Polymer microenvironmental effects on the photophysics of cinchonine dication

Photophysical properties of cinchonine dication (C⁺⁺) have been studied in protic and aprotic polymers by monitoring steady state and time resolved measurements. It is found to be sensitive towards the microenvironment of polymers. Edge excitation red shifted emission (EERS) is observed in all polymeric matrices. However, the magnitude of EERS is relatively high in protic as compared to aprotic polymer. Isobestic point in excitation spectra and three decay components in time resolved measurements indicate more than two trapped chemical species in the heterogeneous environment of the polymer. Solute-polymer interactions are found to produce the third decay channel, unlike in solution phase and may be useful to understand the polymer microenvironment.     

Separation of Cinchona alkaloids on a novel strong cation-exchange-type chiral stationary phase—comparison with commercially available strong cation exchanger and reversed-phase packing materials

A recently reported chiral strong cation exchanger (cSCX) type stationary phase was investigated for the LC separation of a series of Cinchona alkaloids and synthetic derivatives thereof to test its usefulness as alternative methodology for the separation of those important pharmaceuticals. The cSCX column-packing material was qualitatively compared on the one hand against a commercially available non-enantioselective SCX-material, PolySulfoethyl-A, and, on the other hand, against a modern C18 reversed-phase stationary phase which is commonly employed for Cinchona alkaloid analysis. Both SCX columns showed no pronounced peak-tailing phenomena which typically hamper Cinchona alkaloid RP analysis and require specific optimization. Thus, the cSCX-based assay provided new feasibilities for the separation of the Cinchona alkaloids in polar organic mode as opposed to conventional reversed-phase methodologies. In particular, a method for the simultaneous determination of eight Cinchona alkaloids (quinine, quinidine, cinchonine, cinchonidine, and their corresponding dihydro analogs) using the cSCX column in HPLC has been developed and exemplarily applied to impurity profiling of a commercial alkaloid sample. Furthermore, both SCX materials allowed successful separation of C9-epi and 10,11-didehydro derivatives from their respective educts in an application in synthetic Cinchona alkaloid chemistry. Figure An alternative separation principle - HPLC separation of strongly basic natural Cinchona alkaloids and synthetic derivatives thereof by means of a strong cation-exchanger type chiral stationary phase     

含金鸡钠碱的光活性聚合物：2.含辛可宁的两亲单体及其两亲聚合物

通过两亲单体２－丙烯酰胺基烷磺酸与辛可宁成盐后再聚合，或ＡＭＣｎＳ聚合成梳型两亲聚合物后再生ＣＮ成盐，可获得含辛可宁的两亲聚合物。ＡＭＣｎＳ－ＣＮ盐及其相应的两亲聚合物具有比ＣＮ好得多的溶解性，易溶于氯仿、ＴＨＦ、乙醇、ＤＭＦ和ＤＭＳ等极性不同的溶剂。ＡＭＣｓＳ－ＣＮ盐好得多的溶解性，易溶于氯仿、ＴＨＦ、乙醇、ＤＭＦ和ＤＭＳＯ等极性不同的溶剂。ＡＭＣｎＳ－ＣＮ盐在乙醇／氯仿（Ｖ／Ｖ＝１／２）中比旋     

金鸡纳生物碱电喷雾质谱裂解规律研究

利用电喷雾离子阱质谱（ES-ITMS）技术进行了金鸡纳中4种喹啉类生物碱（奎宁、奎尼定、辛可宁和辛可尼定）的电喷雾质谱研究。在优化的质谱条件下,正离子全扫描时,4种生物碱都易形成带一个质子的分子离子;进一步碰撞诱导解离四种母离子,二级质谱表明羟基丢失、奎宁环断裂及重排为其主要裂解方式。     

Electrochemical sensor for cinchonine based on a competitive host-guest complexation

An electrochemical sensor for cinchonine (CCN) using the β-cyclodextrin (β-CD) modified poly(N-acetylaniline) (PAA) electrode has been developed, in which 1,4-hydroquinone (HQ) was chosen as a probe. Complexation of HQ with β-CD modified on the glassy carbon electrode (GCE) was examined by cyclic voltammetry (CV). HQ was included in the cavity of β-CD and reversible voltammograms were observed. In the presence of CCN, a competitive inclusion equilibrium with β-CD was established between HQ and CCN, lowering the peak current of HQ. The decrease in the peak current of HQ is directly proportional to the amount of CCN. Linear calibration plot was obtained over the range from 4.0 × 10⁻⁶ to 8.0 × 10⁻⁵ M with a detection limit (S/N = 3) of 2.0 × 10⁻⁶ M. From the inhibitory effect of CCN on the inclusion of HQ by β-CD, the apparent formation constant of CCN with the immobilized β-CD was estimated. This electrochemical sensor showed excellent sensitivity, repeatability, stability and recovery for the determination of CCN. The response mechanism of the sensor was discussed in detail. The optimum steric configuration of inclusion complex was presented by molecular dynamics simulation.     

