Metal-Free Regioselective Monocyanation of Hydroxy-, Alkoxy-, and Benzyloxyarenes by Potassium Thiocyanate and Silica Sulfuric Acid as a Cyanating Agent

Sardarian, Ali Reza; Inaloo, Iman Dindarloo; Modarresi‐Alam, Ali Reza; Kleinpeter, Erich; Schilde, Uwe

doi:10.1021/acs.joc.8b02191

Cited by 31 publications

(14 citation statements)

References 79 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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“…During attempts to improve this synthetic step, we successfully explored a new methodology for synthesizing the 1,2,4,5-tetraoxane subunit, involving the use of readily available and low-cost silica sulfuric acid (SSA) as a catalyst. Silica-supported catalysts have attracted attention in recent years due to their promising reactivity and recoverable and reusable properties, leading to economic and environmental benefits. , SSA was reported by Azarifar et al. as an effective catalyst for the preparation of gem -dihydroperoxides (DHPs).…”

Section: Introductionmentioning

confidence: 99%

“…Silica-supported catalysts have attracted attention in recent years due to their promising reactivity and recoverable and reusable properties, leading to economic and environmental benefits. 20,21 SSA was reported by Azarifar et al 22 as an effective catalyst for the preparation of gem-dihydroperoxides (DHPs). Peroxyacetalization is the first step in the most broadly used method for synthesizing 1,2,4,5-tetraoxanes, which involves the acid-catalyzed cyclocondensation of a ketone or aldehyde with an active DHP intermediate prepared in situ.…”

Section: ■ Introductionmentioning

confidence: 99%

Synthesis of Non-symmetrical Dispiro-1,2,4,5-Tetraoxanes and Dispiro-1,2,4-Trioxanes Catalyzed by Silica Sulfuric Acid

et al. 2021

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A novel protocol for the preparation of non-symmetrical 1,2,4,5-tetraoxanes and 1,2,4-trioxanes, promoted by the heterogeneous silica sulfuric acid (SSA) catalyst, is reported. Different ketones react under mild conditions with gem-dihydroperoxides or peroxysilyl alcohols/β-hydroperoxy alcohols to generate the corresponding endoperoxides in good yields. Our mechanistic proposal, assisted by molecular orbital calculations, at the ωB97XD/def2-TZVPP/PCM(DCM)//B3LYP/6-31G(d) level of theory, enhances the role of SSA in the cyclocondensation step. This novel procedure differs from previously reported methods by using readily available and inexpensive reagents, with recyclable properties, thereby establishing a valid alternative approach for the synthesis of new biologically active endoperoxides.

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“…According to these interactions, it is possible to prepare pseudo-supramolecular structures through sequential and predictable bonds between different organic moieties 15 . Further, grafting of the functionalized organic chains to the magnetic substrates is one of the best procedures for the construction of heterogeneous catalysts 16 with high stability, activity and reusability 17 – 22 .…”

Section: Introductionmentioning

confidence: 99%

Fe3O4/SiO2 decorated trimesic acid-melamine nanocomposite: a reusable supramolecular organocatalyst for efficient multicomponent synthesis of imidazole derivatives

Fattahi

Dekamin

2023

Sci Rep

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This article describes supramolecular Fe3O4/SiO2 decorated trimesic acid-melamine (Fe3O4/SiO2-TMA-Me) nanocomposite that can be prepared with features that combine properties of different materials to fabricate a structurally unique hybrid material. In particular, we have focused on design, synthesis and evaluation a heterogeneous magnetic organocatalyst containing acidic functional-groups for the synthesis of biologically important imidazole derivatives in good to excellent yields. The introduced Fe3O4/SiO2-TMA-Me nanomaterial was characterized by different techniques such as FTIR, XRD, EDX, FESEM, TEM, TGA and DTA. As a noteworthy point, the magnetic catalytic system can be recycled and reused for more than seven consecutive runs while its high catalytic activity remains under the optimized conditions.

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Metal-Free Regioselective Monocyanation of Hydroxy-, Alkoxy-, and Benzyloxyarenes by Potassium Thiocyanate and Silica Sulfuric Acid as a Cyanating Agent

Cited by 31 publications

References 79 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

Synthesis of Non-symmetrical Dispiro-1,2,4,5-Tetraoxanes and Dispiro-1,2,4-Trioxanes Catalyzed by Silica Sulfuric Acid

Fe3O4/SiO2 decorated trimesic acid-melamine nanocomposite: a reusable supramolecular organocatalyst for efficient multicomponent synthesis of imidazole derivatives

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