键合型纤维素3，5-二甲基苯基氨基甲酸酯手性固定相的制备及分离性能研究

将溶于N,N-二甲基乙酰胺-LiCl-吡啶的纤维素混合液直接涂敷于氨丙基硅胶上,分别以4,4′-二苯基甲烷二异氰酸酯和1,6-己二异氰酸酯为间隔臂将纤维素键合到硅胶上,并通过与过量的3,5-二甲基苯基异氰酸酯反应,制得2种键合型纤维素3,5-二甲基苯基氨基甲酸酯手性固定相。考察了固定相的分离性能。研究表明,所制备的手性固定相具有较高的手性识别能力和溶剂耐受性,相比于常规流动相（正己烷/异丙醇混合液）,当流动相中含有三氯甲烷或四氢呋喃时,多数对映体得到了更好的分离,且二异氰酸酯的种类对手性固定相的手性识别能力影响较小。     

键合型纤维素3,5-二甲基苯基氨基甲酸酯手性固定相的制备及分离性能研究

将溶于N,N-二甲基乙酰胺-LiCl-吡啶的纤维素混合液直接涂敷于氨丙基硅胶上,分别以4,4'-二苯基甲烷二异氰酸酯和1,6-己二异氰酸酯为间隔臂将纤维素键合到硅胶上,并通过与过量的3,5-二甲基苯基异氰酸酯反应,制得2种键合型纤维素3,5-二甲基苯基氨基甲酸酯手性固定相。考察了固定相的分离性能。研究表明,所制备的手性固定相具有较高的手性识别能力和溶剂耐受性,相比于常规流动相(正己烷/异丙醇混合液),当流动相中含有三氯甲烷或四氢呋喃时,多数对映体得到了更好的分离,且二异氰酸酯的种类对手性固定相的手性识别能力影响较小。     

一种手性中间体在键合型和涂覆型纤维素手性固定相上的拆分

制备了涂覆型和键合型纤维素-(3, 5-二甲基苯基氨基甲酸酯)固定相, 分别在制备的纤维素手性固定相上成功地拆分了一种手性中间体, 通过考察流动相中的改性剂(醇、四氢呋喃、三氯甲烷)对手性拆分的影响, 优化了手性中间体在两种手性固定相上的色谱分离条件, 并比较了手性中间体在涂覆和键合型纤维素手性固定相上的拆分. 结果表明, 涂覆型和键合型手性固定相对这种手性中间体均有较好的拆分效果, 在150 mm的色谱柱上, 这两种手性固定相对这种手性中间体的拆分能力相差不大, 但键合型固定相上可选择的流动相范围更广.     

含磷手性化合物在多聚糖类手性固定相上的手性分离

在纤维素 三(3,5 二甲基苯基氨基甲酸酯)(ChiralcelOD)和直链淀粉 三(3,5 二甲基苯基氨基甲酸酯)(ChiralpakAD H)手性固定相上,采用高效液相色谱正相条件,分离了系列含磷手性化合物。考察了流动相中有机改性剂的种类及浓度对手性分离的影响;研究了化合物的结构与保留及对映体选择性的关系;并探讨了手性识别机理。     

高效液相色谱的4种商品手性柱对38种手性化合物的拆分研究

采用纤维素-三(3,5-二甲基苯基氨基甲酸酯)涂敷型手性固定相(Chiralcel OD柱)、直链淀粉-三(3,5-二甲基苯基氨基甲酸酯)涂敷型手性固定相(Chiralpak AD柱)、直链淀粉-三(3,5-二甲基苯基氨基甲酸酯)键合型手性固定相(Chiralpak IA柱)和Pirkle型的(S,S)-Whelk-01手性固定相对38种外消旋体化合物进行手性拆分。实验结果表明,4种固定相的手性识别能力为:OD>AD>IA>(S,S)-Whelk-01,OD固定相的手性识别率达到60%,并且它们之间的手性识别性能还具有一定的互补性。本研究对4种常用手性固定相的拆分能力进行了对比,为拆分手性化合物时有的放矢地选择手性固定相提供了参考。     

