501-52-0Relevant articles and documents
Rapid production of nitrilase containing silica nanoparticles offers an effective and reusable biocatalyst for synthetic nitrile hydrolysis
Swartz, Joshua D.,Miller, Scott A.,Wright, David
, p. 584 - 589 (2009)
Rapid and efficient immobilization of nitrilase within silica nanoparticles overcomes many hurdles associated with biocatalysis. A water-miscible dendrimer catalyzes the condensation of silicic acid to silica dioxide, entrapping electrostatically bound nitrilase molecules. Michaelis-Menten kinetics shows encapsulated nitrilase functions similarly to free nitrilase in solution. Additionally, HPLC analysis demonstrates that simple benchtop separation and recycling of the biocatalyst over 10 individual reactions are achieved without significant loss of enzyme and/or function. These findings broaden the use of nitrilases in the production of fine chemicals as well as general syntheses by overcoming some of the traditional barriers associated with enzyme reagents and nitrile conversion.
Palladium-Catalyzed Selective β-Arylation of Aliphatic Amides Using a Removable N,O-Bidentate Auxiliary
Zhang, Shou-Kun,Yang, Xin-Yan,Zhao, Xue-Mei,Li, Peng-Xiang,Niu, Jun-Long,Song, Mao-Ping
, p. 4331 - 4339 (2015)
A new method for palladium-catalyzed β-arylation of aliphatic and cycloaliphatic amides without conventional silver salts utilizing 2-aminopyridine-1-oxide moiety (PyO) as an N,O-bidentate group has been developed. Reactions proceeded smoothly in DMSO solvent in the presence of K2HPO4·3H2O, providing the β-arylated aliphatic amide products in a moderate-to-good yield. An important cyclopalladium intermediate, successfully obtained with a modest yield, could be converted to the monoarylation product and be used as catalyst in arylation reaction. Moreover, the PyO directing group was easily removed under base condition to generate aliphatic acids.
Mild deprotection of methyl, benzyl, methoxymethyl, methylthiomethyl, methoxyethoxymethyl, and β-(trimethylsilyl)ethoxymethyl esters with AlCl3- N,N-dimethylaniline
Akiyama,Hirofuji,Hirose,Ozaki
, p. 2179 - 2185 (1994)
Methyl, benzyl, methoxymethyl, methylthiomethyl, methoxyethoxymethyl, and β-(trimethylsilyl)ethoxymethyl esters could be cleaved readily under mild conditions on treatment with AlCl3-N,N-dimethylaniline in CH2Cl2 to give parent carboxylic acids in high yields.
Preparation of magnetic mesoporous core-shell nanocomposites for cinnamic acid hydrogenation
Liu, Xiaofang,Shi, Lingjuan,Feng, Wenhui,Niu, Libo,Liu, Chen,Bai, Guoyi
, p. 44302 - 44306 (2014)
A novel magnetic mesoporous core-shell nanocomposite Fe3O4@nSiO2@mSiO2@Ni-Co-B was prepared by the combination of a modified St?ber sol-gel process, a surfactant-templating method and self-assembly. It has a multi-shell structure with ferroferric oxide as core, dense nonporous silica and mesoporous silica as middle layers in sequence and an Ni-Co-B amorphous alloy as outer layer, as confirmed by transmission electron microscopy and nitrogen adsorption-desorption. This nanocomposite showed high activity and good selectivity in the selective hydrogenation of cinnamic acid to hydrocinnamic acid. Notably, it can be easily separated by a magnet after reaction due to its high magnetism and recycled effectively five times.
Application of Laser Induced Breakdown Spectroscopy as a Novel Approach for Monitoring of the Activity of Nano Palladium Catalyst as Compared to Two Well-known Methods
Belyani, Sahar,Keshavarz, Mohammad Hossein,Darbani, Seyyed Mohammad Reza,Tehrani, Masoud Kavosh
, p. 65 - 69 (2020)
Catalyst deactivation is an unavoidable process that occurs in catalytic chemical reactions. Laser Induced Breakdown Spectroscopy (LIBS) is used here as a novel approach to investigate the activity of palladium supported with carbon catalyst (Pd/C) over the hydrogenation of cinnamic acid with tetralin. Their outputs for four catalyst samples are reported for different time intervals of 0, 5, 10, 15 min during the reaction. The results of LIBS analysis are compared to Inductively Coupled Plasma Mass Spectrometry (ICP-MS), which shows a good agreement. Experimental data specify that line intensities of palladium (Pd) are decreased significantly with an increment of the reaction time. Moreover, the Field Emission Scanning Electron Microscope with energy dispersive spectroscopy (FESEM-EDS) of catalysts samples show aggregation of palladium particles for some places in the catalyst surface. The changes of Pd content and sintering of Pd particles in the catalyst during the reaction play substantial roles in catalyst deactivation.
