Preparation method of substituted 1,2,3,4-tetrahydroquinoline

Abstract

The invention belongs to the technical field of medical and natural compound chemical intermediates and relevant chemicals and relates to a preparation method of substituted 1,2,3,4-tetrahydroquinoline. The preparation method of the substituted 1,2,3,4-tetrahydroquinoline is characterized by taking quinoline and derivatives thereof as raw materials, taking a nano porous palladium catalyst as a catalyst, taking hydrogen as a hydrogen source, and carrying out selective hydrogenation to prepare 1,2,3,4-tetrahydroquinoline, wherein the pressure of hydrogen is 0.1-20.0MPa; the molar concentration of quinoline and derivatives thereof in a solvent is 0.01-2mmol/mL; the catalyst porous framework size is 1-50nm; the mole ratio of quinoline and derivatives thereof to the catalyst is (1 to 0.01)-(1 to 0.5). The preparation method of substituted 1,2,3,4-tetrahydroquinoline has the beneficial effects that the product selectivity is high, the reaction condition is extremely mild, operation and post-treatment are simple, the catalyst reproducibility is high, the catalysis effect is not obviously reduced after being repeatedly used, and the possibility is provided for implementation of industrialization.

Description

technical field [0001] The invention belongs to the field of pharmaceutical and natural compound chemical intermediates and related chemical technology, and relates to a preparation method of substituted 1,2,3,4-tetrahydroquinoline. Background technique [0002] The selective reduction of quinoline to 1,2,3,4-tetrahydroquinoline (py-THQ) is an important step in organic synthesis, especially in the synthesis of some important high-value compounds (such as bioactive molecules , natural products and industrial materials of other important natural products), the synthesis of high-purity py-THQ is a key step. [0003] The traditional catalysts for the selective reduction of quinoline to prepare py-THQ are mainly divided into two categories, one is a homogeneous catalyst composed of Ru, Rh, Ir and other transition metals combined with ligands, this type of catalyst has high activity and high selectivity However, these catalysts are expensive, difficult to separate and recover, an...

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Problems solved by technology

[0003] The traditional catalysts for the selective reduction of quinoline to prepare py-THQ are mainly divided into two categories, one is a homogeneous catalyst composed of Ru, Rh, Ir and other transition metals combined with ligands, this type of catalyst has high activity and high selectivity However, these catalysts are expensive, difficult to separate and recover, and cannot be reused [ROSALES M, VALLEJO R, SOTO JJ, et al. Catal. Lett. 2006, 106, 101–105.; DOBEREINER G E, NOVA A, SCHLEY N D , CRABTREE R H, et al.J.Am.Chem.Soc.2011,133,7547–7562.; WANG T L,ZHUO L G,LI ZW,CHAN A S C,et al.J.Am.Chem.Soc.2011,133 ,9878–9891.]; the second is heterogeneous catalysts that have been studied more, such catalysts include supported Ru, Pd-BT-CF and Au / HS-TiO 2 etc., but there are generally disadvantages such as high temperature, high hydrogen pressure, and poor regioselectivity, which limit industrial applications.

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