丝裂霉素在β-环糊精修饰电极上的电化学研究

研究了丝裂霉素(MMC)在β-环糊精(β-CD)修饰金电极上的电化学行为。结果表明,β-CD/Au电极能与MMC发生表面包络反应。25℃,pH 7.0时,该电极表面包络常数为3.32×105L/mol,且表面包络常数随温度升高而增大,表现为吸热过程。该电极与MMC的包络呈不可逆的电化学过程。25℃,pH 7.0时,其速率常数为0.0706 s-1,且速率常数值随温度升高而增大,活化能为2.13 kJ/mol。在4~8μmol/L浓度范围内β-CD/Au电极上MMC的还原峰电流与浓度呈线性关系,线性方程Ip=14.86+0.43c,相关系数0.9931,检出限0.75μmol/L。     

环糊精包络物的循环伏安法研究

本文采用玻碳电极以循环伏安法研究了水溶液体系中二茂铁衍生物及芳香族衍生物与环糊精(α-CD, α-CD)的包络行为. 当电活性客体分子被包络时, 在循环伏安图上表现为峰电流和峰电位的变化, 用电流和电位法测定了包络物的解离常数, 并根据解离常数的大小次序探讨了主体分子与客体分子之间的匹配情况同包络物稳定性之间的关系.     

β-环糊精与阿霉素表面包络作用的电化学研究

研究了阿霉素（ADM）在β-环糊精（β-CD）修饰金电极上（β-CD/Au）的电化学行为.结果表明,ADM在β-CD/Au电极上发生表面包络反应.25℃,pH=7.0时,该电极表面包络常数为9.54×104 L·mol^-1,并随温度呈规律性变化,最适宜反应温度为30℃.该电极ADM包络呈准可逆的电化学反应,速率常数为...     

β-环糊精修饰电极对柔红霉素的电化学定量测定

柔红霉素(DNR)是强效的抗白血病制剂,但具有心脏毒性,基因毒性和生殖器官毒性。因此,研究柔红霉素的用量,建立多种微量检测方法,在临床医学方面具有积极的和现实的意义。本文研究了DNR在β-环糊精（β-CD）修饰金电极上的电化学行为,发现DNR能在β-CD俢饰电极上发生包络反应,其包络常数为6.1×104 L•mol-1。而且,只有包络的DNR能进行不可逆的电化学反应。其速率常数为28.03 s-1。在3-30 μmol• L-1的浓度范围内,DNR还原峰峰电流与DNR浓度成线性关系,因此,β-CD修饰电极可用于DNR的定量检测。在pH=7.0的中性电解液和温度接近40℃时,DNR在β-CD修饰电极上有最好的电化学活性。此时,β-CD修饰电极对DNR有较低的检出极限。     

自组装单层界面β-环糊精非电活性客体的电化学测定

提出了用电化学技术测定非电活性物质的新方法.利用合成的β-CD对甲苯磺酸基衍生物(Ts-β-CD)获得新型β-CD单层.虽然β-CD的覆盖率只有10%左右,但该单层对二茂铁表现出有效的主客体响应.界面上二茂铁的包络符合Langmuir吸附响应.利用Langmuir吸附等温式,得到二茂铁与β-环糊精形成包络物的包络常数为4.2×10~4mol-1·L二茂铁在该单层上的最大表面覆盖度为8.6×10~(-12)mol/cm2.当二茂铁溶液中含有非电活性物质间甲苯甲酸(mTA)或十二烷基磺酸钠(SDS)时,mTA和SDS与包络在电极表面的二茂铁发生客体竞争反应而使二茂铁的氧化还原峰电流降低.利用该原理,分别测定了非电活性物质mTA和SDS,线性范围分别为0.8~2.7μmol/L和5~100nmol/L.     

