Method for catalyzing hydroboronation of aza-aromatic ring compound by using triazole salt and conjugated base thereof

Abstract

The invention provides a method for catalyzing hydroboronation of an aza-aromatic ring compound by using a triazole salt and a conjugated base thereof, wherein the structural formulas of the triazolesalt and the conjugated base thereof are represented by formulas I and II. The method for catalyzing the hydroboronation of the aza-aromatic ring compound by using the triazole salt and the conjugatebase thereof comprises the following step of: reacting the aza-aromatic ring compound with HBpin in the presence of the triazole salt and the conjugate base thereof to obtain a hydroboronation product, wherein the aza-aromatic ring compound is one of pyridine, acridine, pyrimidine, quinoline, isoquinoline, benzothiazole, pyrazine, triazine and derivatives thereof. According to the method, the triazole salt and the conjugate base system are used for catalyzing the hydroboronation reaction of the aza-aromatic ring compound for the first time, a traditional Lewis catalytic system is abandoned, ametal-free Lewis base catalyzed nitrogen heterocyclic compound hydroboronation system is realized for the first time, the catalyst dosage is small, and the yield is good.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to a method for catalyzing the hydroboration of nitrogen heteroaryl ring compounds by using triazole salts and their conjugate bases. Background technique [0002] Reduced nitrogen heterocycles are important components of many pharmaceutical and agrochemical products. For example, the most common dihydropyridine (DHP) derivatives are ubiquitous in natural molecules, such as NADH and other biologically active substances (nicotinamide adenine di nucleotides), and molecules of great medicinal value, such as Hantzsch esters. Therefore, it is of great significance to develop effective synthetic methods of DHP and its derivatives. Although there are currently some synthetic methods in which strong reducing agents are used to activate pyridine, as a conventional synthetic method for 1,2- or 1,4-DHP derivatives, subsequent use of relatively weak reducing agents such as silane and borane in...

AI Technical Summary

Problems solved by technology

Although there are currently some synthetic methods in which strong reducing agents are used to activate pyridine, as a conventional synthetic method for 1,2- or 1,4-DHP derivatives, subsequent use of relatively weak reducing agents such as silane and borane instead of the hydrogen reduction system are considered effective because they avoid the use of highly flammable and high-pressure hydrogen and avoid over-reduction to piperidine, but significant challenges remain with this system

[0003] In recent years, several schemes for the direct catalytic reduction of pyridine and nitrogen heterocycles have been developed. However, the early studies on such reactions mainly focused on metal-catalyzed systems, and mainly based on noble transition metals (ruthenium, rhodium, etc.), Therefore, there are problems of high cost and metal residues. It was not until 2015 that this metal-free catalyzed pyridine reductive hydroboration system was realized for the first time, but still requires 10% catalyst

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