138729-47-2

High-performance liquid chromatography (HPLC) and gas chromatography (GC) over chiral stationary phases (CSPs) represent the most popular and highly applicable technology in the field of chiral separation, but there are currently no CSPs that can be used for both liquid and gas chromatography simultaneously. We demonstrate here that two olefin-linked covalent organic frameworks (COFs) featuring chiral crown ether groups can be general CSPs for extensive separation not only in GC but also in normal-phase and reversed-phase HPLC. Both COFs have the same 2D layered porous structure but channels of different sizes and display high stability under different chemical environments including water, organic solvents, acids, and bases. Chiral crown ethers are periodically aligned within the COF channels, allowing for enantioselective recognition of guest molecules through intermolecular interactions. The COF-packed HPLC and GC columns show excellent complementarity and each affords high resolution, selectivity, and durability for the separation of a wide range of racemic compounds, including amino acids, esters, lactones, amides, alcohols, aldehydes, ketones, and drugs. The resolution performances are comparable to and the versatility is superior to those of the most widely used commercial chiral columns, showing promises for practical applications. This work thus advances COFs with high stability as potential universal CSPs for chromatography that are otherwise hard or impossible to produce.

The invention discloses an eszopiclone microcrystalline and a preparation method thereof. The preparation method comprises the following steps: (1) eszopiclone is dissolved in an acid solution containing an acidulant to obtain a medicated solution; or a water-soluble eszopiclone salt is dissolved in water to get a medicated solution; wherein the solvent of the acid solution containing the acidulant is a solvent A and / or water; the solvent A is an organic solvent capable of being mixedly dissolved in water in any proportion; and (2) under stirring, an alkalizing agent is added into the medicated solution. The eszopiclone microcrystalline prepared by the preparation method is free of residual organic solvent, microcrystalline particle size and particle size distribution are controllable, and the microcrystalline product can be directly used for the preparation of pharmaceutical formulations without further grinding, so that the dissolution rate and content uniformity of prepared pharmaceutical formulation products are increased, and bioavailability improvement and individual difference reduction can be facilitated.

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.

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.

Rapid and simple isocratic high-performance liquid chromatographic methods with UV detection were developed and validated for the direct resolution of racemic mixtures of hyoscyamine sulfate and zopiclone. The method involved the use of αl-acid glycoprotein (AGP) as chiral stationary phase. The stereochemical separation factor (Greek small letter alpha with tonos) and the stereochemical resolution factor (Rs) obtained were 1.29 and 1.60 for hyoscyamine sulfate and 1.47 and 2.45 for zopiclone, respectively. The method was used for determination of chiral switching (eutomer) isomers: S-hyoscyamine sulfate and eszopiclone. Several mobile phase parameters were investigated for controlling enantioselective retention and resolution on the chiral AGP column. The influence of mobile phase, concentration and type of uncharged organic modifier, ionic strength, and column temperature on enantioselectivity were studied. Calibration curves were linear in the ranges of 1-10 μg mL-1 and 0.5-5 μg mL-1 for S-hyoscyamine sulfate and eszopiclone, respectively. The method is specific and sensitive, with lower limits of detection and quantifications of 0.156, 0.515 and 0.106, 0.349 for S-hyoscyamine sulfate and eszopiclone, respectively. The method was used to identify quantitatively the enantiomers profile of the racemic mixtures of the studied drugs in their pharmaceutical preparations. Thermodynamic studies were performed to calculate the enthalpic ΔH and entropic ΔS terms. The results showed that enantiomer separation of the studied drugs were an enthalpic process.

