138729-47-2Relevant articles and documents
Are Highly Stable Covalent Organic Frameworks the Key to Universal Chiral Stationary Phases for Liquid and Gas Chromatographic Separations?
Cui, Yong,Jia, Wenyan,Li, Yanan,Yu, Ziyun,Yuan, Chen,Yuan, Li-Ming,Zi, Min
, p. 891 - 900 (2022/02/03)
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.
Method for synthesizing eszopiclone
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Paragraph 0047-0049, (2018/04/02)
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.
Eszopiclone microcrystalline and its preparation method
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Paragraph 0055-0060; 0063; 0068-0070; 0072; 0075; 0078, (2017/08/24)
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.
A method for preparing eszopiclone
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Paragraph 0072; 0074, (2017/05/05)
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.
Strategy Approach for Direct Enantioseparation of Hyoscyamine Sulfate and Zopiclone on a Chiral αl-Acid Glycoprotein Column and Determination of Their Eutomers: Thermodynamic Study of Complexation
Zaazaa, Hala E.,Salama, Nahla N.,Abd El Halim, Lobna M.,Salem, Maissa Y.,Abd El Fattah, Laila E.
, p. 49 - 57 (2016/02/20)
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.
Preparation of a β-cyclodextrin-based open-tubular capillary electrochromatography column and application for enantioseparations of ten basic drugs
Fang, Linlin,Yu, Jia,Jiang, Zhen,Guo, Xingjie
, (2016/01/29)
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.
CRYSTALLINE OF ESZOPICLONE, ITS COMPOSITION, PREPARATION AND USES THEREOF
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Page/Page column 12, (2011/04/24)
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
Process for Resolving Zopiclone
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Page/Page column 4, (2011/10/13)
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
A process for racemisation of 6-(5-chloropyridin-2-yl)-7-(4-methyl-1-piperazinyl)carbonyloxy-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine
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Page/Page column 11, (2011/08/04)
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.
PROCESS FOR RESOLVING ZOPICLONE
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Page/Page column 11-12, (2010/06/11)
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.