- Spectroscopic properties and gelling ability of a set of rod-like 2,3-disubstituted anthracenes
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The UV absorption spectra of 2,3-didecyloxyanthracene (DDOA) recorded in methanol, ethanol, 1-propanol, acetonitrile and methylcyclohexane reveal interesting features: they show a striking contrast between the isotropic solution and the gel state where, at ambient temperature, a fine structure appears with an apparent bathochromic shift (Δυ ≈ -700 cm -1), as observed in the solid state. Such an effect was mimicked by 2,3-dioxydi- (and -tri-) methyleneanthracenes in which the conformational mobility of the two juxtanuclear oxygen atoms is reduced in a manner similar to that assumed in the gel state. The fluorescence emission of DDOA (10 -5 M) at very low temperature exhibits a loss of fine structure and a bathochromic shift, for the gel state, in agreement with the presence of aggregates; the excitation spectra were found to be superimposable upon the absorption spectra of the isotropic and gel phases, respectively. Solvent screening for DDOA gelling ability has shown that the most efficient solvents are CH3OH and CH3CN. From the phase transition diagram (temperatures of gel setting, Tgel, and gel melting, Tm, versus concentration), thermodynamic parameters were derived: ΔH gel0/kJ mol-1 = -70 (CH3OH), -66 (CH 3CN); ΔSgel0/(J K-1 mol -1 = -147 (CH3OH), -140 (CH3CN) and ΔGgel0/kJ mol-1 (at 300 K) ≈ -26 (CH3OH), -24 (CH3CN). These parameters attest to the good stability of these gel systems. Finally, the influence of the chain length (n = C7H15 to C12H25) on the efficiency of gel formation (or melting) was investigated in methanol, ethanol, acetonitrile and heptane. It emerges that, to form gels, n-decyl and n-undecyl were found to be the most suitable chains and methanol and ethanol the most efficient solvents. It should be noted that the ability to form gels in methanol at a concentration of 0.6 mM at ambient temperature qualifies DDOA as a supergelator.
- Desvergne, Jean-Pierre,Brotin, Thierry,Meerschaut, Danny,Clavier, Gilles,Placin, Frederic,Pozzo, Jean-Luc,Bouas-Laurent, Henri
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- Synthesis of tetrafunctionalized pentiptycenequinones for construction of cyclic dimers with a cylindrical shape by boronate ester formation
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Abstract New tetrasubstituted pentiptycenequinone derivatives 1 and 2 having two sets of diol moieties in a syn orientation were synthesized from the corresponding 2,3-disubstituted anthracene derivatives. The semicircular scaffold of these molecules is expected to be useful to create a belt-like structure having an aromatic π-wall. Indeed, the reaction of 1 with 1,4-phenylenediboronic acid or 4,4′-biphenyldiboronic acid quantitatively gave a 2:2 macrocyclic product via boronate ester formation. The efficient formation of these cyclic structures can be explained by favorable intramolecular cyclization at the final step.
- Akine, Shigehisa,Kusama, Daisuke,Takatsuki, Yuri,Nabeshima, Tatsuya
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- Palladium-Catalyzed Direct Acylation: One-Pot Relay Synthesis of Anthraquinones
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A bis-acylation strategy to access functionalized anthraquinones via one-pot relay process, is presented. The first acylation was feasible under [Pd]-catalyzed intermolecular direct acylation reaction, while, the second acylation was accomplished by using intramolecular Friedel-Crafts acylation. Notably, benchtop aldehydes have been utilized as non-toxic acylation agents in the key [Pd]-catalyzed acylation.
- Suchand, Basuli,Satyanarayana, Gedu
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p. 769 - 779
(2019/01/23)
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- Efficient Synthesis of Anthraquinones from Diaryl Carboxylic Acids via Palladium(II)-Catalyzed and Visible Light-Mediated Transformations
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Irradiation of 9-ester-substituted anthracenes with visible light results in the formation of endoperoxides in the absence of a photocatalyst, which further undergo base-assisted fragmentation to afford anthraquinones. The excited state species of anthracene generated by energy transfer, interacts with 3O2 to afford 1O2 by energy transfer and undergoes cycloaddition with 1O2. By employing palladium(II)-catalyzed and visible light-mediated transformations, we have developed an efficient synthetic protocol for accessing diverse anthraquinones from readily available diaryl carboxylic acids. The optimal result was obtained with palladium(II) acetate, Ac-Ile-OH, benzoquinone and potassium carbonate in tert-amyl alcohol under O2 at 90 °C with irradiation from a 30 W fluorescent light bulb. (Figure presented.).
