535-11-5Relevant academic research and scientific papers
Acridine Orange Hemi(Zinc Chloride) Salt as a Lewis Acid-Photoredox Hybrid Catalyst for the Generation of α-Carbonyl Radicals
Das, Sanju,De Sarkar, Suman,Mandal, Tanumoy
supporting information, (2021/12/10)
A readily accessible organic-inorganic hybrid catalyst is reported for the reductive fragmentation of α-halocarbonyl compounds. The robust hybrid catalyst is a self-stabilizing combination of ZnCl2 Lewis acid and acridine orange as the photoactive organic dye. Mechanistic specifics of this hybrid catalyst have been studied in detail using both photophysical and electrochemical experiments. A systematic study enabled the discovery of the appropriate Lewis acid for the effective LUMO stabilization of α-halocarbonyl compounds and thereby lowering of reduction potential within the range of a standard organic dye. This strategy resolves the issues like dehalogenative hydrogenation or homo-coupling of alkyl radicals by guiding the photoredox cycle through an oxidative quenching pathway. The cooperativity between the photoactive organic dye and the Lewis acid counterparts empowers functionalization with a wide range of coupling partners through efficient and controlled generation of alkyl radicals and serves as an appropriate alternative to the expensive late transition metal-based photocatalysts. To demonstrate the application potential of this cooperative catalytic system, four different synthetic transformations of α-carbonyl bromides were explored with broad substrate scopes.
Regio- and Stereoselective Nickel-Catalyzed Coupling of Boronic Acids with Allenoates
Liu, Yang,Daka, Mario,Bandini, Marco
, p. 3187 - 3196 (2018/08/17)
The Ni(II)-catalyzed cross-coupling of arylboronic acids with allenoates is documented. The high regio- and stereoselectivity of the process enables a wide range of β-aryl β,γ-unsaturated esters to be prepared in good to excellent yields (up to 95%) and high E / Z -selectivity. Additionally, [3+2]-cascade sequence was observed when 2-formylphenylboronic acid was employed.
Synthesis of [13C3]-B6 vitamers labelled at three consecutive positions starting from [13C3]-propionic acid
Bachmann, Thomas,Rychlik, Michael
, (2018/09/11)
[13C3]-labelled vitamers (PN, PL and PM) of the B6 group were prepared starting from [13C3]-propionic acid. [13C3]-PN was synthesized in ten linear steps with an overall yield of 17%. Hereby, higher alkyl homologues of involved esters showed a positive impact on the reaction outcome of the intermediates in the chosen synthetic route. Oxidation of [13C3]-PN to [13C3]-PL was undertaken using potassium permanganate and methylamine followed by acid hydrolysis of the imine derivative. [13C3]-PM could be prepared from the oxime derivative of [13C3]-PN by hydrogenation with palladium.
Prototypic 18F-Labeled Argininamide-Type Neuropeptide Y Y1R Antagonists as Tracers for PET Imaging of Mammary Carcinoma
Keller, Max,Maschauer, Simone,Brennauer, Albert,Tripal, Philipp,Koglin, Norman,Dittrich, Ralf,Bernhardt, Günther,Kuwert, Torsten,Wester, Hans-Jürgen,Buschauer, Armin,Prante, Olaf
supporting information, p. 304 - 309 (2017/03/17)
The neuropeptide Y (NPY) Y1 receptor (Y1R) selective radioligand (R)-Nα-(2,2-diphenylacetyl)-Nω-[4-(2-[18F]fluoropropanoylamino)butyl]aminocarbonyl-N-(4-hydroxybenzyl)argininamide ([18F]23), derived from the high-affinity Y1R antagonist BIBP3226, was developed for imaging studies of Y1R-positive tumors. Starting from the argininamide core bearing amine-functionalized spacer moieties, a series of fluoropropanoylated and fluorobenzoylated derivatives was synthesized and studied for Y1R affinity. The fluoropropanoylated derivative 23 displayed high affinity (Ki = 1.3 nM) and selectivity toward Y1R. Radiosynthesis was accomplished via 18F-fluoropropanoylation, yielding [18F]23 with excellent stability in mice; however, the biodistribution study revealed pronounced hepatobiliary clearance with high accumulation in the gall bladder (>100 %ID/g). Despite the unfavorable biodistribution, [18F]23 was successfully used for imaging of Y1R positive MCF-7 tumors in nude mice. Therefore, we suggest [18F]23 as a lead for the design of PET ligands with optimized physicochemical properties resulting in more favorable biodistribution and higher Y1R-dependent enrichment in mammary carcinoma.
