Pirkle型手性固定相拆分盐酸克伦特罗对映体

建立并优化了高效液相色谱手性固定相分离盐酸克伦特罗对映体的方法。使用两种Pirkle型手性固定相(α-Burke-2和Pirkle-1J)拆分了盐酸克伦特罗对映体,考察了缓冲盐添加剂,有机溶剂种类和浓度,以及柱温对保留行为和分离的影响。当流动相为二氯甲烷-乙醇(19:1,V/V)含5 mmol/L乙酸铵,流速2.0 mL/min,柱温20℃时,盐酸克伦特罗对映体在α-Burke-2色谱柱上能实现较好的分离,分离度可达1.85;在Pirkle-1J色谱柱上,分离度可达0.64。盐酸克伦特罗对映体与Pirkle型固定相之间的π-π主客体相互作用和氢键作用是实现对映体分离的最主要分离机制。方法可用于盐酸克伦特罗对映体的质量控制及立体选择性药代动力学的研究。     

手性共价有机骨架用于高效液相色谱固定相拆分13种外消旋化合物

共价有机骨架材料(COFs)作为一种新型的晶体多孔材料,在手性分离领域得到了广泛的关注。本文以1,3,5-三醛基间苯三酚(Tp)和(+)-二乙酰基-L-酒石酸酐反应合成的CTp作为手性有机单体和2,5-二甲基-1,4-苯二胺(Pa-2)发生席夫碱反应,制备了一种手性共价有机骨架材料CTpPa-2。将该手性COF材料CTpPa-2与C_(18)硅胶混合均匀作为固定相,成功制备了高效液相色谱手性柱。以正己烷/异丙醇作为流动相,在一定的色谱条件下,考察了该手性柱对一系列外消旋化合物的拆分性能。实验结果表明,基于手性COF材料CTpPa-2的新型高效液相色谱固定相对13种手性化合物具有较好的对映选择分离能力。将该手性柱与之前我们课题组报道的手性MOF[Ni(L)(bpe)_2(H_2O)_2]H_2O柱和商品AD柱进行比较,该手性柱表现出较好的手性拆分互补作用。     

手性化合物

手性问题与我们的生活密切相关，它涉及到生命、动植物、药物、食品、香料、农药等诸多领域，本文介绍了手性化合物的一些性质、手性药物、手性化合物的拆分、尤其是手性化合物的现代色谱分离方法。     

毛细管电泳在手性氨基酸拆分中的研究进展

毛细管电泳(capillary electrophoresis,CE)作为一种强有力的手性分离技术,由于操作简单、试剂消耗少及柱效高等优点,受到广泛关注,是近年来手性分离领域的研究热点.氨基酸是组成蛋白质的基本单元,且大多数氨基酸具有手性中心,手性氨基酸是生命体系的一个重要特征.具有手性中心的氨基酸,其对映体间的生物活性往往存在着较大的差异,因此,氨基酸的手性拆分对了解人体及动物生命活动起着举足轻重的作用.主要总结了近5年来毛细管电泳的3种分离模式(毛细管区带电泳、胶束电动毛细管色谱、毛细管电色谱)在氨基酸手性拆分中的发展和应用.     

D-苯甘氨酸手性固定相的制备及对多种手性化合物的拆分

以D-3,5-二硝基苯甲酰苯甘氨酸和3-氨丙基硅烷化硅胶合成了D-苯甘氨酸衍生手性固定相,并自制了手性高效液相色谱分离柱,用正己烷-异丙醇作流动相,对非衍生化的氨基酸、胺、醇和羧酸类等10种手性化合物进行了高效液相色谱拆分。结果表明:所拆分的10种手性化合物,有7种手性化合物能得到基线分离,最好的分离度Rs=5.56。该文还用苯对柱性能进行了评价,理论塔板数达每米8万块。     

戊唑醇和三唑酮对映体的手性拆分

以纤维素-三(3,5-二甲基苯基氨基甲酸酯)(CDMPC)高效液相色谱手性固定相(CSP)成功地拆分了戊唑醇和三唑酮对映异构体,通过考察流动相中异丙醇的含量、柱长及温度对手性拆分的影响,优化色谱分离条件。结果显示：该固定相对两种手性农药有较好的拆分效果,使用250mm色谱柱,流动相中含5％异丙醇时戊唑醇得到最佳分离,分离度为1．22;三唑酮在异丙醇含量为2％时有最大分离度1．47。减少异丙醇含量对两种农药均有利于增大分离度,温度升高则降低分离效果。     

酰胺类手性液相色谱柱对烯唑醇光学异构体的直接拆分

以正己烷-12-二氯乙烷为流动相,添加乙腈为改性剂,在酰胺类手性液相色谱柱上实现了对烯唑醇光学异构体的直接拆分.探讨了色谱柱、温度和乙腈的含量对拆分效果的影响,优化了色谱条件.实验结果显示:单独使用KR100-5CHI-DMB色谱柱时,烯唑醇中的光学异构体仅稍微分离;而单独使用Chirex 3001时,烯唑醇中的光学异构体则不分离;当KR100-5CHI-DMB与Chirex 3001串联使用时,烯唑醇中光学异构体能够得到很好的分离;在流动相中加入少量的乙腈作为极性添加剂,有助于改善异构体的分离度.当流动相为正己烷-12-二氯乙烷-乙腈(体积比8 ∶ 1 ∶ 1),流速1.0 mL/min,检测波长254 nm,柱温10 ℃时,烯唑醇中光学异构体得到很好的分离,分离度(R)为3.26.结果表明,酰胺类手性液相色谱柱能有效分离烯唑醇的光学异构体,方法简便、快速.     

乙酸丁酸纤维素手性固定相的制备及对手性化合物的拆分

将乙酸丁酸纤维素涂敷在硅烷化的硅胶上制备了涂渍型高效液相色谱固定相,在40MPa压力下将所得固定相装入色谱柱.在正相的条件下,对20种手性化合物进行拆分,包括醇类,胺类,氨基酸类手性化合物以及外消旋体药物,有13种手性化合物得到了较好的分离.     

奥美拉唑、兰索拉唑对映体及相关物质在不同手性柱的分离比较

考察了奥美拉唑、兰索拉唑对映体及其拆分剂联二萘酚在4种手性柱（chiralcel OD、chiralpak AD、kromasil CHI-TBB和chiral-AGP)上的色谱行为。实验结果表明：Chiralpak AD、 Chiral-AGP柱分离度大，柱效稳定，并且这两种柱子的配合使用实现了对包结拆分的全过程监控。此外，本文根据对映体在不同手性柱的出峰顺序进行了讨论。     

以万古霉素为流动相添加剂的高效液相色谱法手性分析系统的建立

以丹酰化苯甘氨酸、丹酰化苯丙氨酸、丹酰化丝氨酸、丹酯化丙氨酸为模型化合物，通过对色谱柱类型、缓冲液类型、pH和盐浓度、万古霉素用量、甲醇用量、柱温等色谱参数进行考察，建立了以万古霉素为手性流动相添加剂在普通色谱柱上进行手性分析的色谱系统，并在该系统中成功地拆分了酮洛芬对映体。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.