Heterosubstituted or Functionalized Derivatives of 1‐ and 2‐(Trifluoromethyl)naphthalenes Emanating from Aryne Adducts.

Bailly, Frédéric; Cottet, Fabrice; Schlosser, Manfred

doi:10.1002/chin.200533114

Cited by 1 publication

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“…tization. 45,46 In the benzyne route, furan was mixed with dehydrobenzene intermediates (4) that were generated in situ when either chlorobenzenes were treated with n-BuLi, 47 anthranilic acids were treated with nitrite, 48 or diaryliodonium salts were treated with lithium hexamethyldisilazane (LHMDS). 49 The resulting Diels−Alder cycloadducts1,4dihydro-1,4-epoxynaphthalenes (5)then isomerized with acid to 1-naphthols.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…1,5-, 1,6-, and 1,7-Naphthalenediols ( 6a – c ) are commercially available, and we successfully synthesized a small library of nitro-, bromo-, cyano-, fluoro-, and trifluoromethyl-substituted 1-naphthols ( 6d – j ) using either α-tetralones or benzynes as starting materials (Scheme ). In the tetralone approach to naphthols, tetralones ( 3 ) were prompted to undergo Pd/C-catalyzed dehydrogenative aromatization. , In the benzyne route, furan was mixed with dehydrobenzene intermediates ( 4 ) that were generated in situ when either chlorobenzenes were treated with n -BuLi, anthranilic acids were treated with nitrite, or diaryliodonium salts were treated with lithium hexamethyldisilazane (LHMDS) . The resulting Diels–Alder cycloadducts1,4-dihydro-1,4-epoxynaphthalenes ( 5 )then isomerized with acid to 1-naphthols .…”

Section: Resultsmentioning

confidence: 99%

“…6-Trifluoromethyl-1-naphthol (6h) and 7-Trifluoromethyl-1naphthol (6i). 47 To a stirred solution of 4-chlorobenzotrifluoride (2.96 mL, 22.2 mmol) in anhydrous THF (30 mL) at −78 °C was added dropwise a n-butyllithium solution (2.5 M in hexanes, 8.86 mL, 22.2 mmol). The reaction mixture was stirred at −78 °C for 60 min, after which it was cannulated slowly through Teflon tubing into a flask containing stirred furan (16.1 mL, 0.22 mol) at 25 °C.…”

Section: ■ Experimental Detailsmentioning

confidence: 99%

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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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