淀粉及纤维素三(3-三氟甲基苯基氨基甲酸酯)手性固定相的制备及其性能评价

为了扩展多糖类手性固定相的种类,制备了基于淀粉及纤维素三(3-三氟甲基苯基氨基甲酸酯)的涂敷型手性固定相,以正己烷-异丙醇混合液为流动相,对8种手性化合物进行了高效液相色谱拆分。研究表明: 虽然与应用最广泛的分别以淀粉及纤维素三(3,5-二甲基苯基氨基甲酸酯)为手性选择因子的商品化手性柱Chiralpak AD和Chiralcel OD相比,所制备的手性固定相的手性分离能力较低,但纤维素三(3-三氟甲基苯基氨基甲酸酯)手性固定相显示出特异的手性识别能力,一些手性化合物在此固定相上得到了比在Chiracel OD上更好的分离;所制备的手性固定相的手性识别能力随流动相中异丙醇含量的降低而变好,当流动相中正己烷与异丙醇的体积比为95:5时所制备的手性固定相显示出相对较高的手性识别能力;总体来说,淀粉三(3-三氟甲基苯基氨基甲酸酯)手性固定相的手性识别能力稍强于纤维素三(3-三氟甲基苯基氨基甲酸酯)手性固定相,同时两种手性固定相的手性识别能力具有一定的互补性。     

非均匀取代淀粉衍生物手性固定相的制备及其手性识别能力

通过区域选择性方法制备了两种新型淀粉衍生物,分别为淀粉2-苯甲酸酯-3-(4-甲基苯基氨基甲酸酯)-6-(3,5-二氯苯基氨基甲酸酯)和淀粉2-苯甲酸酯-3-(3,5-二氯苯基氨基甲酸酯)-6-(4-甲基苯基氨基甲酸酯),将二者分别涂覆于氨丙基硅胶后用作液相色谱手性固定相。研究表明:所制备的手性固定相显示出特异的手性识别能力,其手性识别能力明显高于均匀取代淀粉衍生物——淀粉三(3,5-二氯苯基氨基甲酸酯),取代基的性质及在葡萄糖单元上的位置对手性固定相的手性识别能力有较大的影响。一些未在商品化的手性柱Chiralpak AD上得到有效分离的手性化合物在所制备的固定相上得到了更好的分离。所测试的8对对映体在淀粉2-苯甲酸酯-3-(4-甲基苯基氨基甲酸酯)-6-(3,5-二氯苯基氨基甲酸酯)固定相上均得到了分离,因而此固定相的手性识别能力较强,具有潜在的应用价值。     

正反相模式下键合纤维素手性固定相对手性化合物的拆分

在自行合成的键合型纤维素-(3,5-二甲基苯基氨基甲酸酯)(CDMPC-CSP)手性固定相上,在正相模式下对苯偶姻和甲霜灵外消旋体进行了拆分,考察了流动相中醇以及温度在手性识别中对手性分离的影响。同时考察了反相模式下外消旋体的拆分。     

纤维素2,3-位和2,3,6-位苯基氨基甲酸酯手性固定相的选择性研究

合成了纤维素-2,3,6-三苯基氨基甲酸酯、纤维素-2,3-二苯基氨基甲酸酯、纤维素-2,3,6-三(3,5-二甲基苯基氨基甲酸酯)和纤维素-2,3-二(3,5-二甲基苯基氨基甲酸酯)4种纤维素衍生物手性固定相,用正己烷-异丙醇（体积比为9∶1）混合液作流动相,对9种手性化合物进行了高效液相色谱拆分。实验结果表明:对所测的9个样品,纤维素-2,3-二苯基氨基甲酸酯的手性选择性大大好于纤维素-2,3,6-三苯基氨基甲酸酯;而纤维素-2,3-二(3,5-二甲基苯基氨基甲酸酯)与纤维素-2,3,6-三(3,5-二甲基苯基氨基甲酸酯)的分离因子针对不同的对映体各有优点,但前者通常具有更小的保留因子,可以缩短一定的分析时间。     

新型键合型纤维素类手性固定相的制备及安息香分离

采用六亚甲基二异氰酸酯作为键合试剂,制备了键合型纤维素3,5-二甲基苯基氨基甲酸酯手性固定相。分别往正己烷/乙醇或正己烷/异丙醇中添加四氢呋喃和二氯甲烷,系统地考察了四氢呋喃和二氯甲烷的含量对安息香外消旋体拆分的影响。实验结果表明,安息香两对映体的容量因子随二者含量的增加而降低,但分离效果变化不大,分离因子均在1.2以上。所制备的CSP在采用含有高浓度四氢呋喃(23%)、二氯甲烷的流动相进行手性分离时仍具有良好的稳定性。与涂敷型固定相相比,流动相选择范围更广。     