- Kim, Kiho,Min, Minsik,Hong, Sungwoo
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supporting information
p. 848 - 852
(2017/03/11)
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- Lewis acid/Broensted acid mediated benz-annulation of thiophenes and electron-rich arenes
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A facile preparation of benz-annulated heterocycles were achieved at rt involving a Lewis acid/Broensted acid mediated annulation of heterocycles using 2,5-dimethoxytetrahydrofuran as a four-carbon synthon. The benz-/naphth-annulation was found to be successful with electron-rich arenes as well.
- Rafiq, Settu Muhamad,Sivasakthikumaran, Ramakrishnan,Mohanakrishnan, Arasambattu K.
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supporting information
p. 2720 - 2723
(2014/06/09)
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- Synthesis of fluorenone and anthraquinone derivatives from aryl- and aroyl-substituted propiolates
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Fluorenone derivatives were generated from aryl-substituted propiolates via a cobalt-catalyzed Diels-Alder reaction/DDQ-oxidation and Friedel-Crafts-type cyclization. Several functional groups are tolerated, and good to excellent overall yields (up to 89%) could be achieved. For the synthesis of anthraquinone derivatives, aroyl-substituted propiolates were applied in a zinc iodide catalyzed Diels-Alder reaction with 1,3-dienes. The subsequent DDQ oxidation and Friedel-Crafts-type cyclization led to symmetrical as well as some unsymmetrical anthraquinones in good to excellent yields of up to 87% over the three-step reaction sequence.
- Puenner, Florian,Schieven, Justin,Hilt, Gerhard
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p. 4888 - 4891
(2013/10/08)
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- Different synthetic routes towards efficient organogelators: 2,3-substituted anthracenes
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Three synthetic approaches towards 2,3-substituted anthracenes are reported and discussed in terms of selectivity and viability. This allowed us to introduce a variety of substituents as sidearms. Promising results have been found using a tandem Diels-Alder aromatization reaction using 2,2,3-dimethoxybuladiene 9 as a key intermediate. However, for multigram preparations the Friedel-Crafts approach is preferred.
- Pozzo, Jean-Luc,Clavier, Gilles M.,Colomes, Michel,Bouas-Laurent, Henri
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p. 6377 - 6390
(2007/10/03)
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- 1H and 13C NMR studies of some anthraquinones and anthracenetetrones
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1H and 13C NMR chemical shifts are reported and assigned for 1,4,9,10- and 2,3,9,10-anthracenetetrone. In addition, NMR data are given for 2,3-dihydroxy-9, 10-anthraquinone, 2,3-dimethoxy-9,10-anthraquinone and 1-hydroxy-2-acetoxy-9,10-anthraquinone, encountered during the preparation of the anthracenetetrones.
- Danielsen,Francis,Aksnes
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p. 1043 - 1045
(2007/10/03)
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- Orthobromodiphenylmethane derivatives as starting materials for the total synthesis of anthraquinones
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In this communication we describe the synthesis of four simple anthraquinones by a five-step sequence, using easily available bromobenzaldehydes and phenyllithium derivatives as starting materials.
- Almeida, Wanda P.,Costa, Paulo R.R.
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p. 4507 - 4518
(2007/10/03)
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- A New Route to Anthraquinones
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The lithium salts derived from position 3 of phthalides react with arynes to form adducts, which, upon aerial oxidation, produce anthraquinones in moderate to good yields.Substituted phthalides and arynes also participate in this general reaction.The addition to unsymmetrically substituted arynes shows regioselectivity, whilst the availability of a new general route to phthalides extends the scope of this reaction.
- Dodsworth, David J.,Calcagno, Maria-Pia,Ehrmann, E. Ursula,Devadas, Bhatt,Sammes, Peter G.
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p. 2120 - 2124
(2007/10/02)
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