1122-72-1Relevant academic research and scientific papers
Nanoreactor of MOF-Derived Yolk-Shell Co@C-N: Precisely Controllable Structure and Enhanced Catalytic Activity
Chen, Huirong,Shen, Kui,Mao, Qing,Chen, Junying,Li, Yingwei
, p. 1417 - 1426 (2018)
Hollow yolk-shell nanoreactors are of great interest in heterogeneous catalysis owing to their improved mass transfer ability and stability. Here, we report a facile and straight route to synthesize a highly efficient and recyclable yolk-shell Co@C-N nanoreactor with controllable properties by the direct thermolysis of a hollow Zn/Co-ZIF precursor. Based on systematical optimization of the pyrolysis temperature and the shell-thickness of Zn/Co-ZIFs, we could completely anchor and stabilize uniform Co nanoparticles (NPs) in the hollow yolk, accommodated by the Co-ZIF derived N-doped carbon nanosheets. This nanosheet-assembled yolk was further confined by a permeable and robust N-doped carbon (C-N) shell to protect the Co NPs against leaching and also enabled the reaction to take place in the hollow void. Consequently, the optimal yolk-shell Co@C-N nanoreactor showed a significantly enhanced catalytic activity for the aqueous oxidation of alcohols, yielding >99% conversion under atmospheric air and base-free conditions, which was much higher than that of the solid counterparts derived from pure ZIF-67 and solid core-shell ZIF-67@ZIF-8 precursors (with 14% and 59% conversion under the same reaction condition, respectively). The enhanced catalytic activity should be attributed to the yolk-shell structure that could facilitate the transport of reactant/product and the strong interaction between the Co NPs and N-doped carbon nanosheet to afford positive synergistic effects. Moreover, this catalyst also showed good recyclability, magnetically reusability, and general applicability for a broad substrate scope, further highlighting the structure superiority of our yolk-shell nanoreactor. This strategy might open an avenue to synthesize various hollow yolk-shell nanoreactors with controllable structures and enhanced catalytic performances.
Microwave Assisted Improved Synthesis of 6-Formylpterin and Other Heterocyclic Mono- and Di-aldehydes
Goswami, Shyamaprosad,Adak, Avijit Kumar
, p. 475 - 480 (2003)
2-Pivaloylamino-6-formylpterin (1a) and a series of other important heterocyclic aldehydes (2a, 3a, 4a, 6a, and 7a) have been synthesized in good yield by microwave assisted selenium dioxide oxidation. Interestingly, 2-methylpyrazine gives 2-pyrazinecarboxylic acid (5a) under the similar condition.
Aerobic oxidation of primary alcohols catalyzed by copper complexes of 1,10-phenanthroline-derived ligands
Das, Oindrila,Paine, Tapan Kanti
, p. 11476 - 11481 (2012)
Five copper complexes [(L1)2Cu(H2O)] (ClO4)2 (1), [(L1)Cu(H2O) 3](ClO4)2 (1a), [(L3) 2Cu(H2O)](ClO4)2 (2), [(L 5)2Cu(H2O)](ClO4)2 (3) and [(L6)2Cu](ClO4) (4) (where L1 = 1,10-phenanthroline, L3 = 1,10-phenanthroline-5,6-dione, L 5 = 1,10-phenanthrolinefuroxan and L6 = 2,9-dimethyl-1,10-phenanthrolinefuroxan), and in situ prepared copper complexes of 2,9-dimethyl-1,10-phenanthroline (L2) or 2,9-dimethyl-1,10- phenanthrolinedione (L4) were used for aerial oxidation of primary alcohols to the corresponding aldehydes under ambient conditions. The copper catalysts have been found to catalyze a series of primary alcohols including one secondary alcohol with moderate turnover numbers and selectivity towards primary alcohols. Copper(ii) complexes 1 (or 1a) and 2 were found to be the better catalysts among all other systems explored in this study. A copper(ii)-superoxo species is implicated to initiate the oxidation reaction. Structural and electronic factors of 1,10-phenanthroline-based ligands affecting the catalytic results for aerial oxidation of alcohols are discussed.
