- Preparation and characterization of a new open-tubular capillary column for enantioseparation by capillary electrochromatography
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In order to use the enantioseparation capability of cationic cyclodextrin and to combine the advantages of capillary electrochromatography (CEC) with open-tubular (OT) column, in this study, a new OT-CEC, coated with cationic cyclodextrin (1-allylimidazolium-β-cyclodextrin [AI-β-CD]) as chiral stationary phase (CSP), was prepared and applied for enantioseparation. Synthesized AI-β-CD was characterized by infrared (IR) spectrometry and mass spectrometry (MS). The preparation conditions for the AI-β-CD-coated column were optimized with the orthogonal experiment design L9(34). The column prepared was characterized by scanning electron microscopy (SEM) and elemental analysis (EA). The results showed that the thickness of stationary phase in the inner surface of the AI-β-CD-coated columns was about 0.2 to 0.5?μm. The AI-β-CD content in stationary phase based on the EA was approximately 2.77?mmol·m?2. The AI-β-CD-coated columns could separate all 14 chiral compounds (histidine, lysine, arginine, glutamate, aspartic acid, cysteine, serine, valine, isoleucine, phenylalanine, salbutamol, atenolol, ibuprofen, and napropamide) successfully in the study and exhibit excellent reproducibility and stability. We propose that the column, coated with AI-β-CD, has a great potential for enantioseparation in OT-CEC.
- Li, Yingjie,Tang, Yimin,Qin, Shili,Li, Xue,Dai, Qiang,Gao, Lidi
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p. 283 - 292
(2019/02/05)
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- Resorcinol-, catechol- and saligenin-based bronchodilating β2-agonists as inhibitors of human cholinesterase activity
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We investigated the influence of bronchodilating β2-agonists on the activity of human acetylcholinesterase (AChE) and usual, atypical and fluoride-resistant butyrylcholinesterase (BChE). We determined the inhibition potency of racemate and enantiomers of fenoterol as a resorcinol derivative, isoetharine and epinephrine as catechol derivatives and salbutamol and salmeterol as saligenin derivatives. All of the tested compounds reversibly inhibited cholinesterases with Ki constants ranging from 9.4 μM to 6.4 mM and had the highest inhibition potency towards usual BChE, but generally none of the cholinesterases displayed any stereoselectivity. Kinetic and docking results revealed that the inhibition potency of the studied compounds could be related to the size of the hydroxyaminoethyl chain on the benzene ring. The additional π–π interaction of salmeterol’s benzene ring and Trp286 and hydrogen bond with His447 probably enhanced inhibition by salmeterol which was singled out as the most potent inhibitor of all the cholinesterases.
- Bosak, Anita,Kne?evi?, Anamarija,Gazi? Smilovi?, Ivana,?inko, Goran,Kovarik, Zrinka
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p. 789 - 797
(2017/06/13)
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- (R)- albuterol hydrochloride asymmetric preparation method (by machine translation)
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The present invention relates to a high-efficient chiral catalyst synthesis of (R)- albuterol hydrochloride the asymmetric synthesis of the new method, the synthesis step includes: 1) salicylaldehyde with a halo of acetyl halogen crafts acylation reaction halo; 2) obtained after the the halogenated ketone uses unclebutylamine amine solution obtained after hydrolysis to the protection of the salicylaldehyde aminoketone; 3) this aminoketone in chiral amino alcohol derivative of the chiral borane the presence of a catalyst, is reduced to (R)- albuterol crude product, then the purified hydrochloric salt to obtain the high purity of the (R)- albuterol hydrochloride. (by machine translation)
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- Effect of additives on eremomycin sorbent selectivity in separation of salbutamol enantiomers using supercritical fluid chromatography
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A regime is found in which chiral stationary phase based on macrocyclic glycopeptide eremomycin allows separation of salbutamol sulfate enantiomers in supercritical fluid chromatography. Enantioseparation occurs only when two dynamic modifiers are used simultaneously: isopropylamin + trifluoroacetic acid or isopropylamin + ammonium acetate. Amine molar concentration in mobile phase has to be higher than acid molar concentration, otherwise enantiomers coelute. We suppose that with amine excess a mechanism of enantiorecognition is realized which involves ionic sorbent-sorbate interactions. Such mechanism is well-known for glycopeptide chiral selectors in liquid chromatography, but for supercritical fluid chromatography it is reported for the first time.