Synthesis and enantioseparation behaviors of novel immobilized 3,5‐dimethylphenylcarbamoylated polysaccharide chiral stationary phases

Two new polysaccharide‐derived chiral selectors, namely, 6‐azido‐6‐deoxy‐3,5‐dimethylphenylcarbamoylated amylose and 6‐azido‐6‐deoxy‐3,5‐dimethylphenyl carbamoylated cellulose, were synthesized under homogeneous conditions and immobilized onto aminized silica gel by the Staudinger reaction, resulting in two new immobilized polysaccharide chiral stationary phases (CSPs). Their enantioseparation performances were investigated under normal‐phase mode by HPLC. Among 17 analytes, baseline separations of 12 pairs of enantiomers are achieved on the immobilized cellulose CSP, which demonstrates that this new cellulose material exhibits almost the same enantioseparation performance as the coated cellulose CSP. In addition, the amylose‐derived CSP presents limited enantiorecognition ability but certain complementarity with the immobilized and coated cellulose‐based materials. Neither metolachlor nor paclitaxel side chain acids are separated on two cellulose‐derived CSPs, but effective separations are obtained on the immobilized amylose column.     

Immobilized Polysaccharide-Based Stationary Phases for Enantioseparation in Normal Versus Reversed Phase HPLC

A set of 31 structurally different chiral pharmaceutical compounds was used as model analytes for investigation of the enantioselective potential of two immobilized polysaccharide-based chiral stationary phases under normal and reversed phase separation conditions. These chiral stationary phases differed in the polymeric backbone, amylose or cellulose, but possessed the same derivatization functionality. The results showed that the tris(3,5-dimethylphenylcarbamate) of amylose and cellulose have very broad, and often complementary, enantiorecognition abilities. In general, normal phase separation mode seemed to be more advantageous for separation of the majority of studied pharmaceuticals no matter if amylose- or cellulose-based columns were used. However, in certain cases the reversed phase separation system yielded better results. The combination of these two immobilized chiral stationary phases offers a powerful tool for enantioseparation of different types of pharmaceuticals in the normal and/or reversed phase mode.

     

High-performance liquid chromatographic evaluation of a coated cellulose tris(3,5-dimethylphenylcarbamate) chiral stationary phase having a small-pore silica support

A two-step coating/precipitation synthetic procedure has been developed for the preparation of cellulose tris(3,5-dimethylphenylcarbamate) chiral stationary phase (CSP) having a small-pore silica support. With this synthetic strategy, monodisperse, spherical CSP particles can be produced without the need for a wasteful and time-consuming sieving process. The performance of the synthesized CSP towards a variety of racemates was evaluated in the normal-phase HPLC mode. HPLC separation experiments revealed that the synthesized CSP exhibited a chiral recognition ability fully comparable to the corresponding commercial columns prepared using conventional large-pore silica as the support. Moreover, the synthesized CSP was successfully applied to semipreparative enantioseparation of a new triazole antifungal agent.     

Enantioselective separation of indole derivatives by liquid chromatography using immobilized cellulose (3,5-dimethylphenylcarbamate) chiral stationary phase

A new chiral stationary phase of 3,5-dimethylphenylcarbamates of cellulose chemically bonded to 3-aminopropyl silica gel was prepared, which may be used with a wide range of solvents including standard and non-standard ones. Several racemic indole derivatives have been resolved using standard and non-standard solvents on the immobilized chiral column (15 cm × 0.46 cm) at a flow rate of 1.0 mL/min or 0.5 mL/min with a UV detection at 230 nm. Separation of indole derivatives on immobilized and coated chiral stationary phases (CSP) in HPLC using a mixture of hexane/2-propanol as mobile phase was compared. The resolution factors for immobilized and coated chiral column were 0.57–2.02 and 0.61–4.03, respectively. It was found that both coated and immbolized chiral stationary phases were suitable for the separation of indole derivatives; however, the coated CSP possesses a higher resolving power than the immobilized one. The article is published in the original.     

