CN101134742A - A kind of synthetic method of 2,2'-biquinoline - Google Patents

Abstract

The present invention relates to a kind of synthesis method of 2,2'-biquinoline, which uses quinoline as shown in formula (II) as raw material and Pd/C as catalyst, in water and polyethylene glycol system solvent, in React at 80-140°C for 4-20 hours, and post-treat the reaction liquid to obtain 2,2'-biquinoline; the mass ratio of polyethylene glycol to water in the water and PEG system solvent is 0.2-2:1; the Pd The Pd loading of the /C catalyst is 1% to 10%; the polyethylene glycol is polyethylene glycol with a molecular weight of 400 to 6000, and the mass ratio of the Pd/C catalyst to quinoline is 0.1 to 1 : 1; the mass ratio of the amount of the water/polyethylene glycol system solvent to quinoline is 3 to 10: 1. The solution of the invention has low cost of raw materials, simple operation, high yield, little environmental pollution and is beneficial to industrialized production.

Description

A kind of synthetic method of 2,2'-biquinoline

(1) Technical field

The present invention relates to a kind of synthetic method of 2,2'-biquinoline.

(2) Background technology

As important organic raw materials, 2,2'-biquinoline and its derivatives are widely used in medicine, detection, optoelectronic materials and other fields. Biquinoline can form a metal complex of a conjugated system with a variety of metals, and has a wide range of applications in the detection and content determination of trace metals. For example, 2,2'-biquinoline, also known as cuprous reagent, reacts with monovalent cupric ions to turn purple, and is a highly selective reagent for the determination of cuprous. Disodium 2,2'-biquinoline-4,4'-dicarboxylate is an excellent protein detection reagent. Biquinoline derivatives, as dopants for organic light-emitting devices, have important application values in photoconduction, photoelectric conversion, photoelectrochemical catalysis, light sensitivity, gas sensitivity, etc., and show good application prospects. With the rapid growth of market demand, its development prospects are broad.

The synthesis of 2,2'-biquinoline has been reported in the literature as follows. Method 1: Grignard reagent of quinoline and haloquinoline undergo nucleophilic substitution reaction under the catalysis of metal complexes such as Ni or Pd to obtain the target product. This method needs to prepare the Grignard reagent of haloquinoline and quinoline from quinoline, and then couple to obtain 2,2'-biquinoline. The operation is complicated and the cost is high. The reaction needs to use a catalyst ligand, which is easy to use. The environment is polluted. Method 2: Using palladium acetate as a catalyst and haloquinoline as a raw material, the target product is obtained through Ullman type reductive coupling reaction. This method also needs to prepare haloquinoline from quinoline first, which increases the production cost; and the catalyst used is relatively expensive and cannot be recycled and reused. Method 3: After mixing o-aminobenzaldehyde and 2-quinolyl methyl ketone in ethanol, potassium hydroxide is added to react to obtain the target product. The raw material cost of this method is higher, and the product purity is lower, which is unfavorable for industrialized production.

The above method of synthesizing 2,2'-biquinoline, or raw material cost is too high, or uses expensive catalyst.

(3) Contents of the invention

The purpose of the present invention is to provide a method for synthesizing 2,2'-biquinoline, especially in the presence of Pd/C catalyst, using H ₂ O/PEG as solvent and quinoline as raw material to efficiently obtain 2, 2'-biquinoline method. The method has low cost of raw materials, simple operation, high yield, little environmental pollution and is beneficial to industrialized production.

The technical scheme adopted in the present invention is as follows:

Using quinoline as shown in formula (II) as a raw material, using Pd/C as a catalyst, in water and a polyethylene glycol system solvent, reacting at 80-140°C for 4-20h, and post-processing the reaction solution to obtain 2,2 '-biquinoline; the mass ratio of polyethylene glycol to water in the water and the PEG system solvent is 0.2 to 2:1; the Pd loading of the Pd/C catalyst is 1% to 10%; the poly Ethylene glycol (PEG) is the PEG of molecular weight 400～6000, and the mass ratio of described Pd/C catalyst mass and quinoline is 0.1～1: 1; The consumption of described water/polyethylene glycol system solvent and The mass ratio of quinoline is 3-10:1.

The reaction equation is as follows:

The mass ratio of water and polyethylene glycol in the water of the present invention and PEG system solvent is preferably 1: 1; The mass ratio of described Pd/C catalyst and quinoline is preferably 0.4: 1; Described water/ The mass ratio of the amount of polyethylene glycol system solvent to quinoline is preferably 6:1.

The polyethylene glycol of the present invention is PEG-400, PEG-600, PEG-1000, PEG-2000, PEG-6000, preferably PEG-400.

