91-01-0Relevant articles and documents
Vitvitskaya et al.
, (1975)
Continuous synthesis of peralkylated imidazoles and their transformation into ionic liquids with improved (electro)chemical stabilities
Maton, Cedric,De Vos, Nils,Roman, Bart I.,Stevens, Christian V.,Vanecht, Evert,Brooks, Neil R.,Binnemans, Koen,Schaltin, Stijn,Fransaer, Jan
, p. 3146 - 3157,12 (2012)
A versatile and efficient method to synthesize tetrasubstituted imidazoles via a one-pot modified Debus-Radziszewski reaction and their subsequent transformation into the corresponding imidazolium ionic liquids is reported. The tetrasubstituted imidazoles were also synthesized by means of a continuous flow process. This straightforward synthetic procedure allows for a fast and selective synthesis of tetrasubstituted imidazoles on a large scale. The completely substituted imidazolium dicyanamide and bis(trifluoromethylsulfonyl) imide salts were obtained via a metathesis reaction of the imidazolium iodide salts. The melting points and viscosities are of the same order of magnitude as for their non-substituted analogues. In addition to the superior chemical stability of these novel ionic liquids, which allows them to be applied in strong alkaline media, the improved thermal and electrochemical stabilities of these compounds compared with conventional imidazolium ionic liquids is also demonstrated by thermogravimetrical analysis (TGA) and cyclic voltammetry (CV). Although increased substitution of the ionic liquids does not further increase thermal stability, a definite increase in cathodic stability is observable. Copyright
Walling,Bollyky
, p. 2968 (1961)
Sophisticated Design of Covalent Organic Frameworks with Controllable Bimetallic Docking for a Cascade Reaction
Leng, Wenguang,Peng, Yongsheng,Zhang, Jianqiang,Lu, Hui,Feng, Xiao,Ge, Rile,Dong, Bin,Wang, Bo,Hu, Xiangping,Gao, Yanan
, p. 9087 - 9091 (2016)
Precise control of the number and position of the catalytic metal ions in heterogeneous catalysts remains a big challenge. Here we synthesized a series of two-dimensional (2D) covalent organic frameworks (COFs) containing two different types of nitrogen ligands, namely imine and bipyridine, with controllable contents. For the first time, the selective coordination of the two nitrogen ligands of the 2D COFs to two different metal complexes, chloro(1,5-cyclooctadiene)rhodium(I) (Rh(COD)Cl) and palladium(II) acetate (Pd(OAc)2), has been realized using a programmed synthetic procedure. The bimetallically docked COFs showed excellent catalytic activity in a one-pot addition–oxidation cascade reaction. The high surface area, controllable metal-loading content, and predesigned active sites make them ideal candidates for their use as heterogeneous catalysts in a wide range of chemical reactions.
Synthesis of molecularly imprinted polymer for removal of effective impurity (benzhydrol) from diphenhydramine hydrochloride drug
Hashemi-Moghaddam, Hamid,Alaeian, Mohammad Reza
, p. 643 - 648 (2014)
The present study describes the synthesis and preliminary testing of molecularly imprinted polymers (MIPs) as scavenger resins for removal of the genotoxic impurities (GTI) benzhydrol from active pharmaceutical ingredients (API). A new molecularly imprinted polymer was synthesized using benzhydrol (template molecule), methacrylic acid (functional monomer), ethylene glycol dimethacrylate (cross-linker), 2,2′-azobisisobutironitril (intiator) and chloroform (porogenic solvent). To compare the performance of this polymer, a control polymer or non-imprinted polymer (NIP) was prepared under the same conditions without the use of template molecule. The synthesized polymers were characterized by FT-IR spectroscopy. Selectivity of the molecularly imprinted polymer for absorption benzhydrol impurities through adsorption experiments reviews and the results were compared with the adsorption of impurities by NIP. Various parameters were optimized such as time, pH, type of eluent for elution of impurities from polymer, concentration of sample and saturation of polymer. The proposed method was applied for removal of benzhydrol from Diphenhydramine hydrochloride syrup and passing it through the MIPs led to the quantitative removal of benzhydrol. The present work describes the synthesis and preliminary testing of molecularly imprinted polymers (MIPs) as scavenger resins for removal of the genotoxic impurities (GTI) benzhydrol from active pharmaceutical ingredients (API). Copyright
Transfer hydrogenation catalysis by a N-heterocyclic carbene iridium complex on a polyoxometalate platform
Modugno, Gloria,Monney, Angele,Bonchio, Marcella,Albrecht, Martin,Carraro, Mauro
, p. 2356 - 2360 (2014)
A divacant Keggin polyanion has been decorated with a N-heterocyclic carbene (NHC) iridium(I) organometallic complex to provide a molecular model of an Ir-based supported catalyst. The characterization of the hybrid compound has been performed by multinuc
Hydrosilylation of Aldehydes and Ketones Catalyzed by a 2-Iminopyrrolyl Alkyl-Manganese(II) Complex
Cruz, Tiago F. C.,Veiros, Luís F.,Gomes, Pedro T.
