原子吸收法对藏草药川木香中12种元素的初级形态分析

用原子吸收分光光度法,测定了产于青藏高原的藏草药川木香的全药材、水提液、醇提液中12种元素(Cr、Cu、Fe、Mn、Ni、Se、Zn、K、Ca、Mg、Cd、Pb)的含量,以及水提液中各元素可溶态、水溶态的含量,同时采取正辛醇-水分配体系模拟藏药水提液中各微量元素在人体胃肠中的分配情况,对藏药中微量元素的初级形态进行了分析,初步探讨了酸度变化(人体胃肠酸度)对微量元素的影响,结合藏药药效讨论其相关性,为进一步研究微量元素与藏药药性、药效的关系提供科学的依据和奠定基础.     

穿心莲中7种微量元素的形态分析

采用传统煎煮法对穿心莲中的铁、锰、铜、锌、铝、硼和锶7种微量元素进行提取,用0.45 μm微孔滤膜分离提取液中的可溶态与悬浮态;用LSA-10大孔吸附树脂分离可溶态中的有机态与无机态;并用正辛醇-水分配体系在模拟人体胃肠酸度的条件下,将可溶态中各待测元素分离为醇溶态和水溶态;采用电感耦合等离子原子发射光谱法(ICP-A...     

火焰原子吸收光谱法分析中药中锌的形态

采取正辛醇水分配体系模拟中药水煎液中锌在人体胃肠中的分配情况，用原子吸收光谱法测定了十二味中药药材及其水剪液中锌的含量，水煎液中水溶态锌、醇溶态锌的含量。实验结果表明，中药中锌的水煮溶出率较氏，中药中锌的形态与中药成分，配伍情况及作用靶位（胃肠）的酸度有关，酸度及配伍对中药中锌的溶出率及水煎液中锌的形态影响较大。     

FAAS法分析当归、黄芪及当归补血汤中金属元素的形态

采用正辛醇-水分配体系模拟中药水煎液在人体肠胃中的分配情况,应用火焰原子吸收光谱法测定了当归、黄芪及当归补血汤中锌、铁、锰、铜、镁、钙、镍7种金属元素在药材中的总含量,以及水煎液中各金属元素的水溶态、醇溶态含量,探讨了配伍和酸度对水煎液中金属元素含量的影响。实验结果表明,中药中金属元素的形态与中药成分、配伍情况及作用靶位(肠胃)的酸度有关,配伍及酸度对中药中金属元素的溶出率及水煎液中金属元素的形态影响较大。     

火焰原子吸收光谱法分析中药中锰的形态

1　引　　言中药中锰具抗癌、益精生血、益肝明目及提高机体抵抗力等作用。正辛醇在结构上与人体内的碳水化合物和脂肪类似 ,药理学中药物鉴定用Ｋｏｗ参数 (Ｋｏｗ =Ｃｏ Ｃｗ ,Ｃｏ 和Ｃｗ 分别为该化合物在正辛醇相和水相中的平衡浓度 )评价药物亲脂性及生物活性。正辛醇醇溶态微量元素具较强的亲脂性和生物活性 ,如作为中药有效成分 ,醇溶态含量应与中药药性、药效密切相关。本实验按中药常用煎煮方式制水煮液 ,用正辛醇 水分配体系模拟水煎液中锰在人体胃肠中的分配情况。火焰原子吸收法 (ＦＡＡＳ)测药材、水煎液中锰含量及水溶态锰、…     

中草药龙胆中微量元素的形态分析

采用传统煎煮法对丽水当地中草药龙胆中钙、锌、铁、铜、锰、铅、镉和铬等8种元素进行提取,并用微孔滤膜分离提取液中可溶态与悬浮态;利用大孔吸附树脂分离可溶态中有机态与无机态;采用正辛醇/水分配体系模拟水煎液中这8种微量元素在人体胃肠中分配情况,再用火焰原子吸收光谱法(FAAS)测定了各种形态中的8种元素。研究结果显示:龙胆中8种元素的提取率在34.25%～74.53%,浸留比在49.58%～371.1%,悬浮态颗粒吸附率在6.5%～29.8%,该法对各元素的加标回收率在91.3%～108.5%;相对标准偏差小于3.5%;锌、铁、铜、锰在正辛醇/水分配体系中溶出性受酸碱性影响大些。     

藏药"帕朱胶囊"中微量元素及重金属元素分析

为探讨藏药“帕朱胶囊”中微量元素与其治疗胃病的相关性,以及监测藏药中的重金属含量,采用原子吸收分光光度法,对帕朱胶囊中的11种元素进行了测定。结果表明,帕朱胶囊中Fe元素含量较高,并含有Cu、Zn、Mn、Se等与治疗胃病直接相关的微量元素,重金属元素Pb、As、Hg含量不超标。为研究传统藏药帕朱胶囊的药效物质基础和安全使用,提供了科学依据。     

火焰原子吸收光谱法分析香青兰中微量元素的溶出特性及化学形态

结合香青兰的药用功效,对其铜、锌、锰、铁、镁、镍6种微量元素的含量和形态进行了分析.分别用0.45 μm滤膜、D101型大孔吸附树脂,将香青兰水煎液中铜、锌、锰、铁、镁、镍分为悬浮态和可溶态、有机态和无机态;并采取正辛醇-水分配体系模拟水煎液中铜、锌、锰、铁、镁、镍在人体胃肠中的分配情况,建立了上述6种元素的4种形态分离分析方法,用火焰原子吸收光谱法测定6种微量元素的含量、分布及其在不同溶剂中的溶出特性和化学形态.结果表明,方法的回收率在92%～106%范围内,相对标准偏差均在3.8%以下,铜、锌、锰、铁、镁、镍是各以某种形态为主的多种形态共存的混杂体系.     

败酱草中常量和微量元素的形态分析

按照传统煎煮法对败酱草中Ca、Mg、Fe、Cu、Zn、Al、P、B、Mn和Sr 10种元素进行提取;用0.45μm微孔滤膜分离提取液中的可溶态与悬浮态;LSA-10大孔吸附树脂柱分离可溶态中的有机态与无机态;并采用正辛醇/水分配体系,在模拟人体胃肠环境条件下,将水煎液中这10种元素分离为醇溶态和水溶态;用电感耦合等离子体原子发射光谱法(ICP-AES)对各形态中的10种元素进行测定。结果表明,败酱草中10种元素的总提取率在17.2%～84.2%,悬浮态的颗粒吸附率在2.74%～71.6%,加标回收率在95.0%～105.9%,相对标准偏差(RSD)≤2.4%。     

杜仲叶水煎及醇提液中无机元素赋存形态分析

通过水煎及醇提法对杜仲叶中铁、锌、铜、锰、钾、钠、钙和镁8种无机元素进行提取,分别用微孔滤膜、D101大孔树脂、732阳离子树脂、D402螯合树脂将无机元素分为初级形态及次级形态。采用环己烷-正丁醇分配体系模拟人体肠胃条件将无机元素分为脂溶态和水溶态,用火焰原子吸收光谱法(FAAS)对各种形态的无机元素进行测定。结果表明:杜仲叶醇提液中各无机元素提取率均高于水煎液;杜仲叶醇提液中8种无机元素的提取率为6.61%~89.30%;次级形态分析参数表明各无机元素均以某种次级形态为主的多种形态共存于可溶态溶液中。该法测定各元素的回收率为98.99%~104.0%,相对标准偏差在0.35%~1.11%之间,具有良好的精密度和准确度。     

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.     

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.     

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.     

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.     

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.     

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.     

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.