An open-tubular capillary electrochromatography column was prepared by chemically immobilized β-cyclodextrin modified gold nanoparticles onto new surface with the pre-derivatization of (3-mercaptopropyl)-trimethoxysilane. The synthesized nanoparticles and the prepared column were characterized by transmission electron microscopy, scanning electron microscopy, infrared spectroscopy and ultraviolet visible spectroscopy. When the column was employed as the chiral stationary phase, no enantioselectivity was observed for ten model basic drugs. So β-cyclodextrin was added to the background electrolyte as chiral additive to expect a possible synergistic effect occurring and resulting in a better separation. Fortunately, significant improvement in enantioselectivity was obtained for ten pairs of drug enantiomers. Then, the effects of β-cyclodextrin concentration and background electrolyte pH on the chiral separation were investigated. With the developed separation mode, all the enantiomers (except for venlafaxine) were baseline separated in resolutions of 4.49, 1.68, 1.88, 1.57, 2.52, 2.33, 3.24, 1.63 and 3.90 for zopiclone, chlorphenamine maleate, brompheniramine maleate, dioxopromethazine hydrochloride, carvedilol, homatropine hydrobromide, homatropine methylbromide, venlafaxine, sibutramine hydrochloride and terbutaline sulfate, respectively. Further, the possible separation mechanism involved was discussed.

The present invention disclosed a crystalline of S-zopiclone having a powder X-Ray diffraction spectrum using Cu-Ka radiation with characteristic peaks expressed in terms of 2θ at about 11.08°, about 12.38°, about 15.86°, about 17.88°, about 19.98° and ab

The present invention provides a process for the preparation of the dextrorotatory isomer of zopiclone (eszopiclone). The present invention also provides eszopiclone di-p-anisolyl-L-tartrate and eszopiclone diacetyl-L-tartrate, which are useful as interme

The present invention provides a new process of recovering zopiclone from unwanted enantiomer by racemisation using aliphatic amines in amide solvents. The process of the present invention can give product in high yield with low amount of impurities and can be carried out on an industrial scale. The present invention provides also a method for resolving the enantiomers of zopiclone by means of chiral chromatography using stationary phase which comprises amylose tris (3,5-dimethylphenylcarbamate) immobilised on silica gel.

The present invention provides a process for the preparation of the dextrorotatory isomer of zopiclone (eszopiclone). The present invention also provides eszopiclone di-p-anisolyl-L-tartrate and eszopiclone diacetyl-L-tartrate, which are useful as intermediates in a process for preparing eszopiclone.

Disclosed herein is the process for preparation of 6-(5-chloro-pyrid-2-yl)-5-[(4-methyl-1-piperazinyl)carbonyloxy]-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine (Zopiclone), its resolution to get the dextrorotatory isomer of formula (I) substantially free of R(?) enantiomer and recovery of key raw material i.e. 6-(5-chloro pyrid-2-yl)-5-hydroxy-7-oxo-5,6-dihydropyrrolo[3,4-b]pyrazine from the R-isomer of Zopiclone followed by conversion of the recovered compound to get pure Eszopiclone (I) in high yield and high purity.

Disclosed herein is the process for preparation of 6-(5-chloro-pyrid-2-yl)-5-[(4-methyl-1-piperazinyl) carbonyloxy]-7-oxo-6,7-dihydro-5H-pyrrolo [3,4-b] pyrazine (Zopiclone), its resolution to get the dextrorotatory isomer of formula (I) substantially free of R (-) enantiomer and recovery of key raw material i.e. 6-(5-chloro pyrid-2-yl)-5-hydroxy-7-oxo-5,6-dihydropyrrolo [3,4-b] pyrazine from the R-isomer of Zopiclone followed by conversion of the recovered compound to get pure Eszopiclone (I) in high yield and high purity.

