A method for synthesizing 2,2'-dipolybenzazole compounds

Abstract

The invention discloses a method for synthesizing 2,2'-dindolylmethane compounds. Firstly, 1-(pyrimidinyl-2-yl)-1H-indole compounds are generated in the mode that indole or substituded indole reacts with 2-chloropyrimidine under the sodium hydride alkaline condition with indole compounds as raw materials, indole guiding groups are introduced into the indole compounds, then the 1-(pyrimidinyl-2-base)-1H-indole compounds are subjected to a dimerization reaction under the action of acetic acid copper, silver nitrate and a toluene solvent, and finally the 2,2'-dindolylmethane compounds are synthesized. A direct carbon activation reaction method is applied, reaction steps are reduced, economical efficiency of reaction is improved, the target product 2,2'-dindolylmethane compounds are efficiently synthesized under the mild condition, indole groups can be removed after the 2,2'-dindolylmethane compounds are de-protected, 2,2'-dindolylmethane is generated, and the structural unit has wide biological activity and application prospects.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis chemistry, and in particular relates to a method for synthesizing 2,2'-dibindole compounds. Background technique [0002] 2,2'-dipolyindole homologues or derivatives are important heterocyclic compounds. The 2,2'-dipolyindole structure exists in many natural bioactive molecules, indigo dyes and Thiel red violet dyes. It can be used to prepare organic electroluminescent materials or certain ion receivers or sensor materials, and is widely used in the fields of material chemistry, medicinal chemistry, dyes and the like. [0003] Conventional methods for synthesizing 2,2'-dipolyindole compounds can be mainly divided into two categories: [0004] One is the ring-forming reaction, which is generally dominated by the ring-forming reaction of N,N'-di-o-tolyloxamide or the ring-forming reaction of o-alkynylaniline compounds. The raw materials for this type of reaction are not easy to obtain, a...

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Problems solved by technology

Kumaran's group used the same substrate and transition metal iridium as a catalyst to successfully synthesize 2,2'-dipolyindole under alkaline conditions of sodium tetrafluoroborate, with a yield of 84%. However, the raw material is not easy The source is not extensive (Elumalai, K.; Wai Yip, F.; Kee, L.W., Org. Lett. 2014, 16(5), 1342-1345.)

[0005] The second type is the dehydrogenation coupling reaction catalyzed by transition metals. This type of reaction uses indole compounds with wider sources and lower cost as starting materials. The reaction conditions are relatively mild and the product regioselectivity is high. The defect is the use of noble metals. Palladium catalyst or low yield

Although there are certain advantages in the synthesis of dimerindole by transition metal-catalyzed carbon-hydrogen activation, such reactions are very challenging and there are few research results.

In the past five years, Carretero (García.Rubia, et.al.Chemistry–A European Journal 2010,16(31),9676-9685.) and Hirano (Odani,R.et.al.Heterocycles: an international journal for reviews and communications in heterocyclic chemistry 2014,88(1),595-602.) The group successfully realized the C2 dimerization reaction of nitrogen-heterocyclic-directed indole compounds, but the former used the noble metal catalyst palladium, and the amount of Mg used in the deprotection process was large. The economy is not high, the reaction temperature of the latter is too high, the substrate tolerance is poor, and the yield is only 35-55%

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