4237-46-1Relevant academic research and scientific papers
Time-resolved ESR studies on ketyl type radical - Amine complexes
Kawai, Akio,Aoki, Atsushi,Kobori, Yasuhiro,Obi, Kinichi
, p. 10021 - 10026 (1996)
Time-resolved (TR) ESR spectra were measured for α-hydroxybenzyl-amine (α-HB) and α-hydroxydiphenylmethyl - amine complexes. Hyperfine coupling constants (hfcc) of the complexes were determined, and considerable increase in hfcc was recognized on the hydr
Solvent effects on the complex formation of benzophenone ketyl radical and triethylamine
Abe, Toyohiko,Kawai, Akio,Kajii, Yoshizumi,Shibuya, Kazuhiko,Obi, Kinichi
, p. 1457 - 1462 (1999)
The 1:1 complex formation between benzophenone ketyl radical (BPK) and triethylamine in various solvents was studied by means of nanosecond laser flash photolysis. The complex shows an absorption band slightly red-shifted from that of uncoupled BPK. The formation constants (Kf's) were determined from the absorbance change of the complex against amine concentration. The Kf values are in the range 60-103 M-1 depending on the dielectric constant of solvent (εr = 10.7-1.89). Enthalpy and entropy changes in the complex formation reactions were determined from van't Hoff plots around room temperature. The measured enthalpy change of -2.0 to -7.5 kcal mol-1 depends on εr, which is explained with an Onsager's reaction field theory. The measured entropy change varies from -16.5 cal K mol-1 to nearly zero, and the dependence on the solvent is discussed in terms of the solvation effect.
Specific solvent effects on the structure and reaction dynamics of benzophenone ketyl radical
Kawai, Akio,Hirakawa, Makoto,Abe, Toyohiko,Obi, Kinichi,Shibuya, Kazuhiko
, p. 9628 - 9636 (2001)
Complex formation reaction between benzophenone ketyl (BPK) radical and triethylamine was investigated by means of transient absorption and time-resolved ESR methods. The formation constants (Kf's) in benzene, toluene, o-xylene, and anisole were measured by a transient absorption method. The enthalpy and entropy changes upon the complex formation were determined by van't Hoff plots of Kf values around 300 K. The ΔG values in the complex formation reaction at 298 K were calculated from these thermodynamic parameters, which show notable difference from those in aliphatic solvents and chlorotoluenes previously reported. The BPK conformation in these solvents was investigated by analyzing the time-resolved ESR spectra of BPK and by the DFT calculation. The hyperfine coupling constant of hydroxy-proton (aOH) was found to depend on solvent as well and there exists a clear correlation between the aOH and Kf (or ΔG) values. It was concluded that the conformation of BPK, especially the conformation between OH and two phenyl groups, depends on the solvation and is an important factor to control the complex formation reaction.
A Bifunctional Iron Nanocomposite Catalyst for Efficient Oxidation of Alkenes to Ketones and 1,2-Diketones
Ma, Zhiming,Ren, Peng,Song, Tao,Xiao, Jianliang,Yang, Yong,Yuan, Youzhu
, p. 4617 - 4629 (2020/05/19)
We herein report the fabrication of a bifunctional iron nanocomposite catalyst, in which two catalytically active sites of Fe-Nx and Fe phosphate, as oxidation and Lewis acid sites, were simultaneously integrated into a hierarchical N,P-dual doped porous carbon. As a bifunctional catalyst, it exhibited high efficiency for direct oxidative cleavage of alkenes into ketones or their oxidation into 1,2-diketones with a broad substrate scope and high functional group tolerance using TBHP as the oxidant in water under mild reaction conditions. Furthermore, it could be easily recovered for successive recycling without appreciable loss of activity. Mechanistic studies disclose that the direct oxidation of alkenes proceeds via the formation of an epoxide as intermediate followed by either acid-catalyzed Meinwald rearrangement to give ketones with one carbon shorter or nucleophilic ring-opening to generate 1,2-diketones in a cascade manner. This study not only opens up a fancy pathway in the rational design of Fe-N-C catalysts but also offers a simple and efficient method for accessing industrially important ketones and 1,2-diketones from alkenes in a cost-effective and environmentally benign fashion.