纳米金/β-环糊精复合修饰碳糊电极测定亚硝酸盐

本文研究了亚硝酸盐(NO_2~-)在纳米金和β-环糊精复合修饰碳糊电极(AuNPs-β-CD/CPE)上的电化学行为。实验结果表明,与裸CPE相比,AuNPs-β-CD/CPE对NO_2~-的电化学氧化有显著的促进作用,其氧化峰电流显著增加。同时用循环伏安法(CV)、计时电流法(CA)测定了NO_2~-在AuNPs-β-CD/CPE上的电极反应动力学参数,用线性扫描伏安法(LSV)法测得NO_2~-氧化峰电流与其浓度在6.0×10-6~8.0×10-3 mol·L-1范围内呈良好的线性关系,检出限(S/N=3)为5.7×10-7 mol·L-1。将该传感器应用于水样的检测,相对标准偏差在0.15%~1.40%之间,回收率达99.3%~104.0%,检测结果符合定量测定要求。     

阿托伐他汀钙与β-环糊精相互作用的研究及应用

采用线性扫描伏安法和循环伏安法并结合紫外分光光度法研究了新型抗血脂紊乱药物阿托伐他汀钙(AC)与β-环糊精(-βCD)的相互作用.探讨了-βCD对AC的峰电流及AC对-βCD吸附峰电流的影响,测得在0.06mol/LKH2PO4-Na2HPO4(pH=7.17)缓冲溶液中,AC与-βCD包结比为1:1,用电流法测得包结物的形成常数为9.09×104L/mol.根据碱性介质条件下β-CD分子与AC形成包结物而使β-CD吸附峰电流减小的特性,建立了一种利用β-CD间接测定AC的伏安方法.     

β-环糊精与神经递质的包络作用及其结构

以氢醌(HQ)为探针，用循环伏安法(CV)研究了神经递质(neurotransmitters) 分子与—环彻精(β-CD)单元的包络作用．通过在β-加倍饰电极界面上神经递质对 被包络的HQ的抑制效应，求得各神经递质与β-CD的表面包络常数，该常数因神经 递质所含官能团的不同而不同，且随链长的递增呈现有规律的递增．以甲基橙(M0) 为探针，用紫外—可见光谱法(UV)证明溶液中神经递质分子与β-CD能有效包络， 包络常数及其与神经递质分子结构的关系与循环伏安法的测定结果一致．量子化学 的服法计算得到了神经递质分子与β--CD单元包络的结构．理论计算和实验结果表 明：疏水相互作用、范德华力及氢键等多种非共价链的弱相互作用协同贡献于包络 物的形成，主客体间的结构匹配及溶剂效应对包络物的稳定性起重要作用．     

电聚合β-环糊精修饰电极的制备及其对铜离子的检测

采用循环伏安法(CV),由β-环糊精(β-CD)单体在玻碳电极(GCE)表面电聚合制得聚β-CD膜修饰电极(β-CD/GCE)。实验表明,β-CD/GCE对Cu2+具有明显的电催化作用,在pH=5.85的磷酸盐缓冲溶液(PBS)中,Cu2+浓度与其峰电流在4.01×10-4～1.05×10-7 mol·L-1范围内呈良好的线性关系,线性方程为:ip=-1.975c-1.336×10-4(i:A,c:mol·L-1),相关系数R=0.9981,检出限(S/N=3)为5.03×10-8mol·L-1。方法应用于实际样品测定,回收率在98.0%～103%之间。     

聚亚甲基蓝修饰金电极对抗坏血酸电催化氧化及其电分析方法研究

研究了亚甲基蓝(methylene blue,MB)聚合物膜修饰金电极(PMB/Au)的制备及其性质,通过电化学阻抗谱图对PMB/Au进行了表征,并对抗坏血酸(ascorbic acid,AA)在PMB/Au上的电化学行为进行了研究。结果表明,PMB/Au对AA的氧化具有良好的电催化作用,使AA的过电位降低约200 mV,氧化峰电流明显增大。测得AA在PMB/Au上的电荷转移系数为0.70,催化反应速率常数为5.99×103mol-1.L.s-1。用方波伏安法(Square Wave Voltammetry,SWV)测得氧化峰电流与AA浓度在2.0×10-5~6.0×10-3mol/L范围内呈良好线性关系,检出限为1.0×10-5mol/L。将PMB/Au应用于Vc片剂和Vc注射液中AA的测定。     

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%.     

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.     

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.     

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.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

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.     

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.