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Lookup NU author(s): Dr Paul Waddell, Professor Andrew Benniston
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2024 Wiley-VCH GmbH. The reaction of 7-phenylbenzo[a]phenazine-5(7H)-one (rosindone) with one equivalent of a nitrating mixture (conc. H2SO4/HNO3) produced 6-nitro-7-phenylbenzo[a]phenazine-5(7H)-one (NROS), as confirmed by 1H NMR spectroscopy. The selectivity of the reaction is assigned to an electronic effect. The attempted sulphonation of rosindone with chlorosulfonic acid produced the chlorinated derivative 6-chloro-7-phenylbenzo[a]phenazine-5(7H)-one (CLROS), instead but in low yield. The nitro group of NROS was reduced with SnCl2 to produce a blue solid identified as 6-amino-7-phenylbenzo[a]phenazine-5(7H)-one (AMROS). The X-ray crystal structure confirmed the positioning of the amino group α to the carbonyl group. The reaction of rosindone with one equivalent of lithium trimethylsilylacetylide underwent a Michael addition to introduce the nucleophile β to the carbonyl group. The compound 6a-ethynyl-6a,7-dihydrobenzo[a]phenazine-5(6H)-one (rac-ACROS) was identified by an X-ray crystal structure determination. Coupling of rac-ACROS under standard Glazer conditions produced the dyad of the compound linked via the two ethynyl subunits. A different N-phenyl group was readily introduced into the rosindone basic structure by the reaction of methyl 2-((2-aminophenyl)amino)benzoate with 2-hydroxy-1,4-naphthoquinone to produce methyl 2-(5-oxobenzo[a]phenazine-7(5H)-yl)benzoate (MROS).
Author(s): Clarke B, Wales R, Oates J, Waddell PG, Benniston AC
Publication type: Article
Publication status: Published
Journal: ChemistrySelect
Year: 2024
Volume: 9
Issue: 43
Print publication date: 15/11/2024
Online publication date: 14/11/2024
Acceptance date: 04/11/2024
Date deposited: 22/11/2024
ISSN (electronic): 2365-6549
Publisher: John Wiley and Sons Inc.
URL: https://doi.org/10.1002/slct.202403989
DOI: 10.1002/slct.202403989
ePrints DOI: 10.57711/p02v-w551
Data Access Statement: The data that support the findings of this study are available in the Supporting Information of this article.
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