A novel Friedel–Crafts alkylation of naphthols without Lewis acid

Zhu, Yao; Lin, Kwei-Jay; Ye, Deyong; Zhou, Weicheng

doi:10.1016/j.tetlet.2015.07.024

Cited by 8 publications

(1 citation statement)

References 12 publications

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“…However, upon coupling 1,3-naphthalenediol with N , N -diethyl- p -nitrosoaniline (route B), we noticed remarkably improved reactivity, chemoselectivity, and isolated yield of Nile Red (80% yield). We attribute this to the presumed increase in the nucleophilicity of C-4 in 1,3-naphthalenediol relative to 1-naphthol , and possibly the increased electrophilicity of the nitroso group in the absence of the hydroxyl group. The high yield also implies that the reaction uses ambient air for the oxidative cyclization rather than consuming the nitroso material.…”

Section: Resultsmentioning

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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Section: Resultsmentioning

confidence: 99%

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

et al. 2020

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Aromatic Substitution

Crampton¹

2019

Organic Reaction Mechanisms Series

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Durch sichtbares Licht vermittelte Synthese von β‐Chlorketonen aus Arylcyclopropanen

et al. 2019

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In diesem Beitrag berichten wir über die durch sichtbares Lichtv ermittelte Synthese von b-Chlorketonen aus Arylcyclopropanen, Sauerstoff,S alzsäure und Salpetersäure. Die katalysatorfreie Methode verwendet preisgünstige Standard-Laborreagenzien und toleriert viele verschiedene funktionelle Gruppen. Darüber hinaus ist die Maßstabsvergrçßerung der Reaktion und die späte Funktionalisierung von bioaktiven Verbindungen mçglich, wodurchder Cyclopropanring als maskiertes b-Chlorketon in einer Reaktionssequenz verwendet werden kann. Als Mechanismus schlagen wir eine lichtgetriebene Radikalkette vor,d ie durch die Reaktion von verdünnter Salzsäure und Salpetersäure zu elementarem Chlor ausgelçst wird.Die mechanistische Hypothese wird durch 18 O-Markierungs-und UV/Vis-Experimente sowiec yclovoltammetrische Messungen und diverse Kontrollreaktionen gestützt. KB.C4, Linnaeus väg10, 901 87 Umeå (Schweden) Hintergrundinformationen und die Identifikationsnummer (ORCID) eines Autors sind unter: https://doi.org/10.1002/ange.201902473 zu finden. Schema 1. Überblick über die Herstellungsmethoden für b-chlorierte Ketone. A) Traditionelle Synthese durch Friedel-Crafts-Acylierung. B) Silbervermittelte Ringçffnungschlorierung von Hydroxycyclopropanen. C) Katalysator-und metallfreie Ringçffnungschlorierungvon nicht vorfunktionalisierten Arylcyclopropanen.

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A novel Friedel–Crafts alkylation of naphthols without Lewis acid

Cited by 8 publications

References 12 publications

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

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

Aromatic Substitution

Durch sichtbares Licht vermittelte Synthese von β‐Chlorketonen aus Arylcyclopropanen

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