99-61-6Relevant articles and documents
Acid-Catalyzed Photooxidation of m-Nitrobenzyl Derivatives ib Aqueous Solution
Rafizadeh, Karim,Yates, Keith
, p. 2777 - 2781 (1986)
A variety of m-nitrobenzyl derivatives including alcohols, alkyl ethers, esters, and an amine undergo photooxidation reactions to produce m-nitrobenzaldehyde (or m-nitroacetophenone in two cases) as the major isolated product.The reaction is both solvent and pH dependent and only takes place in essentially aqueous media.The quantum efficiency of product formation reaches a maximum (φ =0.3-0.4) in the 20-50percent sulfuric acid range, depending on the substrate, although the reaction is reasonably efficient even in neutral aqueous solution.The presence of benzylic hydrogen and a heteroatom (O,N) in the α-position appears to be essential for photooxidation to occur.The multiplicity of the reactive state is T1.A solvent isotope effect (φH2O/φD2O = 1.4) was observed.The proposed mechanism involves rate-determining protonation of T1 followed by rapid α-hydrogen abstraction by water.
A facile method for the transformation of acetals and ketals to aldehydes and ketones
Wu,Ding
, p. 2173 - 2177 (1994)
This paper reports a simple and convenient acetyl chloride-samarium trichloride system for the transformation of acetals and ketals to aldehydes and ketones.
Selective oxidation of benzylic alcohols using can supported onto silica gel under microwave irradiation
Heravi, Majid M.,Oskooie, Hossein A.,Kazemian, Pegah,Drikvand, Fatemeh,Ghassemzadeh, Mitra
, p. 2341 - 2344 (2004)
Cerium ammonium nitrate (CAN) adsorbed on HNO3/silica gel is a mild reagent for selective oxidation of benzylic alcohols to the corresponding aldehydes under microwave irradiation in solventless system.
Zinc Photocages with Improved Photophysical Properties and Cell Permeability Imparted by Ternary Complex Formation
Basa, Prem N.,Barr, Chelsea A.,Oakley, Kady M.,Liang, Xiaomeng,Burdette, Shawn C.
, p. 12100 - 12108 (2019)
Photocaged complexes can control the availability of metal ions to interrogate cellular signaling pathways. We describe a new photocage, {bis[(2-pyridyl)methyl]amino}(9-oxo-2-xanthenyl)acetic acid (XDPAdeCage, 1), which utilizes a 2-xanthone acetic acid group to mediate a photodecarboxylation reaction. XDPAdeCage photolyzes with a quantum yield of 27%, and binds Zn2+ with 4.6 pM affinity, which decreases by over 4 orders of magnitude after photolysis. For comparison to our previous approach to Zn2+ release via photodecarboxylation, the analogous photocage {bis[(2-pyridyl)methyl]amino}(m-nitrophenyl)acetic acid (DPAdeCage, 2), which uses a m-nitrobenzyl chromophore, was also prepared and characterized. The advantages of the 2-xanthone acetic acid chromophore include red-shifted excitation and a higher extinction coefficient at the preferred uncaging wavelength. The neutral ternary complex of [Zn(XDPAdeCage)]+ with the anionic ligand pyrithione is membrane permeable, which circumvents the need to utilize invasive techniques to introduce intracellular Zn2+ fluctuations. Using fluorescent imaging, we have confirmed transport of Zn2+ across membranes; in addition, RT-PCR experiments demonstrate changes in expression of Zn2+-responsive proteins after photolysis.
Controlled reduction of activated primary and secondary amides into aldehydes with diisobutylaluminum hydride
Azeez, Sadaf,Kandasamy, Jeyakumar,Sabiah, Shahulhameed,Sureshbabu, Popuri
supporting information, p. 2048 - 2053 (2022/03/31)
A practical method is disclosed for the reduction of activated primary and secondary amides into aldehydes using diisobutylaluminum hydride (DIBAL-H) in toluene. A wide range of aryl and alkyl N-Boc, N,N-diBoc and N-tosyl amides were converted into the corresponding aldehydes in good to excellent yields. Reduction susceptible functional groups such as nitro, cyano, alkene and alkyne groups were found to be stable. Broad substrate scope, functional group compatibility and quick conversions are the salient features of this methodology.
