- Supporting-Electrolyte-Free Anodic Oxidation of Oxamic Acids into Isocyanates: An Expedient Way to Access Ureas, Carbamates, and Thiocarbamates
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We report a new electrochemical supporting-electrolyte-free method for synthesizing ureas, carbamates, and thiocarbamates via the oxidation of oxamic acids. This simple, practical, and phosgene-free route includes the generation of an isocyanate intermediate in situ via anodic decarboxylation of an oxamic acid in the presence of an organic base, followed by the one-pot addition of suitable nucleophiles to afford the corresponding ureas, carbamates, and thiocarbamates. This procedure is applicable to different amines, alcohols, and thiols. Furthermore, when single-pass continuous electrochemical flow conditions were used and this reaction was run in a carbon graphite Cgr/Cgr flow cell, urea compounds could be obtained in high yields within a residence time of 6 min, unlocking access to substrates that were inaccessible under batch conditions while being easily scalable.
- Petti, Alessia,Fagnan, Corentin,van Melis, Carlo G. W.,Tanbouza, Nour,Garcia, Anthony D.,Mastrodonato, Andrea,Leech, Matthew C.,Goodall, Iain C. A.,Dobbs, Adrian P.,Ollevier, Thierry,Lam, Kevin
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p. 2614 - 2621
(2021/06/27)
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- Direct C3 Carbamoylation of 2H-Indazoles
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We developed a novel method for direct C3 carbamoylation of 2H-indazoles using oxamic acids as carbamoyl radical sources. In the presence of ammonium persulfate, carbamoyl radicals were generated from oxamic acids, then used for further reactions with 2H-indazoles to afford the desired products. The reaction proceeds under metal- and catalyst-free conditions. This simple process allows for the efficient synthesis of C3 carbamoylated 2H-indazoles, which are important scaffolds in organic synthesis.
- Bhat, Vighneshwar Shridhar,Lee, Anna
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supporting information
p. 3382 - 3385
(2021/06/28)
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- Urethanes synthesis from oxamic acids under electrochemical conditions
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Urethane synthesis via oxidative decarboxylation of oxamic acids under mild electrochemical conditions is reported. This simple phosgene-free route to urethanes involves an in situ generation of isocyanates by anodic oxidation of oxamic acids in an alcoholic medium. The reaction is applicable to a wide range of oxamic acids, including chiral ones, and alcohols furnishing the desired urethanes in a one-pot process without the use of a chemical oxidant.
- Ogbu, Ikechukwu Martin,Lusseau, Jonathan,Kurtay, Gülbin,Robert, Frédéric,Landais, Yannick
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supporting information
p. 12226 - 12229
(2020/10/26)
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- Visible-light mediated carbamoyl radical addition to heteroarenes
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The generation of carbamoyl radicals, followed by their addition to heteroarenes, was performed under mild conditions through a metal-free photocatalyzed decarboxylation of oxamic acids. The process has been applied to the carbamoylation of heteroaromatic bases using α-aminoacid-derived oxamic acids, leading to the corresponding amides without racemization.
- Jatoi, Ashique Hussain,Pawar, Govind Goroba,Robert, Frédéric,Landais, Yannick
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p. 466 - 469
(2019/01/10)
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- Metal-, Photocatalyst-, and Light-Free Direct C-H Acylation and Carbamoylation of Heterocycles
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Direct C-H acylations and carbamoylations of heterocycles can now be readily achieved without requiring any conventional metal, photocatalyst, electrocatalysis, or light activation, thus significantly improving on sustainability, costs, toxicity, waste, and simplicity of the operational procedure. These mild conditions are also suitable for gram-scale reactions and late-stage functionalizations of complex molecules, including pharmaceuticals, N,N-ligands, and light-sensitive molecules.
- Westwood, Matthew T.,Lamb, Claire J. C.,Sutherland, Daniel R.,Lee, Ai-Lan
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p. 7119 - 7123
(2019/09/03)
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- Visible-light photocatalyzed oxidative decarboxylation of oxamic acids: a green route to urethanes and ureas
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A sustainable metal-free route to urethanes and ureas based on a photocatalyzed oxidative decarboxylation of oxamic acids is described. The reaction includes in situ generation of an isocyanate from the oxamic acid, using an organic dye as a photocatalyst, a hypervalent iodine reagent as an oxidant and a light source, which trigger the free-radical decarboxylation. This protocol successfully avoids the isolation, purification and storage of carcinogenic isocyanates and allows elaboration of urethanes and ureas in a one-pot process from commercially available sources.
