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.