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Preparation method of 2,3,5,6-tetra-substituted symmetric pyridine

A technology of tetrasubstituted and pyridine, which is applied in the field of preparation of 2,3,5,6-tetrasubstituted symmetrical pyridine, can solve the problems of unavailable raw materials, narrow range of substrates, not economical and green, etc. Effects with a wide range and high compatibility

Active Publication Date: 2017-09-05
ZHENGZHOU UNIVERSITY OF LIGHT INDUSTRY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the reaction requires stoichiometric copper salt and iodine, which is not economical and green enough, and the 2-position substituent of pyridine can only be an aryl group
Therefore, based on the previous synthetic methods, we found that these methods generally have disadvantages such as unavailable raw materials, narrow substrate scope, and not being economical or green enough.

Method used

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  • Preparation method of 2,3,5,6-tetra-substituted symmetric pyridine
  • Preparation method of 2,3,5,6-tetra-substituted symmetric pyridine
  • Preparation method of 2,3,5,6-tetra-substituted symmetric pyridine

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Experimental program
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Effect test

Embodiment 1

[0014]

[0015] Add 1a (4mmol, 464mg), cuprous oxide (0.4mmol, 57mg), tert-butyl hydroperoxide (8mmol, 70% aqueous solution, 1.2mL), ammonium acetate (8mmol, 616mg) and DMA (10mL) into the reaction flask , And then heated and reacted at 120°C for 24 hours. After the reaction is completed, it is quenched with saturated sodium sulfite solution, and then extracted with ethyl acetate. The organic phases are combined and dried with anhydrous sodium sulfate. After concentration, the product 2a can be obtained by column chromatography with a mixed solvent of petroleum ether and ethyl acetate. The yield was 82%. White solid, Mp: 100-101℃; 1 H NMR(600MHz, CDCl 3 ): δ8.71(s,1H), 3.93(s,6H), 2.86(s,6H); 13 C NMR(150MHz, CDCl 3 ): δ166.2, 162.6, 141.0, 122.6, 52.3, 24.9.

Embodiment 2

[0017]

[0018] Add 1b (4mmol, 520mg), cuprous oxide (0.4mmol, 57mg), tert-butyl hydroperoxide (8mmol, 70% aqueous solution, 1.2mL), ammonium acetate (8mmol, 616mg) and DMA (10mL) into the reaction flask , And then heated at 120°C for 24 hours. After the reaction is completed, it is quenched with saturated sodium sulfite solution, and then extracted with ethyl acetate. The organic phases are combined and dried with anhydrous sodium sulfate. After concentration, the product 2b is obtained by column chromatography with petroleum ether and ethyl acetate mixed solvent. The yield was 79%. Light yellow solid, Mp: 67-68°C; 1 H NMR(600MHz, CDCl 3 ): δ8.68(s,1H), 4.40(q,J=7.2Hz,4H), 1.42(t,J=7.2Hz,6H); 13 C NMR(150MHz, CDCl 3 ): δ165.9, 162.2, 140.9, 123.0, 61.4, 24.9, 14.2.

Embodiment 3

[0020]

[0021] Add 1c (4mmol, 632mg), cuprous oxide (0.4mmol, 57mg), tert-butyl hydroperoxide (8mmol, 70% aqueous solution, 1.2mL), ammonium acetate (8mmol, 616mg) and DMA (10mL) into the reaction flask , And then heated at 120°C for 24 hours. After the reaction is completed, it is quenched with saturated sodium sulfite solution, and then extracted with ethyl acetate. The organic phases are combined and dried with anhydrous sodium sulfate. After concentration, column chromatography is performed with a mixed solvent of petroleum ether and ethyl acetate to obtain product 2c. The yield was 72%. Yellow liquid 1 H NMR(600MHz, CDCl 3 ): δ8.74(s,1H), 4.12(d,J=6.0Hz,4H), 2.87(s,6H), 2.10(m,J=6.6Hz,2H), 1.04(d,J=7.2Hz ,12H); 13 C NMR(150MHz, CDCl 3 ):δ165.8,162.3,141.0,122.9,71.4,27.7,25.0,19.2; HRMS(ESI):calcd for C 17 H 26 NO 4 [M+H] + 308.1856,found308.1861.

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Abstract

The invention discloses a preparation method of 2,3,5,6-tetra-substituted symmetric pyridine. Specifically, the symmetric 2,3,5,6-tetra-substituted pyridine is prepared by taking beta-ketonic ester as a reaction substrate, a metal copper compound as a catalyst, a peroxide reagent as an oxidizing agent, inorganic ammonium salt as a nitrogen source and N-methylformamides as an organic solvent (also as a carbon source) and through carbon-hydrogen and carbon-nitrogen removal, dehydration condensation and an oxidation aromatization reaction. The preparation method disclosed by the invention has the characteristics of easily available raw materials, cheap and low-toxic catalyst, high catalytic efficiency, wide substrate range, simple and convenient operation, greenness and environmental friendliness and the like.

Description

Technical field [0001] The invention relates to a preparation method of 2,3,5,6-tetrasubstituted symmetric pyridine. Background technique [0002] Pyridine is a very important and valuable nitrogen-containing heterocyclic compound in natural products, functional materials and medicinal chemistry. In particular, polysubstituted symmetric pyridines can be used as fungicides and herbicides due to their good biological activity. In addition, symmetric pyridines can also be used as nitrogen ligands in transition metal-catalyzed organic reactions. [0003] Traditional methods generally synthesize 2,3,5,6-tetrasubstituted symmetrical pyridines through condensation and oxidative aromatization of 1,3-dicarbonyl compounds, formaldehyde and inorganic ammonium salts (J.-J.Xia and G. -W. Wang, Synthesis, 2005, 2379; M. Nasr-Esfahani, B. Karami and M. Behzadi, J. Heterocyclic Chem., 2009, 46, 931; S. Chen, MSHossain and FWFoss, ACS Sustain. Chem. Eng., 2013, 1, 1045; HT Abdel-Mohsen, J. Conra...

Claims

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Application Information

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IPC IPC(8): C07D213/803
CPCC07D213/803
Inventor 闫溢哲李弘毅杨留枝刘延奇李政崔尚牛斌史苗苗周亚萍刘华玲
Owner ZHENGZHOU UNIVERSITY OF LIGHT INDUSTRY
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