Evaluation of differences between Chiralpak IA and Chiralpak AD‐RH amylose‐based chiral stationary phases in reversed‐phase high‐performance liquid chromatography

Polysaccharide‐based chiral stationary phases can be used for the enantioselective separation of a wide range of structurally different compounds. These phases are available with chiral selectors coated or immobilized on silica gel support. The means of attachment of the chiral selector to the carrier can influence the separation performance of these stationary phases. This paper deals with evaluation of differences in the separation abilities of coated Chiralpak AD‐RH versus immobilized Chiralpak IA amylose‐based stationary phases in the reversed–phase mode of high–performance liquid chromatography. A set of chiral analytes was separated under acidic and basic conditions. Differences were observed in the enantioseparation potential of the tested phases. The linear‐free energy relationship and additional evaluation of ionic interactions were used to ascertain whether the interactions that participate in retention and enantioseparation are affected by the means of preparation of these phases. All the interactions covered by the linear‐free energy relationship were significant for the studied phases and their absolute values were almost always higher for the coated phase. Ionic interactions were found to be more important on the immobilized stationary phase but did not contribute to any improvement in the enantioselective separation performance.     

(3,5-二甲基苯基氨基甲酸酯)衍生的纤维素手性固定相

纤维素三（3,5-二甲基苯基氨基甲酸酯）是液相色谱中使用最广泛的手性柱。该文详细地研究了不同程度衍生的纤维素（3,5-二甲基苯基氨基甲酸酯）以及不同硅胶（粗制硅胶、氨丙基粗制硅胶、精制硅胶、氨丙基精制硅胶、大孔硅胶、氨丙基大孔硅胶）作为支撑体对该柱手性分离能力的影响。自制了13根手性色谱柱,分别考察了其对16种外消旋体的拆分,分离结果显示：三取代纤维素柱 > 二取代纤维素柱 > 纤维素柱;精制硅胶和大孔硅胶优于粗制硅胶,大孔硅胶的柱压更低;硅胶的氨丙基化对手性选择性有一定的影响;这些手性柱之间具有一定的互补性,尤其是纤维素柱。该文有助于人们更深刻地理解和更好地把握高效液相色谱手性柱的制备。     

Lipase-mediated enantioselective kinetic resolution of racemic acidic drugs in non-standard organic solvents: Direct chiral liquid chromatography monitoring and accurate determination of the enantiomeric excesses

The enantioselective resolution of a set of racemic acidic compounds such as non-steroidal anti-inflammatory drugs (NSAIDs) of the group arylpropionic acid derivatives is demonstrated. Thus, a set of lipases were screened and manipulated in either the esterification or hydrolysis mode for the enantioselective kinetic resolution of these racemates in non-standard organic solvents. The accurate determination of the enantiomeric excesses of both substrate and product during such reaction is demonstrated. This was based on the development of a direct and reliable enantioselective high performance liquid chromatography (HPLC) procedure for the simultaneous baseline separation of both substrate and product in one run without derivatization. This was achieved using the immobilized chiral stationary phase namely Chiralpak IB, a 3,5-dimethylphenylcarbamate derivative of cellulose (the immobilized version of Chiralcel OD) which proved to be versatile for the monitoring of the lipase-catalyzed kinetic resolution of racemates in non-standard organic solvents.     

Preparation and evaluation of a deoxycholic‐calix[4]arene hybrid‐type receptor as a chiral stationary phase for HPLC

We report the synthesis and enantioseparation characteristics of two novel covalently immobilized deoxycholic acid derivatives as chiral stationary phases for high‐performance liquid chromatography. In the structure of the first stationary phase, the 3‐position of deoxycholic acid is substituted with a 3,5‐dinitrophenylcarbamoyl group and the second one has an additional calix[4]arene attached to the carboxylic group of the deoxycholic acid. The chromatographic performance of the stationary phases was evaluated with enantioseparation of N‐(3,5‐dinitrobenzoyl)‐dl ‐leucine, N‐(3,5‐dinitrobenzoyl)‐dl ‐valine, omeprazole, diclofop‐methyl, dl ‐mandelic acid and (RS)‐pregabalin. Comparison of the performance characteristics of the prepared chiral stationary phases provided evidence for the active involvement of the calix[4]arene unit in the chiral recognition process. Both stationary phases are chemically bonded to the silica and can be used in both normal‐phase and reversed‐phase modes.     

麦草伏甲酯对对映体的高效液相色谱分离

手性分离;麦草伏甲酯对对映体的高效液相色谱分离