12 (B) C ₆ H ₅ CeH π H N ⁺ -O " oil 70 13 (B) C ₆ H ₅ C10H21 H N ⁺ -O " oil 70 14 (A) C ₆ H ₅ me 4-OH N ⁺ -O " > 230 (Z) 60

3) is present as monohydrate

Table 1: 2- (2'-Hydroxyaryl) -1H-imidazole derivatives of the general formula

No. (way)

R ¹

Fp- ( ⁰ C) (LM)

Yield (% of theory)

15 (A) C ₆ H ₆ me C ₄ H ₄ "' N ⁺ -CT 243-245 (Z) 75 (EtOH) 16 (A) C "H" O ₂ ^cl C10H21 H N ⁺ -CT 159-165 80 (EtOAc) 17 (C) C ₆ H ₆ me H N 220-221 90 (MeOH) 18 (D) cehs C10H21 H N 80-81 35 (N-heptane) 19 (C) C ₆ H ₅ et H N 184-186 90 (EtOH)

b) 5,6-fused benzene ring, used aldehyde: 2-hydroxy-1-naphthaldehyde

c) (5'-methyl-2'-phenylcarbonyloxy) -phenyl radical

- S "-

HN

OH

Claims (5)

1. A process for the preparation of 2- (2'-hydroxyaryl) -1H-imidazole derivatives of the general formula R ¹ = alkyl, phenyl, subst. Phenyl, such as alkylphenyl, alkoxyphenyl R ² = H, alkyl, phenyl R = H, hydroxy, nitro, alkyl, alkoxy, halogen X = N, N ⁺ -O- characterized in that α-Oximinoketone be reacted with a 2-hydroxyarylaldehyde in a suitable solvent in the presence of ammonia at temperatures of 60-100 ⁰ C and a reaction time of 0.25-2 Stuffden and the reaction product is optionally subjected to reduction. 2. The method according to claim 1, characterized in that a-oximinoketone and 2-hydroxyarylaldehyde are used in equimolar ratio. 3. The method according to claim 1, characterized in that the a-Oximinoketone in the form of the isolated pure products, but also in the form of the product mixtures of the a-oximation (isonitrosation) of phenylalkyl ketones or nuclear-substituted phenylalkyl ketones, are used. 4. The method according to claim 1, characterized in that the ammonia in the form of organic ammonium salts, preferably ammonium acetate, is used. 5. The method according to claim 1, characterized in that the reaction product is reduced in gereinigtsr form or as a crude product with the system Fe / glacial acetic acid or Zn / glacial acetic acid at temperatures of 20 to 100 ⁰ C.