Regio- and Stereoselective Copper(II)-Catalyzed Hydrosilylation of Activated Allenes in Water: Access to Vinylsilanes
Pashikanti, Srinath,Calderone, Joseph A.,Nguyen, Matthew K.,Sibley, Christopher D.,Santos, Webster L.
supporting information, p. 2443 - 2446 (2016/06/09)
By using catalytic amounts of copper(II), 4-picoline, and dimethylphenylsilylpinacol borane, a series of allenoates were silylated on the β carbon in good to excellent yields and high (E)-selectivity. The mild and efficient silylation method is conducted in water under atmospheric conditions to afford vinylsilanes.
Cobalt-bisoxazoline-catalyzed asymmetric kumada cross-coupling of racemic α-bromo esters with aryl grignard reagents
Mao, Jianyou,Liu, Feipeng,Wang, Min,Wu, Lin,Zheng, Bing,Liu, Shangzhong,Zhong, Jiangchun,Bian, Qinghua,Walsh, Patrick J.
supporting information, p. 17662 - 17668 (2015/02/02)
The first cobalt-catalyzed asymmetric Kumada cross-coupling with high enantioselectivity has been developed. The reaction affords a unique strategy for the enantioselective arylation of α-bromo esters catalyzed by a cobalt-bisoxazoline complex. A variety of chiral α-arylalkanoic esters were prepared in excellent enantioselectivity and yield (up to 97% ee and 96% yield). The arylated products were transformed into α-arylcarboxylic acids and primary alcohols without erosion of ee. The new enantioenriched α-arylpropionic esters synthesized herein are potentially useful in the development of nonsteroidal anti-inflammatory drugs. This method was conducted on gram-scale and applied to the synthesis of highly enantioenriched (S)-fenoprofen and (S)-ar-turmerone.
Highly selective synthesis of α-bromoesters using molecular bromine catalyzed by phosphorus
Sun, Zhaoyun,Peng, Xinhua,Dong, Xiongzi,Shi, Wenwen
experimental part, p. 929 - 930 (2012/07/30)
A series of α-bromoesters have been synthesized by applying Hell-Volhard-Zelinsky reaction catalyzed by phosphorus instead of usual phosphorus tribromide. An excellent regioselectivity to good yields are achieved at comparatively mild reaction conditions of an operational simplicity.
COMPOUNDS USEFUL AS INHIBITORS AS AMPK
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Page/Page column 39, (2010/08/09)
According to the invention there is provided a compound of formula (I), wherein, X, T, Y1, E, M, A1 to A5 and D1 to D5 have meanings given in the description, which compounds are useful in the treatment of cancer
Free radical trapping properties of several ethyl-substituted derivatives of 5-ethoxycarbonyl-5-methyl-1-pyrroline N-oxide (EMPO)
Stolze, Klaus,Rohr-Udilova, Natascha,Rosenau, Thomas,Hofinger, Andreas,Nohl, Hans
, p. 2827 - 2836 (2007/10/03)
The spin trapping behavior of several ethyl-substituted EMPO derivatives, cis- and trans-5-ethoxycarbonyl-3-ethyl-5-methyl-pyrroline N-oxide (3,5-EEMPO), 5-ethoxycarbonyl-4-ethyl-5-methyl-pyrroline N-oxide (4,5-EEMPO), cis- and trans-5-ethoxycarbonyl-5-ethyl-3-methyl-pyrroline N-oxide (5,3-EEMPO), and 5-ethoxycarbonyl-5-ethyl-4-methyl-pyrroline N-oxide (5,4-EEMPO), toward a series of different oxygen- and carbon-centered radicals, is described. Considerably different stabilities of the superoxide adducts (ranging from about 12 to 55 min) as well as the formation of other radical adducts were observed.
Inclusion complexes of EMPO derivatives with 2,6-di-O-methyl-β- cyclodextrin: Synthesis, NMR and EPR investigations for enhanced superoxide detection
Bardelang, David,Rockenbauer, Antal,Karoui, Hakim,Finet, Jean-Pierre,Biskupska, Inga,Banaszak, Karol,Tordo, Paul
, p. 2874 - 2882 (2008/02/08)
The free radical trapping properties of eight 5-alkoxycarbonyl-5-methyl-1- pyrroline N-oxide (EMPO) type nitrones and those of 5,5-dimethyl-1-pyrroline N-oxide (DMPO) were evaluated for trapping of superoxide anion radicals in the presence of 2,6-di-O-methyl-β-cyclodextrin (DM-β-CD). 1H-NMR titrations were performed to determine both stoichiometries and binding constants for the diamagnetic nitrone-DM-β-CD equilibria. EPR titrations were then performed and analyzed using a two-dimensional EPR simulation program affording 1: 1 and 1: 2 stoichiometries for the nitroxide spin adducts with DM-β-CD and the associated binding constants after spin trapping. The nitroxide spin adducts associate more strongly with DM-β-CD than the nitrones. The ability of the nitrones to trap superoxide, the enhancement of the EPR signal intensity and the supramolecular protection by DM-β-CD against sodium l-ascorbate reduction were evaluated. The Royal Society of Chemistry 2006.