Piezoelectric quartz crystal sensors based on ion-pair complexes for the determination of cinchonine in human serum and urine

A new sensing method for the determination of cinchonine was presented, based on the sensitive mass response of PQC and the selective adsorption of cinchonine on PVC membrane containing ion-pair complex. The proposed sensors show much wider working range (pH range), much higher sensitivity and selectivity than those potentiometric and spectrophotometric methods. In this paper, three counter ions were compared and six complexes synthesized. For the sensor modified with cinchonine-monotetraphenylborate-PVC membrane, calibration graph was linear over concentration range of 5×10⁻⁸-2.1×10⁻⁴ M with a detection limit of 4×10⁻⁸ M at pH 7.1, and recoveries 97.7-108.6%. Influencing factors were investigated in detail and optimized. Results from real samples were satisfactory.     

Catalytic Enantioselective Methanolysis of 4 -substituted-2-phenyl-5(4H)-oxazolones by Cinchonine

Theopeningoftheringof5(4H)-oxazolonesisoneofthemethodsforthesynthesisof-..-non-racemica-aminoacids.Thediastereoselectivering-openingof5(4H)-oxazolonesbychiralnucleophilesandenantioselectivehydrolysisandalcoholysisof5(4H)-oxazolonesbyenzymeshavebeenextensivelyinvestigated'.However,toourknow1edgenon-enzymecatalyzedenantioselectivealcoholysisof5(4H)-oxazoloneshasnotbeenreported.Inthispaper,wereportonthefirstnon-enzymecatalyzedenantioselectivealcoholysisof5(4H)-oxazolonesbycinchonine.As4-substit…     

Alkaloid induced asymmetric electrocarboxylation of 4-methylpropiophenone

The alkaloid-induced electrocarboxylation of 4-methylpropiophenone is examined in mild conditions. Comparative studies with several inductors indicate that the efficient enantiodiscrimination of the electrocarboxylation depends on the nucleophilic quinuclidine nitrogen atom and the OH group of the inductors.     

辛可宁季铵盐的合成及催化不对称烷基化研究

探索了辛可宁季铵盐的通用合成方法, 确定辛可宁与取代苄溴在四氢呋喃中回流为最优反应途径, 合成了11个羟基保留的辛可宁季铵盐, 收率57%~88%, 并合成了4种羟基保护季铵盐, 羟基成醚过程在生成季铵盐前后均可进行, 总收率62%~71%; 羟基酯化只能在生成季铵盐之后进行, 总收率78%. 本文共合成了15个季铵盐(Cn-1~Cn-15), 其中5个为新化合物, 另有4个的合成方法未见文献报道. 选用该类季铵盐催化剂催化二苯亚甲基甘氨酸叔丁酯的不对称苄基化反应, 结果发现, 催化剂苄基具有4-Br取代或羟基成醚均有助于提高反应产物的对映选择性. Cn-9可得到最优的反应结果, 产率93%, e.e.值91%.     

磁性粒子表面自组装辛可宁分子印迹电致化学发光传感器

以辛可宁为模板分子、十二烷基硫醇为功能单体,在Fe3 O4@Au纳米粒子表面自组装辛可宁分子印迹膜,构建了新型磁性粒子-分子印迹电化学发光传感器。通过透射电子显微镜对磁性纳米粒子的粒径分布及形貌进行了表征,使用红外光谱对比分析了辛可宁、分子印迹膜洗脱前和洗脱后的结构及成分。结果表明,在最优的实验条件下(0.012 mol/L 硼砂缓冲溶液(pH 9.5),0.8 mmol/L Ru(bpy)2+3),辛可宁浓度的对数在1×10-10~9×10-8 mol/L范围内,与电化学发光强度变化值有良好的线性关系,检出限为3.5×10-11 mol/L。此传感器灵敏度高、选择性好、易于更新,将其用于血清样品的检测,方法回收率为98.8%~104.7%。