- Selective, Catalytic, and Dual C(sp3)-H Oxidation of Piperazines and Morpholines under Transition-Metal-Free Conditions
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By using cheap and innocuous reagents, such as NaClO2, NaOCl, and catalytic amounts of TEMPO, a new environmentally friendly protocol for the selective and catalytic TEMPO C(sp3)-H oxidation of piperazines and morpholines to 2,3-diketopiperazines (2,3-DKP) and 3-morpholinones (3-MPs), respectively, has been developed. This novel direct access to 2,3-DKP from piperazines provides significant advantages over the traditional N-monoacylation/intramolecular C-N cyclization procedure. Additionally, by modulating the amounts of TEMPO, 2-alkoxyamino-3-morpholinone can be prepared from morpholine derivatives, which would enable further functionalization at the C2 position of the morpholine skeleton.
- Chamorro-Arenas, Delfino,Osorio-Nieto, Urbano,Quintero, Leticia,Hernández-García, Luís,Sartillo-Piscil, Fernando
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p. 15333 - 15346
(2019/01/03)
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- Efficient synthesis of unsymmetrical 1,4-disubstituted-2,3-diketopiperazines via tandem reductive amination-cyclization
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Herein we report the efficient syntheses of 1,4-disubstituted-2,3-diketopiperazines and 1,4,5-trisubstituted-2,3-diketopiperazines, which feature a tandem reductive amination and acylation. Aliphatic and aromatic primary amines serve as viable nucleophiles under the mild reaction conditions. (C) 2000 Elsevier Science Ltd.
- Beshore,Dinsmore
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p. 8735 - 8739
(2007/10/03)
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