齐墩果烷型和乌苏烷型五环三萜同分异构体配位色谱法分离机理（英文）

本文主要研究了配位色谱法分离齐墩果烷型和乌苏烷型五环三萜同分异构体的分离机理。基于计算模拟分析,β-环糊精（β-CD）和其衍生物为适宜的配位剂。采用HPLC法测定了包合物的表观形成常数,并制备了asiaticoside-B与β-CD包合物。实验结果显示:流动相中添加葡萄糖基-β-环糊精（Glu-β-CD）时,同分异构体的分离度为11.95,比添加β-CD或添加甲基-β-环糊精（DM-β-CD）时（分别为9.61和9.89）都略高些。假定五环三萜类化合物与β-CD形成1：1的包合物,对于asiaticoside-B,流动相中添加Glu-β-CD时,表观形成常数（K_F）为2534 L/mol,比添加β-CD或添加DM-β-CD时（分别为1467和1373 L/mol）都略大些。根据asiaticoside-B与β-CD包合物的红外光谱解析及计算模拟,推测asiaticoside-B的E环上甲基部分进入了β-CD的空腔内,而其羰基基团没有进入β-CD的空腔内,其糖苷部分与亲水性的β-CD空腔外部形成氢键作用力。因此,配位色谱法分离齐墩果烷型和乌苏烷型五环三萜同分异构体的分离机理可以推测如下：齐墩果烷型和乌苏烷型五环三萜同分异构体E环上甲基的不同空间位阻导致了同分异构体的不同色谱分离行为。     

基于环糊精二聚体与金刚烷修饰的温敏性聚合物的主客体识别构筑超分子水凝胶

利用环糊精二聚体(trans-Stilbene β-CD Dimer)与金刚烷修饰的温敏性聚合物(Pnipam-Ad)的主客体识别作用构筑了超分子水凝胶. 2D NMR 测定结果表明trans-Stilbene β-CD Dimer 和Pnipam-Ad 的主客体相互作用是通过β-CD 空腔和疏水体Ad 形成包结络合物进行的. 环糊精二聚体trans-Stilbene β-CD Dimer 和聚合物Pnipam-Ad 两者之间的缔合程度受trans-Stilbene β-CD Dimer 和Pnipam-Ad 的浓度以及trans-Stilbene β-CD Dimer 光异构的影响. 此外, 由于trans-Stilbene β-CD Dimer 对Pnipam-Ad 聚合物链的物理交联作用使两者混合溶液的最低临界溶解温度(LCST)低于纯聚异丙基丙烯酰胺(Pnipam)的LCST.     

铟(I)/手性磷酸催化简单烯烃与β,γ-不饱和α-酮酸酯的不对称[4+2]环加成反应

报道了In（I）Cl/手性磷酸1a双酸体系催化的简单烯烃和β,γ-不饱和α-酮酸酯的不对称[4+2]环加成反应,可高产率、高选择性（最高99：1dr,99%ee）生成相应的exo-[4+2]环加成产物.InCl和磷酸的协同作用是反应成功的关键,单独使用InCl和磷酸都不能催化反应进行.     

基于环糊精二聚体与紫精聚合物的包结作用制备超分子水凝胶

制备了对苯二甲酸连接的环糊精二聚体(α,α-CD Dimer)及紫精聚合物(VP), 利用α,α-CD Dimer与VP之间的主客体识别作用构筑了一种超分子水凝胶. ¹H NMR测定结果表明α,α-CD Dimer和VP的主客体相互作用是通过α-CD空腔和VP形成包结络合物进行的. 环糊精二聚体α,α-CD Dimer和聚合物VP凝胶体系的构筑受环糊精二聚体类型的影响, 同时该超分子水凝胶对有竞争作用的客体分子表现出响应性, 该超分子水凝胶在竞争性客体分子存在的条件下, 可发生小分子诱导的凝胶与溶胶转化行为. 此外, 该凝胶体系还具有良好的热稳定性.     

不对称双酸催化3,4-二氢-2H-吡喃的反电子Hetero-Diels-Alder反应

研究了双酸催化剂不对称催化烯醚和β,γ-不饱和α-酮酸酯的反电子Hetero-Diels-Alder (HDA)反应, 为手性合成3,4-二氢-2H-吡喃类化合物提供了一种新的催化合成方法. InBr₃与手性磷酸钙盐Ca(1c)₂组合的手性双路易斯酸催化体系能够有效催化3,4-二氢-2H-吡喃和β,γ-不饱和α-酮酸酯的反电子HDA反应, 反应给出优秀的产率(最高达98%), 中等到良好的非对映选择性(最高达89:11)和良好到优秀的对映选择性(最高可达94%). 并且该双酸催化体系也能成功实现其它烯醚(如: 2,3-二氢-2H-呋喃, 乙烯基乙醚)的HDA反应, 获得优秀的非对映选择性(>94:6)和良好的对映选择性.     

