高速逆流色谱制备分离紫甘薯花色苷

采用高速逆流色谱法分离纯化紫甘薯花色苷.以正丁醇-乙酸乙酯-0.5%乙酸(3:1:4,V/V)为溶剂体系,上相为固定相,下相为流动相,流速2mL/min,进样量300mg,分离得到两种花色苷的混合物;混合物再以0.2%三氟乙酸-正丁醇-甲基叔丁基醚-乙腈(6:5:2:1,V/V)为溶剂体系,上相为固定相,下相为流动相,...     

高速逆流色谱分离纯化防风中升麻素苷和5-O-甲基维斯阿米醇苷

建立了高速逆流色谱分离制备防风中有效成分升麻素苷和5-O-甲基维斯阿米醇苷的方法.防风根的粉末经甲醇浸泡提取和减压蒸馏,得粗提浸膏.以V(乙酸乙酯):V(正丁醇):V(水)=2:7:9为溶剂,上相为固定相,下相为流动相,流速2.0 mL/min.从316 mg防风粗提物中一步分离得到13.9 mg升麻素苷和25 mg 5-O-甲基维斯阿米醇苷,纯度分别为98.1%和99 2%.采用ESI-MS, 1H NMR 和13C NMR对目标化合物的结构进行了鉴定.     

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%.     

青海栽培何首乌不同部位中蒽醌类成分的测定

用高效液相色谱法测定青海栽培何首乌中的主要有效成分大黄素、大黄素甲醚等蒽醌类成分。采用kromasil C18柱(4.6 mm i.d.×250 mm,5μm);V(甲醇)∶V(水)∶V(H3PO4)=750∶250∶0.001为流动相,检测波长为254 nm,流速为1mL/min,进样量10μL。用此方法测定青海栽培何首乌不同部位中的蒽醌类成分,大黄素和大黄素甲醚达到基线分离,线性范围分别为0.094~1.50μg(r=0.9992),0.094~1.50μg(r=0.9997),回收率分别为大黄素95%、大黄素甲醚102%。实验发现青海栽培何首乌块根中大黄素和大黄素甲醚成分较藤、叶中高,大黄素含量比大黄素甲醚含量高。     

顺铂冻干粉的含量测定

建立了顺铂冻干粉注射液含量测定方法的正相高效液相色谱法,色谱条件为:氨基键合硅胶柱,二甲基甲酰胺为样品溶剂,流动相为乙酸乙酯∶甲醇∶二甲基甲酰胺∶水(25∶16∶5∶5,V/V/V/V),在310 nm检测,流速1.5 mL/min,进样量20μL.该法线性相关,相关系数r为0.999 6,回收率为99.6%～100.3%,精确度为0.21%(n=6),最小检出限为59.2μg/L,符合含量测定要求.     

高速逆流色谱分离制备甜瓜蒂中葫芦素类化合物

采用高速逆流色谱法分离制备了甜瓜蒂中3种葫芦素类化合物.以正己烷-乙酸乙酯-甲醇-水(1.2:0.8:0.8:1.2,V/V)为两相溶剂系统,上相为固定相,下相为流动相.在主机转速800 r/min、流动相流速2.0mL/min、分离温度25℃、检测波长254nm条件下进行分离,所得产物纯度经HPLC检测,结构经MS、...     

薄层层析法分离菊芋汁中低聚糖

采用薄层层析法(TLC)分离菊芋汁中的低聚糖成分。固定相为硅胶板GF254,展层剂为V正丁醇∶V异丙醇∶V乙酸∶V水=7∶5∶2∶4,显色剂为苯胺(4 mL)-二苯胺(4 g)-磷酸(20 mL)(溶于200 mL丙酮中)试剂。该展层体系可用于快速层析分离菊芋汁中的混合低聚糖,经过两次展层可达到良好分离结果。     

高效液相色谱手性流动相添加剂分离西孟坦对映体

以 β 环糊精作为手性流动相添加剂 ,研究了DL 西孟坦在反相HPLC系统中的拆分。考察了缓冲盐的浓度、pH、β 环糊精的浓度、流动相中甲醇的比例、流动相流速和温度对手性分离的影响 ,建立了 β 环糊精动态手性固定相法分离西孟坦对映体的方法。色谱条件为 :ZirchromKromasilODS 1(5 μm ,15 0mm× 4 .6mm)色谱柱 ,流动相为 2 0mmol/L磷酸盐缓冲液 (pH 6 .0 )含 12mmol/Lβ 环糊精∶甲醇 (70∶30 ,V/V) ,流速为 0 .8mL/min ,温度为 17℃。DL 西孟坦对映体的保留时间分别为 2 2 .5和 2 4 .5min ,分离度为 1.5 7。     

用制备型高效液相色谱分离石油亚砜的馏分

用经典硅胶柱色谱法对石油亚砜 (PSO)进行预分离。PSO被分成 4个馏分 (分别记为PSO1,PSO2 ,PSO3和PSO4)。所用的流动相及洗脱顺序 :苯、二氯甲烷、甲醇 二氯甲烷 (1∶1体积比 )、甲醇。经预分离后 ,PSO中的亚砜成分主要富集在馏分PSO3和PSO2中。用高效制备液相色谱法对这两馏分作进一步的分离和纯化。PSO2的色谱条件是 :色谱柱 μ BondapakC1 85 7mm× 30 0mm ;流动相为二氯甲烷、环己烷、甲醇混合液 ,收集经纯化后的组分PSO2g2 2 ;PSO3被分离为 7个馏分 ,其色谱条件为 :色谱柱μ BondapakC1 85 7mm× 30 0mm ;流动相为 70 %～ 10 0 %甲醇 水 ;梯度洗脱其流量为 80mL min ;进样量为80mL 次 (PSO3用 70 %甲醇 水稀释 10倍 )。取其中较纯的馏分PSO3c ,PSO3e ,PSO3g作进一步的色谱纯化 ,色谱条件为C1 8半制备色谱柱 7.8mm× 30 0mm ;流速 :2 0mL min ;流动相 :甲醇 水 70∶ 30 ,V/V(PSO3c)″80∶2 0 ,V V(PSO3e) ;85∶15 ,V V(PSO3g) ;检测器UV 2 5 4nm     

高效液相色谱法测定菌肥中赤霉素和吲哚乙酸含量方法研究

建立了一种高效液相色谱法分离测定赤霉素(GA3)和吲哚乙酸(IAA)的方法.采用Agilent ZORBA×300SB-C18(4.6 mm×250 mm)色谱柱,以甲醇∶水=35∶65,(V/V,含2%冰醋酸)为流动相,柱温为25℃,流速为0.5 mL/min.系统讨论了流动相组成及pH对分离的影响.本法测定GA3和IAA的线性范围分别为25.0~1 000μg/mL、2.5~50.0μg/mL.方法回收率分别为85.63%、90.21%.并将该方法成功应用于菌肥中GA3和IAA的含量测定,为该类产品的质量控制提供了快速有效的方法.     

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.     

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.     

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.     

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.