A novel lanthanum metal-assisted reaction of diaryl ketones and electrophiles
Umeda, Rui,Ninomiya, Masashi,Nishino, Toshiaki,Kishida, Makoto,Toiya, Shunsuke,Saito, Tomoki,Nishiyama, Yutaka,Sonoda, Noboru
, p. 1287 - 1291 (2015/03/05)
A novel and efficient lanthanum metal-assisted carbon-carbon bond formation of diaryl ketones and various electrophiles, such as carbonyl compounds, esters, nitriles, and epoxides, has been developed. When diaryl ketones were allowed to react with dialkyl ketones in the presence of lanthanum metal and a catalytic amount of iodine, the cross pinacol coupling reaction proceeded to give the corresponding unsymmetrical 1,2-diols in moderate to good yields. α-Hydroxy ketones were prepared by the lanthanum metal-assisted reaction of diaryl ketones with esters or nitriles, followed by hydrolysis with aq HCl. It is interesting to note that for the epoxides, the coupling reaction proceeded via the Meinwald rearrangement of epoxides to give the corresponding 1,2-diols.
Photorelease study of γ-amino glutamate from 1,2,2-triphenyl-ethanone
Jang, Sukjin,Chowdhury, Azhad,Kang, Jeonghee,Lee, Jong I.
, p. 230 - 235 (2014/05/20)
A phototrigger, 1,2,2-triphenylethanone (TPE), was synthesized for the photorelease study. The photorelease of 1,2,2-triphenylethanonyl N-t-Boc-γ-amino glutamate (TPE- N-t-Boc-GABA) showed the quantum efficiency of φ = 0.75. The phototrigger underwent fur
Reactions of organolithiums with dialkyl oxalates. A flow microreactor approach to synthesis of functionalized α-keto esters
Nagaki, Aiichiro,Ichinari, Daisuke,Yoshida, Jun-Ichi
supporting information, p. 3242 - 3244 (2013/05/08)
Reactions of functionalized aryllithiums with dialkyl oxalates were achieved using a flow microreactor to obtain α-keto esters with high selectivity by virtue of fast 1:1 micromixing.
Doing the methylene shuffle - Further insights into the inhibition of mitotic kinesin Eg5 with S-trityl l-cysteine
Abualhasan, Murad N.,Good, James A.D.,Wittayanarakul, Kitiyaporn,Anthony, Nahoum G.,Berretta, Giacomo,Rath, Oliver,Kozielski, Frank,Sutcliffe, Oliver B.,MacKay, Simon P.
experimental part, p. 483 - 498 (2012/09/10)
S-Trityl l-cysteine (STLC) is an inhibitor of the mitotic kinesin Eg5 with potential as an antimitotic chemotherapeutic agent. We previously reported the crystal structure of the ligand-protein complex, and now for the first time, have quantified the interactions using a molecular dynamics based approach. Based on these data, we have explored the SAR of the trityl head group using the methylene shuffle strategy to expand the occupation of one of the hydrophobic pockets. The most potent compounds exhibit strong (100 nM) inhibition of Eg5 in the basal ATPase assay and inhibit growth in a variety of tumour-derived cell lines.
Ruthenium-catalyzed oxidation of alkenes at room temperature: A practical and concise approach to α-diketones
Chen, Shulin,Liu, Zhaojun,Shi, Erbo,Chen, Long,Wei, Wei,Li, Hong,Cheng, Yannan,Wan, Xiaobing
supporting information; experimental part, p. 2274 - 2277 (2011/06/27)
Chemical equations presented. The catalytic oxidation of alkenes to α-diketones is unprecedented. A new oxidation of alkenes, catalyzed by a ruthenium complex, which allows an efficient route to α-diketones using TBHP as an oxidant is described. This methodology is highly functional group tolerant, is practically convenient, requires no additional ligand, and operates under mild conditions with short reaction times. Based upon experimental observations, a plausible mechanism is proposed.
Aerobic oxygenation of benzylic ketones promoted by a gold nanocluster catalyst
Sakurai, Hidehiro,Kamiya, Ikuyo,Kitahara, Hiroaki,Tsunoyama, Hironori,Tsukudad, Tatsuya
scheme or table, p. 245 - 248 (2009/06/23)
Gold nanoclusters stabilized by poly(N-vinyl-2-pyrrolidone) (Au:PVP) promote the oxidation of benzylic ketones, including auto-oxidation-type bond-cleavage reactions and α-hydroxylation, under ambient conditions. The catalyst accelerates the formation of
