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

Abstract

The invention relates to a synthesis method of a pyrrole [1,2a] quinoxaline derivative. The method comprises the steps: dissolving a cuprous complex, 2-bromoaniline, a pyrrole formaldehyde compound and an alkali in an organic solvent, carrying out a reaction, and carrying out separation and purification to obtain the pyrrole[1,2a] quinoxaline derivative, wherein the molar ratio of the cuprous complex to the 2-bromoaniline to the pyrrole formaldehyde compound to the alkali is (0.01-0.03): 1.0: 1.0: 1.5, the reaction temperature is 50-65 DEG C, and the reaction time is 6-8 hours. Compared with the prior art, the method has the advantages of mild reaction conditions, high yield, high substrate universality, less waste and the like.

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 is the backbone structure of many natural product molecules and bioactive molecules, and is widely used in biochemistry, medicinal chemistry, and materials science. [0003] With the continuous development of the field of transition metal catalysis, research on copper catalysts has attracted the most attention. As reported in 2008, pyrrole[1,2-a]quinoxaline derivatives were synthesized by CuI-catalyzed coupling reaction, which requires the hydrolysis of trifluoroacetyl groups and the formation of intermolecular amino compounds; in 2010, the Reeves group reported A copper-catalyzed synthesis of pyrrole[1,2-a]quinoxaline was developed. This system avoids the use of complex substrates, but the reaction requires a higher temperature (130°C), and the structure of the...

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Problems solved by technology

As reported in 2008, pyrrole[1,2-a]quinoxaline derivatives were synthesized by CuI-catalyzed coupling reaction, which requires the hydrolysis of trifluoroacetyl groups and the formation of intermolecular amino compounds; in 2010, the Reeves group reported A copper-catalyzed synthesis of pyrrole[1,2-a]quinoxaline was developed. This system avoids the use of complex substrates, but the reaction requires a higher temperature (130°C), and the structure of the ligand used in the reaction is complex. , expensive; the Valerie group used iron-catalyzed reduction of aryl nitro groups and aerobic oxidation of ethanol to construct pyrrole[1,2-a]quinoxaline derivatives; this system requires nitrobenzene with pyrrole substituents in the ortho position The participation of this complex substrate; the scope of substrate application is not wide enough; in 2013; Ma Chen group reported the use of copper acetate in the air to catalyze N-sulfonyl-2-haloaniline compounds with 2-(chloromethyl)- Synthesis of pyrrole[1,2-a]quinoxaline derivatives from 1H-benzo[d]imidazole compounds; this system is only suitable for haloaniline compounds with sulfonyl groups, which limits the scope of substrate application; in addition The method of 2-halogenated aniline and pyrrole formaldehyde compounds catalyzed by CuI has also been developed, but this method requires the participation of ligands, and the reaction still requires a high temperature environment of 110 ° C, and the substrate can only be used and the price is relatively expensive. Only the 2-iodoaniline can obtain higher yield, and the yield is greatly reduced when using bromide

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