Trifunctional covalent triazine and carbonyl based polymer as a catalyst for one-pot multistep organic transformation
Ravi, Seenu,Raza, A. Ahmed,Sheriff, A. K. Ibrahim,Tajudeen, S. Syed
, (2021/08/24)
Trifunctional covalent triazine and carbonyl based polymer with acid-base and metal active sites (CTCP-SO3H-EDA/Pd) was synthesized by a multistep friedel-crafts reaction, post-synthetic sulfonation, schiff base condensation and metal nanoparticle incorporation. CTCP-SO3H-EDA/Pd was characterized by FT-IR, N2 sorption-desorption isotherm, elemental analysis, ICP-OES, TEM-EDS and TEM. CTCP-SO3H-EDA/Pd was evaluated as a heterogeneous catalyst for the conversion of 1-(dimethoxymethyl)-3-nitrobenzene into 2-(3-aminobenzylidene)malononitrile via a three step deacetylation-Knoevenagel and transfer hydrogenation reaction in one domino process. The cooperation of SO3H acidic sites, EDA and uniformly distributed Pd nanoparticles greatly facilitated the one-pot reaction and produced good yield of the desired product with high selectivity. The catalyst was recovered by simple centrifugation and could be reused for five runs with minor loss of catalytic activity and selectivity. A plausible mechanism for deacetylation, C[sbnd]C bond formation and subsequent chemoselective reduction of nitro functionality over CTCP-SO3H-EDA/Pd was also proposed.
The: In situ fabrication of ZIF-67 on titania-coated magnetic nanoparticles: A new platform for the immobilization of Pd(ii) with enhanced catalytic activity for organic transformations
Kaur, Manpreet,Paul, Satya,Sharma, Chandan,Sharma, Sukanya
, p. 20309 - 20322 (2021/11/22)
Considering the outstanding characteristics of metal organic frameworks (MOFs) and magnetic nanoparticles, herein we report a facile approach for the synthesis of a magnetic zeolitic-imidazolate-framework-supported palladium(ii) catalyst. In brief, zeolitic imidazolate framework-67 (ZIF-67) was successfully incorporated onto the surface of titania-coated magnetic nanoparticles using ethane-1,2-diamine as a linker, and then Pd(ii) was immobilized onto this. The resulting Pd@ZIF-67-Fe3O4-TiO2 catalyst possesses a high surface area (205 m2 g-1), a large pore volume (0.10 cm3 g-1), good magnetic responsivity (10.71 emu g-1), and high stability. A comparative analysis of Pd@ZIF-67-Fe3O4-TiO2 and Pd@Fe3O4-TiO2 catalysts for the oxidation, reduction, and oxidative deprotection of oximes was done to investigate the effects of ZIF-67 on the catalytic performance of Pd species. Substantial differences in activity and stability were observed in the presence of ZIF-67, suggesting that ZIF-67 plays an important role in enhancing the activity of Pd(ii). This superior catalytic activity and stability arises due to a synergistic effect between well-dispersed palladium species and highly porous ZIF-67, which was confirmed via XPS analysis. Moreover, the catalyst retains its structure, chemical environment, and good magnetic response even after five catalytic runs, as confirmed via FTIR, XRD, XPS, and VSM studies of reused catalyst samples.
SBA-15 Supported Silver Catalyst for the Efficient Aerobic Oxidation of Toluene Under Solvent-Free Conditions
Chen, Lei,Chen, Yanjiao,Dai, Xuan,Guo, Jiaming,Peng, Xinhua
, (2021/12/09)
The efficient SBA-15 supported silver catalysts(Ag/SBA-15) were prepared and characterized by ICP-OES, XRD, TEM, SEM, XPS and N2 adsorption–desorption techniques. The catalysts exhibited an excellent catalytic activity for the aerobic oxidation of toluene to benzaldehyde under solvent-free conditions. Conversion of toluene and selectivity of benzaldehyde were 50% and 89% respectively over catalyst with 9.1 wt% Ag loading (10Ag/SBA-15). A wide range of substrates were tolerated under the selected reaction conditions. The kinetic study shows that the oxidation of toluene over 10Ag/SBA-15 is pseudo-first-order reaction and the activation energy Ea is 45.1?kJ/mol. A plausible mechanism involving oxygen free radicals was proposed for the aerobic oxidation reaction. Compared with the traditional method, the newly designed heterogeneous catalytic system shows better economic applicability, environmental friendliness and broader application prospects. Graphical abstract: [Figure not available: see fulltext.]
