Synthesis of Positional Isomeric Phenylphenalenones

Ospina, Felipe; Ramírez, Adrián; Cano, Marisol; Hidalgo, William; Schneider, Bernd; Otálvaro, Felipe

doi:10.1021/acs.joc.6b02985

Cited by 19 publications

(19 citation statements)

References 25 publications

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“…It is known that naphthalenes with electron‐withdrawing group in 1 position undergo electrophilic substitution in 5 position. For example, electrophilic bromination of 1‐nitronaphtalene yielded in 30% of 1‐bromo‐5‐nitronaphtalene . At same the time, nitration of 1‐aminonaphtalene in non‐acidic conditions led in a mixture of 1‐amino‐2‐nitronaphtalene and 1‐amino‐4‐nitronaphtalene in a ratio 22:71% .…”

Section: Resultsmentioning

confidence: 99%

Mechanism of Direct Electrophilic Aromatic Amination: an Electrophile is Found by Quantum‐Chemical Study

et al. 2019

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Direct amination is an extremely valuable reaction, allowing for the one-step preparation of aromatic amines. However, its mechanism was poorly studied. Here, for the first time, using quantum chemical calculations, we have shown that direct amination of arenes by hydrazoic acid follows the classical S E Ar mechanism with aminodiazonium cation H 2 N 3 + as electrophile. The peculiarity of H 2 N 3 + electronic structure has been described using our novel method for tracing the molecular orbitals. The located stationary points and transition states allowed us to define direct amination as S E Ar reaction, which rate is determined by early transition state between πand σcomplexes. Considering the calculated reaction constant 1 and an early transition state, we placed direct amination of arenes by HN 3 somewhere in-between nitration and halogenations. Our results explain the accumulated experimental data and open a prospect for the development of the new aminating agents working in milder conditions.[a] K.

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Section: Resultsmentioning

confidence: 99%

Mechanism of Direct Electrophilic Aromatic Amination: an Electrophile is Found by Quantum‐Chemical Study

et al. 2019

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“…The commercial use of phenylphenalenone scaffolds would only be practical without the need of isolating them from natural sources, as they are normally biosynthesized in extremely low amounts in plants. Efforts to synthesize these compounds have been made [ 47 , 51 , 52 , 53 , 54 , 55 , 56 , 57 ], but the high concentration of phenylphenalenones found in methanolic extracts of S. timida seeds raises the possibility of using this species as an alternative source of phenylphenalenones scaffolds.…”

Section: Discussionmentioning

confidence: 99%

Phytotoxicity of Schiekia timida Seed Extracts, a Mixture of Phenylphenalenones

et al. 2021

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Phenylphenalenones, metabolites found in Schiekia timida (Haemodoraceae), are a class of specialized metabolites with many biological activities, being phytoalexins in banana plants. In the constant search to solve the problem of glyphosate and to avoid resistance to commercial herbicides, this work aimed to investigate the phytotoxic effect of the methanolic extract of S. timida seeds. The chemical composition of the seed extract was directly investigated by NMR and UPLC-QToF MS and the pre- and post-emergence phytotoxic effect on a eudicotyledonous model (Lactuca sativa) and a monocotyledonous model (Allium cepa) was evaluated through germination and seedling growth tests. Three concentrations of the extract (0.25, 0.50, and 1.00 mg/mL) were prepared, and four replicates for each of them were analyzed. Three major phenylphenalenones were identified by NMR spectroscopy: 4-hydroxy-anigorufone, methoxyanigorufone, and anigorufone, two of those reported for the first time in S. timida. The presence of seven other phenylphenalenones was suggested by the LC-MS analyses. The phenylphenalenone mixture did not affect the germination rate, but impaired radicle and hypocotyl growth on both models. The effect in the monocotyledonous model was statistically similar to glyphosate in the lowest concentration (0.25 mg/mL). Therefore, although more research on this topic is required to probe this first report, this investigation suggests for the first time that phenylphenalenone compounds may be post-emergence herbicides.

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“…Scheme 1 displays the synthetic route of the targeting molecules.1-Oxo-1H-phenalen-3-yl trifluoromethanesulfonate (OTf-P) was synthesized according to the literature method (Ospina et al, 2017). By employing an unusual titanium tetrachloride-pyridine catalytic system (Liu et al, 2021b), the cyano-substituted phenalene unit (OTf-PCN) was obtained via a Knoevenagel condensation between OTf-P and malononitrile.…”

Section: Synthesis and Structural Characterizationmentioning

confidence: 99%

Phenalene—A New Ring-Locked Vinyl Bridge for Nonfullerene Acceptors With Enhanced Chemical and Photochemical Stabilities

Liu

Hsieh

et al. 2022

Front. Electron. Mater

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Currently, the two exocyclic vinyl bridges in the acceptor–donor–acceptor (A–D–A)-type nonfullerene acceptors (NFAs) have been widely recognized as one of the most vulnerable sites under external stresses. Embedding the exocyclic vinyl bridges into an aromatic ring could be a feasible solution to stabilize them. Herein, we successfully develop a phenalene-locked vinyl bridge via a titanium tetrachloride—pyridine catalytic Knoevenagel condensation, to synthesize two new A–D–A-type unfused NFAs, EH-FPCN and O-CPCN, wherein malononitrile is used as the electron-deficient terminal group while fluorene and carbazole rings are used as the electron-rich cores, respectively. These two NFAs possess wide bandgaps associated with deep energy levels, and significantly enhanced chemical and photochemical stabilities compared to the analogue molecule O-CzCN with normal exocyclic vinyl bridges. When pairing with a narrow bandgap polymer donor PTB7-Th, the fabricated EH-FPCN- and O-CPCN-based organic solar cells achieved power conversion efficiencies of 0.91 and 1.62%, respectively. The higher efficiencies for O-CPCN is attributed to its better film morphology and higher electron mobility in the blend film. Overall, this work provides a new design strategy to stabilize the vulnerable vinyl bridges of A–D–A-type NFAs.

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Synthesis of Positional Isomeric Phenylphenalenones

Cited by 19 publications

References 25 publications

Mechanism of Direct Electrophilic Aromatic Amination: an Electrophile is Found by Quantum‐Chemical Study

Mechanism of Direct Electrophilic Aromatic Amination: an Electrophile is Found by Quantum‐Chemical Study

Phytotoxicity of Schiekia timida Seed Extracts, a Mixture of Phenylphenalenones

Phenalene—A New Ring-Locked Vinyl Bridge for Nonfullerene Acceptors With Enhanced Chemical and Photochemical Stabilities

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