91-01-0Relevant articles and documents
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
Electrochiroptical response in aqueous media: 9,10-dihydrophenanthrene-9, 10-diyl dications with Michlar's hydrol blue chromophores attached with oligoethylene glycol units
Suzuki, Takanori,Hanada, Keisuke,Katoono, Ryo,Ishigaki, Yusuke,Higasa, Sho,Higuchi, Hiroki,Kikuchi, Hirotsugu,Fujiwara, Kenshu,Yamada, Hidetoshi,Fukushima, Takanori
, p. 982 - 984 (2014)
Upon electrochemical oxidation of configurationally stable biphenyl-based electron donors (Rax)-1a and -1b to butane-1,4- diyl dications (M)-2a2+ and -2b2+, drastic changes were induced not only in UVvis but also in CD spe
Alumina-assisted reduction of carbonyl compounds with sodium borohydride in hexane
Yakabe, Shigetaka,Hirano, Masao,Morimoto, Takashi
, p. 1916 - 1921 (1998)
A broad range of aliphatic, alicyclic, and aromatic ketones and aldehydes underwent smooth reduction with a combination of common, inexpensive laboratory reagents, sodium borohydride and chromatographic neutral alumina, in hexane to afford the correspondi
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.
Adaptive N-Mesoionic Ligands Anchored to a Triazolylidene for Ruthenium-Mediated (De)Hydrogenation Catalysis
Donnelly, Kate F.,Segarra, Candela,Shao, Li-Xiong,Suen, Rachelle,Müller-Bunz, Helge,Albrecht, Martin
, p. 4076 - 4084 (2015)
A ruthenium cymene complex bearing a bidentate ligand composed of the N-mesoionic donor N-[1-methylpyridin-4(1H)-ylidene]amide and the C-mesoionic donor 1,2,3-triazolylidene was prepared. Spectroscopic analyses including UV-vis, electrochemical, and NMR m
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
Kinetics of liquid-phase catalytic hydrogenation of benzophenone to benzhydrol
Bawane, Sunil P.,Sawant, Sudhirprakash B.
, p. 769 - 773 (2003)
Catalytic hydrogenation of benzophenone to benzhydrol was carried out in 2-propanol using Raney nickel as a catalyst at hydrogen pressures in the range of 800-2200 kPa, reaction temperatures 323-343 K, catalyst loadings 4-20 g dm-3 and benzophe
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
A Convenient and Stable Heterogeneous Nickel Catalyst for Hydrodehalogenation of Aryl Halides Using Molecular Hydrogen
Anwar, Muhammad,Beller, Matthias,Dastgir, Sarim,Junge, Kathrin,Leonard, David K.,Ryabchuk, Pavel
, (2022/02/03)
Hydrodehalogenation is an effective strategy for transforming persistent and potentially toxic organohalides into their more benign congeners. Common methods utilize Pd/C or Raney-nickel as catalysts, which are either expensive or have safety concerns. In this study, a nickel-based catalyst supported on titania (Ni-phen@TiO2-800) is used as a safe alternative to pyrophoric Raney-nickel. The catalyst is prepared in a straightforward fashion by deposition of nickel(II)/1,10-phenanthroline on titania, followed by pyrolysis. The catalytic material, which was characterized by SEM, TEM, XRD, and XPS, consists of nickel nanoparticles covered with N-doped carbon layers. By using design of experiments (DoE), this nanostructured catalyst is found to be proficient for the facile and selective hydrodehalogenation of a diverse range of substrates bearing C?I, C?Br, or C?Cl bonds (>30 examples). The practicality of this catalyst system is demonstrated by the dehalogenation of environmentally hazardous and polyhalogenated substrates atrazine, tetrabromobisphenol A, tetrachlorobenzene, and a polybrominated diphenyl ether (PBDE).
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.
