悬浮体进样／氟化电热蒸发（ETV）／ICP—AES直接测定二氧化钛 …

以聚四氟乙烯（ＰＴＦＥ）悬浮体为氟化剂,肖体制样／氟化辅助电热蒸发（ＥＴＶ）／ＩＣＰ－ＡＥＳ直接测定ＴｉＯ２陶瓷粉末中痕量杂质钇考察了影响基体和等测元素的蒸发过程的各种因素,对比研究了待测元素和基体的氟化蒸发行为,实现了基体和待测元素的预分离,显著降低了基体效应。本法的检出限为０．２６μｇ／Ｌ。相对偏差为３．８％（ｎ＝５,ｃ＝０．５ｍｇ／Ｌ）。     

FETV-ICP-AES 直接测定中药漏芦中微量稀土元素的研究

提出了以聚四氟然悬浮为氟化剂,氟化电热蒸发（ＦＥＴＶ）等离子体发射光谱法（ＩＣＰ－ＡＥＳ）直接测定中药漏芦中微量稀土元素Ｌａ、Ｅｕ、Ｙｂ和Ｙ的方法,改进了ＥＴＶ与ＩＣＰ之间的气路接口,研究了影响待测元素信号强度的有关因素,在优化实验条件下,方法的检出限为１．０－３．８ｎｇ／ｍＬ,相对标准偏差为２．７％－４．４％。此法已应用于中药漏芦中微量稀土元素的测定。     

氟化电热蒸发—ICP—AES直接测定生物试样中痕量镧

采用聚四氟乙烯（ＰＴＦＥ）为氟化剂，以悬浮体制样ＥＴＶ－ＩＣＰ－ＡＥＳ直接测定固体生物试样中的难熔稀土元素Ｌａ，研究了粒度效应和Ｌａ的氟化蒸发行为。在优化实验条件下，方法的检出限为２．０ｎｇ／ｍＬ，相对标准偏差为４．５％。该方法简便、灵敏，无需进行化学前处理，可用于固体生物试样的直接分析，分析结果与参考值吻合。     

氟化电热蒸发／ICP—AES直接测定SiO2中痕量Fe

对氟化电热蒸发（ＦＥＴＶ）／ＩＣＰ－ＡＥＳ技术中元素的氟化蒸发行为，基体效应和粒度效应进行了考察，确定了杂质（Ｆｅ）与基体（Ｓｉ）分离的最佳实验条件，本法用于ＳｉＯ２中痕量Ｆｅ的直接测定，有灵敏，简便，试样消耗少和不需化学处理等优点。     

氟化电热蒸发—等离子体原子发射光谱直接测定生物试样中铜的研究

本文采用聚四氟乙烯为氟化剂，以悬浮体制样，ＥＴＶ－ＩＣＰ－ＡＥＳ直接测定生物固体粉末试样中的中等挥发性元素铜。详细研究了试样粒度对分析信号强度的影响，考察了铜在该技术中的蒸发行为以及影响氟化蒸发的主要因素，在优化的实验条件下，本法测定铜的检出限为４２ｐｇ，相对标准偏差为４．５％，本法简单、快速、所得结果与参考值听合很好。     

氟化电热蒸发－等离子体原子发射光谱直接测定生物试样中铜的研究

本文采用聚四氟乙烯（ＰＴＦＥ）为氟化剂，以悬浮体制样，ＥＴＶ－ＩＣＰ－ＡＥＳ直接测定生物固体粉末试样中的中等挥发性元素铜。详细研究了试样粒度对分析信号强度的影响，考察了铜在该技术中的蒸发行为以及影响氟化蒸发的主要因素，在优化的实验条件下，本法测定铜的检出限为４２ｐｇ，相对标准偏差为４．５％（ｎ＝１０，Ｃｕ浓度为０．２μｇ／ｍＬ），本法简单、快速、所得结果与参考值吻合很好。     

氟化电热蒸发／电感耦合等离子体原子发射光谱中的基体效应研究

本文系统研究了氟化电热蒸发／电感耦合等离子体原子发射光谱（ＥＴＶ－ＩＣＰ－ＡＥＳ）测定难熔元素的基体效应。与常规气动雾化（ＰＮ）－ＩＣＰ－ＡＥＳ中的基体效应比较，氟化ＥＴＶ－ＩＣＰ－ＡＥＳ中的基体效应更小。对难熔基体元素，由于基体和待测元素与氟化剂之间的竞争反应，随着基体浓度的增加，待测元素谱线强度降低；对常见基体元素，由于热循环中基体与待测元素之间的选择挥发，对待测元素的蒸发和传输过程无明显影响     

氟化电热蒸发－ICP－AES直接测定生物试样中痕量镧

采用聚四氟乙烯（ＰＴＦＥ）为氟化剂，以悬浮体制样ＥＴＶ－ＩＣＰ－ＡＥＳ直接测定固体生物试样中的难熔稀土元素Ｌａ，研究了粒度效应和Ｌａ的氟化蒸发行为。在优化实验条件下，方法的检出限为２．０ｎｇ／同ｍＬ，相对标准偏差为４．５％。该方法简便、灵敏，无需进行化学前处理，可用于固体生物试样的直接分析，分析结果与参考值吻合。     

氟化辅助电热蒸发/ICP-AES直接测定氧化铝粉末中痕量杂质钇

报道了以聚四氟乙烯（PTFE）悬浮体为氟化剂,悬浮体制样／氟化辅助电热蒸发（ETV）／ICP －AES直接测定两种AI2O3粉末样品中痕量杂质钇。考察了影响基体和待测元素蒸发过程的各种因素;对比研究了待测元素和基体的氟化蒸发行为。在优化实验条件下,方法的检出限为0．1μg/g,相对标准偏差为5．6％（n=5,c=8g/L悬浮体）。并与溶样法气动雾化（PN）－ICP－AES的分析结果进行了对比。本法简便、灵敏、无需任何化学前处理,可用于相关陶瓷生产过程中的质量控制。     

聚三氟氯乙烯化学改进剂在电热蒸发（ETV）—ICP—AES直接测定生物试样…

本文首次提出以聚三氟氯乙烯（ＰＴＦＣＥ）为化学改进剂，应用于悬浮体制样ＥＴＶ－ＩＣＰ－ＡＥＳ直接测定固体生物试样中微量钛，实验采用５％，ＰＴＦＣＥ，促进Ｔｉ的蒸发，方法的绝对检出限为２ｐｇ（按５σ计），ＲＳＤ为２．６％（ｎ＝５），该法用于直接测定ＧＢＷ０８５０５茶叶粉末样品中的Ｔｉ，结果与参考值吻合，回收率为９７．３～１０５．４％。     

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.