聚硅氧烷接枝酯类单体手性固定相的制备及其表征

以S-(-)-乳酸甲酯、S-(-)-α-苯乙醇、(S)-(+)-仲丁醇为手性源,以N,N′-二环己基碳二亚胺(DCC)为缩水剂、4-二甲氨基吡啶为酰化催化剂,分别与上述3种不饱和酸进行酯化反应合成了新的手性不饱和酯类单体,用红外光谱、核磁共振及有机元素分析表征了产物结构. 以聚硅氧烷接枝手性单体,制备得到了手性固定相.     

可聚合手性酰胺类单体的合成

以S-(+)-1-甲基环己乙胺或S-(-)-1-甲基苯乙胺为手性源,分别与甲基丙烯酰氯和10-十一烯酰氯酰胺化合成了4个典型的可聚合手性酰胺类单体,其结构经NMR,IR和元素分析表征。     

丙烯酸三苯甲酯及其衍生物的不对称聚合反应

含有大位阻基团的1,1-双取代α,β-不饱和酯,诸如甲基丙烯酸三苯甲酯(TrMA)、甲基丙烯酸邻甲苯基二苯基甲酯(DPIMA),在不对称聚合反应中,能够形成具有单手螺旋构象的旋光性聚合物。这类聚合物因具有独特的手性识别能力而一直为人们所瞩目。现有的研究结果表明,在这类单体的不对称聚合反应中,手性配体如鹰爪豆碱[(—)-Sp]决定着聚合产物     

毛细管电泳手性分离分析西酞普兰中间体

西酞普兰(citalopram,CIT)适用于抑郁性精神障碍的急性和常规治疗。S-( )-CIT对5-羟色胺有较好的抑制作用,R-(-)-CIT疗效较差[1],故要求以S-( )-CIT单体形式上市。化合物(-)-4-[4-(二甲氨基)-1-(4′-氟苯基)-1-羟丁基]-3-羟甲基-苯氰氢溴盐((-)-CITI)是S-( )-CIT合成中最重要的中间体,手性分离出(-)-CITI后通过环合即可制备S-( )-CIT单体。欲控制S-( )-CIT的光学纯度,必须先控制R-(-)-CITI的纯度。因此,建立(±)-CITI的手性分离方法及异构体的定量方法十分必要。本文在文献[2]的基础上拆分了CITI对映体,定量测定了R-(-)…     

新型多齿手性氨基醇的合成和结构表征

以L-苯甘氨酸和N,N-二甲基苯胺为原料,合成了2种新型多齿手性氨基醇S-1,1,2-三苯基-2-[(2-二甲氨基-5-溴-1-苯基)甲氨基]-1-乙醇和S-2-苯基-2-[(2-二甲氨基-5-溴-1-苯基)甲氨基]-1-乙醇;利用红外光谱仪、核磁共振谱仪及质谱仪表征了合成产物的结构.     

手性γ,γ-偕二芳基羰基化合物的催化不对称合成

正手性γ,γ-偕二芳基羰基化合物及其衍生物广泛存在于天然产物和药物分子中,如鬼臼毒素,Cladosporol和抗抑郁药舍曲林等.通常,手性γ,γ-偕二芳基羰基化合物的合成是以手性化合物为起始原料,通过催化不对称方式来构建这一关键骨架一直是一个挑战性的课题.铑催化芳基硼酸对芳基缺电子烯烃的不对称共轭加成是目前合成手性谐二芳基化合物有效途径之一.利用该策略,选用γ-芳基-β,γ-不饱和酮酸酯(或酮酰胺)类为底物,可能是实现手性γ,γ-偕二     

手性BINOL/Ti(O~iPr)_4配合物催化辛炔对醛的不对称加成反应

利用手性联二萘酚/Ti(O~iPr)_4配合物作为催化剂,对辛炔对醛的不对称加成反应进行了研究。在该体系下,芳香醛、脂肪醛以及α,β-不饱和醛类底物都可通过该方法获取相应手性炔醇产物,并可取得中等至良好的对映选择性。     

侧基对N-炔丙基酰胺螺旋共聚物光学活性的影响

设计并合成了5个系列的带有不同侧基的手性-非手性N-炔丙基酰胺共聚物,以铑有机配合物为催化剂对单体实施聚合反应得到高产率(>95%)的共聚物,聚合物具有高立构规整性(cis-含量高于94%).利用圆二色(CD)及紫外-可见吸收(UV-Vis)光谱技术对共聚物的二级结构及光学活性进行了表征,当非手性单体的酰胺侧基体积适中时,共聚物具有较高的光学活性,部分共聚物的光学活性甚至高于纯手性聚合物.表明通过选择合适的手性-非手性共聚单体及单体配比,可获得具有高光学活性的螺旋聚合物.     