The present invention is related to a novel process for the preparation of eszopiclone (II), that comprises the following steps: (a) preparation of zopiclone (I) by reaction of 6-(5-chloropyridin-2-yl)-5-hydroxy-7-oxo- 5,6-dihydropyrrolo[3,4-b]pyrazine-5-one (5-OH-Py) (III) with chloro-carbonyl-4- methyl-piperazine (CMP) free base (IV) or its acid addition salt in the presence of diazabicylo [5.4.0]undec-7-ene (DBU) or a mixture of DBU and other bases; (b) resolution of racemic zopiclone with dibenzoyl-D-tartaric acid in suitable solvent wherein dibenzoyl-D-tartaric acid addition salt of eszopiclone is separated by the addition of a nitrile solvent; (c) optional purification of dibenzoyl-D-tartaric acid addition salt of eszopiclone by dissolution in solvent selected from alcohols, ketones or mixture thereof followed by the precipitation by adding a nitrile solvent; (d) conversion of the dibenzoyl-D-tartaric acid addition salt of eszopiclone to obtain the eszopiclone free base (II) by treating with an alkaline solution; (e) purification of eszopiclone by dissolving in nitrile solvent followed by addition of ketonic solvent. The eszopiclone (II) obtained by the process of the present invention has chiral purity greater than 99.9% and less amounts of organic volatile impurities. The present invention further provides novel crystalline form B of eszopiclone- Dibenzoyl-D-tartarate salt (V) and its preparation.

Process for synthesis and purification of anhydrous crystalline S-zopiclone for the preparation of enantiomerically pure {S)-5-{chloromethyloxycarbonyloxy)-6-{5-chloropyrid-2-yl)-7-oxo-5,6-dihydropyrrolo[3,4b]pyrazine (S)-(I).

The present invention refers to a process for the resolution into one of its enantiomers of the racemate of compound of formula (I): which comprises separating said one of its enantiomers from a diastereoisomeric salt of formula (II), which is formed by reaction of the racemic mixture with an optically active acetylated amino acid of formula (III). The invention also refers to new intermediates which are useful to carry out the process of the invention.

The present invention refers to a process for the resolution into one of its enantiomers of the racemate of compound of formula (I): which comprises separating said one of its enantiomers from a diastereoisomeric salt of formula (II), which is formed by reaction of the racemic mixture with an optically active acetylated amino acid of formula (III). The invention also refers to new intermediates which are useful to carry out the process of the invention.

In one of the embodiments, the present invention provides a racemization process comprising: removing the organic solvent from a mother liquor comprising R-zopiclone malate, eszopiclone malate and an organic solvent to obtain a mixture of R-zopiclone malate and eszopiclone malate; mixing the mixture with water to obtain a solution; neutralizing R-zopiclone malate and eszopiclone malate in the solution to obtain a precipitate of R-zopiclone and eszopiclone; filtering the precipitate; mixing the precipitate of R-zopiclone and eszopiclone with DBU and an organic inert solvent having a boiling point of at least 80° C.; heating; and cooling to obtain a zopiclone racemate.

The invention relates to a process for making of 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 of zopiclone into its enantiomers (eszopiclone and (R)-zopiclone) and also provides a method of recycling of (R)-zopiclone.

Present invention relates to an improved process for the preparation of Zopiclone and its enantiomerically enriched isomer (Eszopiclone). 6-(5-Chloropyridin-2- yl)-5-hydroxy-7-oxo-5,6-dihydropyrrolo [3,4-b] pyrazine is reacted with 1-chloro- carbonyl-4-methylpiperazine in the presence of alkali earth metal carbonates, hydroxides or oxides in a solvent medium to give Zopiclone. It is reacted with optically active acid in a mixture of water and water miscible organic solvent followed by work up to give Eszopiclone. The present invention also relates to process for the conversion of (R) or (S) Zopiclone to 6-(5-chloropyrid-2-yl)-5-hydroxy-7-oxo-5,6-dihydro- pyrrolo- [3,4-b] - pyrazine of the intermediate which can be converted to racemic Zopiclone.

