高效液相色谱-电喷雾质谱法测定红车轴草中异黄酮类化合物

采用高效液相色谱与电喷雾质谱联用技术研究了红车轴草中的异黄酮类化合物.实验采用反相C18色谱柱,二元线性梯度洗脱,分离并检测了红车轴草中的14种异黄酮类化合物;通过与电喷雾质谱联用获得了相应化合物的分子量信息,并利用质谱的源内碰撞诱导解离技术鉴定这些化合物的可能结构分别为大豆苷、野靛苷-7-O-β-D-葡萄糖苷、芒柄花苷、德鸢尾素-4'-O-β-D-葡萄糖苷、大豆苷元、印度黄檀苷、樱黄素-4'-O-β-D-葡萄糖苷、染料木素、红车轴草素、芒柄花素、樱黄素、鹰嘴豆芽素A、野靛苷和德鸢尾素.     

红车轴草总异黄酮成分DNA结合剂的超滤质谱筛选

采用离心超滤和液相色谱-质谱联用的方法, 从红车轴草异黄酮提取物中筛选DNA结合剂. 结果表明, 红车轴草中10种异黄酮成分与DNA具有不同的结合能力. 采用液相色谱-串联质谱联用技术对其结构进行了鉴定, DNA结合能力较强的5种化合物分别是德鸢尾素-4'-O-β-D-葡萄糖苷、 德鸢尾素、 黄豆黄葡萄糖苷、 红车轴草素和鹰嘴豆牙素A. 为从中药提取物等复杂体系筛选并鉴定DNA结合剂建立了快速的超滤质谱平台.     

高效液相色谱-电喷雾质谱联用测定黄芪黄酮苷酶解产物

高效液相色谱-电喷雾质谱(HPLC-ESI-MS)联用分析黄芪中的黄酮类化合物结果表明黄芪黄酮提取物主要包含毛蕊异黄酮-7-O-β-D-葡萄糖苷、芒柄花苷、9, 10 -二甲氧基紫檀烷-3-O-β-D-葡萄糖苷以及2'-羟基-3',4'-二甲氧基异黄烷-7-O-β-D-葡萄糖苷等黄酮苷,黄芪黄酮提取物经过β-葡萄糖苷酶(1 IU/mL)粗酶液酶解后,HPLC-ESI-MS分析酶解生成产物主要为黄酮苷元毛蕊异黄酮、芒柄花素、3-羟基-9,10 -二甲氧基紫檀烷以及7, 2'-二羟基-3',4'-二甲氧基异黄烷.其中前两种主要的黄酮苷酶解率均达90%以上.酶解后所得产物对DPPH自由基清除率是酶解前的1.4倍.因此,通过β-葡萄糖苷酶水解可以有效地将黄芪黄酮转化为相应的黄酮苷元,大大提高黄芪黄酮提取物的抗氧化活性.     

膜荚黄芪与蒙古黄芪化学成分的高效液相色谱-质谱研究

采用高效液相色谱-质谱联用技术对膜荚黄芪及蒙古黄芪药材的甲醇提取物进行了对比分析。选用Inertsil ODS C18不锈钢柱，以乙腈-水梯度洗脱，流速1．0mL／min，柱温25℃，二级管阵列（PDA）和电喷雾电离质谱（ESI-MS）同时在线检测。通过与标准品对照、紫外光谱及多级质谱分析并与文献对照鉴定了14个成分，分别是：毛蕊异黄酮-7-O-β-D-吡喃葡萄糖苷（1）、芒柄花苷（2）、9，10．二甲氧基紫檀烷．3-O-β-D．吡喃葡萄糖苷（3）、2’-羟基-3’，4’-二甲氧基异黄烷-7-O-β-D-吡喃葡萄糖苷（4）、毛蕊异黄酮（5）、黄芪甲苷（6）、黄芪皂苷Ⅱ（7）、异黄芪皂苷Ⅱ（8）、芒柄花素（9）、黄芪皂苷Ⅰ（10）、异黄芪皂苷Ⅰ（11）、蔗糖（12）、毛蕊异黄酮（7-O-β-D-吡喃葡萄糖苷-6″-O-丙二酸酯（13）、乙酰黄芪皂苷Ⅰ（14）。经对比发现，膜荚黄芪和蒙古黄芪的主要化学成分相似但也存在一些差异。对黄芪主要成分的电喷雾质谱裂解规律进行了归纳总结。     

