83380-47-6Relevant articles and documents
In-situ and one-step preparation of protein film in capillary column for open tubular capillary electrochromatography enantioseparation
Li, Ling,Xue, Xuqi,Zhang, Huige,Lv, Wenjuan,Qi, Shengda,Du, Hongying,Manyande, Anne,Chen, Hongli
supporting information, p. 2139 - 2142 (2021/04/07)
In this work, the phase-transitioned BSA (PTB) film using the mild and fast fabrication process adhered to the capillary inner wall uniformly, and the fabricated PTB film-coated capillary column was applied to realize open tubular capillary electrochromatography (OT-CEC) enantioseparation. The enantioseparation ability of PTB film-coated capillary was evaluated with eight pairs of chiral analytes including drugs and neurotransmitters, all achieving good resolution and symmetrical peak shape. For three consecutive runs, the relative standard deviations (RSD) of migration time for intra-day, inter-day, and column-to-column repeatability were in the range of 0.3%–3.5%, 0.2%–4.9% and 2.1%–7.7%, respectively. Moreover, the PTB film-coated capillary column ran continuously over 300 times with high separation efficiency. Therefore, the coating method based on BSA self-assembly supramolecular film can be extended to the preparation of other proteinaceous capillary columns.
Experimental and computational study on the enantioseparation of four chiral fluoroquinolones by capillary electrophoresis with sulfated-β-cyclodextrin as chiral selector
Ma, Qianyun,Cong, Wei,Liu, Ye,Geng, Zikai,Lin, Ying,Wang, Zhaokun
, p. 549 - 557 (2021/07/20)
In this work, enantioseparation of four chiral fluoroquinolones (FQs), namely, ofloxacin, gemifloxacin, lomefloxacin, and gatifloxacin, was achieved by capillary electrophoresis with sulfated-β-cyclodextrin (S-β-CD) as chiral selector. Factors affecting the enantiomeric resolution, such as the concentrations of S-β-CD, BGE pH conditions, and the buffer types and concentrations, were optimized and discussed. A BGE consisting of 30 g/L S-β-CD and 30-mM phosphate at pH?4.0 was found fit for enantiomeric resolution of ofloxacin and gemifloxacin, while the same BGE at pH?3.0 was suitable for enantioseparation of lomefloxacin and gatifloxacin. The pH-dependent experiments showed that separation resolutions of four FQs enantiomers were significantly affected by BGE pH, which was thought to be related with the varying electrostatic attraction between the enantiomers and chiral selector. To verify this speculation, molecular docking studies were used for further investigation of the enantiomeric recognition mechanism of S-β-CD. Molecular model indicated that hydrophobic effect and hydrogen bond were involved in host-guest inclusion, but the electrostatic attraction enhanced the chiral discrimination by increasing the difference in binding energy between individual enantiomers and S-β-CD. This work provided a further insight into the chiral recognition mechanisms of CD derivatives.
Preparation method of levofloxacin and intermediates thereof
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Paragraph 0053-0056, (2021/03/30)
The invention relates to a preparation method of levofloxacin and intermediates thereof, and belongs to the field of medicinal chemistry. The preparation method comprises the following steps of: carrying out amino substitution and ring closing reaction on an intermediate substrate to integrate a plurality of intermediates into a one-pot reaction, and hydrolyzing under an acidic condition to obtainlevofloxacin. According to the method provided by the invention, the intermediates do not need to be separated, the reaction operation is simplified, the production period is greatly shortened, multiple times of after-treatment are not needed, emission of three wastes is reduced, the method is more environmentally friendly, the reaction yield is increased compared with the prior art, and the method is suitable for industrial amplification.
Preparation method of levofloxacin and intermediates thereof
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Paragraph 0065-0068, (2021/03/30)
The invention relates to a preparation method of levofloxacin and intermediates thereof, and belongs to the field of medicinal chemistry. The preparation method comprises the following steps of: carrying out amino substitution and ring closing reaction on a fluorine-substituted substrate to integrate a plurality of intermediates into a one-pot reaction, and hydrolyzing under acidic conditions to obtain levofloxacin. According to the method, the reaction operation is simplified, the production period is greatly shortened, multiple times of after-treatment are not needed, emission of three wastes is reduced, the method is more environmentally friendly, the reaction yield is increased by about 20% compared with the prior art, and the method is suitable for industrial amplification.
Novel marking method of levofloxacin
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Paragraph 0019-0030, (2021/01/30)
The invention provides a synthetic method of levofloxacin, which uses formaldehyde and formic acid to methylate N-demethylated levofloxacin to obtain levofloxacin, and the method has the characteristics of high yield and high purity, and is suitable for labeling levofloxacin and isotopes thereof.
Preparation of polar group derivative β-cyclodextrin bonded hydride silica chiral stationary phases and their chromatography separation performances
Zhao, Baojing,Li, Lan,Wang, Yuting,Zhou, Zhiming
, p. 643 - 649 (2018/11/27)
Three novel β-cyclodextrin compounds derived with piperidine which is flexible, L-proline containing a chiral center, ionic liquid with 3,5-diamino-1,2,4-triazole as the cation were designed and synthesized as chiral selectors for enantiomer separation, whose name were (mono-6-deoxy-6-(piperidine)-β-cyclodextrin, mono-6-deoxy-6-(L-proline)-β-cyclodextrin, mono-6-deoxy-6-(3,5-diamino-1,2,4-triazole)-β-cyclodextrin, multi-substituted 3,5-diamino-1,2,4- triazole-(p-toluenesulfonic)-β-cyclodextrin), respectively. In addition, to enhance the polarity of chiral stationary phases, hydrosilylation and silylation reactions were implemented to derive ordinary silica, the common used selector carrier, to hydride silica, whose surface is covered with proton. 31 pyrrolidine compounds and some chiral drugs were tested in both polar organic mobile phase mode and normal mobile phase mode. 6-Deoxy-6-L-proline-β-cyclodextrin-CSP showed satisfactory separations in polar organic mobile phase mode and exihibited a strong separation capability in different pH values; multi-substituted 3,5-diamino-1,2,4-triazole-(p-toluenesulfonic)-β-cyclodextrin-CSP can separate pyrrolidine compounds in both mobile phase modes with high resolutions and separation efficiency compared to commercially available CSPs, making it to be the most valuable object to study. The composition of mobile phase, type of stationary phase as well as the peak problem of chromatograms was discussed deeply.