Mild and convenient oxidation of aromatic heterocyclic primary alcohols by 4-acetylamino-2,2,6,6-tetramethylpiperidine-1-oxoammonium perchlorate
Kernag, Casey A.,Bobbitt, James M.,McGrath, Dominic V.
, p. 1635 - 1636 (1999)
Hydroxymethyl substituted aromatic heterocycles, including pyridines, furans, and thiophenes, are oxidized to the corresponding aldehydes in excellent yields by 4-acetylamino-2,2,6,6-tetramethylpiperidine-1- oxoammonium perchlorate (1) with minimal workup.
ANALOGS OF 2-PRALIDOXIME AS ANTIDOTES AGAINST ORGANOPHOSPHORUS NERVE AGENTS
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, (2020/02/23)
Provided herein are compounds useful in treating exposure to an organophosphorus compound, such as a nerve agent, pesticide, or, generally, an acetylcholinesterase inhibitor, such as sarin. Compositions, e.g. pharmaceutical compositions or dosage forms, comprising the compounds also are provided herein. Methods of treating a patient exposed to a nerve agent, pesticide, or, generally, an acetylcholinesterase inhibitor, e.g., an organophosphorus compound, such as sarin, also are provided.
Methyl Scanning and Revised Binding Mode of 2-Pralidoxime, an Antidote for Nerve Agent Poisoning
Gambino, Adriana,Burnett, James C.,Koide, Kazunori
, p. 1893 - 1898 (2020/02/06)
Organophosphorus nerve agents (OPNAs) inhibit acetylcholinesterase (AChE) and, despite the Chemical Weapons Convention arms control treaty, continue to represent a threat to both military personnel and civilians. 2-Pralidoxime (2-PAM) is currently the only therapeutic countermeasure approved by the United States Food and Drug Administration for treating OPNA poisoning. However, 2-PAM is not centrally active due to its hydrophilicity and resulting poor blood-brain barrier permeability; hence, these deficiencies warrant the development of more hydrophobic analogs. Specifically, gaps exist in previously published structure activity relationship (SAR) studies for 2-PAM, thereby making it difficult to rationally design novel analogs that are concomitantly more permeable and more efficacious. In this study, we methodically performed a methyl scan on the core pyridinium of 2-PAM to identify ring positions that could tolerate both additional steric bulk and hydrophobicity. Subsequently, SAR-guided molecular docking was used to rationalize hydropathically feasible binding modes for 2-PAM and the reported derivatives. Overall, the data presented herein provide new insights that may facilitate the rational design of more efficacious 2-PAM analogs.
Effect of substituent in pyridine-2-carbaldehydes on their heterocyclization to 1,2,4-triazines and 1,2,4-triazine 4-oxides
Krinochkin,Kopchuk,Chepchugov,Kovalev,Zyryanov,Rusinov,Chupakhin
, p. 963 - 970 (2017/09/07)
A series of substituted pyridine-2-carbaldehydes were brought into heterocyclization with isonitrosoacetophenone hydrazones, followed by aromatization by the action of oxidants or by dehydration in boiling acetic acid. As a result, substituted 3-(pyridin-2-yl)-1,2,4-triazines or 3-(pyridin-2-yl)-1,2,4-triazine 4-oxides were formed. 6-Formylpyridine-2-carbonitrile failed to undergo heterocyclization, 6-methylpyridine-2-carbaldehyde and methyl 6-formylpyridine-3-carboxylate can be converted to both 1,2,4-triazine and 1,2,4-triazine 4-oxide derivative, and only 1,2,4-triazine 4 oxides were obtained from 6-bromopyridine-2-carbaldehyde and 6-formyl-3-phenylpyridine-2-carbonitrile. Convenient procedures were proposed for the synthesis of some initial pyridinecarbaldehydes.