The Pd/C catalyst of the present invention preferably has a Pd loading of 5%.

The Pd/C catalyst of the present invention is conveniently synthesized in a manner well known to those skilled in the art, and can be referred to "Preparation, Characterization and Activity Research of Pd/C Catalyst" (Zhang Jianyuan, Kang Baoan. Printing and Dyeing Auxiliaries. 23rd in 2006 Volume 5, No. 34, page 34), or commercially available products.

The reaction temperature in the present invention is preferably 120° C., and the reaction time is preferably 10 h.

The post-treatment steps of the reaction liquid in the present invention are as follows: filter the reaction liquid to obtain a filter residue and a filtrate, extract the filtrate with ethyl acetate, take the ethyl acetate layer and evaporate the solvent to obtain a crude 2,2'-biquinoline, recrystallize, In 2,2'-biquinoline.

The filter residue of the present invention is washed with water to obtain a recovered Pd/C catalyst for reuse.

The method of the present invention is specifically carried out according to the following steps: using quinoline as shown in formula (II) as a raw material, using Pd/C with a Pd loading of 5% as a catalyst, in the ratio of water to polyethylene glycol mass In a 1:1 water and polyethylene glycol system solvent, react at 120°C for 10 h, filter the reaction solution to obtain a filter residue and a filtrate, extract the filtrate with ethyl acetate, take the ethyl acetate layer and evaporate the solvent to obtain 2,2' -The crude product of biquinoline is recrystallized to obtain 2,2'-biquinoline; the filter residue is washed with water to obtain a recycled Pd/C catalyst for reuse; the polyethylene glycol is PEG with a molecular weight of 400, and the Pd/C The mass ratio of catalyst mass to quinoline is 0.4:1, and the mass ratio of the water/polyethylene glycol system solvent to quinoline is 6:1.

Synthetic 2 of the present invention, the beneficial effect of 2 '-biquinoline method is mainly reflected in:

(1) With quinoline as raw material, the cost is low, side reactions are few, and unreacted quinoline can be recycled.

(2) Using water/PEG as solvent, no pollution, simple post-treatment, high product yield and purity.

(3) Using low-priced Pd/C as a catalyst can be recycled and reused, and the yield does not decrease, the cost is low, and the impact on the environment is small.

(4) Specific implementation methods

The present invention will be further described below through specific examples, but the protection scope of the present invention is not limited thereto.

The 1%, 5%, and 10% Pd/C catalysts used in the following examples are all products produced by Chengdu Kelong Chemical Reagent Factory.

Example 1

Add H ₂ O (5.0g), PEG-400 (1.0g), quinoline (1.0g) successively in a 50mL round bottom flask, stir well, add 1% Pd/C catalyst (0.1g) at 80°C After reacting for 20 hours, the reaction solution was cooled and suction filtered, and the filter cake Pd/C was washed with water, which could be recovered and reused; the filtrate was extracted with ethyl acetate, the solvent was evaporated, concentrated, and crystals were precipitated to obtain a crude product, which was recrystallized to obtain white 2, 0.12 g of 2'-biquinoline crystals, yield 11.9%, melting point 196-197°C. ¹ H NMR (400MHz, CDCl ₃ ) δppm: 8.86(d, 2H, J=8.1Hz), 8.34(d, 2H, J=8.6Hz), 8.25(dd, 2H, J=2.4Hz), 7.89(dd , 2H, J=7.0Hz), 7.59 (m, 2H), 7.77 (m, 2H); ¹³ C NMR (CDCl ₃ ) δppm: 152, 147.5, 137, 129.5, 128.0, 127.5, 127.0, 119.0; MS ( EI): m/z (%): 256 (100) [M ⁺ ], 128 (30), 101 (13).

Example 2

Add H ₂ O (1.0g), PEG-1000 (2.0g), quinoline (1.0g) successively in a 50mL round bottom flask, stir well, then add 10% Pd/C catalyst (0.4g) at 140°C After reacting for 15 hours, the reaction liquid was cooled and suction filtered, and the filter cake Pd/C was washed with water, which could be recovered and reused; the filtrate was extracted with ethyl acetate, the solvent was evaporated, concentrated, and crystals were precipitated to obtain a crude product, which was recrystallized to obtain a white crystal of 0.53 g, yield 52.6%.

Example 3

Add H ₂ O (3.0g), PEG-400 (3.0g), quinoline (1.0g) successively in a 50mL round bottom flask, stir well, then add 5% Pd/C catalyst (1.0g) at 120°C After reacting for 4 hours, the reaction solution was cooled and suction filtered, and the filter cake Pd/C was washed with water, which could be recycled and reused; the filtrate was extracted with ethyl acetate, the solvent was evaporated, concentrated, and crystals were precipitated to obtain a crude product, which was recrystallized to obtain a white crystal of 0.58 g, yield 57.6%.

