高效液相色谱指纹图谱应用于地黄的研究

利用高效液相色谱建立了地黄的色谱指纹图谱。采用反相C1 8柱 (5 μm ,1 5 0mm× 4.6mm) ,流动相甲醇∶水 (V V =5∶95 ) ,检测波长为 2 80nm ,流速 1 .0mL min进行实验。根据相对保留值和相对面积值对色谱指纹图谱进行分析对比研究 ,建立了控制地黄药材质量的新方法。该法为中药样品的鉴定提供了较全面的信息 ,并为HPLC在复杂组分的样品分析领域开拓了新的应用途径。     

RP-HPLC法测定唐古特铁线莲中芦丁的含量

建立了唐古特铁线莲中芦丁含量测定的RP-HPLC方法.色谱条件:采用C18柱 (4.6 mm×250 mm,5 μm),流动相:V(甲醇)∶V(0.4% H3PO4)=55∶45,流速:1.0 mL/min,柱温:30 ℃,检测波长:360 nm,芦丁在0.24～1.2 μg范围内成良好的线性关系,r=0.9992,回收率RSD=1.0%,对青海省不同地区唐古特铁线莲中芦丁进行了定量分析,测定结果:不同产地该药材中芦丁的含量有较大差异,含量在0.119%～0.317%之间.     

反相高效液相色谱法测定长柄扁桃仁产品中苦杏仁苷含量

本文采用反相高效液相色谱建立了长柄扁桃仁系列产品中苦杏仁苷含量的测定方法。长柄扁桃仁系列产品中的苦杏仁苷经甲醇提取,以V(甲醇)∶V(水)∶V(乙腈)=2∶85∶13为流动相进行洗脱,在220nm检测波长下,测得长柄扁桃仁中苦杏仁苷的平均质量分数为1.44%。方法线性范围为50～300μg/mL,线性相关系数r=0.9996,检出限为1.2μg/mL,平均回收率为98.97%(n=5)。     

新型除草剂2.5%稻杰的有效成分测定-高效液相色谱法

采用高效液相色谱测定了新型除草剂2.5%稻杰(FENCER)的有效成分,用外标法进行定量分析.条件为:Waters Symmetry C8色谱柱;流动相包括V(乙腈)∶V(水)∶V(1% H3PO4=60∶40∶0.1;检测波长为285 nm;流速为1.0 mL/min,柱温为室温;进样量为10 μL;实验结果表明,样品平均回收率为98%,精密度为0.13%.     

怀地黄中微量铁的测定

为探讨邻二氮菲分光光度法测定怀地黄中微量元素铁含量的可行性,根据铁离子与特定显色剂显色产生可见吸收的原理,采用混合酸V(HN03)+V(HClO4)=4+1对怀地黄样品湿法消化处理,在pH2-9的溶液中试剂与铁生成稳定的橙色络合物,并用分光光度法测定了怀地黄中微量元素铁含量.结果表明,怀地黄中铁含量为552.48-56...     

反相高效液相色谱法测定人尿中利凡诺

建立了运用反相高效液相色谱法测定人尿中利凡诺的方法.采用Spherisorb C18色谱柱(250 mm×4.6 mm i.d.,5 μm);流动相: V(甲醇)∶V(乙腈)∶V(0.2 mol/L NH4Ac)=60∶37∶3;流速: 1.0 mL/min;柱温: 40 ℃;荧光检测器: 激发波长360 nm,发射波长500 nm.在5 ng/mL～1 μg/mL质量浓度范围内,呈现良好线性(r=0.9999),检出限为1 ng/mL.     

