三甲基杯[6]芳烃固相微萃取-气相色谱法测定土壤中的多环芳烃

采用溶胶-凝胶方法制备了三甲基杯[6]芳烃/羟基硅油(C[6]/OH-TSO)固相微萃取(SPME)探头,通过与气相色谱-氢火焰(GC-FID)联用测定了土壤中的多环芳烃(PAHs)。考察了影响萃取效率的因素如时间、温度和盐浓度等,比较了杯[6]芳烃探头和杯[4]芳烃探头以及商用PDMS探头对PAHs的萃取效果。结果表明:杯[6]芳烃SPME探头具有耐高温(380℃)、使用寿命长(7200次)等特点,对样品中PAHs的萃取效果明显优于其它探头。本方法检出限低(0.008~0.440mg/L),重现性好(RSD<7%),线性范围宽(3个数量级)。回收率在70.20%~105.1%之间。     

多重氮杂杯[4]芳烃和双杯[4]芳烃的合成与阳离子萃取性能

多重氮杂杯[4]芳烃和双杯[4]芳烃的合成与阳离子萃取性能;杯[4]芳烃;双杯[4]芳烃;多重氮杂;萃取     

硫(硒)杂多杯[4]芳烃合成及其络合性能研究

合成了下缘硫、硒杂杯[4]芳烃, 然后与杯芳烃片段2,6-二(溴甲基)-4-甲氧基-甲苯在NaH存在条件下缩合得到硫、硒杂多杯[4]芳烃5a和5b. 离子萃取实验表明硫、硒杂多杯[4]芳烃显著增加了对Ag＋和Hg2＋重金属离子的萃取效果.     

三苄基杯[6]芳烃固相微萃取复合涂层的研制及其应用

采用溶胶-凝胶方法制备了三苄基杯[6]芳烃/羟基硅油(C[6]/OH-TSO)固相微萃取(SPME)探头, 通过对多环芳烃和酞酸酯(PAEs)的分析考察了新型C[6]/OH-TSO探头的性能. 结果表明: 杯[6]芳烃SPME探头对这些非极性和弱极性的芳香化合物有很好的萃取效果和选择性, 具有耐高温、使用寿命长等特点. 建立了SPME与气相色谱-氢火焰(GC-FID)联用测定化妆品中PAEs的方法. 该方法检测限低, 重现性好(RSD＜9%), 线性范围宽(2～3个数量级). 回收率在83.42%～98.85%之间.     

杯芳烃的配位化学研究 Ⅰ.对叔丁基杯芳烃对铜的萃取

新一代大环化合物杯芳烃(calixarcne)的研究已引起广泛的兴趣,它是由酚环和亚甲基组成的环多聚体,其结构呈杯状.杯底OH及杯盖R基可被各种基团取代,在其环形结构中具有适当体积的洞穴,在此空穴中能容纳客体而形成主客体配合物,可模拟酶催化的初始过程,在催化及分析分离等方面也有广泛的应用.但杯芳烃的配位化学研究很少,本文首先合成了对叔丁基杯[4]芳烃、对叔丁基杯[6]芳烃及对叔了基杯[8]芳烃(分别简称杯[4]、杯[6]及杯[8]),研究它们对铜的萃取,并探讨了萃取机理.     

杯芳烃的配位化学研究 Ⅰ.对叔丁基杯芳烃对铜的萃取

新一代大环化合物杯芳烃(calixarcne)的研究已引起广泛的兴趣,它是由酚环和亚甲基组成的环多聚体,其结构呈杯状.杯底OH及杯盖R基可被各种基团取代,在其环形结构中具有适当体积的洞穴,在此空穴中能容纳客体而形成主客体配合物,可模拟酶催化的初始过程,在催化及分析分离等方面也有广泛的应用.但杯芳烃的配位化学研究很少,本文首先合成了对叔丁基杯[4]芳烃、对叔丁基杯[6]芳烃及对叔了基杯[8]芳烃(分别简称杯[4]、杯[6]及杯[8]),研究它们对铜的萃取,并探讨了萃取机理.     

含卤素杯[4]芳烃衍生物的合成及其对金属离子的萃取性能

以对叔丁基苯酚为原料,经逐步反应在对叔丁基杯[4]芳烃的下缘引入含卤素的基团,得到了一系列含卤素的杯[4]芳烃衍生物(记为1,2,3,4);利用核磁共振谱和气相色谱-质谱证实了目标产物的结构;并评价了产物对水中的Cr3+、Cu2+、Ag+的萃取性能.结果表明:杯[4]芳烃衍生物2、3和4分别对Cr3+、Cu2+和Ag+具有较好的萃取效果.     

新型杯[4]芳烃衍生物的合成及其氨基酸萃取性能

杯[4]-1,3-二乙酸乙酯衍生物(1)与水合肼反应生成杯[4]芳烃酰肼衍生物(2),化合物(2)与异硫氰酸苯酯反应得到含酰胺和硫脲单元的新型杯[4]芳烃衍生物(3).总产率达70%.系列氨基酸萃取实验表明化合物(3)对异亮氨酸有较好的选择性萃取能力.     

两亲型杯芳烃诱导ZnO微纳结构的合成及光催化性能

回流条件下将两亲型杯芳烃,即丙基间苯二酚杯[4]芳烃(PRCA)、己基间苯二酚杯[4]芳烃(HRCA)和壬基间苯二酚杯[4]芳烃(NRCA),应用于诱导制备ZnO微纳结构,采用X射线衍射、扫描电镜、紫外可见漫反射光谱、红外光谱、X射线光电子能谱等分析了所制备ZnO样品的组成、形貌与微观结构,并以罗丹明B为模型污染物考察了所制备杯芳烃保护的ZnO样品的光催化性能。表征结果显示当杯芳环下缘所连直链烷基中含较多碳原子个数时(HRCA和NRCA),可调控ZnO粒子的尺寸和形貌;而无保护剂和下缘连接较短直链烷基的间苯二酚杯[4]芳烃(PRCA)调控ZnO形貌的能力较弱。模拟太阳光照射下,HRCA-ZnO和NRCA-ZnO的光催化效率相近且均高于无保护剂制备的ZnO和PRCA-ZnO。     

杯芳烃酰胺类衍生物对金属离子的萃取性能

以吗啉和六氢吡啶修饰的四种对叔丁基杯[n]芳烃酰胺类衍生物(n=6,8)为萃取试剂,研究了它们对Na+,K+及部分过渡金属等十种金属离子的萃取作用.结果表明此类杯芳烃酰胺类衍生物对过渡金属离子有良好的选择性识别作用.其中,吗啉取代基修饰的杯[8]芳烃萃取效果最好.     

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.