- Pawar, Govind Goroba,Robert, Frédéric,Grau, Etienne,Cramail, Henri,Landais, Yannick
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supporting information
p. 9337 - 9340
(2018/08/31)
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- Synthesis, crystal structure, and insecticidal activity of novel N-alkyloxyoxalyl derivatives of 2-arylpyrrole
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Two series of novel N-alkyloxyoxalyl derivatives of 2-arylpyrrole were synthesized, and their structures were characterized by 1H NMR spectroscopy, elemental analysis, and single-crystal X-ray diffraction analysis. The insecticidal activities of the new compounds were evaluated. The results of bioassays indicated that some of these title compounds exhibited excellent insecticidal activities, and their insecticidal activities against oriental armyworm, mosquito, and spider mite are comparable to those of the commercialized Chlorfenapyr.
- Zhao, Yu,Mao, Chunhui,Li, Yongqiang,Zhang, Pengxiang,Huang, Zhiqiang,Bi, Fuchun,Huang, Runqiu,Wang, Qingmin
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experimental part
p. 7326 - 7332
(2010/06/11)
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- First-in-class pan caspase inhibitor developed for the treatment of liver disease
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A series of oxamyl dipeptides were optimized for pan caspase inhibition, anti-apoptotic cellular activity and in vivo efficacy. This structure-activity relationship study focused on the P4 oxamides and warhead moieties. Primarily on the basis of in vitro data, inhibitors were selected for study in a murine model of α-Fas-induced liver injury. IDN-6556 (1) was further profiled in additional in vivo models and pharmacokinetic studies. This first-in-class caspase inhibitor is now the subject of two Phase II clinical trials, evaluating its safety and efficacy for use in liver disease.
- Linton, Steven D.,Aja, Teresa,Armstrong, Robert A.,Bai, Xu,Chen, Long-Shiuh,Chen, Ning,Ching, Brett,Contreras, Patricia,Diaz, Jose-Luis,Fisher, Craig D.,Fritz, Lawrence C.,Gladstone, Patricia,Groessl, Todd,Gu, Xin,Herrmann, Julia,Hirakawa, Brad P.,Hoglen, Niel C.,Jahangiri, Kathy G.,Kalish, Vincent J.,Karanewsky, Donald S.,Kodandapani, Lalitha,Krebs, Joseph,McQuiston, Jeff,Meduna, Steven P.,Nalley, Kip,Robinson, Edward D.,Sayers, Robert O.,Sebring, Kristen,Spada, Alfred P.,Ternansky, Robert J.,Tomaselli, Kevin J.,Ullman, Brett R.,Valentino, Karen L.,Weeks, Suzanne,Winn, David,Wu, Joe C.,Yeo, Pauline,Zhang, Cheng-Zhi
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p. 6779 - 6782
(2007/10/03)
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- Oxamyl dipeptide caspase inhibitors developed for the treatment of stroke
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Structural modifications were made to a previously described acyl dipeptide caspase inhibitor, leading to the oxamyl dipeptide series. Subsequent SAR studies directed toward the warhead, P2, and P4 regions of this novel peptidomimetic are described herein.
- Linton, Steven D.,Aja, Teresa,Allegrini, Peter R.,Deckwerth, Thomas L.,Diaz, Jose-Luis,Hengerer, Bastian,Herrmann, Julia,Jahangiri, Kathy G.,Kallen, Joerg,Karanewsky, Donald S.,Meduna, Steven P.,Nalley, Kip,Robinson, Edward D.,Roggo, Silvio,Rovelli, Giorgio,Sauter, Andre,Sayers, Robert O.,Schmitz, Albert,Smidt, Robert,Ternansky, Robert J.,Tomaselli, Kevin J.,Ullman, Brett R.,Wiessner, Christoph,Wu, Joe C.
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p. 2685 - 2691
(2007/10/03)
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- Reactivity of Carbamoyl Radicals. A New, General, Convenient Free-Radical Synthesis of Isocyanates from Monoamides of Oxalic Acid
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A new, general, simple synthesis of isocyanates was developed by oxidation of monoamides of oxalix acid with peroxydisulfate catalyzed by Ag and Cu salts.The reaction was carried out in a two-phase system (water and an organic solvent), and it is suitable also for practical applications, due to the simple experimental conditions and the inexpensive as well as nontoxic reagents.The first example of homolytic intramolecular aromatic carbamoylation is also reported.
- Minisci, Francesco,Fontana, Francesca,Coppa, Fausta,Yan, Yong Ming
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p. 5430 - 5433
(2007/10/02)
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- A FACILE, CONVENIENT AND SELECTIVE HOMOLYTIC CARBAMOYLATION OF HETEROAROMATIC BASES
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The oxidative decarboxylation of monoamides of oxalic acid provides carbamoyl radicals, which are useful for the selective carbamoylation of protonated heteroaromatic bases; this reaction represents the first general and selective method for the N-alkyl or N-arylcarbamoylation of heteroaromatic bases.Compared to alkoxycarbonylation, this reaction is much more effective and selective, owing to more favourable polar and enthalpic effects.The importance of the steric effects is also emphasized.
- Coppa, Fausta,Fontana, Francesca,Lazzarini, Edoardo,Minisci, Francesco
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p. 2687 - 2696
(2007/10/02)
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