铜催化格氏试剂不对称共轭加成研究进展

铜催化格氏试剂不对称1,4-、1,6-及1,2-共轭加成是构建手性碳的重要方法,其加成产物是许多天然产物以及手性药物合成的关键中间体.对铜催化的格氏试剂不对称1,4-、1,6-及1,2-共轭加成反应进行了较全面的综述,其中涉及的受体种类包括α,β-不饱和酮、不饱和酯、不饱和内酯、不饱和硫酯、不饱和醛和不饱和砜.此外,对不对称1,4-共轭加成反应的机理研究也进行了较详细的介绍.     

L-亮氨酸衍生物手性氨基醇的合成与应用

以N,N-二甲基苯胺为原料,经对位溴化、邻位甲酰化得到5-溴-2-(二甲氨基)苯甲醛;L-亮氨酸经酯化、格氏反应得到二齿手性氨基醇;将5-溴-2-(二甲氨基)苯甲醛与上述氨基醇经缩合、还原得到三齿手性氨基醇;产物经红外光谱(IR)、质谱(MS)及核磁共振氢谱(1H-NMR)表征,考察了二齿手性氨基醇和三齿手性氨基醇作为...     

新型手性配体交换色谱固定相的制备及应用

 合成了 2 -(2 -羟基 -3 -烷氧基 )丙基 -(S) -1 ,2 ,3 ,4-四氢 -3 -异喹啉羧酸手性选择子 ,制备了两种新型涂渍手性配体交换色谱固定相 ,拆分了某些 DL-氨基酸 ,比较了 DL-氨基酸在两种手性相上的色谱分辨。     

An efficient chiral synthesis of (R)-N-[3-acetyl-4-(2-hydroxy-3-isopropylamino-propoxy)phenyl]-butanamide with high enantioselectivity

R-Enantiomer of the β-receptor antagonist N-[3-acetyl-4-(2-hydroxy-3-isopropylamino-propoxy)phenyl] butanamide with high enantioselectivity was synthesized from cheap starting materials and enantiopure chiral reagent through an efficient, convenient and practical synthetic strategy. Title product was detected by ¹H NMR, ¹³C NMR, and MS, and the enatiomeric excess was determined by chiral HPLC analysis using a chiracel AD-H column. Supported by the National Natural Science Foundation of China (Grant Nos. 20472090 & 10576034) and PLA General Armament Department (Grant No. 9140A28010707zk7301)     

全衍生化羟丙基-β-环糊精固定相的制备及应用

研究了3, 5-二甲基苯基异氰酸酯对羟丙基-β-环糊精固定相的手性识别影响.通过异氰酸丙基三乙氧基硅烷作偶联剂,将羟丙基-β-环糊精键合到3-氨丙基硅烷化硅胶上,再用3, 5-二甲基苯基异氰酸酯对β-环糊精和硅胶其余羟基进行衍生化,制得一种新型的3, 5-二甲基苯基氨基甲酸酯全衍生化羟丙基-β-环糊精键合硅胶手性固定相.在反相色谱条件下,对9种手性药物进行了拆分,结果表明,3, 5-二甲基苯基氨基全衍生化固定相较之羟丙基-β-环糊精固定相有更好的分离效果.     

A Chiral Recognition Mechanism Proposed for Resolving π-Acidic Racemates on π-Acidic Chiral Stationary Phases Derived from (S)-Leucine

A chiral recognition mechanism which can rationalize the resolution of N-(3,5-dinitrobenzoyl)-α-amino amides on chiral stationary phases (CSPs) obtained from N-(3,5-dinitrobenzoyl)leucine amide derivatives has been proposed on the basis of the chromatographic resolution behavior of various N-(3,5-dinitrobenzoyl)-α-amino acid derivatives and N-(various benzoyl)leucine N-propyl amides. The proposed chiral recognition mechanism utilizes two hydrogen bonding interactions between the CSP and the analyte and a π-π donor-acceptor interaction between the N-(3,5-dinitrobenzoyl) groups of the CSP and the analyte. From the chiral recognition mechanism proposed, it has been concluded that the resolution of π-acidic N-(3,5-dinitrobenzoyl)-α-amino acid derivatives on π-acidic CSPs derived from N-(3,5-dinitrobenzoyl)leucine amide delivatives is not unusual, but is merely the extension of the resolution of the π-basic racemates on π-acidic CSPs. However, the chromatographic behavior of the resolution of N-(3,5-dinitrobenzoyl)phenylglycine derivatives on CSPs derived from N-(3,5-dinitrobenzoyl)leucine amide derivatives is different from that of the resolution of other N-(3,5-dinitrobenzoyl)-α-amino acid derivatives. To rationalize this exceptional behavior, a second chiral recognition mechanism which utilizes two hydrogen bonding interactions (which are different from those of the first chiral recognition mechanism) between the CSP and the analytes and a π-π donor-acceptor interaction between the N-(3,5-dinitrobenzoyl) group of the CSP and the phenyl group of the analytes has been proposed to compete with the first chiral recognition mechanism. In this instance, it has been proposed that the separation factors and the elution orders of the resolution of N-(3,5-dinitrobenzoyl)phenylglycine derivatives are dependent on the balance of the two competing chiral recognition mechanisms.     

