Synthesis process of (S)-rivastigmine

Abstract

The invention discloses an unsymmetrical synthesis method of (S)-rivastigmine. The method comprises the following steps of: reacting hydroxyacetophenone with methylethylcarbamoyl chloride to generate N-ethyl-N-methyl-carbamate 3-acetylphenyl formate, carrying out chiral reduction on the N-ethyl-N-methyl-carbamate 3-acetylphenyl formate under the catalysis effect of a complex of (S)-(-)-alpha, alpha-diphenyl prolinol and trimethyl borate, carrying out methanol dissociation to generate N-ethyl-N-methyl- carbamate 3-[(R)-1-hydroxyethyl]phenyl formate, and reacting the N-ethyl-N-methyl- carbamate 3-[(R)-1-hydroxyethyl]phenyl formate with methylsufonyl chloride and dimethylamine hydrochloride to obtain the (S)-rivastigmine. According to the method disclosed by the invention, a target product can be prepared from conventional reagents only through a three-step reaction, the reaction yield reaches 40% and is far higher than that by a racemic resolution method and that by other chiral synthesis methods, the application of virulent reagents and highly corrosive reagents are avoided in the process, and the unsymmetrical synthesis method is easy to operate, environment-friendly, low in production cost, and suitable for industrialized production.

Description

technical field [0001] The invention belongs to the technical field of chiral drug synthesis, in particular to a method for synthesizing optically pure (S)-rivastigmine, specifically an asymmetric synthesis method of (S)-rivastigmine. Background technique [0002] Exelon (Exelon) is a new type of carbamate brain-selective cholinesterase inhibitor that was launched in 1997 for the treatment of senile dementia. It is the second generation drug for the treatment of senile dementia. Its active ingredient: rivastigmine bitartrate (rivastigmine), is an amino acid formic acid brain tissue selective cholinesterase inhibitor, although the half-life of the drug is relatively short, but the inhibitory effect on cholinesterase can reach 10 hours, the The drug promotes cholinergic nerve conduction by delaying the degradation of acetylcholine released by cholinergic neurons, thereby increasing the content of acetylcholine. Rivastigmine hydrogentartrate, the chemical name is N-ethyl-N-met...

AI Technical Summary

Problems solved by technology

[0004] In the resolution method, because only half of the synthesized racemate is the target product, the yield is low, and multiple resolutions make the process more complicated and the production cost higher

[0005] Asymmetric synthesis methods mainly include chiral tert-butyl sulfinamide method, tetraisopropyl titanate catalytic method, etc., but such reactions often have many steps, chiral reagents cannot be recycled, and toxic and harmful reagents are used. , it is difficult to produce industrially

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