Oxidation/ MCR domino protocol for direct transformation of methyl benzene, alcohol, and nitro compounds to the corresponding tetrazole using a three-functional redox catalytic system bearing TEMPO/Co(III)-porphyrin/ Ni(II) complex
Mahmoudi, Boshra,Rostami, Amin,Kazemnejadi, Milad,Hamah-Ameen, Baram Ahmed
, (2020/12/21)
A redox catalytic system for oxidation-reduction reactions and the domino preparation of tetrazole compounds from nitro and alcohol precursors was designed, prepared and characterized by UV–vis, GPC, TGA, XRD, EDX, XPS, VSM, FE-SEM, TEM, DLS, BET, NMR, and ICP analyses. The catalyst was prepared via several successive steps by demetalation of chlorophyll b, copolymerization with acrylated TEMPO monomers, complexation with Ni and Co metals (In two different steps), then immobilized on magnetic nanoparticles. The presence of three functional groups including TEMPO, coordinated cobalt, and coordinated nickel in the catalyst, allowed the oxidation of various types of alcohols, alkyl benzenes as well as the reduction of nitro compounds by a single catalyst. All reactions yielded up to 97 % selectivity for oxidation and reduction reactions. Next, the ability of the catalyst to successfully convert alcohol, methyl benzenes and nitro to their corresponding tetrazoles was studied.
g-C3N4@Ce-MOF Z-scheme heterojunction photocatalyzed cascade aerobic oxidative functionalization of styrene
Karimia, Meghdad,Sadeghia, Samira,Gavinehroudi, Reza Ghahremani,Mohebali, Haleh,Mahjoub, Alireza,Heydari, Akbar
, p. 6671 - 6681 (2021/04/22)
A special composite of the cerium-based metal-organic framework (Ce-UiO-66) modified with graphitic carbon nitride nanosheets (g-C3N4) has been synthesized. In order to make a comparison, a series of composites comprising g-C3N4and Ce-MOF were synthesized as well. Their structural features were investigated using Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD), sorption of nitrogen (BET and BJH), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), X-ray fluorescence spectroscopy (XRF) and diffuse reflectance UV-Vis spectroscopy (UV-Vis DRS) and electron spin resonance (ESR) techniques. According to the obtained results, it was found that nanosheets of mesoporous g-C3N4act as linkers between the cerium sites, playing a critical role in the formation of composites. In fact, the embedded g-C3N4nanoparticles in the Ce-MOF cause a new kind of meso-porosity. Moreover, the coordination of nitrogen atoms in the graphitic carbon nitride structure to cerium atoms of the crystal brings about substantial changes in the optical properties, increasing the photoreactivity. On the other hand, since there is a physical contact between Ce-UiO-66 and g-C3N4in the composite, the unaltered pore volume and optical properties lead to the formation of a physical mixture rather than a composite. The g-C3N4@Ce-MOF as a photocatalyst was employed in photocatalytic aerobic oxidative Hantzsch pyridine synthesis of styrene and indicated high performance under visible light. The stability and reusability of g-C3N4@Ce-MOF were also examined and showed high efficiency up to the 5th run. Besides, the PXRD and FT-IR analyses taken from the retrieved g-C3N4@Ce-MOF nanocomposite confirmed the catalyst stability after the completion of the cascade aerobic oxidative reaction. Despite the photocatalytic performance, the synergistic effect of open metal sites in the MOF as Lewis acid and nitrogen in g-C3N4have greatly improved the efficiency of the catalyst. Moreover, the study of the reaction mechanism using ESR indicates the positive effect of composite formation on the performance of the photocatalytic aerobic oxidation reaction by the superoxide radical (O2˙—), as a selective oxidant species.
