Recent advancement in the synthesis of phenoxazine derivatives and their analogues

Shruti, .; Dwivedi, Jaya; Kishore, Dharma; Sain, Shalu

doi:10.1080/00397911.2018.1448090

Cited by 14 publications

(6 citation statements)

References 27 publications

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“…Simple 2-aminophenoxazin-3-ones and 3-aminophenoxazin-2-one exhibit antitumor, antimicrobial, and antiviral activity in vitro and in vivo [ 75 , 102 , 103 , 104 , 105 ]. Due to their importance, a variety of synthetic procedures has been described [ 106 , 107 ].…”

Section: Application Of Laccases In Bio-oxidative Synthesis Of Heterocyclic Compoundsmentioning

confidence: 99%

Laccases: Versatile Biocatalysts for the Synthesis of Heterocyclic Cores

2021

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Laccases are multicopper oxidases that have shown a great potential in various biotechnological and green chemistry processes mainly due to their high relative non-specific oxidation of phenols, arylamines and some inorganic metals, and their high redox potentials that can span from 500 to 800 mV vs. SHE. Other advantages of laccases include the use of readily available oxygen as a second substrate, the formation of water as a side-product and no requirement for cofactors. Importantly, addition of low-molecular-weight redox mediators that act as electron shuttles, promoting the oxidation of complex bulky substrates and/or of higher redox potential than the enzymes themselves, can further expand their substrate scope, in the so-called laccase-mediated systems (LMS). Laccase bioprocesses can be designed for efficiency at both acidic and basic conditions since it is known that fungal and bacterial laccases exhibit distinct optimal pH values for the similar phenolic and aromatic amines. This review covers studies on the synthesis of five- and six-membered ring heterocyclic cores, such as benzimidazoles, benzofurans, benzothiazoles, quinazoline and quinazolinone, phenazine, phenoxazine, phenoxazinone and phenothiazine derivatives. The enzymes used and the reaction protocols are briefly outlined, and the mechanistic pathways described.

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Section: Application Of Laccases In Bio-oxidative Synthesis Of Heterocyclic Compoundsmentioning

confidence: 99%

Laccases: Versatile Biocatalysts for the Synthesis of Heterocyclic Cores

2021

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“…Not only have the structures shown potent anticancer, − antimalaria, antibiotic, , and antifungal activities, but also they have been widely applied as dyes and pigments due to their intense colors. − While the unsubstituted ring system is not particularly fluorescent, this situation may be drastically altered by the addition of substituents that can donate or accept electron density . A selection of such dyes based on the benzo[ a ]phenoxazine core have been reported in the literature; , the most notable ones being Meldola’s blue, Nile Blue, and Nile Red (Scheme a). These bear dialkylamino groups at the 9-position that are vital to their luminescence by donating electron density into the π ring system.…”

Section: Introductionmentioning

confidence: 99%

Substituted 9-Diethylaminobenzo[a]phenoxazin-5-ones (Nile Red Analogues): Synthesis and Photophysical Properties

et al. 2020

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Nile Red is a benzo[a]phenoxazone dye containing a diethylamino substituent at the 9-position. In recent years, it has become a popular histological stain for cellular membranes and lipid droplets due to its unrivaled fluorescent properties in lipophilic environments. This makes it an attractive lead for chemical decoration to tweak its attributes and optimize it for more specialized microscopy techniques, e.g., fluorescence lifetime imaging or two-photon excited fluorescence microscopy, to which Nile Red has never been optimized. Herein, we present synthesis approaches to a series of monosubstituted Nile Red derivatives (9-diethylbenzo[a]phenoxazin-5-ones) starting from 1-naphthols or 1,3-naphthalenediols. The solvatochromic responsiveness of these fluorophores is reported with focus on how the substituents affect the absorption and emission spectra, luminosity, fluorescence lifetimes, and two-photon absorptivity. Several of the analogues emerge as strong candidates for reporting the polarity of their local environment. Specifically, the one- and two-photon excited fluorescence of Nile Red turns out to be very responsive to substitution, and the spectroscopic features can be finely tuned by judiciously introducing substituents of distinct electronic character at specific positions. This new toolkit of 9-diethylbenzo[a]phenoxazine-5-ones constitutes a step toward the next generation of optical molecular probes for advancing the understanding of lipid structures and cellular processes.

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“…They are also useful precursors for the manufacturing of pharmaceuticals ( Cholo et al, 2012 ), fine chemicals ( Forte et al, 2010 ; Morel and Christie, 2011 ), and biosensors ( Piro et al, 2013 ). Furthermore, synthetic chemical approaches for the synthesis of these heteroaromatic compounds use stoichiometric amounts of chemicals, strong acids, and high temperatures and result in low production yields ( Shruti et al, 2018 ). In order to set up not only environment-friendly but also cost-effective processes, we performed dye conversion assays using free and immobilised whole-cell systems that overproduced the enzymes of interest.…”

Section: Resultsmentioning

confidence: 99%

Wasteful Azo Dyes as a Source of Biologically Active Building Blocks

Fernándes

Pinto

Bonardo

et al. 2021

Front. Bioeng. Biotechnol.

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In this work, an environment-friendly enzymatic strategy was developed for the valorisation of dye-containing wastewaters. We set up biocatalytic processes for the conversion of azo dyes representative of the main classes used in the textile industry into valuable aromatic compounds: aromatic amines, phenoxazinones, phenazines, and naphthoquinones. First, purified preparations of PpAzoR azoreductase efficiently reduced mordant, acid, reactive, and direct azo dyes into aromatic amines, and CotA-laccase oxidised these compounds into phenazines, phenoxazinones, and naphthoquinones. Second, whole cells containing the overproduced enzymes were utilised in the two-step enzymatic conversion of the model mordant black 9 dye into sodium 2-amino-3-oxo-3H-phenoxazine-8-sulphonate, allowing to overcome the drawbacks associated with the use of expensive purified enzymes, co-factors, or exquisite reaction conditions. Third, cells immobilised in sodium alginate allowed recycling the biocatalysts and achieving very good to excellent final phenoxazine product yields (up to 80%) in water and with less impurities in the final reaction mixtures. Finally, one-pot systems using recycled immobilised cells co-producing both enzymes resulted in the highest phenoxazinone yields (90%) through the sequential use of static and stirring conditions, controlling the oxygenation of reaction mixtures and the successive activity of azoreductase (anaerobic) and laccase (aerobic).

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Recent advancement in the synthesis of phenoxazine derivatives and their analogues

Cited by 14 publications

References 27 publications

Laccases: Versatile Biocatalysts for the Synthesis of Heterocyclic Cores

Laccases: Versatile Biocatalysts for the Synthesis of Heterocyclic Cores

Substituted 9-Diethylaminobenzo[a]phenoxazin-5-ones (Nile Red Analogues): Synthesis and Photophysical Properties

Wasteful Azo Dyes as a Source of Biologically Active Building Blocks

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