Example 4

Add H ₂ O (5.0g) and PEG-6000 (5.0g) to a 50mL round bottom flask in turn, heat to 90°C, add quinoline (1.0g) after the PEG-6000 is completely melted, stir well, then add 5% The Pd/C catalyst (0.4g) was reacted at 130°C for 10h, the reaction liquid was cooled and suction filtered, and the filter cake Pd/C was washed with water, which could be recycled and reused; the filtrate was extracted with ethyl acetate, the solvent was evaporated, concentrated, and crystals were precipitated , the crude product was obtained, and recrystallized to obtain 0.48 g of white crystals, with a yield of 47.6%.

Example 5

Add H ₂ O (3.0g), PEG-400 (3.0g), quinoline (1.0g) successively in a 50mL round bottom flask, stir well, add 5% Pd/C catalyst (0.4g) at 120°C After reacting for 10 hours, the reaction solution was cooled and suction filtered, and the filter cake Pd/C was washed with water, which could be recycled and reused; the filtrate was extracted with ethyl acetate, the solvent was evaporated, concentrated, and crystals were precipitated to obtain a crude product, which was recrystallized to obtain a white crystal of 0.61 g, yield 60.5%.

Claims (9)

1. a kind of 2 as shown in formula (I), the synthetic method of 2'-biquinoline is characterized in that taking quinoline as shown in formula (II) as raw material, with Pd/C as catalyzer, in water and polyethylene glycol system solvent, react at 80-140 °C for 4-20 hours, and the reaction liquid is post-treated to obtain 2,2'-biquinoline; in the water and polyethylene glycol system solvent, polyethylene glycol and water The mass ratio of the Pd/C catalyst is 0.2～2:1; the Pd loading amount of the Pd/C catalyst is 1%～10%; The mass ratio of phenoline is 0.1-1:1; the mass ratio of the amount of the water/polyethylene glycol system solvent to quinoline is 3-10:1.

2. a kind of 2 as claimed in claim 1, the synthetic method of 2 '-biquinoline is characterized in that the mass ratio of polyethylene glycol and water in described water and polyethylene glycol system solvent is 1: 1; The mass ratio of the Pd/C catalyst mass to quinoline is 0.4:1; the mass ratio of the water/polyethylene glycol system solvent to quinoline is 6:1. 3. a kind of 2 as claimed in claim 1, the synthetic method of 2'-biquinoline is characterized in that described polyethylene glycol is PEG-400, PEG-600, PEG-1000, PEG-2000, PEG -6000. 4. a kind of 2 as claimed in claim 1, the synthetic method of 2'-biquinoline is characterized in that described polyethylene glycol is PEG-400. 5. a kind of 2 as claimed in claim 1, the synthetic method of 2'-biquinoline is characterized in that described Pd/C catalyst Pd loading capacity is 5%. 6. a kind of 2 as claimed in claim 1, the synthetic method of 2'-biquinoline is characterized in that described reaction temperature is 120 ℃, and described reaction times is 10h. 7. a kind of 2 as claimed in claim 1, the synthetic method of 2'-biquinoline is characterized in that described reaction solution aftertreatment step is: reaction solution is filtered, obtain filter residue and filtrate, and filtrate is extracted with ethyl acetate , take the ethyl acetate layer and evaporate the solvent to obtain crude 2,2'-biquinoline, which is recrystallized to obtain 2,2'-biquinoline. 8. a kind of 2 as claimed in claim 1, the synthetic method of 2'-biquinoline is characterized in that described filter residue is through washing, must reclaim Pd/C catalyst and reuse. 9. a kind of 2 as claimed in claim 1, the synthetic method of 2'-biquinoline is characterized in that, with the quinoline shown in formula (II) as raw material, be the Pd of 5% with Pd carrying capacity /C is a catalyst, in the water and polyethylene glycol system solvent with a mass ratio of water and polyethylene glycol of 1:1, react at 120°C for 10h, filter the reaction solution to obtain filter residue and filtrate, and use ethyl acetate to obtain the filtrate extraction, taking the ethyl acetate layer and evaporating the solvent to obtain crude 2,2'-biquinoline, which was recrystallized to obtain 2,2'-biquinoline; the filter residue was washed with water to obtain a recovered Pd/C catalyst for reuse; the polymer Ethylene glycol is the polyethylene glycol of molecular weight 400, and the mass ratio of described Pd/C catalyst quality and quinoline is 0.4: 1, the consumption of described water/polyethylene glycol system solvent and the mass ratio of quinoline It is 6:1.