溶剂浮选法分离富集淫羊霍提取液中淫羊霍苷

应用溶剂浮选法对淫羊霍提取液中的淫羊霍苷进行分离富集,并用高效液相色谱法测定淫羊霍苷的含量。考察了浮选溶剂的用量、氮气流速、浮选液pH值、浮选时间和电解质NaCl浓度对浮选效率的影响,并与泡沫浮选法以及溶剂萃取法进行了比较。结果表明溶剂浮选法分离富集的效果最好,泡沫浮选法次之,溶剂萃取法最差,富集倍数分别为6.4、5.9和1.4倍,收率分别为64.4%、58.8%和28.4%。     

溶剂浮选法分离富集大黄中的有效成分

采用溶剂浮选法对大黄提取液中的芦荟大黄素、大黄素、大黄酚以及大黄素甲醚进行了分离富集,并用高效液相色谱法分别测定了其含量。考察了料液浓度、浮选溶剂、浮选时间、浮选液pH值、氮气流速和电解质NaCl浓度对浮选效率的影响,并与泡沫浮选法和溶剂萃取法进行了比较。结果表明：溶剂萃取效果最差,泡沫浮选次之,溶剂浮选法分离富集效果最好。当料液浓度为6．4mg／mL,浮选时间为30min,浮选液pH一1～2,氮气流速为20mL／min,电解质NaCl浓度为0．4mol／L时,溶剂浮选效率最佳。     

花生壳提取物中木犀草素及总黄酮含量的测定

首次采用高效液相色谱法测定不同溶剂提取物中木犀草素的含量;并用分光光度法测定花生壳不同提取物中的黄酮类化合物.结果表明,60%丙酮为提取剂时,提取物中木犀草素及总黄酮含量较高.     

动态泡沫浮选法分离富集人参提取液中的二醇型人参皂苷

采用动态泡沫浮选法分离富集人参提取液中的二醇型人参皂苷, 用高效液相色谱法测定6种人参皂苷Rg₁, Re, Rb₁, Rc, Rb₂和Rd的含量. 考察了浮选液pH值、电解质NaCl浓度、载气流量、料液浓度及料液流速对人参皂苷浮选率的影响, 确定了动态泡沫浮选的最佳条件, 并与溶剂提取法、溶剂浮选法以及静态泡沫浮选法进行了比较. 结果表明, 动态泡沫浮选法对二醇型人参皂苷Rb₁, Rc, Rb₂和Rd具有高富集效率, 回收率分别为93.3%, 98.6%, 96.9%和98.3%, 而对三醇型人参皂苷Rg1和Re的富集效率却很低, 回收率分别为4.8%和4.2%. 该法是分离纯化二醇型人参皂苷的一种简便有效的方法.     

溶剂浮选-高效液相色谱法同时测定水体中痕量4-硝基甲苯、二苯甲酮和正丁苯

建立了一种同时测定水体中痕量4-硝基甲苯、二苯甲酮和正丁苯含量的新方法, 即采用溶剂浮选法分离富集水体中的痕量 4-硝基甲苯、二苯甲酮和正丁苯类环境激素, 用高效液相色谱法测定其含量. 考察了浮选溶剂、试液 pH、氮气流速、浮选时间等因素对浮选效果的影响, 优选出最佳浮选条件. 采用所述方法对石化地区水体中 4-硝基甲苯、二苯甲酮和正丁苯类环境激素进行测定, 样品加标回收率为92.7%～114.3%, RSD为4.8%～8.4%.     

