6312-12-5Relevant academic research and scientific papers
Introverted Br?nsted acid cavitands for selective conjugate addition reactions
Iwasawa, Tetsuo,Maruyama, Tomoyuki,Matsumoto, Yasuhiro,Taguchi, Yuta,Tokai, Shugo,Yoshida, Naruhiro
, (2021/11/09)
Four new quinoxaline-spanned cavitands having a diester hydrogen phosphate group were successfully synthesised. These phosphorous derivatives were applied in Br?nsted acid-assisted catalytic conjugate addition reactions. The results were ranked with the c
Exploring the acidic catalytic role of differently structured deep eutectic solvents in the aza-Michael addition of amines to 2-vinylpiridine
Ballarotto, Marco,Cappellini, Federico,Del Giacco, Tiziana,Di Profio, Pietro,Germani, Raimondo,Maestri, Riccardo,Tiecco, Matteo
, (2020/08/26)
Abstract: The search for innovative and green reaction media is a prominent topic in the recent research in chemistry. Deep Eutectic Solvents (DESs) are currently gaining relevance in this field thanks to their unique properties in terms of their “greenness” as well as in terms of their catalytic properties. In this work we developed an efficient protocol for the conjugate aza-Michael addition of amines to 2-vinylpyridine using 14 differently structured acid DESs as both reaction media and catalysts, so preventing the use of other acid additives. The results are influenced by the acidity of the components of the DESs, showing the best results with weak acids in the DESs components, with isolated yields up to 86%. The aza-Michael reaction is a widely used synthetic route for the C–N bond formation in organic synthesis. In particular, the addition of amines to 2-vinylpyridine is used for the realization of pharmaceutically relevant compounds with anticancer, antiarrhythmic, and analgesic properties. Comparing the results with the ones observed in literature for the same reaction, this procedure revealed to be a convenient and efficient method for this relevant transformation. Graphic abstract: [Figure not available: see fulltext.]
The catalytic effect of anion-exchanged supported ionic liquid on aza-Michael-type addition
Ghasemi, Mohammad Hadi,Kowsari, Elaheh
, p. 3691 - 3709 (2017/06/20)
Abstract: An effective synthesis of anion-exchanged supported ionic liquids using diatomaceous earth as solid support and its catalytic effect on the aza-Michael-type addition is described. Anionic polytungstophosphate and bisulfate ion are used in the anion-exchange step in catalyst design. In addition, the aza-Michael-type addition of various amines to 2- and 4-vinyl pyridine was examined in this article. The catalytic system can be separated from the reaction mixture and recycled in subsequent reactions. The structure of anion-exchanged supported ionic liquid on diatomaceous earth was studied by XRD, FT-IR, SEM, TGA and BET techniques. The structure of organic products was determined by 1HNMR, 13CNMR, FTIR, CHN and MASS spectroscopy. Graphical Abstract: [Figure not available: see fulltext.].
Aza-Michael-type addition reaction catalysed by a supported ionic liquid phase incorporating an anionic heteropoly acid
Ghasemi, Mohammad Hadi,Kowsari, Elaheh,Shafiee, Abbas
supporting information, p. 1150 - 1153 (2016/03/09)
In this work, we have obtained substituted amines under mild conditions in good yields using the Aza-Michael-type addition of various amines to vinyl compounds catalysed by a supported ionic liquid incorporating an anionic heteropoly acid. Different catalysts, including Lewis acids, Br?nsted acids and heteropoly acids were investigated in which heteropoly acids having dual Br?nsted and Lewis acid characteristics were excellent catalysts. The ionic liquid incorporating a polytungstate anion supported on magnetic diatomaceous earth as a magnetically separable heterogeneous catalyst offered the best results in terms of yield. The solid nanocatalyst was easily removed with a magnet.
Quantifying factors that influence metal ion release in photocaged complexes using ZinCast derivatives
Gwizdala, Celina,Singh, Charlene V.,Friss, Tracey R.,MacDonald, John C.,Burdette, Shawn C.
scheme or table, p. 8162 - 8174 (2012/08/08)
Two generations of nitrobenzhydrol-based photocages for Zn2+ have been prepared and characterized. The first series includes the tridentate ZinCast-1 utilizes a bis-pyridin-2-ylmethyl-aniline ligand that forms a 5,5-chelate ring upon metal binding. The related photocages ZinCast-2 with a N-[2-(pyridine-2-yl)ethyl]-N-(pyridine-2-ylmethyl)aniline (5,6-chelate ring) and ZinCast-3 with a N,N-bis[2-(pyridine-2-yl)ethyl]aniline (6,6-chelate ring) were synthesized for comparative studies. The complexes formed by the ions Cu 2+, Zn2+ and Cd2+ with three ZinCast and their photoproducts (ZinUnc) were interrogated by UV-Vis spectroscopy. The studies indicate that ZinCast-1 forms complexes of the highest stability and ZinCast-3 exhibits the most significant changes in metal affinity upon uncaging. These results suggest that the changes in nitrogen atom donor ability as well as the initial complex stability must be considered to design a photocage with the desired properties. The composite results were used to design ZinCast-4 and ZinCast-5, the second generation photocages that incorporate an additional adjacent ether ligand into the Zn2+ chelator.
Reductive Amination of Ethynylpyridines with Sodium Cyanoborohydride
Sakamoto, Takao,Nagata, Hideo,Kondo, Yoshinori,Sato, Kaori,Yamanaka, Hiroshi
, p. 4866 - 4872 (2007/10/02)
In order to investigate the structure-activity relationship of betahistine derivatives, a general synthesis of methylated 2-(2-methylaminoethyl)pyridines was developed based on the addition of methylamine hydrochloride to methylated 2-ethynylpyridines under reductive conditions.In addition, the scope and limitations of the reductive addition were briefly examined.For example, the reaction proceeded smoothly with p-nitrophenylacetylene, whereas phenylacetylene itself did not react with methylamine.Keywords - ethynylpyridine; sodium cyanoborohydride; reductive amination; betahistine; palladium-catalyzed reaction; ethyl pyridineacetate; 2-(2-pyridyl)ethylamine
