- A Sustainable Synthesis of Asymmetric Phenazines and Phenoxazinones Mediated by CotA-Laccase
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An efficient and sustainable one-step procedure for the synthesis of new asymmetric phenazines and phenoxazinones from commercially available ortho-substituted diamines and ortho-substituted hydroxyamines is reported. In this study we have expanded the substrate scope of CotA-laccase-catalyzed aerobic oxidations through the use of aromatic amines presenting variable functional groups, including N-substitution, contributing to the rational synthesis of different heterocyclic scaffolds. The transformations proceed smoothly through a cascade of oxidative reactions to the benzoquinonediimine intermediates followed by nucleophilic addition, intramolecular cyclization and aromatization, all performed in mild conditions. (Figure presented.).
- Sousa, Ana Catarina,Concei??o Oliveira,Martins, Lígia O.,Robalo, M. Paula
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- Visible-light-mediated synthesis of substituted phenazine and phenoxazinone using eosin y as a photoredox catalyst
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This paper describes an efficient, sustainable, one-step procedure for synthesizing substituted phenazines and phenoxazinones from commercially available ortho-substituted aromatic amines with very good yield (≥80%) in water. The procedure uses eosin Y (EY) as a photoredox catalyst at room temperature (RT). The highly reactive o-quinone-diimine or o-quinone-imine intermediate was characterized by the HR-MS technique.
- Dhar, Basab Bijayi,Dhara, Ashish Kumar,Maity, Sayantan
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p. 3269 - 3273
(2021/05/31)
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- TEMPO-catalyzed electrochemical dehydrogenative cyclocondensation of: O -aminophenols: Synthesis of aminophenoxazinones as antiproliferative agents
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The aminophenoxazinone core is widely prevalent in natural products, dyes and pharmaceutical molecules. We report here a TEMPO-catalyzed electrosynthetic method allowing the dehydrogenative cyclocondensation of o-aminophenols. This mild and sustainable method proceeds in the absence of stoichiometric oxidants and uses an easily available organo-electrocatalyst to access pharmaceutically valuable 2-aminophenoxazinones. Mechanistic studies indicate that the electrochemically generated TEMPO+ enables the oxidative radical homo-dimerization of o-aminophenols. The application of electrosynthesis provides an approach for the synthesis of pseudo-aminophenoxazinone alkaloids with improved structural diversification and bioactivities. This journal is
- Cai, Yun-Rui,Ji, Su-Hui,Ma, Zhi-Yuan,Shonhe, Chantale,Zhou, Jianmin
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p. 8566 - 8570
(2021/11/17)
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- Optimization of the clofazimine structure leads to a highly water-soluble C3-aminopyridinyl riminophenazine endowed with improved anti-Wnt and anti-cancer activity in vitro and in vivo
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Triple-negative breast cancer (TNBC) is a cancer subtype critically dependent upon excessive activation of Wnt pathway. The anti-mycobacterial drug clofazimine is an efficient inhibitor of canonical Wnt signaling in TNBC, reducing tumor cell proliferation
- Koval, Alexey,Bassanini, Ivan,Xu, Jiabin,Tonelli, Michele,Boido, Vito,Sparatore, Fabio,Amant, Frederic,Annibali, Daniela,Leucci, Eleonora,Sparatore, Anna,Katanaev, Vladimir L.
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- Waste minimized synthesis of pharmaceutically active compounds: Via heterogeneous manganese catalysed C-H oxidation in flow
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Herein, we present our results on the development of a continuous flow protocol enabling the waste minimised synthesis of relevant pharmaceuticals and natural compounds. Heterogeneous manganese catalytic systems have been used in combination with molecular oxygen to promote the C-H oxidative coupling of 2-aminophenols, benzenetriols and o-phenylenediamines to access a variety of 2-aminophenoxazin-3-ones (2a-i) and related diaminophenazines (2j-k) and purpurogallin (2l) with minimal metal contamination. Making use of safe and green cyclopentyl methyl ether (CPME), this methodology allowed a fast synthesis of fully decorated molecular entities, preserving the stability of the heterogeneous catalyst which showed minimal metal leaching, with minimal waste production (low E-factor).
- Ferlin, Francesco,Luque Navarro, Pilar María,Gu, Yanlong,Lanari, Daniela,Vaccaro, Luigi
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p. 397 - 403
(2020/02/13)
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