- A General Organocatalytic System for Electron Donor-Acceptor Complex Photoactivation and Its Use in Radical Processes
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We report herein a modular class of organic catalysts that, acting as donors, can readily form photoactive electron donor-acceptor (EDA) complexes with a variety of radical precursors. Excitation with visible light generates open-shell intermediates under mild conditions, including nonstabilized carbon radicals and nitrogen-centered radicals. The modular nature of the commercially available xanthogenate and dithiocarbamate anion organocatalysts offers a versatile EDA complex catalytic platform for developing mechanistically distinct radical reactions, encompassing redox-neutral and net-reductive processes. Mechanistic investigations, by means of quantum yield determination, established that a closed catalytic cycle is operational for all of the developed radical processes, highlighting the ability of the organic catalysts to turn over and iteratively drive every catalytic cycle. We also demonstrate how the catalysts' stability and the method's high functional group tolerance could be advantageous for the direct radical functionalization of abundant functional groups, including aliphatic carboxylic acids and amines, and for applications in the late-stage elaboration of biorelevant compounds and enantioselective radical catalysis.
- De Pedro Beato, Eduardo,Melchiorre, Paolo,Spinnato, Davide,Zhou, Wei
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supporting information
p. 12304 - 12314
(2021/08/20)
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- A Facile Direct Route to N-(Un)substituted Lactams by Cycloamination of Oxocarboxylic Acids without External Hydrogen
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Lactams are privileged in bioactive natural products and pharmaceutical agents and widely featured in functional materials. This study presents a novel versatile approach to the direct synthesis of lactams from oxocarboxylic acids without catalyst or external hydrogen. The method involves the in situ release of formic acid from formamides induced by water to facilitate efficient cycloamination. Water also suppresses the formation of byproducts. This unconventional pathway is elucidated by a combination of model experiments and density functional theory calculations, whereby cyclic imines (5-methyl-3,4-dihydro-2-pyrrolone and its tautomeric structures) are found to be favorable intermediates toward lactam formation, in contrast to the conventional approach encompassing cascade reductive amination and cyclization. This sustainable and simple protocol is broadly applicable for the efficient production of various N-unsubstituted and N-substituted lactams.
- Li, Hu,Wu, Hongguo,Zhang, Heng,Su, Yaqiong,Yang, Song,Hensen, Emiel J. M.
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p. 3778 - 3784
(2019/08/07)
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- Raney-Ni catalyzed conversion of levulinic acid to 5-methyl-2-pyrrolidone using ammonium formate as the H and N source
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Renewable biomass based levulinic acid was converted to 5-methyl-2-pyrrolidone in 94% yield by a Raney-Ni catalyzed process using ammonium formate in aqueous medium and heating at 180 °C for 3 h. The Raney-Ni could be reused for four catalytic cycles with about 10% loss in catalytic activity. In a similar reaction levulinic acid could be converted 1-substituted-5-methyl-2-pyrrolidones in 90–95% yield by using a mixture of formic acid and the corresponding primary amine.
- Amarasekara, Ananda S.,Lawrence, Yen Maroney
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supporting information
p. 1832 - 1835
(2018/04/11)
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- Visible-Light-Mediated Synthesis of Amidyl Radicals: Transition-Metal-Free Hydroamination and N-Arylation Reactions
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The development of photoredox reactions of aryloxy-amides for the generation of amidyl radicals and their use in hydroamination-cyclization and N-arylation reactions is reported. Owing to the ease of single-electron-transfer reduction of the aryloxy-amides, the organic dye eosin Y was used as the photoredox catalyst, which results in fully transition-metal-free processes. These transformations exhibit a broad scope, are tolerant to several important functionalities, and have been used in the late-stage modification of complex and high-value N-containing molecules.
- Davies, Jacob,Svejstrup, Thomas D.,Fernandez Reina, Daniel,Sheikh, Nadeem S.,Leonori, Daniele
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p. 8092 - 8095
(2016/07/16)
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- Palladium-catalyzed C - O hydrogenolysis in γ-hydroxy γ-lactams as an efficient approach to 5-alkyl(aryl)pyrrolidin-2-ones
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5-R-Pyrrolidin-2-ones were synthesized by Pd/Sibunit-catalyzed C - O hydrogenolysis of 5-R-5-hydroxypyrrolidin-2-ones with molecular hydrogen.