Nano-Fe3 O4@ZrO2-SO3 H as highly efficient recyclable catalyst for the green synthesis of fluoroquinolones
Nakhaei, Ahmad,Ramezani, Shirin,Shams-Najafi, Sayyed Jalal,Farsinejad, Sadaf
, p. 739 - 746 (2018/09/26)
Nano-Fe3 O4 @ZrO2-SO3 H (n-FZSA), was utilized as a magnetic catalyst for the synthesis of various fluoroquinolone compounds. These compounds were prepared by the direct amination of 7-halo-6-fluoroquinolone-3-carboxylic acids with piperazine derivatives and (4aR,7aR)-octahydro-1H-pyrrolo[3,4-b] pyridine in water. The results showed that n-FZSA exhibited high catalytic activity towards the synthesis of fluoroquinolone derivatives, giving the desired products in high yields. Furthermore, the catalyst was recyclable and could be used at least seven times without any discernible loss in its catalytic activity. Overall, this new catalytic method for the synthesis of fluoroquinolone derivatives provides rapid access to the desired compounds in refluxing water following a simple work-up procedure, and avoids the use of organic solvents.
Structure-retention relationship for enantioseparation of selected fluoroquinolones
Hassan, Rasha M.,Yehia, Ali M.,Saleh, Ola A.,El-Azzouny, Aida A.,Aboul-Enein, Hassan Y.
, p. 828 - 836 (2018/04/10)
Fluoroquinolones are popular class of antibiotics with distinct chemical functionality. Most of them are ampholytes with one chiral center. Stereogeneic center is located either in the side ring of Gatifloxacin (GFLX) or in the quinolone core of Ofloxacin (OFLX). These two amphoteric fluoroquinolones have terminal amino groups in common. The unusual Nadifloxacin (NFLX) is an acidic fluoroquinolone with a core chiral center. Owing to chirality and functionality differences among GFLX, OFLX, and NFLX, we mapped these enantiomers onto structure-retention relationship. Amount of acetic acid modifier was studied in screened mobile phase and cellulose tris(3-chloro-4-methyl phenyl carbamate) (Lux cellulose-2) stationary phase. Experimental design of acetic acid% along with column temperature have been applied. Resolution and enantioselectivity have been related to structural features of the studied enantiomers. High amount of acid (0.4%) was optimum for the separation of either side chirality with a proximate amino group (GFLX) or core chirality without basic functionality (NFLX), while low amount (0.2%) is optimum for core chiral center with distal amino group (OFLX). Temperature has no significant effect on resolution and retention of enantiomers except for OFLX. Enantio-retention explains possible chiral selective and nonselective interactions. The proposed methods have been validated for pharmaceutical analyses.
Chiral separation and modeling of quinolones on teicoplanin macrocyclic glycopeptide antibiotics CSP
Ali, Imran,Suhail, Mohd,Asnin, Leonid
, p. 1304 - 1311 (2018/10/24)
New chiral high-performance liquid chromatography (HPLC) method for the enantiomeric resolution of quinolones is developed and described. The column used was Chirobiotic T (150?×?4.6?mm, 5.0?μm). Three mobile phases used were MeOH:ACN:Water:TEA (70:10:20:0.1%), (60:30:10:0.1%), and (50:30:20:0.1%). The flow rate of the mobile phases was 1.0?mL/min with UV detection at different wavelengths. The values of retention, resolution, and separation factors ranged from 1.5 to 6.0, 1.80 to 2.25, and 2.86 to 6.0, respectively. The limit of detection and quantification ranged from 4.0 to 12?ng and 40 to 52?ng, respectively. The modeling studies indicated strong interactions of R-enantiomers with teicoplanin chiral selector than S-enantiomers. The supra molecular mechanism of the chiral recognition was established by modeling and chromatographic studies. It was observed that hydrogen bondings and π-π interactions are the major forces for chiral separation. The present chiral HPLC method may be used for enantiomeric resolution of quinolones in any matrices.
Synthesizing method of ofloxacin and levofloxacin
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Paragraph 0017; 0023, (2019/01/06)
The invention relates to a novel method for preparing ofloxacin and levofloxacin. The method includes: using ofloxacin carboxylic acid (ester) or levofloxacin carboxylic acid (ester) as the raw material, allowing the ofloxacin carboxylic acid (ester) or levofloxacin carboxylic acid (ester) to have reaction with borate to generate intermediate 1A or intermediate 1, allowing the intermediate 1A or intermediate 1 to have reaction with N- methyl piperazine to generated intermediate 2A or intermediate 2, hydrolyzing the intermediate 2A or intermediate 2 under an acid condition to obtain levofloxacin/ofloxacin salt, and freeing and extracting the levofloxacin/ofloxacin salt under a corresponding alkaline condition to obtain levofloxacin/ofloxacin or hydrate thereof. The method has the advantagesthat the initial materials and reagents used by the method are easy to obtain, the method is simple to operate, mild in reaction conditions, high in yield, low in cost and suitable for industrial production, and the purity of the levofloxacin/ofloxacin or hydrate thereof prepared by the method reaches up to 99.9%.
