580-22-3Relevant articles and documents
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Tsuchiya et al.
, p. 1856,1860 (1977)
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Luthy et al.
, p. 322,325, 326 (1949)
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Site-Selective Deoxygenative Amination of Azine N-Oxides with Carbodiimides under Catalyst-, Activator-, Base-, and Solvent-Free Conditions
Sarmah, Bikash Kumar,Konwar, Monuranjan,Das, Animesh
, p. 10762 - 10772 (2021/07/31)
An operationally simple method for synthesizing 2-amino azines via [3+2] dipolar cycloaddition of azine N-oxide with carbodiimide has been demonstrated. The reaction can proceed smoothly under simple heating conditions without any transition metal catalyst, activator, base, and solvent. This transformation demonstrates a broad substrate scope and produces CO2 as the only co-product. The applicability of this method is highlighted by the late-stage modification of bioactive molecules, including quinine, (±)-α-tocopherol, and tryptamine modified quinoline.
Catalyst-free synthesis of substituted pyridin-2-yl, quinolin-2-yl, and isoquinolin-1-yl carbamates from the corresponding hetaryl ureas and alcohols
Baykov, Sergey V.,Boyarskaya, Irina A.,Boyarskiy, Vadim P.,Geyl, Kirill K.,Kasatkina, Svetlana O.
, p. 6059 - 6065 (2021/07/21)
A novel catalyst-free synthesis ofN-pyridin-2-yl,N-quinolin-2-yl, andN-isoquinolin-1-yl carbamates utilizes easily accessibleN-hetaryl ureas and alcohols. The proposed environmentally friendly technique is suitable for the good-to-high yielding synthesis of a wide range ofN-pyridin-2-yl orN-quinolin-2-yl substituted carbamates featuring electron-donating and electron-withdrawing groups in the azine rings and containing various primary, secondary, and even tertiary alkyl substituents at the oxygen atom (48-94%; 31 examples). The DFT calculation and experimental study showed that the reaction proceeds through the intermediate formation of hetaryl isocyanates. The method can be applied to obtainN-isoquinolin-1-yl carbamates, although in lower yields, and ethyl benzo[h]quinolin-2-yl carbamate has also been successfully synthesized (68%).
Reaction of Pyridine-N-Oxides with Tertiary sp2-N-Nucleophiles: An Efficient Synthesis of Precursors for N-(Pyrid-2-yl)-Substituted N-Heterocyclic Carbenes
Bugaenko, Dmitry I.,Karchava, Alexander V.,Yurovskaya, Marina A.
, p. 5777 - 5782 (2020/12/01)
N-(Pyrid-2-yl)-substituted azolium and pyridinium salts, precursors for hybrid NHC-containing ligands, were obtained with excellent regioselectivity, employing a deoxygenative CH-functionalization of pyridine-N-oxides with substituted imidazoles, thiazoles, and pyridine. Unlike the traditional SNAr-based methods, this approach provides high yields for substrates bearing substituents of different electronic nature. The utility of azolium and pyridinium salts thus prepared was also highlighted by the synthesis of pyridyl-substituted imidazolyl-2-thione, benzodiazepine as well as 2-aminopyridines.