From Sergeants and Soldiers to Chiral Conflict Effects in Helical Polymers by Acting on the Conformational Composition of the Comonomers

Different communication mechanisms can be switched within a copolymer by acting on the conformational composition of the components and their chirality. Thus, a sergeant and soldiers effect is produced in two diastereomeric copolymer series, poly[(S)- 1 _r-co-(S)- 2 _(1−r)] and poly[(R)- 1 _r-co-(S)- 2 _(1−r)], owing to the presence in chloroform of a preferred conformation in (S)- 2 , and a conformational equilibrium in 1 , where a P helix is induced independently of the absolute configuration of the soldier. In THF, the presence of a conformational equilibrium at the pendants of the two components produces a reciprocal chiral enhancement effect by copolymerization of the two monomers, while in DMF, a third chiral to chiral communication switch is produced due to the presence of a single conformer at the pendant group of the two components. In such a case, a chiral conflict or chiral accord effect is produced depending if the two components induce the same or the opposite helical sense.     

Preparation and chromatographic evaluation of β-cyclodextrin derivative CSPs bearing substituted phenylcarbamate groups for HPLC

Five β-cyclodextrin (β-CD) derivatives bearing substituted phenylcarbamate/3-(triethoxysilyl)propylcarbamate groups at the 2-, 3-, and 6-positions of glucose unit and another five derivatives containing benzoate at the 2-position and substituted phenylcarbamate/3-(triethoxysilyl)propylcarbamate groups at the 3- and 6-positions were synthesized using the regioselective esterification method. The obtained β-CD derivatives were efficiently immobilized onto the silica gel through the intermolecular polycondensation of a small amount of the triethoxysilyl groups, which were used as the chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC). The chiral separation properties of these CSPs were evaluated under the normal-phase HPLC. The effects of solvent polarity and the side chain structures of β-CD derivatives on the chiral recognition ability of the immobilized CSPs were investigated. Among these β-CD derivative CSPs, 2,3,6-tris(3,5-dichlorophenylcarbamate)-β-CD CSP showed a relatively high chiral recognition ability for the studied racemates. The regioselective esterification at the 2-position of glucose unit in the β-CD decreased the chiral recognition ability at the same conditions. For some racemates, the β-CD derivative CSPs showed chiral recognition abilities comparable or better to some chemical bonded β-CD derivative CSPs and 3,5-dichloro- and 3,5-dimethylphenylcarbamates of cellulose and amylose CSPs.     

环境中手性污染物对映体分析方法的研究进展

手性污染物对映体尽管具有相似的物理化学性质,但在环境中的吸附、转移、降解等过程往往存在一定差异。生态安全问题与人类健康密切相关,因此,对手性环境污染物进行对映体水平上的分离分析是十分重要的研究课题。目前,国内外对环境中的手性污染物已开展了相关研究,然而全面评述相关分析测定方法的新进展鲜有报道。本文主要对环境中手性污染物的种类以及近5年环境中手性污染物的分析检测技术如液相色谱-质谱联用法、气相色谱-质谱联用法、毛细管电泳法、超临界流体色谱-质谱联用法等进行了归纳、综述和展望,为后续手性污染物的分析检测提供依据和参考。     

手性固定相AD、AS和OD的拆分性能

手性固定相-高效液相色谱法在手性药物、手性农药等的分离分析中应用广泛。本文采用3种多糖衍生物的手性固定相(即EnantioPak AD、AS和OD)对20种手性化合物开展手性分离研究,进而探讨样品分子结构、多糖骨架和衍生基团对手性分离的影响。结果表明,除化合物13外,其余化合物在EnantioPak AD上均实现基线分离,分离度多在2.0以上,在正己烷-醇流动相中加入酸碱添加剂可改善和优化酸性或碱性化合物的分离效果;芳香醇(化合物13~16)随着侧链碳数增加在色谱柱上的保留减弱,其分离度呈现增加的趋势;对比8种化合物在3种手性固定相上的分离结果可知,EnantioPak AD表现出更优的分离性能。这为深入研究和了解多糖手性固定相、拓展其手性分离应用提供了参考。     

电喷雾质谱在手性识别和分析中的应用

近年来电喷雾质谱以其快速、灵敏、简便、样品用量少等特点被越来越多地应用于手性分析研究中。本文综述了目前电喷雾质谱法在手性识别和分析中的应用,包括常用的分析方法及常用的质谱手性选择剂,并对其发展进行了展望。