免疫亲和固相萃取-超高效合相色谱-串联质谱法同时测定牛奶中6种玉米赤霉醇类化合物残留

建立了免疫亲和固相萃取（IAC-SPE）-超高效合相色谱-串联质谱（UPC²-MS/MS）同时测定牛奶中α-玉米赤霉醇、β-玉米赤霉醇、α-玉米赤霉烯醇、β-玉米赤霉烯醇、玉米赤霉烯酮和玉米赤霉酮残留的分析方法。样品用去离子水稀释,经IAC-SPE富集净化后,采用Waters ACQUITY UPC² Torus 2-PIC色谱柱（50 mm×3.0 mm,1.7 μm）分离,以超临界CO₂和0.1%（v/v）甲酸甲醇溶液为流动相,经梯度洗脱后在ESI^-模式下检测。经过稀释离心的牛奶样品采用免疫亲和柱净化后没有明显的基质效应,6种目标化合物在1~200 ng/mL范围内线性关系良好,相关系数（r²）≥0.9957;6种目标化合物在3个加标水平下的平均回收率为75.9%~106.5%,日内和日间精密度均≤11.4%。该法专属性好,操作简便,有机溶剂使用量小,与已有的样品测定方法比较更绿色环保,可用于牛奶中α-玉米赤霉醇、β-玉米赤霉醇、α-玉米赤霉烯醇、β-玉米赤霉烯醇、玉米赤霉酮和玉米赤霉烯酮的残留检测。     

哌嗪衍生物和环糊精分子非共价作用的分析

采用电喷雾质谱(ESI-MS)和核磁共振谱(1HNMR)等方法研究了抗抑郁哌嗪衍生物化合物SIPI5838,SIPI5357和SIPI5358与α-,β-或γ-环糊精(CD)分子生成的非共价复合物及其键合位点。质谱分析结果表明,在水溶液中,SIPI5838分子可以与α-,β-或γ-环糊精分子通过反应生成非共价复合物,其中与β-环糊精可以生成配合比为1:1或1:2的非共价复合物,与α-或γ-环糊精分子则生成配合比为1:1的非共价复合物。SIPI5357与α-,β-或γ-环糊精(CD)分子仅生成配合比为1:1的非共价复合物。核磁共振谱(1HNMR)表明,α-环糊精主要与SIPI5838分子中的苯基结合,β-环糊精可同时与SIPI5838分子中的苯基和萘基结合配合比1:2的非共价复合物,而γ-环糊精则主要与SIPI5838分子中的萘基结合。溶解度实验表明,SIPI5358与α-,β-及γ-环糊精在液相中的结合常数分别为15.4,29.2和175.2mol/L。     

Lewis酸对氮杂环卡宾协同催化体系中反应途径的调控

该研究基于氮杂环卡宾（N-heterocyclic carbene,NHC）新颖的协同催化策略,通过Lewis酸共催化剂调控反应具体途径.从α,β-不饱和醛类化合物出发,立足于多反应位点的高烯醇中间体,与氯化镁协作实现高对映选择性的质子转移历程,构建β-手性酯类产物;在相似的反应体系中与氯化钌协作实现高效的空气氧化,构建α,β-不饱和酯类化合物.这两个迥异的反应途径对底物均有较好的官能团容忍性,以高转化率得到目标产物.     

在线二维集束毛细管柱-高气压光电离-飞行时间质谱用于单萜类化合物的快速测量

单萜类化合物是大气中生物源挥发性有机物（BVOCs）的一个主要组分，具有同分异构体种类多、寿命短、浓度低、时空变化快等特点。将集束毛细管柱（MCC）和高气压光电离-飞行时间质谱仪（HPPI-TOF MS）相结合，搭建MCC-HPPI-TOF MS联用装置，并开发一种二维GC-MS快速在线检测方法，用于单萜同分异构体的快速定性和定量分析。实验结果表明，在无任何样品预富集的前提下，该方法可在180 s内实现α-蒎烯、β-蒎烯、α-萜烯、γ-萜烯、3-蒈烯及柠檬烯等6种单萜同分异构体的在线检测，检出限（LODs）低至μg/m³量级。该方法已经用于松树和柏树枝叶释放出的单萜化合物的快速在线分析，展示了其在环境监测、过程分析等领域复杂混合物样品在线检测的能力和应用前景。     

一种新型酶生物燃料电池阳极构建及性能研究

通过酸化碳纳米管(CNTs)和β-环糊精(β-CD)之间的范德华力作用, 实现CNTs的β-CD功能化. β-CD具有内腔疏水、外壁亲水的环状结构, 其内腔容易与二茂铁(Fc)形成稳定的主客体包合结构, 实现Fc在碳纳米管上的高效固载; 再将CNTs-β-CD-Fc复合物与葡萄糖氧化酶(GOD)混合, 采用戊二醛实现酶分子间的交联, 形成GOD/CNTs-β-CD-Fc复合物, 然后将其涂覆到玻碳电极(GC)上, 得到一种新型的酶生物燃料电池阳极(GOD/CNTs-β-CD-Fc/GC). 采用同步热分析法、傅里叶变换红外光谱和透射电子显微镜对所制备的CNTs-β-CD-Fc复合物进行了表征, 采用循环伏安法研究了GOD/CNTs-β-CD-Fc/GC电极对葡萄糖氧化的催化性能. 结果表明: 在同等实验条件下, 没有固载Fc的GOD/CNTs- β-CD/GC电极基本无催化电流, 而GOD/CNTs-β-CD-Fc/GC电极表现出比GOD/CNTs-Fc/GC电极更为优越的电催化性能. 进一步以GOD/CNTs-β-CD-Fc/GC电极或GOD/CNTs-Fc/GC电极为酶阳极, 商用催化剂E-TEK Pt/C电极(E-TEK Pt/C/GC)为阴极, 构建葡萄糖/氧气生物燃料电池(EBFC), 结果表明前者的最大功率密度(33 μW·cm^-2, 0.18 V)几乎是后者的三倍(11.7 μW·cm^-2, 0.16 V). 通过记录开路电位随时间的变化研究了EBFC的稳定性, 以GOD/CNTs-β-CD-Fc/GC电极为阳极的EBFC在连续工作9 h后仍保留了92%的开路电位, 表明该电池具有良好的连续工作稳定性. 我们提出的这种新型生物燃料电池阳极的构造方法, 为构建高性能、高稳定性的葡萄糖/氧气EBFC提供了新的思路.     

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.     

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.     

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.     

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.     

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.     

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.     

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.