棠梨枝叶的化学成分研究

从棠梨枝叶(Pyrus pashia Buch.-Ham.ex D.Don)的甲醇提取物中分离得到了17个化合物,采用高分辨质谱、一维和二维核磁共振等现代波谱技术,鉴定上述化合物的结构分别为:pashinin A(1),天麻苷-7-O-顺式咖啡酸酯(2),天麻苷-7-O-反式咖啡酸酯(3),山奈酚-3-O-β-D-(6′′-O-对香豆酸酯)吡喃葡萄糖苷(4),山奈酚-3-O-β-D-(6′′-O-顺式对香豆酰)吡喃葡萄糖苷(5),天麻苷-7-O-对羟基苯甲酸酯(6),熊果苷(7),robustaside B(8),委陵菜酸(9),蔷薇酸(10),槲皮素3-O-β-D-吡喃葡萄糖苷(11),2R,3R-二氢槲皮素(12),木犀草素-4′-O-β-D-吡喃葡萄糖苷(13),芹黄素-4′-O-β-D-吡喃葡萄糖苷(14),5,7,4′-三羟基异黄酮-7-O-β-D-吡喃葡萄糖苷(15),染料木素(16),咖啡酸(17),其中化合物1和2为新化合物,化合物3为新的天然产物.除化合物17外,其余化合物均首次从该植物中分离得到.化合物1～3的抗肿瘤细胞活性实验表明其没有体外肿瘤细胞生长抑制活性(IC50>40μmol L-1);抗HIV病毒(HIV-1IIIB)实验显示:化合物1有极弱的抗HIV-1的活性,化合物4有弱的抗HIV-1的活性.     

基于高剪切分散乳化技术的黄芪中黄酮类化合物提取方法及动力学研究

利用高剪切分散乳化(High shear dispersing emulsifier,HSDE)技术为样品前处理方法,以甲醇为提取剂.通过单因素实验、L9(34)正交试验,优选出HSDE提取黄芪中4种黄酮类化合物(毛蕊异黄酮-7-O β-D葡萄糖苷、毛蕊异黄酮、芒柄花素、芒柄花苷)的最佳条件为:料液比1∶20,转速16000 r/min,时间180 s.在此提取条件下进行黄芪提取的动力学研究,结果表明,黄芪中4种黄酮类化合物的HSDE提取过程符合准二级动力学方程特征.以时间(t)为横坐标,时间与峰面积的比值(t/A)为纵坐标,进行线性拟合,方程分别为:毛蕊异黄酮-7-O-β-D-葡萄糖苷:y=0.00974x+ 0.00869,R2=0.99736;毛蕊异黄酮:y=0.00153x+0.01654,R2=0.9862;芒柄化素:y=0.00196x+0.02322,R2=0.98492;芒柄花苷:y=0.00527x+ 0.046,R2=0.99228.在实验的基础上推测其提取机理为气蚀效应、机械效应和剪切效应的协同作用.     

应用电喷雾质谱技术分析鉴定桑叶中黄酮类化合物

通过电喷雾多级串联质谱技术分析、鉴定了桑叶提取物中的槲皮素、山奈酚-7-葡萄糖苷、异槲皮苷、山奈酚-3-O-(6″-O-乙酰基)-β-D-吡喃葡萄糖苷、槲皮素-3-O-(6″-O-乙酰基)-β-D-吡喃葡萄糖苷和芦丁6种黄酮类化合物.根据一些特征的中性碎片丢失,提出了该类化合物的质谱裂解规律.通过得到的相对分子质量和中性碎片信息并与文献中的已知化合物比较,建立了这一类化合物快速鉴定的质谱新方法.     

藿香的化学成分分析

从藿香茎叶的乙醇提取物中共分离鉴定出5个化合物:异鼠李素-3-O-β-D-半乳糖苷(1)、金丝桃苷(2)、3,5,8,3,′4′-五羟基-7-甲氧基黄酮-3-O-β-D-吡喃葡萄糖苷(3)、尼泊尔鸢尾异黄酮-7-O-α-L-吡喃鼠李糖苷(4)和正三十烷酸(5).其中化合物3和4为首次从该属植物中分离得到.     

破骨风中木脂素类化合物的分离鉴定及抗氧化活性

以破骨风(Jasminum lanceolarium Roxb.)为研究对象,采用硅胶柱和Sephadex LH-20凝胶柱层析等手段,从中分离获得7个木脂素类化合物:Jasminlanoside A(1)、(+)-环橄榄树脂素(2)、丁香脂素-4-O-β-D-葡萄糖苷(3)、(+)-环橄榄树脂素-6-O-β-D-葡萄糖苷(4)、(+)-环橄榄树脂素-4'-O-β-D-葡萄糖苷(5)、橄榄素4″-O-β-D-葡萄糖苷(6)和丁香脂素-4,4'-O-双-β-D-葡萄糖苷(7),其中化合物1为新化合物,化合物3~6均为首次从本属植物中分离得到.利用一维核磁共振谱(1D NMR)、二维核磁共振谱(2D NMR)和高分辨电喷雾电离质谱(HR-ESI-MS)对化合物1的结构进行了鉴定.抗氧化活性测试结果表明,化合物1,2,4和5表现出一定的抗氧化活性,化合物5的1,1-二苯基-2-三硝基苯肼(DPPH)清除活性最强,IC_(50)值为(0.148±0.005)μmol/L.     

大黄柳中两种黄酮化合物的结构解析

利用聚酰胺色谱法及制备型高效液相色谱法从大黄柳叶中分离得到2种黄酮化合物。利用核磁共振谱、质谱、紫外光谱及红外光谱对化合物结构进行了分析和表征。结果表明：这两种化合物分别为木樨草素7-O-α-L-吡哺阿拉伯糖(1→6)β-D-吡哺葡萄糖苷(Ⅰ)和木樨草素7-O-β-D-吡哺木糖(1→6)β-D-吡哺葡萄糖苷(Ⅱ)。这2种化合物为首次从柳属植物中分得。     

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.     

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.     

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.     

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.