黄芩及其制剂中黄芩素和黄芩甙的

用毛细管区带电泳 -电化学检测法测定了黄芩及其制剂中黄芩素和黄芩甙的含量。研究了电极电位、电解液酸度和浓度、电泳电压及进样时间等对电泳的影响 ,得到了较为优化的测定条件。以直径为300μm的碳圆盘电极为检测电极 ,电极电位为0.90V(vsSCE) ,在100mmol/L硼酸盐缓冲液(pH9.0)中 ,上述两组分在8min内完全分离。黄芩素和黄芩甙浓度与电泳峰电流分别在5.0×10 -7～1.0×10 -3mol/L和1.0×10 -6～1.0×10 -3mol/L范围内呈良好线性 ,检出限分别为2.24×10 -7mol/L和5.48×10 -7mol/L。7次测定分别含5.0×10 -4mol/L黄芩素和黄芩甙试样溶液 ,峰高的相对标准偏差分别为3.53%和4.03%。     

毛细管电泳-电化学检测法测定蜘蛛香中多元酚类化合物

采用毛细管电泳 电化学检测法(CE ED)同时测定了蜘蛛香根中香叶木素、山奈酚、芹菜素、绿原酸 和咖啡酸等5种主要生物活性成分的含量,考察了运行缓冲液酸度、浓度、分离电压、氧化电位和进样时间等 实验参数对分离、检测的影响。在最佳实验条件下,以直径300μm的碳圆盘电极为工作电极,检测电位为+ 950mV(vs.SCE),在50mmol/L的硼砂缓冲溶液(pH9.23)中,上述各组分在23min内能完全分离。5种组 分在两个数量级的范围内呈良好线性关系,检测下限(S/N=3)达1.7×10-4～1.8×10-5g/mL。该法已成功 地应用于蜘蛛香根中活性成分的分离检测,结果令人满意。     

毛细管区带电泳法分析绿茶中的痕量成份

采用毛细管电泳/安培检测法(CE/AD)同时分离测定了绿茶中的芦丁、没食子酸、槲皮素、绿原酸等生物活性成分的含量, 考察了运行缓冲液酸度、浓度、分离电压、氧化电位和进样时间等实验参数对分离、检测的影响。在最优化条件下, 以300 μm碳圆盘电极为检测电极, 检测电位为+ 950 mV (vs. SCE) , 60 mmol/L硼酸盐运行缓冲液(pH 8.7)中, 上述各组分在20 min内可实现基线分离。各组分浓度与峰电流在3个数量级范围内呈良好线性, 检出限(S/N=3)在1.0×10^-7到1.0×10^-4g^.mL^-1范围,四种标样7次平行进样的相对标准偏差(RSD)小于3.0 %。该方法已成功地应用于绿茶中生物活性成分的测定, 结果令人满意。     

毛细管电泳-电化学检测测定茶叶中咖啡因、表儿茶素和抗坏血酸

高效毛细管电泳电化学检测同时测定了6种茶叶中的咖啡因、表儿茶素和抗坏血酸的含量,考察了实验参数对分离、检测的影响。在最佳实验条件下,以300 靘直径的碳圆盘电极为检测电极,检测电极为1.20 V(vs.SCE),在25 mmol/L硼酸盐25 mmol/L磷酸盐(pH 7.6)的混合运行缓冲液中,上述各组分在16 min内能完全分离。咖啡因、表儿茶素和抗坏血酸在2×10-3mol/L～１×10-5 mol/L、5×10-5mol/L～5×10-7mol/L、2×10-4 mol/L～1×10-5mol/L范围内呈线性关系,检测下限分别为6×10-6mol/L、4×10-7mol/L和1×10-6mol/L。该法直接用于茶叶中咖啡因、表儿茶素和抗坏血酸的测定,结果令人满意。     

沙棘黄酮口服液中芦丁和5-羟色胺的毛细管区带电泳电化学检测

建立了毛细管区带电泳 -电化学检测法 (CE -ED)测定芦丁和5_羟色胺含量的方法 ,研究了电极电位、运行缓冲液的酸度和浓度、电泳电压及进样时间等因素对分离检测的影响,确定了最佳测定条件 ;以直径为300μm的碳圆盘电极为检测电极,电极电位为0.90V(vsSCE),在50mmol/L硼酸盐缓冲液(pH8.5)中,上述2组分在12min内完全分离 ,被分析物的电流响应与浓度在约3个数量级范围内呈良好线性关系,检出限分别为3×10-7 mol/L和8×10-8 mol/L ,7次测定含5.0×10-4 mol/L的芦丁和5_羟色胺的标准溶液,峰高的相对标准偏差分别为2.5 %和3.8 % ;该法成功地用于中药沙棘黄酮口服液中芦丁和5_羟色胺的测定     

