Method for synthesis of pyrrolo[1,2-a]quinoxaline derivatives

A 2-a, quinoxaline technology, applied in the field of synthesizing pyrrole [1,2-a] quinoxaline derivatives, can solve the problems of harsh conditions, complex substrates restricting industrial application, high price and the like

Inactive Publication Date: 2013-10-09
NANJING UNIV OF TECH
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Problems solved by technology

[0004] However, there are some defects in the above-mentioned various methods, the reaction steps are more loaded down with trivial details, the conditions are harsher, the yield is lower, the post-treatment is more difficult, the use of some toxic solvents, especially the need for complex ligands, high price, Strong toxicity and dependence on complex substrates severely restrict its industrial application in many fields

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  • Method for synthesis of pyrrolo[1,2-a]quinoxaline derivatives
  • Method for synthesis of pyrrolo[1,2-a]quinoxaline derivatives
  • Method for synthesis of pyrrolo[1,2-a]quinoxaline derivatives

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Embodiment 1

[0028] This embodiment is the synthesis of pyrrole [1,2-a] quinoxaline, with 2-iodoaniline, pyrrole-2 formaldehyde, K 3 PO 4 , CuI, dimethylformamide, and 2,2-bipyridine are raw materials, and the reaction formula is as follows:

[0029]

[0030] Preparation method: Add 0.215mmol pyrrole-2 carboxaldehyde, 0.215mmol 2-iodoaniline, 0.645mmol K to a 25ml eggplant-shaped bottle 3 PO 4 , 0.0215mmol CuI, 0.043mmol 2,2-bipyridine, and then add 1.5ml dimethylformamide, nitrogen protection, stirring at 110°C for 20 hours, the color of the solution becomes transparent, and a product is formed.

[0031] The reaction solution was cooled, extracted, dried, distilled under reduced pressure, washed, recrystallized and filtered to obtain a white solid.

[0032] The yield is 89%, and 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(...

Embodiment 2

[0034] This embodiment is the synthesis of pyrrole [1,2-a] quinoxaline, with 2-iodoaniline, pyrrole-2 formaldehyde, K 3 PO 4 , CuI, dimethylformamide, and 2,2-bipyridine are raw materials, and the reaction formula is as follows:

[0035]

[0036] Preparation method: Add 0.215mmol pyrrole-2 carboxaldehyde, 0.215mmol 2-iodoaniline, 0.645mmol K to a 25ml eggplant-shaped bottle 3 PO 4 , 0.0215mmol CuI, 0.043mmol 2,2-bipyridine, and then add 1.5ml dimethylformamide, under argon protection, and stir at 110°C for 20 hours, the color of the solution becomes transparent, and a product is formed.

[0037] The reaction solution was cooled, extracted, dried, distilled under reduced pressure, washed, recrystallized and filtered to obtain a white solid.

[0038] The yield is 89%, and 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....

Embodiment 3

[0040] This embodiment is the synthesis of pyrrole [1,2-a] quinoxaline, with 2-iodoaniline, pyrrole-2 formaldehyde, K 3 PO 4 , CuI, dimethylformamide, and 2,2-bipyridine are raw materials, and the reaction formula is as follows:

[0041]

[0042] Preparation method: Add 0.215mmol pyrrole-2 carboxaldehyde, 0.215mmol 2-iodoaniline, 0.645mmol Cs into a 25ml eggplant-shaped bottle 2 CO 3 , 0.0215mmol CuI, 0.043mmol 2,2-bipyridine, and then add 1.5ml dimethylformamide, nitrogen protection, stirring at 110°C for 20 hours, the color of the solution becomes transparent, and a product is formed.

[0043] The reaction solution was cooled, extracted, dried, distilled under reduced pressure, washed, recrystallized and filtered to obtain a white solid.

[0044] The yield is 80%, and 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....

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Abstract

The invention relates to a method for synthesis of pyrrolo[1,2-a]quinoxaline derivatives and belongs to the technical field of chemical preparation. The method comprises the following steps that 2-halogenated arylamine and a 2-formyl azole compound as raw materials are weighed according to a mole ratio of 1-2: 1; the weighed raw materials are dissolved in an organic solvent; a transition metal salt, a ligand and an alkaline medium are added into the solution; the mixed solution undergo a reaction in an inert gas protective atmosphere at a temperature of 100-110 DEG C with stirring for 15-20h to produce the pyrrolo[1,2-a]quinoxaline derivative; and the pyrrolo[1,2-a]quinoxaline derivative is subjected to cooling, extraction, drying and reduced pressure distillation to form a pure product. The method for synthesis of the pyrrolo[1,2-a]quinoxaline derivatives has the advantages that 1, reaction conditions are mild, catalytic activity is high, a reaction yield is high and can reach to 90%, product selectivity is high, and a substrate expanding rang is wide; and 2, through a catalysis system, an expensive ligand is avoided, a reaction temperature is reduced, a cost is low, safety and convenience are obtained, and the pollution produced by the reaction system on the environment is low.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to a method for synthesizing 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 of synthesizing pyrrole [1,2-a] quinoxaline derivatives is through two steps: first, the aryl 1,2-diamine compound and 2,5-diethoxytetrahydrofuran are heated Generate 1-2-aminophenylpyrrole, then add formic acid, heat and reflux for 10-13h to obtain the product, the yield is 28% (Cheeseman et al. Chem. Ind, 1965, 1382.). [0003] In recent years, many literatures have reported methods for synthesizing pyrrole[1,2-a]quinoxaline derivatives: For example, Kob...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D487/04C07D471/14
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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