61 results about "Eszopiclone" patented technology

Eszopiclone is prepared by reacting zopiclone with an enatiomerically pure di-p-toluoyl tartaric acid, recovering a solid salt, and reacting a solid salt with a base. Zopiclone is prepared by reacting 6-(5-chloropyrid-2-yl)-5-hydroxy-7-oxo-5,6-dihydropyrrolo[3,4-b]-pyrazine with 1-chlorocarbonyl-4-methylpiperazine hydrochloride.

The invention relates to a process for making 6-(5-chloro-2-pyridinyl)-6,7-dihydro-7-oxo-5H-pyrrolo-[3,4-b]pyrazin-5-yl-4-methyl piperazine-1-carboxylate, also known as zopiclone. The invention further describes an effective method for resolving zopiclone into its enantiomers (eszopiclone and (R)-zopiclone) and also provides a method of recycling of (R)-zopiclone. The process for making (S)-6(S)-6-(5-chloro-2-pyridinyl)-6,7-dihydro-7-oxo-5H-pyrrolo-[3,4-b]pyrazin-5-yl-4-methyl piperazine-1-carboxylate (eszopiclone), comprises reacting 2-amino 5-chloropyridine with pyrazine 2,3,dicarboxylic acid anhydride at room temperature to obtain 3-(5-chloropyrid-2-yl)carbamoyl-2-pyrazine-2-carboxylic acid; cyclizing the 3-(5-chloropyrid-2-yl)carbamoyl-2-pyrazine-2-carboxylic acid in a second inert organic solvent to obtain 6-(5-chloropyrid-2-yl)5,7-dioxo-5,6-dihydropyrrolo[3,4-b]-pyrazine; reducing the 6-(5-chloropyrid-2-yl)5,7-dioxo-5,6-dihydropyrrolo[3,4-b]-pyrazine to obtain 6-(5-chloropyrid-2-yl)-5-hydroxy-7-oxo-5,6-dihydropyrrolo-[3,4-b]pyrazine; pyrazine with 1-chlorocarbonyl-4-methylpiperazine hydrochloride in a third organic solvent in presence of triethyl amine along with a catalytic amount of an acylation catalyst to obtain racemic zopiclone; e) recrystallizing the zopiclone from an alkyl ester solvent followed by purifying in suitable alcohols or mixtures thereof; and resolving the racemic zopiclone by treating with (+)-O—O′ dibenzoyl tartaric acid to obtain eszopiclone.

The invention relates to an eszopiclone preparation method comprising main steps that: zopiclone is subjected to a reaction with D-dibenzoyltartaric acid or a hydrate thereof, such that dextral zopiclone-D-dibenzoyltartrate is produced; and the salt is dissociated, such that eszopiclone is obtained. According to the method, D-dibenzoyltartaric acid with a substance amount of a quarter to a half of that of zopiclone is adopted. The reaction conditions are mild, operation is convenient, product yield is high, and product purity is high. The method is suitable for large-scale industrialized productions.

The invention provides a method for synthesizing eszopiclone. According to the method, chiral imidazo thiazole is taken as a catalyst to catalyze a racemic hemiacetal intermediate and chloro-formic ester to produce kinetic resolution reaction, and (S)-hemiacetal carbonic ester with good yield and enantioselectivity is obtained. The (S)-hemiacetal carbonic ester is reacted with N-methyl piperazine, so that eszopiclone can be obtained. The method has the advantages that the chiral imidazo thiazole which is low in cost and easy to obtain is used as the catalyst, operation procedures are simple, the production cost is low, and the method has very high application value for the industrial preparation of eszopiclone.