头孢克洛和δ-3-头孢克洛的毛细管区带电泳分离

建立了分离头孢克洛和δ-3-头孢克洛的毛细管区带电泳法(CZE)；在CZE中，以4-磺酸杯芳烃[6]作为异构体选择性试剂成功地分离了头孢克洛和δ-3-头孢克洛；当以4-磺酸杯芳烃[6]作为异构体选择性试剂时，背景缓冲液的pH值和4-磺酸杯芳烃[6]的浓度是影响头孢克洛和δ-3-头孢克洛分离的重要参数；同时还考察了有机溶剂和β-环糊精对分离的影响；并将该方法成功地用于测定口服头孢克洛干混悬剂中的有效成分——头孢克洛，结果令人满意。     

杯[4]芳烃在毛细管电泳中的应用研究

最近,杯芳烃在分离科学中的应用研究激起了人们的很大兴趣．在液相色谱中,固载化的杯芳烃被用作固定相,对金属离子和氨基酸酯的盐酸盐进行了分离[1]．在气相色谱中,钟振林等[2]评价了主链含杯芳烃的聚硅氧烷作为毛细管固定相的性能．杯芳烃在毛细管电泳中的应用仅见1篇应用杯「6］芳烃的报道[3]．本文首次报道杯卜[4]芳烃在毛细管电泳中的应用．鉴于毛细管电泳一般在水介质中进行,本文合成了水溶性的磺化杯卜[4]芳烃,并将其作为毛细管电泳添加剂来分离硝基苯酚异构体,获得满意的结果．1仪器和试剂Spectra－Phoresis1000型毛细管电泳…     

水相中磺化杯[6]芳烃催化醇的胺基化反应研究

研究了水相中磺化杯[6]芳烃在酸性条件下催化合成含C—N键类化合物的反应,高效的合成了一系列产物,其结构经1H NMR,13C NMR表征.并探究了时间、温度对反应的影响和催化剂的循环使用情况.研究表明水溶性的磺化杯[6]芳烃具有很好的相转移催化性能和多次重复使用性.     

美洛昔康与4-磺化杯[4]芳烃包合作用的荧光光谱研究

采用荧光光谱研究了不同酸度下美洛昔康(ME)与4-磺化杯[4]芳烃(SCX4)的包合作用.结果表明,在酸性和中性条件下,美洛昔康与4-磺化杯[4]芳烃均形成1∶1的包合物;以包合形成常数为包合物稳定性的量度,不同酸度下形成的包合物的稳定性排序为碱性>中性>酸性.     

对磺酸基杯[6]芳烃与葛根素相互作用的荧光光谱研究

采用荧光光谱法研究了在pH=6、不同温度(25、35和45℃)下对磺酸基杯[6]芳烃(SCX6)与葛根素的包合作用;并利用最小二乘法进行非线性拟合,计算出不同温度下的包合常数,初步验证了SCX6与葛根素的包合模式.结果表明,固定葛根素的浓度、逐渐增加对磺酸基杯[6]芳烃的浓度,葛根素荧光强度有规律地降低,表明SCX6和葛根素形成主-客体包合物.在不同温度下,葛根素与SCX6的包合比均为1∶1;且其包合过程可自发进行,温度越高,包合越易发生.     

新型杯[6]芳烃活化KOH催化合成(Z)-1,2-二芳硒基烯

以对叔丁基苯酚为原料，经一步法制得对叔丁基杯[6]芳烃。通过逆傅克反应、亲核取代反应制得二烷基化杯[6]芳烃。最后通过磺化、亲核取代等反应，合成了下缘含喹啉基长链的新型夹状醚杯[6]芳烃化合物（2a~2c），其结构经¹H NMR, ¹³C NMR和HR-MS(ESI-QTOF)表征。以10.0 mol%杯[6]芳烃化合物（2b)为相转移催化剂，20.0 mol%KOH为催化剂，THF为溶剂，较高产率和高选择性地合成了一系列(Z)-1,2-二芳硒基烯化合物，其结构经¹H NMR和NOESY确证。2b重复使用6次，催化活性无明显降低。     

毛细管电泳柱端电化学发光法测定文拉法辛对映异构体浓度

以磺化β-环糊精(S-β-CD)为手性选择剂,建立了毛细管电泳-电化学发光法测定文拉法辛(VEN)对映体浓度的方法.考察了S-β-CD浓度、缓冲液pH值及浓度、进样时间与电压、分离电压和检测电位对VEN对映体分离以及联吡啶钌电致化学发光检测的影响,优化了分离条件,考察了VEN的电化学行为与发光机理.在优化条件下,2种V...     

以L-Cys-GNPs为手性选择剂对异丙肾上腺素的毛细管电泳分析

本文采用柠檬酸钠还原法合成了纳米金,并以L-半胱氨酸对其进行表面修饰,得到络合物L-Cys-GNPs。然后以该络合物为手性选择剂,采用毛细管区带电泳法对盐酸异丙肾上腺素进行手性拆分。对络合物浓度、缓冲液的浓度、pH值、运行电压等方面进行考察和优化。结果表明,当L-半胱氨酸的络合浓度为2.61×10~(-3)mmol·L~(-1)时,以15mmol·L~(-1)磷酸盐缓冲液(pH=7.0)为运行缓冲液、运行电压20kV、分离柱温25℃、进样量0.5Psi×5s以及214nm的检测波长下,盐酸异丙肾上腺素达到了基线分离,在7min内分离度达到10.49。     

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.     

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.     

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.     

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.     

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.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

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.