Provided is a process for the preparation of zopiclone, an intermediate in the synthesis of eszopiclone. The present invention provides a process for preparing zopiclone by combining 6-(5-chloro-2-pyridinyl]-6,7-dihydro-7-hydroxy-5H-pyrroIo[3,4-b]pyrazine-5-one (7-OH-Py) having the formula (I), with chloro-carbonyl-4-methyl-piperazine (CMP) as a free base or an acid addition salt having the formula (II), 4-N,N-dimethylamino-Pyridine (DMAP) catalyst and a base in the presence of a polar solvent.

The invention relates to an S-zopiclone-L-tartrate compound, to a process, which comprises reacting a mixture of R- and S-zopiclone and/or a salt thereof with L-tartaric acid in a solvent to form a solution containing zopiclone ions and L-tartaric acid ions, to a process for increasing the enantiomeric purity of S-zopiclone, which comprises: (a) selectively precipitating from a solution, which contains zopiclone and tartaric acid as solutes and acetonitrile as a solvent, an S-zopiclone-L-tartrate acetonitrile solvate; and (b) treating said S-zopiclone-L-tartrate acetonitrile solvate with a base to form enriched S-zopiclone and to the use of L-tartaric acid in the making of enriched S-zopiclone and/or its L-tartrate compound.

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-dihydropyrr

A substantially pure dextrorotatory isomer of zopiclone or a pharmaceutically acceptable salt thereof and crystalline forms thereof are provided. Also provided is a process for its preparation and pharmaceutical compositions containing same.

The present invention provides methods for preparing eszopiclone Form A, substantially chemically pure eszopiclone, or eszopiclone with low level(s) of residual solvent(s). The present invention also provides eszopiclone with low level(s) of residual solvent(s). The present invention also provides a process for optical enrichment of eszopiclone free base. For instance, one of the embodiments of the invention is directed to a method of preparing eszopiclone Form A, wherein the method comprises crystallizing eszopiclone free base from a solvent selected from the group consisting of isopropanol (IPA), methyl isobutyl ketone (MIBK), acetone, n-butanol, i-butanolisobutanol, 2-butanol, tetrahydrofuran (THF), dimethyl carbonate, methanol, ethanol, ethyl lactate, dimethylformamide (DMF), carbon tetrachloride, toluene, iso-butyl acetate and mixtures thereof.

The present invention relates to a process for optically resolving eszopiclone, comprising chiral chromatography. Preferably the process comprises a multi-column continuous process or a simulated moving bed process. Preferably the stationary phase used in the chiral chromatography process comprises an amylose or cellulose derivative of tris (3,5-dimethylphenyl carbamate), or an amylose derivative of tris-α-methylbenzylcarbamate. The process of the present invention has the advantage that it is high yielding and can be carried out on an industrial scale. The present invention also provides eszopiclone, or a pharmaceutically acceptable salt thereof, obtained by the chiral chromatography process. The eszopiclone or salt thereof is suitable for use as a medicament, for example, for the treatment of anxiety or insomnia.

In the present invention new compounds of formula II, in enantiomerically enriched forms, are described for the first time, where R1 is chloroalkyl. The present invention also includes several new enzymatic processes for the resolution of the e

One aspect of the present invention relates to pharmaceutical compositions comprising a sedative agent; and melatonin or a melatonin analog, collectively referred to as "melatonin agents." In a preferred embodiment, the sedative agent is eszopiclone. The pharmaceutical compositions of the invention are useful in the treatment of various sleep disorders. In addition, the present invention also relates to a method of treating a patient suffering from a sleep abnormality or insomnia comprising administering a therapeutically effective amount of a pharmaceutical composition of the invention.

The lipase from Candida antarctica B catalyzes the enantioselective hydrolysis of (±)-6-(5-chloropyridin-2-yl)-7-chloromethyloxycarbonyloxy-6,7- dihydro-5H-pyrrolo[3,4-b]pyrazin-5-one, a useful intermediate in the synthesis of (S)-(+)-zopiclone. This enzyme also catalyzes the resolution of the corresponding 2-chloroethylcarbonate derivative.