- Turova,Berezhnaya,Starodubtseva,Ferapontov,Vinogradov
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p. 859 - 863
(2015/12/24)
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- Ruthenium-catalyzed conversion of levulinic acid to pyrrolidines by reductive amination
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Combo deal: An aqueous solution of levulinic acid (LA) and formic acid (FA) derived from biomass-based carbohydrates can be converted efficiently to pyrrolidines via a ruthenium catalyst without need for an energy-intensive separation of LA or an external H2 source. The ruthenium catalyst combines two processes: decomposition of FA to H2 and reductive amination of LA with an amine. Copyright
- Huang, Yao-Bing,Dai, Jian-Jun,Deng, Xiao-Jian,Qu, Yan-Chao,Guo, Qing-Xiang,Fu, Yao
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experimental part
p. 1578 - 1581
(2012/03/22)
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- Process for converting alpha-angelica lactone to 5-methyl-N-alkyl-2-pyrrolidone using alkyl amines
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This invention relates to a process for producing 5-methyl-N-alkyl-2-pyrrolidone by a) reacting α-angelica lactone with alkyl amines and b) hydrogenating the products of step (a) in the presence of a metal catalyst, which is optionally supported.
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Page/Page column 4
(2008/06/13)
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- Production of 5-methyl-1-hydrocarbyl-2-pyrrolidone by reductive amination of levulinic acid
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This invention relates to a process for producing 5-methyl-1-R-2-pyrrolidone or 5-methyl-2-pyrrolidone, wherein R is a hydrocarbyl or substituted hydrocarbyl, by reductive amination of levulinic acid utilizing a metal catalyst, which may be optionally supported.
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- SUBSTITUTION OF 3H-FURAN-2-ONES IN AMINATION AND HYDROAMINATION REACTIONS
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The amination and hydroamination of 5-alkyl-3H-furan-2-ones and their 3-benzylidene- and 3-formyl-derivatives were studied.The characteristics of the reactions, the requirements for the nature of the nucleophilic reagents, and the reaction conditions leading to the destruction of the furan ring and recyclization to pyrrolidinone and pyrrolinone structures are indicated.
- Morozova, N. A.,Sedavkina, V. A.,Egorova, A. Yu.
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p. 308 - 311
(2007/10/02)
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- Cosmetic composition
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A composition suitable for topical application to mammalian skin or hair for inducing, maintaining or increasing hair growth comprises: (i) a first chemical inhibitor chosen from proteoglycanase inhibitors, glycosaminoglycanase inhibitors, glycosaminoglycan chain cellular uptake inhibitors or mixtures thereof; and (ii) a cosmetically acceptable vehicle for the chemical inhibitor; provided that when the first chemical inhibitor is a weak inhibitor, such that a 1 mM aqueous solution of the inhibitor reduces proteoglycanase activity, glycosaminoglycanase activity or cellular uptake of glycosaminoglycan chains, by from 5 to 50%, in accordance with at least one of the assay tests as herein described, then there is also present in the composition a second chemical inhibitor and/or an activity enhancer. When minoxidil is the sole chemical inhibitor, then the activity enhancer is a penetration enhancer chosen from a limited number of materials, including certain esters and cationic polymers. The total amount of chemical inhibitor present in the composition is sufficient to increase hair growth in the rat, when said composition is applied topically thereto, by at least 10% more than that obtainable using a control composition from which the said inhibitors have been omitted.
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- An Investigation of the Intramolecular Ene Reaction of N-Acyl Imines
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N-Acyl imines, produced by the flash vacuum thermolysis of hydroxamic acid derivatives, participate in the intramolecular ene reaction to give nitrogen heterocycles.The reaction is accelerated by carboxyl substituents on the carbon atom of the N-acyl imine, and the reaction is more succesful for the production of pyrrolidine rather than piperidine derivatives.
- Lin, Jyh-Ming,Koch, Kevin,Fowler, Frank W.
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p. 167 - 174
(2007/10/02)
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- THE INTRAMOLECULAR ENE REACTION OF CARBON-NITROGEN DOUBLE BONDS
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Acyl imines, prepared from hydroxyl amine derivatives, have been observed to undergo the intramolecular ene reaction producing nitrogen heterocycles.
- Koch, Kevin,Lin, Jyh-Ming,Fowler, Frank W.
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p. 1581 - 1584
(2007/10/02)
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