Synthesis method of pyrrole[1,2-a]quinoxaline derivative

A synthetic method, 2-a technology, applied in the direction of organic chemistry, etc., can solve the problems of harsh conditions, complex ligands, difficult post-processing, etc.

Active Publication Date: 2013-10-02
NANJING UNIV OF TECH
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

[0005] However, there are some defects in the above-mentioned various methods. The reaction steps are cumbersome, the conditions are harsh, the yield is low, the post-treatment is difficult, complex ligands are required, and some toxic solvents are used, especially some transition metals. Catalyst, high price, strong toxicity and dependence on highly toxic phosphorus-containing ligands severely restrict its industrial application in many fields

Method used

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  • Synthesis method of pyrrole[1,2-a]quinoxaline derivative
  • Synthesis method of pyrrole[1,2-a]quinoxaline derivative
  • Synthesis method of pyrrole[1,2-a]quinoxaline derivative

Examples

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Effect test

Embodiment 1

[0027] This example is the synthesis of pyrrole[1,2-a]quinoxaline, using 2-iodoaniline, pyrrole-2 formaldehyde, potassium tert-butoxide, and dimethyl sulfoxide as raw materials, and the reaction formula is as follows:

[0028]

[0029] Preparation method: add 0.215mmol pyrrole-2 formaldehyde, 0.215mmol 2-iodoaniline, 0.54mmol potassium tert-butoxide into a 25ml eggplant-shaped bottle, then add 1.5ml dimethyl sulfoxide, nitrogen protection, stir at 100°C for 24 hours, the solution The color becomes transparent, and a product is formed.

[0030] The reaction solution was cooled, extracted, dried, distilled under reduced pressure, washed, recrystallized and filtered to obtain a white solid.

[0031] Yield 99%, the melting point of this pyrrole[1,2-a]quinoxaline is 131-133°C; H NMR spectrum (500Hz, CDCl 3 ): δ8.79(s,1H),7.94(d,J=7.95Hz,1H),7.89(s,1H),7.82(d,J=8.15Hz,1H),7.51-7.48(m,1H) ,7.44-7.41(m,1H),6.88-6.86(m,2H); high resolution mass spectrum: m / z(%), calcd for C 11 h ...

Embodiment 2

[0033] This example is the synthesis of pyrrole[1,2-a]quinoxaline, using 2-iodoaniline, pyrrole-2 formaldehyde, potassium tert-butoxide, and dimethyl sulfoxide as raw materials, and the reaction formula is as follows:

[0034]

[0035] Preparation method: Add 0.215mmol pyrrole-2 carboxaldehyde, 0.215mmol 2-iodoaniline, 0.54mmol potassium tert-butoxide to a 25ml eggplant-shaped bottle, then add 1.5ml dimethyl sulfoxide, under argon protection, stir at 100°C for 24 hours , the color of the solution becomes transparent, and a product is formed.

[0036] The reaction solution was cooled, extracted, dried, distilled under reduced pressure, washed, recrystallized and filtered to obtain a white solid.

[0037] Yield 99%, the melting point of this pyrrole[1,2-a]quinoxaline is 131-133°C; H NMR spectrum (500Hz, CDCl 3 ): δ8.79(s,1H),7.94(d,J=7.95Hz,1H),7.89(s,1H),7.82(d,J=8.15Hz,1H),7.51-7.48(m,1H) ,7.44-7.41(m,1H),6.88-6.86(m,2H); high resolution mass spectrum: m / z(%), calcd for C...

Embodiment 3

[0039] This example is the synthesis of pyrrole[1,2-a]quinoxaline, using 2-iodoaniline, pyrrole-2 formaldehyde, potassium tert-butoxide, and dimethyl sulfoxide as raw materials, and the reaction formula is as follows:

[0040]

[0041] Preparation method: add 0.215mmol pyrrole-2 carboxaldehyde, 0.43mmol 2-iodoaniline, 0.54mmol potassium tert-butoxide to a 25ml eggplant-shaped bottle, then add 1.5ml dimethyl sulfoxide, nitrogen protection, stir at 100°C for 24 hours, The color of the solution becomes transparent, and a product is formed.

[0042] The reaction solution was cooled, extracted, dried, distilled under reduced pressure, washed, recrystallized and filtered to obtain a white solid.

[0043] Yield 99%, the melting point of this pyrrole[1,2-a]quinoxaline is 131-133°C; H NMR spectrum (500Hz, CDCl 3 ): δ8.79(s,1H),7.94(d,J=7.95Hz,1H),7.89(s,1H),7.82(d,J=8.15Hz,1H),7.51-7.48(m,1H) ,7.44-7.41(m,1H),6.88-6.86(m,2H); high resolution mass spectrum: m / z(%), calcd for C 11 ...

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Abstract

The invention relates to a synthesis method of a pyrrole[1,2-a]quinoxaline derivative, belonging to the technical field of chemical preparation. The synthesis method is characterized by comprising the following steps of: with 2-halogenated aromatic amine and 2-formylazoles as raw materials, dissolving the 2-formylazoles and the 2-halogenated aromatic amine in a ratio of amount of substances of (1-3):1 into an organic solvent, adding an alkaline medium, stirring the materials for 12-24 hours at 80-100 DEG C under inert gas shielding to react to obtain a pyrrole[1,2-a]quinoxaline derivative and cooling, extracting, drying and distilling the pyrrole[1,2-a]quinoxaline derivative at reduced pressure to obtain the pure product. The method has the beneficial effects that (1) the reaction conditions are more moderate, the catalytic activity is high, the reaction yield is above 90% and can reach 100% at most, the product selectivity is high and the substrate expansion range is wide; and (2) a catalytic system avoids use of compounds of transition metals, especially precious metals, is low in cost and is safe and convenient; and a reaction system produces slight pollution to the environments.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to a synthesis method of pyrrole [1,2-a] quinoxaline derivatives. Background technique [0002] Pyrrole[1,2-a]quinoxaline derivatives are important benzopyrazine heterocyclic compounds with high thermal stability and electron affinity potential energy. The conjugated structure is an important skeleton of many important biologically active compounds, and is also widely used in fluorescent probe materials. The traditional method for synthesizing pyrrole[1,2-a]quinoxaline is to go through two steps: firstly, aryl 1,2-diamine compound and 2,5-diethoxytetrahydrofuran are heated to generate 1 -2-aminophenylpyrrole, then add formic acid, [0003] Heating to reflux for 10-13 hours gave the product with a yield of 28% (Cheeseman et al. Chem. Ind, 1965, 1382.). [0004] In recent years, many literatures have reported the method of synthesizing pyrrole [1,2-a] quinoxaline: For example, Koba...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D487/04C07D471/14C07D487/14
Inventor 韩世清蒋增强张杰童耀何国珍周双利赵丹
Owner NANJING UNIV OF TECH
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