89794-53-6Relevant articles and documents
Aluminum Metal-Organic Framework-Ligated Single-Site Nickel(II)-Hydride for Heterogeneous Chemoselective Catalysis
Antil, Neha,Kumar, Ajay,Akhtar, Naved,Newar, Rajashree,Begum, Wahida,Dwivedi, Ashutosh,Manna, Kuntal
, p. 3943 - 3957 (2021/04/12)
The development of chemoselective and heterogeneous earth-abundant metal catalysts is essential for environmentally friendly chemical synthesis. We report a highly efficient, chemoselective, and reusable single-site nickel(II) hydride catalyst based on robust and porous aluminum metal-organic frameworks (MOFs) (DUT-5) for hydrogenation of nitro and nitrile compounds to the corresponding amines and hydrogenolysis of aryl ethers under mild conditions. The nickel-hydride catalyst was prepared by the metalation of aluminum hydroxide secondary building units (SBUs) of DUT-5 having the formula of Al(μ2-OH)(bpdc) (bpdc = 4,4′-biphenyldicarboxylate) with NiBr2 followed by a reaction with NaEt3BH. DUT-5-NiH has a broad substrate scope with excellent functional group tolerance in the hydrogenation of aromatic and aliphatic nitro and nitrile compounds under 1 bar H2 and could be recycled and reused at least 10 times. By changing the reaction conditions of the hydrogenation of nitriles, symmetric or unsymmetric secondary amines were also afforded selectively. The experimental and computational studies suggested reversible nitrile coordination to nickel followed by 1,2-insertion of coordinated nitrile into the nickel-hydride bond occurring in the turnover-limiting step. In addition, DUT-5-NiH is also an active catalyst for chemoselective hydrogenolysis of carbon-oxygen bonds in aryl ethers to afford hydrocarbons under atmospheric hydrogen in the absence of any base, which is important for the generation of fuels from biomass. This work highlights the potential of MOF-based single-site earth-abundant metal catalysts for practical and eco-friendly production of chemical feedstocks and biofuels.
Hydrogenation of CO2, carbonyl and imine substrates catalyzed by [IrH3(PhPNHP)] complex
Ramaraj, Ayyappan,Nethaji, Munirathinam,Jagirdar, Balaji R.
supporting information, p. 25 - 34 (2019/01/24)
A series of iridium and rhodium complexes [M(COD)(PhPNHP)]Cl {M = Ir (1), Rh (2)}, [MH2Cl(PhPNHP)] {M = Ir (3), Rh (4)} and [IrH3(PhPNHP)] (6) supported by pincer ligand H–N(CH2CH2PPh2)2 {PhPNHP} have been synthesized and characterized. All complexes were isolated in good yields. The iridium trihydride complex [IrH3(PhPNHP)] (6) was found to be an active catalyst for the hydrogenation of CO2 in 1 M aqueous KOH solution. It also acts as a catalyst for the base-free hydrogenation of carbonyl and imine substrates in MeOH. Under similar hydrogenation conditions, 2-cyclohexen-1-one undergoes solvent assisted tandem Michael addition-reduction mediated by bifunctional Lewis-acid-catalyst [IrH3(PhPNHP)] in ROH (R = Me, Et) at room temperature. The complexes 1, 3, 4, and 6 were characterized by X-ray crystallography. Extensive hydrogen bonding interactions N–H?H–Ir (2.15 ?), N–H?Cl (2.370 ?) were noted in the crystal structures of these complexes.
