Process for the preparation of highly optical pure carvedilol

Abstract

The present invention relates to a process for the efficient preparation of highly optical pure chiral carvedilol. According to the present invention, a chiral oxazolidin-2-one or oxazolidin-2-thione having formula 2, produced from the reaction of N-protected 2-(2-methoxyphenoxy)ethylamine with a chiral glycidol derivative is used as a key intermediate for the preparation of the chiral carvedilol. Specifically, the process for the preparation of the chiral carvedilol comprises a) reacting a compound of formula 2 with a halogenation agent, a sulfonation agent or a mitsunobu reagent to activate a hydroxyl group of the compound of formula 2, followed by nucleophilic substitution reaction with 9H-4-hydroxy carbazole to produce a compound of formula 7, and b) subjecting the obtained compound of formula 7 to a deprotection reaction in a presence of an inorganic base to produce the targeted chiral carvedilol. The process of the present invention can be accomplished in a mild condition. The process neither requires any extraordinary purification procedure, nor involves decrease of optical purity. Therefore, the process of the present invention provides highly optical pure chiral carvedilol in simple and efficient manner.