Preparation method of loratadine

Abstract

The invention provides a preparation method of loratadine. The method comprises the following steps: taking 2-cyano-3-methylpyridine as a raw material, and carrying out Ritter reaction, m-chlorobenzylchloride condensation, POCl3 deprotection group, Grignard reaction, cyclization and ethyl chloroformate substitution to obtain 4(8-chlorine-5, 6-dihydro-11H-benzo-[5, 6]cycloheptano[1, 2-b]pyridine-11-subunit)-1-piperidine carboxylic acid ethyl ester. According to the invention, a post-treatment process is innovated, and a new cyclization system is adopted to catalyze the reaction, so that the use of high-cost and high-toxicity strong acid is avoided, and a milder and more economical synthesis method is provided for industrial production.

Description

technical field

[0001] The invention belongs to the technical field of medicine synthesis, and in particular relates to a preparation method of loratadine. Background technique

[0002] Allergic reaction refers to the allergic reaction induced by the human body's immune system caused by allergens, and the H1 receptor of histamine plays a very important role in this process. Antiallergic drugs compete with histamine for histamine receptors and block the allergic reaction induced by the immune system, thus playing an antiallergic effect.

[0003] Loratadine (Loratadine), chemical name: 4-(8-chloro-5,6-dihydro-11H-benzo[5,6]cyclohepta[1,2-b]pyridyl-11 alkylene Base) ethyl piperidine-1-carboxylate, its molecular formula is: C 22 h 23 ClN 2 o 2 , the structural formula is: It can be used as an anti-allergic drug.

[0004] At present, the second-generation tricyclic antiallergic drug loratadine, because of its high selectivity to peripheral H1 receptors, has no side effect...

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