无溶剂“一锅法”催化合成氨甲酸酯基烷基萘酚衍生物

无溶剂条件下,对甲基苯磺酸亚铈可有效催化2-萘酚、醛和氨基甲酸酯三组分"一锅法"合成氨甲酸酯基烷基萘酚衍生物。考察了溶剂条件、原料配比、催化剂用量和反应温度对产率的影响。经催化剂循环研究,该催化剂重复使用3次仍保持较高活性。产物的结构通过熔点、IR、1H NMR、13C NMR、质谱和元素分析进行测定和结构表征。同时给出了该反应可能的反应机理。     

苯磺酸铜催化“一锅法”合成1-氨甲酸酯基烷基-2-萘酚

以2-萘酚、醛和氨基甲酸酯为原料,苯磺酸铜为催化剂,在加热、无溶剂条件下,通过三组分"一锅法"合成了1-氨甲酸酯基烷基-2-萘酚衍生物.考察了催化剂用量、反应温度和溶剂对产品收率的影响.结果表明,仅2 mol%苯磺酸铜就可以催化该反应的进行.反应结束后,催化剂重复使用4次,催化活性无明显下降.通过1H NMR,13C NMR,IR,质谱和元素分析对产品结构进行表征.提出了可能的催化作用机理.     

氯化铝高效催化合成1-(1-酰胺基)烷基-2-萘酚类化合物

无溶剂条件下,氯化铝可有效催化2-萘酚、醛和胺/尿素三组分"一锅法"合成1-(1-酰胺基)烷基-2-萘酚.考察了溶剂条件和催化剂用量对产率的影响.与已报道的方法相比,该方法具有反应时间短、产率高、实验操作和后处理步骤简单等优点.     

无水硫酸铁催化多组分反应合成酰胺基烷基萘酚(英文)

无溶剂、80℃条件下,无水硫酸铁可有效催化2-萘酚、醛、和胺/尿素三组分"一锅法"合成酰胺基烷基萘酚。考察了溶剂条件和催化剂用量对产率的影响。与已报道方法相比,该方法具有反应条件温和、反应时间短、产率高、不使用有机溶剂、催化剂廉价易得和后处理步骤简便等优点。     

“一锅法”无溶剂条件下碳基固体酸催化合成萘酚衍生物

无溶剂条件下,含高密度(1.96 mmol·g~(-1))-SO_3H基团的太西煤基活性炭@聚苯胺基磺化固体酸可有效催化2-萘酚、醛和胺三组分反应,并采用"一锅法"合成酰胺基烷基萘酚衍生物。考察了催化剂用量、温度及溶剂条件对产率的影响。结果如下:在无溶剂条件下,反应时间为20-80 min,反应温度为100℃,催化剂用量为1%时,产率可达76%-95%,且该催化剂重复使用4次仍保持较高活性。通过熔点,~1H NMR,~(13)C NMR分析对产物的结构进行测定和表征。同时推测该反应可能的反应机理。     

联二萘酚配合物催化的不对称异原子Diels-Alder反应研究进展

光学活性的联二萘酚及其衍生物作为优良的手性配体在不对称催化反应中的研究已经取得重大进展,本文概述了近些年来以联二萘酚及其衍生物为手性配体和各种金属盐形成的配合物作为手性催化剂在不对称催化的异原子Diels-Alder反应中的应用.总结了各种基于联二萘酚及其衍生物的用于异原子Diels-Alder反应的新的催化剂,以及能有效不对称催化该反应的新条件及新方法.     

手性脲衍生物有机催化α-萘酚和N-Ts芳香醛亚胺的不对称aza-Friedel-Crafts反应

将手性脲衍生物用于有机催化α-萘酚和14种芳香醛亚胺的不对称aza-Friedel-Crafts反应,筛选出最佳的催化条件,以70%~86%的化学产率和最高达78%ee的对映选择性获得了手性氨基萘酚化合物,拓宽了该反应的催化剂类型和底物范围.     

无溶剂条件下离子液体[Hnmp]HSO4催化一锅法合成2 -氨基苯并噻唑-芳甲基-2-萘酚

以离子液体[Hnmp]HSO₄为催化剂, 在无溶剂条件下催化芳香醛、2-氨基苯并噻唑和2-萘酚合成一系列的2 -氨基苯并噻唑-芳甲基-2-萘酚. 该方法条件温和, 反应时间短, 产率高和对环境友好. 此外催化剂可以方便地回收, 且循环使用四次其催化活性并没有显著降低. 目标产物经过了¹H NMR, IR, MS和元素分析确证.     

