A class of o-aminophenol derivatives and preparation method thereof

Abstract

The invention first discloses a preparation method of an ortho-aminophenol derivative. The preparation method comprises the following steps: (1) by adopting an aryl amine compound as a substrate and 2-chloro-5-nitropyridine as a guiding base, reacting in acetonitrile, thus obtaining a pyridine aryl amine compound intermediate; (2) catalyzing the pyridine aryl amine compound intermediate in step (1) to make C-H activation reaction in a solvent by using iodobenzene diacetate as an oxidant and palladium acetate as a catalyst, thus obtaining an acetoxylation aniline derivative, draining, and thenperforming the chromatographic separation and purification; and (3) enabling the acetoxylation aniline derivative in step (2) to react in a tetrahydrofuran solvent for 30 min at a normal temperature by virtue of hydrazine hydrate, thus obtaining the ortho-aminophenol derivative, quenching, washing, extracting, drying, draining, and performing the chromatographic separation and purification. The invention also discloses the ortho-aminophenol derivative prepared by the method.

Description

technical field [0001] The invention belongs to the field of chemical synthesis, and in particular relates to a class of o-aminophenol derivatives and a preparation method thereof. Background technique [0002] In recent years, with the rise of transition metal-catalyzed C–H bond functionalization, directing groups assist C sp2 -H bond functionalization has attracted extensive attention. Various directing groups such as amines, imines, oximes, diazenes, amides, pyridines, pyrimidines, carboxylic acids, etc., were used to achieve regioselective C–H functionalization. Although the introduction and removal of the introducing group usually adds two steps to the overall synthesis, it can become more manipulable if the directing group (DG) is only briefly attached to the substrate molecule during the functionalization step. However, only very limited success examples have been obtained, and only a few reports have been recorded, and the substrates are limited to amines and forma...

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Problems solved by technology

It has been reported in many literatures that the introduction of DG is relatively easy, but the conditions for removing DG are quite harsh. For example, these conditions generally require the use of particularly active metals such as sodium or potassium, and they are still under high temperature conditions. In these literatures, a lot of risk factors have been subtly added to the experiment. What is more serious is that the conditions of these reactions are difficult to achieve in the stage of mass production in practical application. If the company follows this traditional old method to In terms of operation, even small batches of gram-level reactions are difficult to achieve

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