Aluminium dodecatungstophosphate (AlPW12O40) as a highly efficient catalyst for the selective acetylation of –OH, –SH and –NH2 functional groups in the absence of solvent at room temperature
AlPW12O40 was found to be an effective catalyst for the selective acetylation of alcohols, thiols, and amines in the absence of solvent at room temperature.
AlPW12O40被发现是一种有效的催化剂,可在室温无溶剂条件下选择性乙酰化醇、硫醇和胺。
<i>o</i>-Benzenedisulfonimide as a Soft, Efficient, and Recyclable Catalyst for the Acylation of Alcohols, Phenols, and Thiols under Solvent-Free Conditions: Advantages and Limitations
o-Benzenedisulfonimide turns out to be a highly efficient Bronsted acid catalyst for the acylation of a number of alcohols, phenols, and thiols under a metal- and solvent-free procedure; reaction conditions are mild and yields very good. After the workup, the catalyst can be easily recovered and purified, ready to be reused, with economic and ecological advantages.
Werner‐type transition‐metal complexes (WTMC) such as [Co(NH3)5Cl]Cl2, Cu[(NH3)4]SO4, Mn(acac)3, Ni[(NH3)6]Cl2, Ni[(en)3]S2O3, and Hg[Co(SCN)4] efficiently promote the chemoselective acetylation of phenols and anilines under solvent‐free condition. The results of this study clearly shows that the optimal condition for the acetylation of anilines/phenols (1 mmol) (2a–r) with acetic anhydride (1.2 mmol)
Werner型过渡金属络合物(WTMC),例如[Co(NH 3)5 Cl] Cl 2,Cu [(NH 3)4 ] SO 4,Mn(acac)3,Ni [(NH 3)6 ] Cl 2,Ni [(en)3 ] S 2 O 3和Hg [Co(SCN)4 ]在无溶剂条件下有效地促进了苯酚和苯胺的化学选择性乙酰化。这项研究的结果清楚地表明,在存在WTMC(1 mmol)和两滴H的条件下,用乙酸酐(1.2 mmol)乙酰苯胺/苯酚(1 mmol)(2a–r)进行乙酰化的最佳条件在无溶剂条件下加热10分钟可得到3 PO 4,其相应的乙酰苯胺/乙酸苯酯(3a–r)良好或优异。此外,该方法简便,高效,化学选择性且在无溶剂条件下对生态环境友好,用于使用无水乙酸作为乙酰化剂,WTMC促进的苯胺和苯酚的乙酰化。催化剂的简单制备,乙酰化反应的简便程序以及简单的后处理都表明了WTMC对于此类反应的重要性。
Highly efficient dynamic kinetic resolution of secondary aromatic alcohols with low-cost and easily available acid resins as racemization catalysts
作者:Yongmei Cheng、Gang Xu、Jianping Wu、Chensheng Zhang、Lirong Yang
DOI:10.1016/j.tetlet.2010.02.152
日期:2010.4
A new and efficient dynamic kineticresolution (DKR) process of secondary aromatic alcohols was developed with acid resins as racemization catalysts. Acid resin CD8604 was shown to have excellent racemization activity and good biocompatibility. When employing CD8604 and complex acyl donors as racemization catalyst and acyl donor, respectively, enantiomerically pure aromatic acetate was obtained with
A Conformationally Restricted Aza-BODIPY Platform for Stimulus-Responsive Probes with Enhanced Photoacoustic Properties
作者:Effie Y. Zhou、Hailey J. Knox、Chang Liu、Weili Zhao、Jefferson Chan
DOI:10.1021/jacs.9b06694
日期:2019.11.6
rational manner. Herein we synthesized and evaluated six modifications to the aza-BODIPYdye platform with respect to their absorbance, fluorescence, and PA properties. We identified a promising conformationallyrestrictedaza-BODIPY (CRaB) scaffold that prioritizes three criteria necessary for the design of stimulus-responsive dyes with optimal ratiometric PA response: absorbance at NIR wavelengths, strong
光声 (PA) 染料吸收近红外 (NIR) 光以产生超声波信号,可以在厘米深度的组织中检测到,其分辨率明显高于使用基于荧光的方法成像的染料。因此,PA 试剂作为研究活体动物疾病模型的研究工具显示出巨大的前景。然而,可激活的 PA 探针的开发受到了适当的 PA 活性分子平台的相对稀缺性的阻碍,这些平台具有可以以合理方式操纵的特性。在此,我们合成并评估了 aza-BODIPY 染料平台在吸光度、荧光和 PA 特性方面的六种修改。我们确定了一种有前途的构象限制 aza-BODIPY (CRaB) 支架,它优先考虑了设计具有最佳比例 PA 响应的刺激响应染料所需的三个标准:NIR 波长处的吸光度、强 PA 强度和与所需刺激相互作用时的大 Δλ . 使用这种支架,我们合成了三种化学上不同的刺激响应 PA 探针,并证明了体外理论比率响应的 2 到 8 倍改进。这表明 PA 参数的改进是可推广的。最后,我们验证了每个