- Unexpected reactivity in naphthoquinone series
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An unexpected reactivity of 2-chloromethyl-3-methyl-1,4-naphthoquinone 1 with primary nitroalkanes in classical SRN1 reaction conditions gives two series of new quinones: dialkyl anthraquinones and C-alkylated naphthoquinones.
- Vanelle, Patrice,Terme, Thierry,Giraud, Luc,Crozet, Michel P.
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- Compression of a Flapping Mechanophore Accompanied by Thermal Void Collapse in a Crystalline Phase
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Mechanical control of the molecular energy landscape is an important issue in modern materials science. Mechanophores play a unique role in that the mechanical responses are induced against the activation barrier for intramolecular transformation with the aid of external forces. Here we report an unprecedented activation process of a flexible flapping mechanophore. Namely, thermal void collapse in a crystalline phase triggers mechanophore compression in a definite proportion. Unfavored conformational planarization of the flapping mechanophore is compulsorily induced by packing force, leading to a total energy gain in crystal packing. Fluorescence chromism indicates extended π conjugation resulting from the mechanophore compression, giving rise to an energy transfer from the unpressed to compressed conformers.
- Yamakado, Takuya,Otsubo, Kazuya,Osuka, Atsuhiro,Saito, Shohei
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- Design, Synthesis, Molecular Docking, and Biological Evaluation of New Emodin Anthraquinone Derivatives as Potential Antitumor Substances
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The emodin anthraquinone derivatives are generally used in traditional Chinese medicine due to their various pharmacological activities. In the present study, a series of emodin anthraquinone derivatives have been designed and synthesized, among which 1,3-dihydroxy-6,8-dimethoxyanthracene-9,10-dione is a natural compound that has been synthesized for the very first time, and 1,3-dimethoxy-5,8-dimethylanthracene-9,10-dione is a compound that has never been reported earlier. Interestingly, while total seven of these compounds showed neuraminidase inhibitory activity in influenza virus with inhibition rate more than 50 %, specific four compounds exhibited significant inhibition of tumor cell proliferation. The further results demonstrate that 1,3-dimethoxy-5,8-dimethylanthracene-9,10-dione showed the best anticancer activity among all the synthesized compounds by inducing highest apoptosis rate to HCT116 cancer cells and arresting their G0/G1 cell cycle phase, through elevation of intracellular level of reactive oxygen species (ROS). Moreover, the binding of 1,3-dimethoxy-5,8-dimethylanthracene-9,10-dione with BSA protein has thoroughly been investigated. Altogether, this study suggests the neuraminidase inhibitory activity and antitumor potential of the new emodin anthraquinone derivatives.
- Li, Yuying,Guo, Fang,Chen, Tinggui,Zhang, Liwei,Wang, Zhuanhua,Su, Qiang,Feng, Liheng
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- A Ni-Mg-Al layered triple hydroxide-supported Pd catalyst for heterogeneous acceptorless dehydrogenative aromatization
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In the presence of a Ni-Mg-Al layered triple hydroxide-supported Pd catalyst, the acceptorless dehydrogenative aromatization of a wide range of cyclohexanols/cyclohexanones and cyclohexylamines efficiently proceeded to give the corresponding phenols and anilines, respectively, in moderate to high yields with the liberation of molecular hydrogen.
- Jin, Xiongjie,Taniguchi, Kento,Yamaguchi, Kazuya,Nozaki, Kyoko,Mizuno, Noritaka
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p. 5267 - 5270
(2017/07/10)
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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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p. 4880 - 4884
(2015/07/28)
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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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supporting information
p. 4888 - 4891
(2013/10/08)
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- Metal-free activation of C-C multiple bonds through halide ion pairs: Diels-Alder reactions with subsequent aromatization
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Imidazolium and ammonium halides, both in homogeneous phase or immobilized on mesoporous silica, proved able to promote the aromatization reaction of Diels-Alder adducts under ethylene and H2 elimination. These observations point to the increased nucleophilicity of such halide ions. They also open the possibility to employ such ion pairs as nucleophilic organocatalysts, for example, as substitutes for phosphines or amines.
