联萘酚对映体的毛细管电泳/方波安培法分离检测

建立了毛细管电泳/方波安培法分离检测联萘酚对映体的新方法.对影响对映体分离度的影响因素,如手性选择剂β 环糊精浓度、氢氧化钠浓度、硼酸浓度、分离电压进行了探讨。在16mmol/L氢氧化钠+14mmol/Lβ 环糊精+4mmol/L硼酸的电泳运行液,方波平衡电位+0.90V和10kV的分离电压条件下,联萘酚对映体在10min内得到基线分离,检出限为1.0×10-6mol/L。     

毛细管电泳手性分离-激光诱导荧光检测普萘洛尔对映体

用异硫氰酸荧光素衍生普萘洛尔,衍生产物用毛细管电泳分离,激光诱导荧光方法检测。在含有10mmol/L-βCD,50mmol/L硼砂(pH=9.0)的溶液中,普萘洛尔对映体得到了基线分离。本方法线性范围宽(R型:2.0×10-3~1mg/L),灵敏度高(检出限均为1.24μg/L),可用于活体中普萘洛尔对映体的药代动力学研究。     

高效毛细管电泳电导检测对阴离子表面活性剂分离测定的研究

以Ca2 +为分离介质 ,甲酰胺为添加剂 ,通过对缓冲体系、缓冲液浓度、酸度、Ca2 +浓度、甲酰胺浓度、电泳电压和进样时间的优化选择 ,用毛细管电泳 -电导检测法分离了十二烷基硫酸钠(K12)和十二烷基苯磺酸钠(LAS) ;在10mmol/LTris -11mmol/LCit(pH4.5)运行缓冲液中 ,上述两组分在16min内完全分离 ;K12和LAS的线性范围分别为5.0×10-6～8.0×10-3 mol/L和5.0×10-6 ～5.0×10-3 mol/L ;检出限(S/N=3)分别为2.5×10-6 和3.0×10-6 mol/L,应用于合成洗衣粉样和合成水样中K12 和LAS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。     

毛细管电泳-间接化学发光法检测染发剂中苯二酚异构体和苯酚

根据某些酚类化合物在碱性条件下具有能猝灭鲁米诺-铁氰化钾体系化学发光信号的特性,建立了毛细管电泳-间接化学发光分离检测苯二酚异构体和苯酚的新方法.电泳缓冲溶液选用7.5 mmol/L Na2B4O7-2.5 mmol/L Na2HPO4.在优化的化学发光和电泳条件下,对苯二酚、间苯二酚、邻苯二酚和苯酚在10 min内可直接实现分离,其检出限(S/N=3)分别为2.9×10-8 mol/L、3.7×10-7 mol/L、8.4×10-8 mol/L和4.4×10-6 mol/L;相对标准偏差(RSD)为2.5%～4.8%(n=5).通过对不同染发剂实际样品进行分离分析研究,证明该方法可以用于实际染发剂样品的分析测定,结果令人满意.     

托吡卡胺对映体的毛细管电泳-方波安培分离检测

采用毛细管电泳-方波安培检测法,在熔融石英毛细管(75 μm i.d.×50 cm)中,以7 mmol/L 三羟甲基氨基甲烷(Tris)-10 mmol/L柠檬酸-2 mmol/L硼酸-15mmol/L β-环糊精 （β-CD） (pH 3.0)为电泳介质,采用重力进样,高度差为20 cm,进样时间为10 s,在分离电压为15 kV,方波平衡电位+0.8 V的条件下,实现了托吡卡胺对映体的分离检测。线性范围为5~750 μmol/L,检出限为2 μmol/L。对影响分离度的因素β-CD浓度、硼酸浓度及p     

扑尔敏对映体的毛细管电泳-方波安培分离检测

报道了以未涂层融硅石英毛细管(50 cm×75 μm)为分离柱,5 mmol/L NaOH+10 mmol/L Citric acid +3 mmol/L H3BO3+10 mmol/L β-CD (pH 3.5) 为电泳介质,分离电压12 kV,检测电压0.80 V,建立了朴尔敏对映体拆分的高效毛细管电泳-方波安培检测方法.对缓冲溶液的种类、浓度、pH、分离电压对拆分效果的影响进行了讨论,并对拆分机理进行了探讨.     

手性药物异丙嗪对映体的毛细管电泳-方波安培法检测

以未涂层融硅石英毛细管 (5 0cm× 75 μm)为分离柱 ,5mmol/LNaOH +10mmol/LCitricacid +3mmol/LH3 BO3 +10mmol/L β 环糊精 (β CD) (pH =3.5 )为电泳介质 ,分离电压 12kV ,采用毛细管电泳 方波安培法对手性药物异丙嗪对映体实现了分离检测。对影响手性对映体分离检测效果的缓冲溶液的种类、浓度和 pH等诸因素进行了研究。结果表明 :硼酸与手性选择剂 β CD分子中糖羟基发生键合配位作用 ,增加了β CD 的负电性的特性 ,在对映体拆分中起到关键性的作用。     

生物分子的毛细管电泳-化学发光检测法研究

根据某些氨基酸和蛋白质在碱性条件下具有能显著增强鲁米诺-铁氰化钾体系化学发光信号的特性,对毛细管电泳-化学发光法直接分离测定生物分子的可行性进行了研究.电泳所用缓冲溶液为2.5 mmol/L、含2.0 mmol/L鲁米诺的硼砂缓冲溶液;氧化试剂为2.0×10-4 mol/L铁氰化钾.在优化条件下,L-精氨酸和胃蛋白酶可直接实现分离,其检出限(S/N=3)分别为1.3×10-4 mol/L和7.1×10-7 mol/L.通过对市售的3种L-精氨酸标准样品进行分离分析研究,证明该方法可应用于L-精氨酸标准样品的纯度分析.     

二元手性选择体系毛细管电泳/电化学分离检测手性药物酚苄明对映体

采用羟丙基-β-环糊精(HP-β-CD)和羟丙基甲基纤维素(HPMC)组成的二元手性选择剂体系,以8mmol/L三羟甲基氨基甲烷(Tris) 10mmol/L柠檬酸(Cit) 10mg/LHPMC 25mmol/LHP-β-CD为电泳运行液,在熔融石英毛细管(50μmi.d.×45cm)中,分离电压 15kV,方波安培检测,手性药物酚苄明对映体获得良好的基线分离,线性检测范围为4～105μmol/L,检出限为1.5μmol/L。对影响灵敏度和分离度的电泳运行液组成、手性选择剂(HP-β-CD、HPMC)浓度以及进样方式和样品介质等进行了详细讨论。应用于市售盐酸酚苄明片剂中酚苄明对映体的分离检测,取得满意结果。     

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.     

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.