Acceptorless dehydrogenation of alcohols on a diruthenium(II,II) platform
Dutta, Indranil,Sarbajna, Abir,Pandey, Pragati,Rahaman, S. M. Wahidur,Singh, Kuldeep,Bera, Jitendra K.
, p. 1505 - 1513 (2016/06/09)
The diruthenium(II,II) complex [Ru2(L1)(OAc)3]Cl (1), spanned by a naphthyridine-diimine ligand and bridged by three acetates, has been synthesized. The catalytic efficacy of complex 1 has been evaluated for the acceptorless dehydrogenation (AD) of alcohols and for the dehydrogenative coupling reactions of alcohols with Wittig reagents. The diruthenium(II,II) complex is an excellent catalyst for AD of a diverse range of alcohols, and it is shown to be particularly effective for the conversion of primary alcohols to the corresponding aldehydes without undesired side products such as esters. Triphenylphosphonium ylides in a one-pot reaction with alcohols afforded the corresponding olefins in high yields with excellent E selectivity. The liberated dihydrogen gas was identified and measured to be 1 equiv with respect to alcohol. Deuteration studies with PhCD2OH revealed the absence of isotope scrambling in the product, indicating the involvement of a Ru-monohydride intermediate. Kinetic studies and DFT calculations suggest a low-energy bimetallic β-hydride elimination pathway where rate-limiting intramolecular proton transfer from alcohol to metal-bound hydride constitutes the dehydrogenation step. The general utility of metal-metal bonded compounds for alcohol AD and subsequent coupling reactions is demonstrated here.
Manganese oxide promoted liquid-phase aerobic oxidative amidation of methylarenes to monoamides using ammonia surrogates
Wang, Ye,Yamaguchi, Kazuya,Mizuno, Noritaka
supporting information; experimental part, p. 7250 - 7253 (2012/08/28)
In the presence of amorphous MnO2, various methylarenes (even with two or more methyl groups) could be selectively converted into the corresponding primary monoamides in moderate to high yields. The observed catalysis was truly heterogeneous, and the retrieved amorphous MnO2 catalyst could be reused without an appreciable loss of its catalytic performance. Copyright
Synthesis, structures of (aminopyridine)nickel complexes and their use for catalytic ethylene polymerization
Lin, Ya-Chi,Yu, Kuo-Hsuan,Lin, Ya-Fan,Lee, Gene-Hsiang,Wang, Yu,Liu, Shiuh-Tzung,Chen, Jwu-Ting
experimental part, p. 6661 - 6670 (2012/08/08)
A series of α-aminopyridines in the form of (2,6-C6H 3N)(R1)(CHR2NR3R4) (R1 = R2 = H R3 = H R4 = iPr (L1a), R4 = tBu (L1b), R4 = Ph (L1c), R4 = 2,6-Me2C6H3 (L1d), R4 = 2,6-iPr2C6H3 (L1e), R1 = R2 = H R3 = R4 = Et (L1f), R1 = H R2 = Me R3 = H R4 = iPr (L2a), R4 = Ph (L2c), R4 = 2,6-Me 2C6H3 (L2d), R4 = 2,6- iPr2C6H3 (L2e), R1 = Me R2 = H R3 = H R4 = 2,6-iPr 2C6H3 (L3e)) and β-aminopyridines in the form of (2-C6H4N)(CH2CH2NR 1R2) (R1 = H R2 = iPr (4a), R2 = tBu (L4b), R1 = R2 = Et (L4f)) have been prepared. Their corresponding halonickel complexes 1a-4f are synthesized by ligand substitution from (DME)NiBr2 and the molecular structures are characterized. Four types of coordination modes include four-coordinate mononuclear species with one ligand, five-coordinate mononuclear species with two ligands, five-coordinate dinuclear species with two ligands, and a six-coordinate polymeric framework were determined by X-ray crystallography. Using methylaluminoxanes (MAO) as the activator, the nickel complexes can catalyze ethylene polymerization under moderate pressure and ambient temperature. The activity reaches 105 g PE mol-1 Ni h. The PE products with high branching and high crystallinity have M n ～ 103 with PDI 2.