- Kaper, Helena,Antonietti, Markus,Goettmann, Frédéric
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p. 4546 - 4549
(2008/09/21)
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- Formation of arenes via diallylarenes: Strategic utilization of Suzuki-Miyaura cross-coupling, Claisen rearrangement and ring-closing metathesis
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Two new synthetic strategies for benzoannulation are reported. The first strategy is based on the Suzuki-Miyaura cross-coupling reaction. To this end, various ortho-diallylbenzene derivatives were prepared from the corrresponding diiodo derivatives by an allylation strategy using an allylboronate as coupling partner. These diallyl derivatives were subjected to a ring-closing metathesis (RCM) and one-pot dichlorodicyanoquinone (DDQ) oxidation sequence to deliver 2-substituted naphthalenes. In the second strategy, a double Claisen rearrangement and RCM protocol have been used as key steps to give highly functionalized benzoannulated quinone derivatives.
- Kotha, Sambasivarao,Shah, Vrajesh R.,Mandal, Kalyaneswar
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p. 1159 - 1172
(2008/04/03)
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- Nitrous oxide oxidation catalyzed by ruthenium porphyrin complex
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Dinitrogen oxide was employed as a clean oxidant for various oxidations in the presence of a catalytic amount of dioxoruthenium tetramesitylporphyrin complex (Ru(tmp)(O)2). A variety of olefins, secondary alcohols, and benzyl alcohols were smoothly oxidized to the corresponding epoxides, ketones, and aldehydes in high yields. In the oxidation of 9,10-dihydroanthracene derivatives, the competitive reactions affording anthraquinones and anthracenes could be regulated by the reaction conditions. At a high temperature (200°C), anthraquinones were selectively produced, while the anthracenes were selectively produced by the addition of sulfuric acid.
- Tanaka, Hirotaka,Hashimoto, Kentaro,Suzuki, Kyosuke,Kitaichi, Yasunori,Sato, Mitsuo,Ikeno, Taketo,Yamada, Tohru
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p. 1905 - 1914
(2007/10/03)
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- Oxidative dehydrogenation and the aromatization of polycycles using o-iodoxybenzoic acid (IBX)
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An efficient and convenient method for the dehydrogenation and aromatization of various polycycles using o-iodoxybenzoic acid (IBX) is described.
- Kotha, Sambasivarao,Banerjee, Shaibal,Mandal, Kalyaneswar
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p. 2043 - 2045
(2007/10/03)
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- Selective nitrous oxide oxidation for C-H oxidation and aromatization of 9,10-dihydroanthracene derivatives
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During the nitrous oxide oxidation of 9,10-dihydroanthracene derivatives catalyzed by the ruthenium-porphyrin complexes, anthraquinones were selectively afforded by the C-H oxidation of the benzylic carbon under the appropriate reaction conditions, whereas anthracenes as a result of oxidative aromatization were selectively obtained in the presence of sulfuric acid.
