A highlyefficient cyanosilylation protocol mediated by the easily available n-BuLi with a wide range of aldehydes and ketones was developed. This protocol features excellent yields with very low n-BuLi loadings (0.01–0.05 mol%) at room temperature, solvent-free process, good chemo-/regio-selectivity and functional group tolerance and scalability. A possible reaction pathway based upon stoichiometric
Calcined MgAICO<sub>3</sub>-HT Catalysed Cyanosilylation of Carbonyl Compounds and Nucleophilic Ring Opening of Oxiranes Using TMSCN
作者:B. M. Choudary、N. Narender、V. Bhuma
DOI:10.1080/00397919508011830
日期:1995.9
Nucleophilic addition of TMSCN to carbonyl compounds is found to be catalysed efficiently using hydrotalcite as a solid base. The catalyst is also found to be active in the nucleophilicringopening of oxiranes giving high regioselectivity.
Bacteriorhodopsin: The influence of the cyclohexene-ring methyls
作者:J. M. L. Courtin、L. Verhagen、P. L. Biesheuvel、J. Lugtenburg、R. L. van der Bend、K. van Dam
DOI:10.1002/recl.19871060402
日期:——
of the modified bacteriorhodopsins were much lower than those of the native system. UV-Vis and 1H NMR data support a planar 6-s-transconformation for the demethylated retinals in solution rather than a twisted 6-s-cis conformation (torsion angle 40-60°) as found in retinal. This explains the lower opsin shift and the better fit of these demethylated retinals in bacteriorhodopsin's binding site, which
四个环去甲基化视网膜,即。1,1,5'-tridemethylretinal,1,1'-didemethylretinal,1,5-didemethylretinal和1-didemethylretinal已通过新的简单方案合成。研究了这些修饰的视网膜,其质子化的席夫碱和相应的细菌视紫红质的特性,并将其与天然系统进行了比较。还对这些细菌视紫红质类似物的质子泵效率进行了测试。发现缺少5-甲基的类似物的质子泵活性大大降低。总体而言,修饰的细菌视紫红质的视蛋白移位远低于天然系统。UV-Vis和1 H NMR数据支持平面6 -s-trans溶液中去甲基化的视网膜的构象,而不是视网膜中扭曲的6 -s-顺式构象(扭转角40-60°)。这解释了视紫红质视蛋白移位较低,且这些去甲基化的视网膜更适合细菌视紫红质的结合位点,而细菌视紫红质的结合位点以其天然形式包含6 -s-反生色团。
Dodecatungestophosphoric acid (H3PW12O40) as a solid green BrØnsted acid catalyzes high yielding and efficient trimethylcyanosylilation reactions of aldehydes and ketones by trimethylsilyl cyanide
作者:Habib Firouzabadi、Nasser Iranpoor、Abbas Ali Jafari
DOI:10.1016/j.jorganchem.2004.12.025
日期:2005.3
An efficient solvent-free method is described for the addition of TMSCN to carbonyl groups employing dodecatungestophosphoric acid (H3PW12O40) as a heterogeneous and environmentally benign catalyst. By this method, aromatic, aliphatic, cyclic and heterocyclic aldehydes and ketones are converted into their corresponding cyanotrimethylsilyl ethers in excellent yields (89-98%) in short reaction times (< 10 min). (c) 2004 Published by Elsevier B.V.
Iodine as novel reagent for the 1,2-addition of trimethylsilyl cyanide to ketones including α,β-unsaturated ketones
Molecular iodine is found to catalyze efficiently the addition of trimethylsilyl cyanide to a range of simple and functionalized ketones under very mild and convenient conditions to afford the corresponding cyanohydrin trimethylsilyl ethers in excellent yields in a short reaction period with high selectivity. a,P-Unsaturated ketones selectively afford the corresponding 1,2-adducts without the formation of 1,4-adducts under similar reaction conditions. (C) 2002 Elsevier Science Ltd. All rights reserved.