491-38-3Relevant academic research and scientific papers
Lewis Acid-catalysed Facile Elimination of the Diazo Group in 3-Diazochromanones. Novel Conversion of Chromanones into Chromones
Mandal, Pranab,Venkateswaran, Ramanathapuram V.
, p. 88 - 89 (1998)
3-Diazochromanones undergo rapid elimination of the diazo group in presence of BF3- Et2O to furnish chromones.
Oxidation of chromanones and 2-spirochromanones with [hydroxy(tosyloxy)iodo]benzene in acetonitrile under reflux as well as ultrasound: A convenient route for the synthesis of chromones, tetrahydroxanthones and their higher homologues
Kumar,Singh,Prakash,Singh
, p. 2637 - 2644 (1994)
Oxidation of chromanones (1a-i) and 2-spiro-chromanones (1j-m) using [hydroxy(tosyloxy)iodo]benzene in refluxing acetonitrile as well as using ultrasound via dehydrogenation and 2,3-alkyl migration provides a convenient route for the synthesis of chromones (2a-i), tetrahydroxanthones (2j, k) and their higher homologues (2l, m). The ultrasound also enhances substantially the rate of above transformations.
Gold(I)-Catalyzed Hydroxy Group Assisted C(sp2)-H Alkylation of Enaminones with Diazo Compounds to Access 3-Alkyl Chromones
Bagle, Pradip N.,Mane, Manoj V.,Sancheti, Shashank P.,Gade, Amol B.,Shaikh, Samir R.,Baik, Mu-Hyun,Patil, Nitin T.
, p. 335 - 339 (2019)
A strategy for expedient synthesis of 3-substituted chromones from easily available o-hydroxyarylenaminones and diazo compounds has been developed. Carefully conducted experimental and computational studies led us to propose an uncommon mechanistic pathway involving the hydroxyl group assisted alkylation of enaminones with in situ generated gold carbenes.
Visible Light-Promoted Selenylation/Cyclization of Enaminones toward the Formation of 3-Selanyl-4H-Chromen-4-Ones
Liu, Hao-Yang,Zhang, Jia-Rong,Huang, Guo-Bao,Zhou, Yi-Huan,Chen, Yan-Yan,Xu, Yan-Li
supporting information, p. 1656 - 1661 (2021/02/12)
A simple and efficient visible-light-promoted selenylation/cyclization of enaminones have been realized for the practical synthesis of 3-selanyl-4H-chromen-4-ones. This reaction is performed in the mild conditions, no transition metal catalyst or photocatalysts and no additional oxidants are required. In addition, the 3-selanyl-4H-chromen-4-ones could be easily converted to selanyl-functionalized pyrimidines by reacting with benzamidine substrates. (Figure presented.).
Exploiting a silver-bismuth hybrid material as heterogeneous noble metal catalyst for decarboxylations and decarboxylative deuterations of carboxylic acids under batch and continuous flow conditions
?tv?s, Sándor B.,Fül?p, Ferenc,Kónya, Zoltán,Kukovecz, ákos,Márton, András,Mészáros, Rebeka,Pálinkó, István,Szabados, Márton,Varga, Gábor
, p. 4685 - 4696 (2021/07/12)
Herein, we report novel catalytic methodologies for protodecarboxylations and decarboxylative deuterations of carboxylic acids utilizing a silver-containing hybrid material as a heterogeneous noble metal catalyst. After an initial batch method development, a chemically intensified continuous flow process was established in a simple packed-bed system which enabled gram-scale protodecarboxlyations without detectable structural degradation of the catalyst. The scope and applicability of the batch and flow processes were demonstrated through decarboxylations of a diverse set of aromatic carboxylic acids. Catalytic decarboxylative deuterations were achieved on the basis of the reaction conditions developed for the protodecarboxylations using D2O as a readily available deuterium source.