Mammalian exocrine secretions XVI. Constituents of secretion of supplementary sacculi of dwarf hamster, Phodopus sungorus sungorus
Burger,Smit,Spies,Schmidt,Schmidt,Telitsina
, p. 1277 - 1288 (2001)
As a first step in a study of the role of the secretion of the supplementary sacculi (buccal secretion) of the dwarf hamster, Phodopus sungorus sungorus, almost complete chemical characterization of the secretion was achieved. The 35 compounds identified include carbon dioxide, hydrogen sulfide, a large number of carboxylic acids (representing the bulk of the organic volatile fraction of the secretion), phenol, 2-piperidone, indole, two long-chain hydroxyesters, cholestrol, desmosterol, and lanosterol. The position of the double bonds in γ-icosadienyl-γ-butyrolactone and γ-henicosadienyl-γ-butyrolactone could not be determined, and these two compounds remained only partially characterized. Large variations were found in the relative concentrations in which the short-chain carboxylic acids are present in the secretions of individual animals, and although this aspect was not investigated in sufficient detail in the present investigation, the difference in the carboxylic acid profiles of the secretions of individual animals could play a role in individual recognition in this animal.
New bis-thioglycosyl-1,1′-disulfides from Nasturtium officinale R. Br. and their anti-neuroinflammatory effect
Lee, Tae Hyun,Khan, Zahra,Subedi, Lalita,Kim, Sun Yeou,Lee, Kang Ro
, p. 501 - 506 (2019)
As a part of our continuing search for bioactive constituents from Brassicaceae family, three new bis-thioglycosides (1–3) were isolated from the 80% MeOH extract of Nasturtium officinale, together with 13 known compounds (4–16). The chemical structures of three new bis-thioglycosides (1–3) were elucidated using NMR techniques (1H and 13C NMR, 1H–1H COSY, HSQC, and HMBC), HRESIMS, and a chemical method. All the compounds were evaluated for their inhibitory effects on nitric oxide (NO) levels in lipopolysaccharide (LPS)-stimulated murine microglia BV-2 cells. Among the isolates, compound 5 exhibited a strong inhibitory effect on NO production, and compounds 4 and 15 showed moderate inhibitory activities, suggesting the neuroprotective and anti-neuroinflammatory effects of bis-thioglycosides from N. officinale.
Gram-scale synthesis of carboxylic acids via catalytic acceptorless dehydrogenative coupling of alcohols and hydroxides at an ultralow Ru loading
Chen, Cheng,Cheng, Hua,Verpoort, Francis,Wang, Zhi-Qin,Wu, Zhe,Yuan, Ye,Zheng, Zhong-Hui
, (2021/12/13)
Acceptorless dehydrogenative coupling (ADC) of alcohols and water/hydroxides is an emergent and graceful approach to produce carboxylic acids. Therefore, it is of high demand to develop active and practical catalysts/catalytic systems for this attractive transformation. Herein, we designed and fabricated a series of cyclometallated N-heterocyclic carbene-Ru (NHC-Ru) complexes via ligand tuning of [Ru-1], the superior complex in our previous work. Gratifyingly, gram-scale synthesis of carboxylic acids was efficiently enabled at an ultralow Ru loading (62.5 ppm) in open air. Moreover, effects of distinct ancillary NHC ligands and other parameters on this catalytic process were thoroughly studied, while further systematic studies were carried out to provide rationales for the activity trend of [Ru-1]-[Ru-7]. Finally, determination of quantitative green metrics illustrated that the present work exhibited superiority over representative literature reports. Hopefully, this study could provide valuable input for researchers who are engaging in metal-catalyzed ADC reactions.
Enantioselective Flow Synthesis of Rolipram Enabled by a Telescoped Asymmetric Conjugate Addition-Oxidative Aldehyde Esterification Sequence Using in Situ-Generated Persulfuric Acid as Oxidant
Nagy, Bence S.,Llanes, Patricia,Pericas, Miquel A.,Kappe, C. Oliver,?tv?s, Sándor B.
supporting information, (2022/02/05)
A novel approach is reported for the enantioselective flow synthesis of rolipram comprising a telescoped asymmetric conjugate addition-oxidative aldehyde esterification sequence followed by trichlorosilane-mediated nitro group reduction and concomitant la
Synthesis of α-Hydroxy Acids via Dehydrogenative Cross-Coupling of a Sustainable C2 Chemical (Ethylene Glycol) with Alcohols
Byeon, Heemin,Jang, Hye-Young,Lee, Mi-Hyun
supporting information, p. 4631 - 4639 (2022/04/07)
Ir(NHC) (NHC, N-heterocyclic carbene)-catalyzed dehydrogenative coupling of sustainable ethylene glycol and various bioalcohols can produce industrially valuable α-hydroxy acids (AHAs). This study is the first to report the sustainable synthesis of higher Cn AHAs, in addition to glycolic acid (C2 AHA) and lactic acid (C3 AHA). This catalytic system can be recycled to the seventh cycle while maintaining good yields. A reaction mechanism, including facile dehydrogenation of each alcohol and fast cross-coupling of dehydrogenated aldehydes forming products, was proposed based on 18O- and 2H-labeling experiments and electron spray ionization-mass spectrometry (ESI-MS) and NMR spectral analyses.