- Pokrovskiy,Kayda,Usovich,Parenago,Lunin
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p. 2288 - 2290
(2017/10/06)
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- Comparison of three S-β-CDs with different degrees of substitution for the chiral separation of 12 drugs in capillary electrophoresis
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Three kinds of sulfated β-cyclodextrin (S-β-CD), including a single isomer, heptakis-6-sulfato-β-cyclodextrin (HS-β-CD), degree of substitution (DS) of 7, which was synthesized in our laboratory and another two commercialized randomly substituted mixtures, a sulfated β-cyclodextrin with DS of 7 to 11, as well as a highly sulfated-β-cyclodextrin with DS of 12 to 15, were used for the enantioresolution of 12 drugs (the β-blockers, phenethylamines, and anticholinergic agents) in capillary electrophoresis. The enantioseparation under varying concentrations of S-β-CD and background electrolyte pH were systematically investigated and compared. Based on the experimental results, the effect of the nature of S-β-CD and analyte structure on the enantioseparation is discussed.
- Wang, Zhaokun,Zhang, Qiongwen,Luo, Linda,Sun, Tiemin,Guo, Xingjie
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p. 558 - 565
(2017/08/26)
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- Preparing method of levalbuterol
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The invention provides a preparing method of levalbuterol (5) shown in the formula (5). The preparing method includes the steps that a compound shown in the formula (1) reacts with formaldehyde and acetic anhydride to obtain a compound (2) shown in the formula (2); a compound (3) shown in the formula (3) is obtained through bromination; a compound (4) shown in the formula (4) is obtained through asymmetric reduction; the compound finally reacts with tert-butylamine, and the protecting group is removed to obtain levalbuterol (5) shown in the formula (5). The preparing method is simple in path, easy to operate, mild in reaction condition, high in yield and stereoselectivity and low in industrial production, and has short steps and high practical application value and social economic benefits.
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- Preparation of levalbuterol hydrochloride
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Provided are processes for the preparation of (R)-SLB.D-DBTA salt and levalbuterol hydrochloride. Also provided are levalbuterol hydrochloride degradation products and processes for preparing them. Pharmaceutical compositions comprising at least one levalbuterol hydrochloride of the invention and at least one pharmaceutically-acceptable excipient are also provided.
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Page/Page column 8-10
(2008/06/13)
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- Process for preparing (R) salbutamol
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The present invention relates to an improved process for preparing levosalbutamol or the pharmacologically acceptable salts thereof on an industrial scale, using asymmetric hydrogenation as the key step and optionally a special sequence of subsequent steps, using rhodium as catalyst and a chiral bidentate phosphine ligand such as (2R, 4R)-4-(dicyclohexylphosphino)-2-(diphenyl-phosphino-methyl)-N-methyl-aminocarbonyl-pyrrolidine as catalyst system.
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- Process for the production of optically enriched (R)- or (S)-albuterol
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A process for the production of optically enriched (R)- or (S)-albuterol or (R)- or (S)-albuterol salts by the resolution of a novel ketal derivative 2-(N-t-butylamino)-1-(+2,2-dimethyl-1,2-benzodioxin-6-yl) ethanol, with a chiral tartaric acid derivative.
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- Enantioselective preparation of optically pure albuterol
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The invention relates to a method for producing albuterol by the resolution of a mixture of enantiomers of 5-[2-[(1,1-dimethylethyl)amino]-1-hydroxyethyl]-2-hydroxybenzoate using ditoluoyltartaric acid.
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- Asymmetric Reduction of α-Ketoimines with Oxazaborolidine Catalysts: A Novel, Practical Approach to Chiral Arylethanolamines
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Asymmetric borane reduction of α-ketoimines with oxazaborolidine catalysts has been studied.The ee's of the resulting arylethanolamines are uo to 93percent using 20 molpercent of the catalyst.
- Hong, Yaping,Gao, Yun,Nie, Xiaoyi,Zepp, Charles M.
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p. 5551 - 5554
(2007/10/02)
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