Elucidating the reactivity of methoxyphenol positional isomers towards hydrogen-transfer reactions by ATR-IR spectroscopy of the liquid-solid interface of RANEY Ni
De Castro, Ilton Barros Daltro,Gra?a, Inês,Rodríguez-García, Laura,Kennema, Marco,Rinaldi, Roberto,Meemken, Fabian
, p. 3107 - 3114 (2018/06/29)
In the valorisation of lignin, the application of catalytic hydrogen transfer reactions (e.g. in catalytic upstream biorefining or lignin-first biorefining) has brought a renewed interest in the fundamental understanding of hydrogen-transfer processes in the defunctionalisation of lignin-derived phenolics. In this report, we address fundamental questions underlining the distinct reactivity patterns of positional isomers of guaiacol towards H-transfer reactions in the presence of RANEY Ni and 2-PrOH (solvent and H-donor). We studied the relationship between reactivity patterns of 2-, 3- and 4-methoxyphenols and their interactions at the liquid-solid interface of RANEY Ni as probed by attenuated total reflection infrared (ATR-IR) spectroscopy. Regarding the reactivity patterns, 2-methoxyphenol or guaiacol is predominantly converted into cyclohexanol through a sequence of reactions including demethoxylation of 2-methoxyphenol to phenol followed by hydrogenation of phenol to cyclohexanol. By contrast, for the conversion of the two non-lignin related positional isomers, the corresponding 3- and 4-methoxycyclohexanols are the major reaction products. The ATR-IR spectra of the liquid-solid interface of RANEY Ni revealed that the adsorbed 2-methoxyphenol assumes a parallel orientation to the catalyst surface, which allows a strong interaction between the methoxy C-O bond and the surface. Conversely, the adsorption of 3- or 4-methoxyphenol leads to a tilted surface complex in which the methoxy C-O bond establishes no interaction with the catalyst. These observations are also corroborated by a smaller activation entropy found for the conversion of 2-methoxyphenol relative to those of the other two positional isomers.
Robustly supported rhodium nanoclusters: Synthesis and application in selective hydrogenation of lignin derived phenolic compounds
Fehn, Sonja,Zaheer, Muhammad,Denner, Christine E.,Friedrich, Martin,Kempe, Rhett
, p. 9252 - 9256 (2016/11/11)
The stabilization of small rhodium nanoclusters (NCs) in a polymer derived silicon carbonitride (SiCN) matrix has been reported to generate highly robust and active solid catalysts for the selective hydrogenation of phenolic compounds. An aminopyridinato Rh complex was used to modify a preceramic polymer (HTT 1800) followed by its pyrolysis at 1100 °C to afford small Rh NCs nicely dispersed over dense SiCN ceramic. For the synthesis of porous catalysts containing Rh NCs, microphase separation (followed by pyrolysis) of a diblock copolymer of HTT 1800 with hydroxy-polyethylene (PE-OH) was used. Both catalysts exhibit high activity in the hydrogenation of substituted phenols at room temperature and under low hydrogen pressure. The catalysts remained highly active and selective for six consecutive catalytic runs.
Upgrading of aromatic compounds in bio-oil over ultrathin graphene encapsulated Ru nanoparticles
Shi, Juanjuan,Zhao, Mengsi,Wang, Yingyu,Fu, Jie,Lu, Xiuyang,Hou, Zhaoyin
supporting information, p. 5842 - 5848 (2016/05/24)
Fast pyrolysis of biomass for bio-oil production is a direct route to renewable liquid fuels, but raw bio-oil must be upgraded in order to remove easily polymerized compounds (such as phenols and furfurals). Herein, a synthesis strategy for graphene encapsulated Ru nanoparticles (NPs) on carbon sheets (denoted as Ru@G-CS) and their excellent performance for the upgrading of raw bio-oil were reported. Ru@G-CS composites were prepared via the direct pyrolysis of mixed glucose, melamine and RuCl3 at varied temperatures (500-800 °C). Characterization indicated that very fine Ru NPs (2.5 ± 1.0 nm) that were encapsulated within 1-2 layered N-doped graphene were fabricated on N-doped carbon sheets (CS) in Ru@G-CS-700 (pyrolysis at 700 °C). And the Ru@G-CS-700 composite was highly active and stable for hydrogenation of unstable components in bio-oil (31 samples including phenols, furfurals and aromatics) even in aqueous media under mild conditions. This work provides a new protocol to the utilization of biomass, especially for the upgrading of bio-oil.