乙酰基萘酚钛配合物[O,O]_nTiCl_(4-n)的合成、负载及催化乙烯聚合反应的研究

合成一类新型非茂钛 乙酰基萘酚钛配合物 [O ,O]nTiCl4 n,该系列催化剂可在较温和的条件下催化乙烯聚合 ,其催化活性在 10 4gPE (molTi·h)左右 ;由于配合物在溶剂中存在缔合现象 ,是导致活性降低和产物分子量分布加宽 .通过将乙酰基萘酚钛配合物 [O ,O]nTiCl4 n负载到MgCl2 上 ,可以大大提高催化活性 ,使之达到 10 6 gPE (molTi·h)以上 .负载后的催化剂反应平稳 ,寿命较长 .而且反应的铝钛比较低 ,并可以使用烷基铝作助催化剂 .负载催化剂所得的聚合物分子量要高于均相所得聚合物分子量 ,且分子量分布变窄 .用粉末X 衍射考察了负载催化剂的结构 .通过X 射线光电子能谱的分析 ,考察负载前后钛、镁、氯元素的电子结合能变化对催化乙烯聚合活性的影响 .     

乙二胺四乙酸四钠“一锅法”催化合成2-氨基-2-色烯衍生物

乙二胺四乙酸四钠能有效地催化芳香醛、丙二腈、1-萘酚在体积分数为95%乙醇介质中一锅法合成2-氨基-2-色烯衍生物. 该法具有催化剂价廉易得、反应条件温和、实验操作和后处理简便、收率高、催化剂能重复使用等优点.     

Mobile phase compensation to improve NMR spectral properties during solvent gradients

A solvent compensation method based on flow injection analysis is used to obtain high quality nuclear magnetic resonance (NMR) spectra during solvent gradients. Using a binary solvent system containing D2O and CD3OD, NMR line broadening and chemical shift changes are observed with a 10% methanol per min solvent composition gradient. However, by creating a second equal but reverse gradient and combining the two solvent gradients before the NMR detector, the composition of solvent reaching the NMR flow cell is kept constant. We demonstrate a system using flow injection analysis of combining solvent gradients and show constant NMR spectral performance as a function of time as the combined flow has a constant solvent composition irrespective of the initial solvent gradient. Using this approach, methods can be developed to measure high quality NMR spectra during on-flow gradient LC-NMR experiments. The ultimate ability of this approach depends on the ability to compensate for the disturbance of the solvent gradient and reverse gradient by a pair of LC columns (the analytical and reverse gradient columns).     

Thermal and solvent effects on NMR indirect spin-spin coupling constants of a prototypical Chagas disease drug

NMR J-couplings across hydrogen bonds reflect the static and dynamic character of hydrogen bonding. They are affected by thermal and solvent effects and can therefore be used to probe such effects. We have applied density functional theory (DFT) to compute the NMR (n)J(N,H) scalar couplings of a prototypical Chagas disease drug (metronidazole). The calculations were done for the molecule in vacuo, in microsolvated cluster models with one or few water molecules, in snapshots obtained from molecular dynamics simulations with explicit water solvent, and in a polarizable dielectric continuum. Hyperconjugative and electrostatic effects on spin-spin coupling constants were assessed through DFT calculations using natural bond orbital (NBO) analysis and atoms in molecules (AIM) theory. In the calculations with explicit solvent molecules, special attention was given to the nature of the hydrogen bonds formed with the solvent molecules. The results highlight the importance of properly incorporating thermal and solvent effects into NMR calculations in the condensed phase.     

二氟亚甲氧基苯类液晶的合成与低温性能

合成了4个二氟亚甲氧基苯类液晶化合物,经过IR、1H NMR、13C NMR、19F NMR和MS谱图表明分子结构正确;并用动态流变仪测试分析了不同温度下的粘度,发现这些液晶不仅粘度低、对温度的依赖小,而且可以用作替代酯类的液晶溶剂。 如果用于液晶溶剂可以提高液晶器件的低温响应速度。     

液体样品对核磁图谱质量影响因素探讨

结合样品核磁测试结果,以具体实例的形式,总结了核磁样品分析的基本要求,分析了核磁管和氘代试剂的选择、样品制备及pH值等因素对核磁测试结果的影响,并提出了样品最优测试条件:核磁管管体内外表面要足够光洁均匀,在高温条件下,优先选用升温核磁管.尽量选择小支封装氘代试剂,降低水峰的影响,并且应考虑样品的性质,避免试剂与测试样品发生反应.样品必须与溶剂充分混合均匀,样品量要在溶液粘度与灵敏度之间做好平衡.在分析与氧、氮和硫共价相连的氢原子时,应该选择恰当的pH溶液.以上研究结果可以为其它样品核磁测试提供借鉴指导.     