高效液相色谱指纹图谱在地黄研究中的应用(Ⅰ)

长期以来,中药有效成分的提取分离和质量控制一直是中药产业中特有和尚未很好解决的问题.随着天然产物化学和现代仪器分析技术等相关学科的迅速发展,国内外在植物药及其制剂质量控制研究方面的重点均已转向利用各种仪器进行品质评价方面.中药来源于自然,其化学成分的多样性和复杂性是中药发挥其疗效的物质基础,同时也是质量评价与控制的重点与难点.中药的化学成分复杂,所体现的是综合效应和整体疗效.然而多年以来在中药的研究靠中,采取了与化学药品相同的研究思路,结果将药材及制剂内部各成分的综合作用和相互关系彼此孤立.在中药材及复方制剂质量标准的研究制定中,也往往是采用各种分析检测手段测定其中某种有效成分,并以其含量多少来判断比较某种药材的质量.这种质量控制模式很难做到全面衡量中药及其制剂的质量、疗效和稳定性.单一成分含量达标并不能说明该中药材质量合格.指纹图谱质量控制模式能综合反映某一特定药材各主要组分及其相对含量.因此它比测定任何一种或几种成分所提供的信息都丰富和有用的多.中药提取物在给定的实验条件下所得到色谱指纹图谱反映了该中药的化学组成及其含量分布状况,其特征峰可作为鉴别中药的依据.本文研究结果表明,利用色谱指纹图谱的相关参数来对中药原药材的质量进行控制,进而使中成药的质量得到保证,此方法的运用是切实可行的.另外,在有效成分不明确的前提下,利用色谱指纹图谱来评价中药的质量是有其意义的.色谱指纹图谱作为控制中药质量的新手段将在推进中药现代化进程上起到积极的作用.本文利用高效液相色谱建立了地黄的色谱指纹图谱.采用反相C18柱(5μm,150 mm×4.6 mm)、流动相甲醇:水(V/V=5:95)、检测波长为280 nm、流速1.0 mL/min进行试验.根据相对保留值和相对面积值对色谱指纹图谱进行分析对比研究,建立了控制地黄药材质量的新方法.该法为中药样品的鉴定提供了较全面的信息.     

高效液相色谱法测定九味石灰华散中羟基红花黄色素A和红景天苷的含量

建立了测定中药复方制剂九味石灰华散中羟基红花黄色素A和红景天苷含量的高效液相色谱方法.采用Kromasil C18色谱柱(5μm,250 mm×4.6 mm),以乙腈∶0.1%磷酸溶液(12∶88,V/V)为流动相,流速1.0 mL/min,羟基红花黄色素A的检测波长为403 nm,红景天苷的检测波长为275 nm.羟基红花黄色素A和红景天苷分别在0.288~180μg/mL和4.8~1 200μg/mL范围内呈良好的线性关系(r值为0.999 8~0.999 9),最低检出限分别为0.03μg/mL和0.5μg/mL(S/N=3),加标回收率分别为95.7%~97.4%和95.9%~98.6%.该方法简便、准确、重现性好,可用于九味石灰华散的质量控制.     

HPLC法测定不同溶剂对红景天中红景天苷提取率的影响

建立用HPLC法测定甲醇、乙醇、水等不同溶剂对红景天苷提取率的影响。采用Thermo-C18(4.6 mm×200 mm,5μm)为色谱柱,V(甲醇)∶V(水)=12∶88为流动相,流速1.0 mL/min,检测波长275 nm,柱温20℃。红景天苷的线性范围为1.74~6.38μg;平均回收率为99.24%(RSD=1.4%)。所建立的HPLC法可用于测定不同溶剂对红景天苷提取率的影响。     

高速逆流色谱法对独角莲中有效成分皂苷的分离纯化

本文采用高速逆流色谱法对独角莲中的有效成分皂苷进行分离纯化.分别以乙酸乙酯∶正丁醇∶乙腈∶水=5∶1∶1∶5(V/V)及乙酸乙酯∶正丁醇∶乙醇∶水=5∶10∶2∶20(V/V)为溶剂系统,用下相作流动相,上相作固定相,分别采用2 mL/min及1.5 mL/min 的流动相流速、800 r/min的转速对独角莲中的有效成分皂苷进行分离,得到纯度98%的胡萝卜苷6 mg.     

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.     

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.     

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.     

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.     

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.