Selective production of cyclohexanol and methanol from guaiacol over Ru catalyst combined with MgO
Nakagawa, Yoshinao,Ishikawa, Momoko,Tamura, Masazumi,Tomishige, Keiichi
, p. 2197 - 2203 (2014/04/17)
Selective demethoxylation from aqueous guaiacol proceeded over Ru catalysts at relatively lower temperatures (≤433 K). Addition of MgO to the reaction media suppressed the unselective C-O dissociation. Cyclohexanol and methanol were obtained in high yield (>80%). A reaction route is proposed where partially hydrogenated guaiacol is decomposed into methanol and phenol, which is further hydrogenated to cyclohexanol. the Partner Organisations 2014.
Catalytic hydrogenation of aromatic rings catalyzed by Pd/NiO
Wang, Yanan,Cui, Xinjiang,Deng, Youquan,Shi, Feng
, p. 2729 - 2732 (2014/01/06)
A simple and efficient heterogeneous palladium catalyst was prepared for aromatic ring hydrogenation. The catalyst was prepared by a reduction-deposition method and exhibited high activity and selectivity for the hydrogenation of a variety of substituted aromatic compounds to the corresponding cyclohexane and cyclohexanol derivatives with up to 99% yields. The catalyst was characterized by BET, TEM, XRD, XPS and ICP. Meanwhile the reusability of the catalyst was investigated, and it can be reused for several runs without significant deactivation.
Hydrogenolysis-hydrogenation of aryl ethers: Selectivity pattern
Samant, Bhupesh S.,Kabalka, George W.
supporting information; experimental part, p. 8658 - 8660 (2012/10/08)
The selectivity pattern of nickel-catalyzed hydrogenolysis-hydrogenation of aryl ethers has been studied in the micellar media. The micellar conditions selectively formed arenes and alcohols with enhanced yields.
4 - [CYCLOALKYLOXY (HETERO) ARYLAMINO] THIENO [2, 3 - D] PYRIMIDINES HAVING MNKL/ MNK2 INHIBITING ACTIVITY FOR PHARMACEUTICAL COMPOSITIONS
-
Page/Page column 86, (2011/09/30)
The present invention relates to novel thienopyrimidine compounds of general formula (I), pharmaceutical compositions comprising these compounds and their therapeutic use for the prophylaxis and/or treatment of diseases which can be influenced by the inhibition of the kinase activity of Mnk1 and/or Mnk2 (Mnk2a or Mnk2b) and/or variants thereof.
Hydrogen bonding lowers intrinsic nucleophilicity of solvated nucleophiles
Chen, Xin,Brauman, John I.
scheme or table, p. 15038 - 15046 (2009/03/12)
The relationship between nucleophilicity and the structure/environment of the nucleophile is of fundamental importance in organic chemistry. In this work, we have measured nucleophilicities of a series of substituted alkoxides in the gas phase. The functional group substitutions affect the nucleophiles through ion-dipole, ion-induced dipole interactions and through hydrogen bonding whenever structurally possible. This set of alkoxides serves as an ideal model system for studying nucleophiles under microsolvation settings. Marcus theory was applied to analyze the results. Using Marcus theory, we separate nucleophilicity into two independent components, an intrinsic nucleophilicity and a thermodynamic driving force determined solely by the overall reaction exothermicity. It is found that the apparent nucleophilicities of the substituted alkoxides are always much lower than those of the unsubstituted ones. However, ion-dipole, ion-induced dipole interactions, by themselves, do not significantly affect the intrinsic nucleophilicity; the decrease in the apparent nucleophilicity results from a weaker thermodynamic driving force. On the other hand, hydrogen bonding not only stabilizes the nucleophile but also increases the intrinsic barrier height by 3 to ～4 kcal mol-1. In this regard, the hydrogen bond is not acting as a perturbation in the sense of an external dipole but more directly affects the electronic structure and reactivity of the nucleophilic alkoxide. This finding offers a deeper insight into the solvation effect on nucleophilicity, such as the remarkably lower reactivities in nucleophilic substitution reactions in protic solvents than in aprotic solvents.