芳醚的催化氧化反应

以取代芳醚为原料,碘苯醋酸酯为氧化剂,二氯甲烷为溶剂,在醋酸铑催化下合成了一系列醌类化合物,其结构经1H NMR,13C NMR和HR-MS确证。     

NMR对MDI在稀溶液中水解反应机理的表征

采用核磁共振波谱(NMR)研究了二苯基甲烷二异氰酸酯(MDI)在稀溶液中的水解反应机理.将同一MDI样品分别溶解在氘代氯仿、氘代丙酮和加入少量水分的氘代二甲基亚砜溶剂(DMSO)中,进行核磁共振氢谱(1H NMR)、核磁共振碳谱(13C NMR)测试.结果显示,MDI在含水的DMSO溶剂中测得的谱图与氘代氯仿、氘代丙酮中的差别显著.对该溶液进行了13C-1H异核近程相关(HMQC)、13C-1H异核远程相关(HMBC)及碳原子级数(DEPT 135)测试,并利用经验公式对其进行了详细归属,确认了反应产物的结构.分析得知MDI在含水溶剂中迅速反应,异氰酸酯基转化为脲基和氨基基团.异氰酸酯与水反应生成氨基基团,其与异氰酸酯反应活性比水高,对位取代氨基与水的竞聚率比值为7.1,邻位为1.4,对位取代氨基活性约是邻位的5倍.     

Stimuli-Responsive Polymers in Solution Investigated by NMR and Infrared Spectroscopy

Summary: Temperature-induced and solvent composition-induced phase separation in solutions of poly(N-isopropylmethacrylamide) (PIPMAm) and other thermoresponsive polymers as studied by NMR and infrared (IR) spectroscopy is discussed. The fraction p of phase-separated units (units with significantly reduced mobility) and subsequently, e.g., thermodynamic parameters characterizing the coil-globule phase transition induced by temperature, were determined from reduced integrated intensities in high-resolution ¹H NMR spectra. This approach can be especially useful in investigations of phase separation in solutions of binary polymer systems. Information on behaviour of water during temperature-induced phase transition was obtained from measurements of ¹H NMR relaxation times of HDO molecules. NMR and IR spectroscopy were used to investigate PIPMAm solutions in water/ethanol (D₂O/EtOH) mixtures where the phase separation can be induced by solvent composition (cononsolvency). Some differences in globular-like structures induced by temperature and solvent composition were revealed by these methods.     

CuI/TMEDA催化合成芳基葡萄糖碳苷化合物

以THF为溶剂, CuI/TMEDA为催化剂,四乙酰溴代葡萄糖与芳基溴化镁经取代反应合成了芳基葡萄糖碳苷（2a~2c）,其结构经¹H NMR和¹³C NMR确证。该方法立体选择性较好。在最佳反应条件(THF为溶剂,10% CuI和10% TMEDA为催化剂,于0 ℃反应至终点)下,2a~2c的收率为58%~71%, α/β为1/6.5~1/7.1。     

Union of capillary high-performance liquid chromatography and microcoil nuclear magnetic resonance spectroscopy applied to the separation and identification of terpenoids

This paper describes the first coupling of a commercial capillary HPLC system with a diode array spectrophotometric detector and a custom-built nuclear magnetic resonance (NMR) flow microprobe. The eluent from a 3-microm diameter C18 HPLC column is linked to a 500 MHz 1H-NMR microcoil probe with an observe volume of 1.1 microl. The separation and structurally-rich detection of a mixture of terpenoids under both isocratic and gradient solvent elution conditions is presented. The lowest limits of detection yet reported for capillary HPLC on-line measurement (i.e., 37 ng for alpha-pinene) are achieved with this system. The complementary nature of diode array and NMR detection allows stopped-flow data collection from analytes which would otherwise go unnoticed in continuous-flow NMR. Moreover, stopped-flow NMR data is presented for the detection of a trace (sub-nmol) impurity in the sample mixture. Since NMR signals degrade and shift during solvent gradients, flow injection analysis studies are conducted with injected solvent plugs differing in mobile phase composition. The NMR signal degradation accompanying these injections is largely due to the variance in chemical shift with the solvent composition rather than to changes in magnetic susceptibility of the solvent. Characterization of such effects enables the development of improved NMR probes for the coupling of capillary HPLC and NMR.     

降冰片烯桥联双酰胺化合物的合成与表征

在干燥非质子性溶剂中,以3,6-桥-亚甲基-1,2,3,6-四氢邻苯二甲酰氯与N-(3-氨基丙基)眯唑和1-氨基-4-甲基哌嗪为原料,合成了两种降冰片烯桥联双酰胺化合物,并考察了反应温度、溶剂及缚酸剂对酰氯氨解反应的影响,目标化合物结构经核磁共振氢谱、核磁共振碳谱、红外光谱及元素分析进行表征确证.