Site-Selective Acceptorless Dehydrogenation of Aliphatics Enabled by Organophotoredox/Cobalt Dual Catalysis
Zhou, Min-Jie,Zhang, Lei,Liu, Guixia,Xu, Chen,Huang, Zheng
supporting information, p. 16470 - 16485 (2021/10/20)
The value of catalytic dehydrogenation of aliphatics (CDA) in organic synthesis has remained largely underexplored. Known homogeneous CDA systems often require the use of sacrificial hydrogen acceptors (or oxidants), precious metal catalysts, and harsh reaction conditions, thus limiting most existing methods to dehydrogenation of non- or low-functionalized alkanes. Here we describe a visible-light-driven, dual-catalyst system consisting of inexpensive organophotoredox and base-metal catalysts for room-temperature, acceptorless-CDA (Al-CDA). Initiated by photoexited 2-chloroanthraquinone, the process involves H atom transfer (HAT) of aliphatics to form alkyl radicals, which then react with cobaloxime to produce olefins and H2. This operationally simple method enables direct dehydrogenation of readily available chemical feedstocks to diversely functionalized olefins. For example, we demonstrate, for the first time, the oxidant-free desaturation of thioethers and amides to alkenyl sulfides and enamides, respectively. Moreover, the system's exceptional site selectivity and functional group tolerance are illustrated by late-stage dehydrogenation and synthesis of 14 biologically relevant molecules and pharmaceutical ingredients. Mechanistic studies have revealed a dual HAT process and provided insights into the origin of reactivity and site selectivity.
Iron-Catalyzed ?±,?-Dehydrogenation of Carbonyl Compounds
Zhang, Xiao-Wei,Jiang, Guo-Qing,Lei, Shu-Hui,Shan, Xiang-Huan,Qu, Jian-Ping,Kang, Yan-Biao
supporting information, p. 1611 - 1615 (2021/03/03)
An iron-catalyzed α,β-dehydrogenation of carbonyl compounds was developed. A broad spectrum of carbonyls or analogues, such as aldehyde, ketone, lactone, lactam, amine, and alcohol, could be converted to their α,β-unsaturated counterparts in a simple one-step reaction with high yields.
Heterogeneously Catalyzed Selective Decarbonylation of Aldehydes by CeO2-Supported Highly Dispersed Non-Electron-Rich Ni(0) Nanospecies
Matsuyama, Takehiro,Yatabe, Takafumi,Yabe, Tomohiro,Yamaguchi, Kazuya
, p. 13745 - 13751 (2021/11/17)
Aldehyde decarbonylation has been extensively investigated, primarily using noble-metal catalysts; however, nonprecious-base-metal-catalyzed aldehyde decarbonylation has been hardly reported. We have established an efficient selective aldehyde decarbonylation reaction with a broad substrate scope and functional group tolerance utilizing a heterogeneous Ni(0) nanospecies catalyst supported on CeO2. The high catalytic performance is attributable to the highly dispersed and non-electron-rich Ni(0) nanospecies, which possibly suppress a side reaction producing esters and adsorbed CO-derived inhibition of the catalytic turnover, according to detailed catalyst characterization and kinetic evaluation.
Iodine-Mediated Synthesis of 2-(Methylthio)-4 H-chromen-4-ones and Study of Their Halogenation Reactions
Elagamy, Amr,Pratap, Ramendra,Shah, Chandan,Shaw, Ranjay
, p. 9478 - 9489 (2021/07/28)
An efficient iodine-mediated method is developed for the synthesis of functionalized 2-(methylthio)-4H-chromen-4-ones by intramolecular cyclization of easily accessible 1-(2-benzyloxy-aryl)-3,3-bis-methylsulfanyl-propenones. The synthesized chromen-4-ones turn out to be a key precursor for various kinds of chemical reactions. Mechanistically, we observed that iodine-mediated intramolecular cyclization of ketene dithioacetal proceeded through a radical pathway. 3-Halo-2-(methylthio)-4H-chromen-4-ones were achieved via various two- or one-pot halogenation approaches.
Synthetic method and application of indolizine compounds
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Paragraph 0034-0037, (2020/11/26)
A synthetic method of the indolizine compound comprises the following steps: mixing a benzopyrone derivative, a bromopyridinium salt derivative, alkali and a solvent in a 10ml round-bottom flask, andstirring the mixture for 2-48 hours at the temperature of 25 DEG C and 100 DEG C; after the reaction is finished, purifying the crude product through silica gel chromatography to obtain a target compound with a structural formula shown as the formula I.