杜仲及其保健品中生物活性成分的毛细管电泳/电化学检测

采用毛细管电泳/电化学检测法(CE/ED)同时分离测定了杜仲叶、杜仲皮及市售杜仲保健品中芦丁、抗坏血酸、金丝桃甙、绿原酸、槲皮素等多种生物活性成分的含量,考察了运行缓冲液酸度和浓度、分离电压、氧化电位和进样时间等实验参数对分离、检测的影响。在最优化条件下,以300μm碳圆盘电极为检测电极,检测电位为 950 mV(vs.SCE),50 mmol/L硼砂的运行缓冲液(pH9.0)中,上述各组分在20 min内可基本实现基线分离。各组分浓度与峰电流在3个数量级范围内呈良好线性,检出限(S/N=3)在3.3×10-5~9.6×10-5g/L范围。该方法已成功地应用于杜仲及其保健品中生物活性成分的测定,结果令人满意。     

散利痛中扑热息痛和异丙基安替比林的毛细管区带电泳电化学检测法测定

毛细管区带电泳 -电化学检测法同时测定散利痛片中有效成分扑热息痛和异丙基安替比林的含量 ;研究了电极电位、电解液浓度和酸度、电泳电压及进样时间等对电泳的影响 ,得到了最优化的测定条件 ;以直径为300μm的碳圆盘电极为检测电极 ,工作电极电位为1.0V(vsSCE) ,在50mmol/L硼砂 -NaOH(pH9.35)运行缓冲液中 ,上述两组分在8min内完全分离 ;扑热息痛和异丙基安替比林线性范围分别为2×10-3～5×10 -6mol/L和2×10 -3～2×10 -6mol/L,检出限分别为5×10 -6mol/L和2×10 -6mol/L ;7次平行进样的相对标准偏差(RSD)为3.5%和1.8 % ,加标回收率(n=3)分别为101 %和98% ,该法灵敏可靠 ,结果令人满意。     

毛细管电泳电化学检测法测定胡黄连中香草酸和阿魏酸的含量

采用毛细管电泳电化学检测法测定了胡黄连中香草酸和阿魏酸的含量 ;研究了电极电位、运行缓冲液的浓度和酸度、电泳电压及进样时间等对电泳的影响 ,得到了最优化的测定条件 ;以直径为300μm的碳圆盘电极为检测电极 ,工作电极电位为0.8V(vs.SCE) ,在50mmol/L硼砂(pH8.4)运行缓冲液中 ,上述两组分在8min内完全分离 ;香草酸和阿魏酸线性范围分别为5×10-4～1×10-6 mol/L和1×10-3～1×10-6 mol/L ,检出限分别为4.2×10 -7和3.0×10 -7mol/L ;7次平行进样的相对标准偏差(RSD)为2.2 %和2.8 % ,回收率(n=3)分别为99%和103 % ,该法灵敏可靠 ,结果令人满意。     

毛细管电泳-电化学检测法测定中药杠版归中的活性成分

采用毛细管电泳-电化学检测法（CE-ED）同时分离测定了中药杠板归中的阿魏酸、香草酸、槲皮素、咖啡酸、原儿茶酸等主要生物活性成分的含量。考察了工作电极电位、运行缓冲液的pH值和浓度、分离电压和进样时间等实验参数对实验结果的影响。在优化的实验条件下,以直径300 μm的碳圆盘电极为工作电极,检测电位为＋0.95V(vs. SCE),在10mmol/L磷酸盐（pH 9.2）的运行缓冲溶液中,五个分析物能够在17min内实现很好的基线分离,被测物浓度与峰电流在3个数量级呈良好的线性,检测限（S/N＝3）范围从7.1×10-8 到 9.3×10-8g mL-1。该方法已应用于实际样品的分析,样品处理简单,获得了令人满意的结果。     

去肾上腺素在L-半胱氨酸修饰金电极上的电化学行为及其分析研究

应用循环伏安法(CV)和方波伏安法(SWV)研究了去甲肾上腺素(NE)在L-半胱氨酸自组装膜修饰金电极(L-Cys/Au)上的电化学行为。结果表明:在pH7.0的磷酸盐缓冲溶液中,L-Cys/Au对去甲肾上腺素具有明显的电催化作用。由方波伏安法测定的氧化峰电流在NE浓度1.0×10-6~4.0×10-5mol/L和6.0×10-5~4.0×10-4mol/L范围内分段呈线性关系,相关系数分别为0.9941和0.9962,检出限为5.0×10-7mol/L。已用于分析针剂样品。     

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%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

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.     

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.     

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.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.