Process for preparing piperidine derivative

Abstract

The invention provides a process for preparing Rupatadine or its salts, wherein the Rupatadine has a chemical formula (I).

Description

field of invention The invention relates to a preparation method of an antiallergic drug rupatadine or a salt thereof. Background of the invention Rupatadine, as a dual antagonist of histamine and platelet aggregation, was launched in Europe in 2003 and is used in the treatment of allergic rhinitis and hay fever, and has broad market prospects. Rupatadine has the chemical structure of the following formula (I). Rupatadine can be synthetically prepared from two synthetic routes using desloratadine as a starting material: Route 1 route 2 Among the above two routes, the yield of route 1 is low, the reaction is difficult to control, and it is difficult to obtain a purer product. The key synthetic step in Route 2 is the reduction of amides. In published literature reports, there are the following two methods for reducing amide compounds to corresponding amines: In the patent ES2087818, it is reported to use POCl 3 / NaBH 4 A method for the reduction of amides a...

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Problems solved by technology

However, this method is cumbersome to operate, and the resulting product is difficult to purify, and column chromatography is required to obtain a qualified product

In U.S. Patent No.5407941, a reduction method using lithium aluminum hydride as a reducing agent in tetrahydrofuran solution was introduced, but the experimental verification was carried out according to this method, and the target product was not obtained as a result

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