, p. 1195 - 1206 (2022/01/11)
A well-defined and very active single-component manganese(II) catalyst system for the hydrosilylation of aldehydes and ketones is presented. First, the reaction of 5-(2,4,6-iPr3C6H2)-2-[N-(2,6-iPr2C6H3)formimino]pyrrolyl potassium (KL) and [MnCl2(Py)2] afforded the binuclear 2-iminopyrrolyl manganese(II) pyridine chloride complex [Mn2{κ2N,N′-5-(2,4,6-iPr3C6H2)-NC4H2-2-C(H)═N(2,6-iPr2C6H3)}2(Py)2(μ-Cl)2] 1. Subsequently, the alkylation reaction of complex 1 with LiCH2SiMe3 afforded the respective (trimethylsilyl)methyl-Mn(II) complex [Mn{κ2N,N′-5-(2,4,6-iPr3C6H2)-NC4H2-2-C(H)═N(2,6-iPr2C6H3)}(Py)CH2SiMe3] 2 in a good yield. Complexes 1 and 2 were characterized by elemental analysis, 1H NMR spectroscopy, Evans' method, FTIR spectroscopy, and single-crystal X-ray diffraction. While the crystal structure of complex 1 has been identified as a binuclear entity, in which the Mn(II) centers present pentacoordinate coordination spheres, that of complex 2 corresponds to a monomer with a distorted tetrahedral coordination geometry. Complex 2 proved to be a very active precatalyst for the atom-economic hydrosilylation of several aldehydes and ketones under very mild conditions, with a maximum turnover frequency of 95 min-1, via a silyl-Mn(II) mechanistic route, as asserted by a combination of experimental and theoretical efforts, the respective silanes were cleanly converted to the respective alcoholic products in high yields.
Intercepting a transient non-hemic pyridine: N -oxide Fe(iii) species involved in OAT reactions
Vo, Nhat Tam,Herrero, Christian,Guillot, Régis,Inceoglu, Tanya,Leibl, Winfried,Clémancey, Martin,Dubourdeaux, Patrick,Blondin, Geneviève,Aukauloo, Ally,Sircoglou, Marie
supporting information, p. 12836 - 12839 (2021/12/10)
In the context of bioinspired OAT catalysis, we developed a tetradentate dipyrrinpyridine ligand, a hybrid of hemic and non-hemic models. The catalytic activity of the iron(iii) derivative was investigated in the presence of iodosylbenzene. Unexpectedly, MS, EPR, M?ssbauer, UV-visible and FTIR spectroscopic signatures supported by DFT calculations provide convincing evidence for the involvement of a relevant FeIII-O-NPy active intermediate. This journal is
Tunable System for Electrochemical Reduction of Ketones and Phthalimides
Chen, Gong,Qiao, Tianjiao,Wang, Yaxin,Zhang, Jian,Zhao, Jianyou
supporting information, p. 3297 - 3302 (2021/10/14)
Herein, we report an efficient, tunable system for electrochemical reduction of ketones and phthalimides at room temperature without the need for stoichiometric external reductants. By utilizing NaN3 as the electrolyte and graphite felt as both the cathode and the anode, we were able to selectively reduce the carbonyl groups of the substrates to alcohols, pinacols, or methylene groups by judiciously choosing the solvent and an acidic additive. The reaction conditions were compatible with a diverse array of functional groups, and phthalimides could undergo one-pot reductive cyclization to afford products with indolizidine scaffolds. Mechanistic studies showed that the reactions involved electron, proton, and hydrogen atom transfers. Importantly, an N3/HN3 cycle operated as a hydrogen atom shuttle, which was critical for reduction of the carbonyl groups to methylene groups.