溶剂浮选-HPLC法测定茵陈中滨蒿内酯的研究

摘要：建立茵陈中滨蒿内酯的溶剂浮选分离富集方法。方法 考察了浮选溶剂、氮气流速、试液 pH、浮选时间及电解质 NaCl 等因素对浮选效果的影响,优选出最佳浮选条件,并由高效液相色谱测定其含量。结果 对最佳条件下的浮选效果进行了评价。结论 加标回收率92.31 ~ 99.97 %; RSD = 3.20 %.溶剂浮选分离富集方法可行。     

泡沫浮选法分离富集三七中的4种人参皂苷

采用泡沫浮选法对三七提取液中的人参皂苷Rg1、Re、Rb1和Rd进行了分离富集,并用高效液相色谱法分别测定了含量.考察了浮选液浓度、浮选时间、浮选液pH值、氮气流速和电解质NaCl浓度对浮选效率的影响.结果表明:泡沫浮选法对4种皂苷均有较好的分离富集效果,尤其是对人参二醇型皂苷(Rb1,Rd)效果更为明显.当浮选液浓度为2.0 mg/mL,pH值为2～3,氮气流速为20 mL/min,浮选时间10 min,电解质氯化钠浓度0.20 mol/L,泡沫浮选效果最佳.     

HPLC法测定杠板归中槲皮素-3-O-β-D-葡萄糖醛酸及槲皮素的含量

建立了高效液相色谱法同时测定杠板归中槲皮素-3-O-β-D-葡萄糖醛酸和槲皮素含量的方法.采用Lichrosher 5-C18色谱柱,以甲醇-0.05％磷酸水溶液为流动相,梯度洗脱,流速为1 mL/min,紫外检测波长为258 nm,柱温为25 ℃,2种化合物在30 min内均得到较好分离.槲皮素-3-O-β-D-葡萄糖醛酸和槲皮素的线性范围分别为0.0376～3.9200 mg和0.0042～0.4400 mg,检出限和定量下限分别为2.509、0.282 ng和6.272、0.702 ng,方法的平均回收率分别为99％和98％.运用该方法对不同产地杠板归药材中的2种黄酮类化合物进行测定,并得出二者含量的比例.方法快速简便,灵敏准确,重现性好,可作为杠板归药材的质量控制方法.     

含羞草中总黄酮的提取与分离纯化

确定含羞草中总黄酮的最佳提取部位,并对其初步分离纯化。通过正交试验,分别筛选含羞草根部、茎叶及种子中总黄酮的最优提取条件,比较三者黄酮总含量,最终确定提取部位为茎叶,最佳提取条件:以70%乙醇为溶剂,按照1∶8配料比,在55~58℃下超声50 min。提取液依次用石油醚、乙酸乙酯液液萃取,蒸干上样,用乙醇水溶液以4 m L/min梯度洗脱Diaion HP–20大孔树脂,收集洗脱液并用液相色谱监测每个梯度洗脱液的总黄酮含量,得到分离纯化过的黄酮类物质。当40%乙醇洗脱部位总黄酮含量最高,达57.7%。该工艺确定了含羞草中茎叶部位总黄酮含量最高,大孔树脂初步纯化黄酮类物质有效,为含羞草中黄酮类物质的应用提供了依据。     

高速逆流色谱法分离制备乌药叶中的黄酮类成分

应用高速逆流色谱法分离制备了乌药叶中的黄酮类成分。以正己烷-乙酸乙酯-正丁醇-冰醋酸-水(体积比为2∶4∶2∶1.5∶6)为两相溶剂系统,在主机转速800 r/min、流速2.0 mL/min、检测波长280 nm条件下进行分离制备。所得流分经高效液相色谱法检测,并经电喷雾电离质谱、核磁共振氢谱、碳谱鉴定化合物的结构。结果表明,从乌药叶总黄酮粗提物中分离得到了5个化合物,分别为槲皮素-3-O-β-D-葡萄糖苷(1)、槲皮素-5-O-β-D-葡萄糖苷(2)、槲皮素-3-O-β-D-呋喃阿拉伯糖苷(3)、槲皮素-3-O-吡喃鼠李糖苷(4)、山奈酚-7-O-α-L-吡喃鼠李糖苷(5),其中化合物1,2,3和5 为首次从该植物中分离得到。该法具有简便、快速的优点。     

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.