- Hashimoto, Kentaro,Tanaka, Hirotaka,Ikeno, Taketo,Yamada, Tohru
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p. 582 - 583
(2007/10/03)
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- Rational design of fluorescein-based fluorescence probes. Mechanism-based design of a maximum fluorescence probe for singlet oxygen
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Fluorescein is one of the best available fluorophores for biological applications, but the factors that control its fluorescence properties are not fully established. Thus, we initiated a study aimed at providing a strategy for rational design of functional fluorescence probes bearing fluorescein structure. We have synthesized various kinds of fluorescein derivatives and examined the relationship between their fluorescence properties and the highest occupied molecular orbital (HOMO) levels of their benzoic acid moieties obtained by semiempirical PM3 calculations. It was concluded that the fluorescence properties of fluorescein derivatives are controlled by a photoinduced electron transfer (PET) process from the benzoic acid moiety to the xanthene ring and that the threshold of fluorescence OFF/ON switching lies around -8.9 eV for the HOMO level of the benzoic acid moiety. This information provides the basis for a practical strategy for rational design of functional fluorescence probes to detect certain biomolecules. We used this approach to design and synthesize 9-[2-(3carboxy-9,10-dimethyl)anthryl]-6-hydroxy-3H-xanthen-3-one (DMAX) as a singlet oxygen probe and confirmed that it is the most sensitive probe currently known for 1O2. This novel fluorescence probe has a 9,10-dimethylanthracene moiety as an extremely fast chemical trap of 1O2. As was expected from PM3 calculations, DMAX scarcely fluoresces, while DMAX endoperoxide (DMAX-EP) is strongly fluorescent. Further, DMAX reacts with 1O2 more rapidly, and its sensitivity is 53-fold higher than that of 9-[2-(3-carboxy-9,10-diphenyl)anthryl]-6-hydroxy-3H-xanthen-3-ones (DPAXs), which are a series of fluorescence probes for singlet oxygen that we recently developed. DMAX should be useful as a fluorescence probe for detecting 1O2 in a variety of biological systems.
- Tanaka,Miura,Umezawa,Urano,Kikuchi,Higuchi,Nagano
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p. 2530 - 2536
(2007/10/03)
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- Rotational isomerization of (E)-(2-anthryl)ethenes. A consideration: Why are the s-cis rotamers more stable than the s-trans rotamers in the excited state and less stable in the ground state?
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Rotational isomerism between s-cis and s-trans rotamers of (E)-1-(2- anthryl)-2-phenylethene (E-2APE) and (E)1-(2-anthryl)-3(3-dimethyl-1-butene (E-2ADB) were investigated by comparing the absorption, emission and transient absorption spectra with those of the model compounds. The s-trans isomer is more stable than the s-cis rotamer in the ground state; however, the s-cis isomer is more stable than the s-trans rotamer in the excited state (the lowest singlet and triplet excited state). In the triplet excited state, s-trans→s-cis one-way rotational isomerization is observed with activation energies of 30 and 18 kJ mol-1 for E-2APE and E-2ADB, respectively. Explanations of why the s-cis rotamer is more stable than the s-trans rotamer in the excited state and less stable in the ground state are proposed using the HOMO and LUMO coefficients estimated by a MOPAC93 (PM3) calculation.
- Karatsu, Takashi,Itoh, Hajime,Yoshikawa, Nobuko,Kitamura, Akihide,Tokumaru, Katsumi
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p. 1837 - 1849
(2007/10/03)
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- An original one-pot synthesis of dialkyl-substituted anthraquinones
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2,3-Bis(chloromethyl)-1,4-naphthoquinone reacts with primary nitroalkanes in a one-pot synthesis to give a series of anthraquinones bearing two n-alkyl substituents at C-2 and C-3 in good yields. The reaction is shown to proceed by two consecutive SRN1 processes followed by base-promoted nitrous acid elimination, electrocyclic ring-closure and dehydrogenation. In comparison with the classical Diels-Alder reaction, the advantage of this route is the simplicity of starting-material preparation.
- Vanelle, Patrice,Terme, Thierry,Maldonado, José,Crozet, Michel P.,Giraud, Luc
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p. 1067 - 1068
(2007/10/03)
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- INVESTIGATION OF THE COMPOSITION OF PETROLEUM ANTHRACENE HYDROCARBONS
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The optimum conditions of adduct formation with maleic anhydride for the isolation of ca. 100percent anthracene hydrocarbons from a mixture with phenanthrenes and other compounds are set out.Gas-liquid chromatography has been used to study the individual composition of anthracene and C1-C3 anthracenes isolated by the method proposed from concentrates of triaromatic hydrocarbons of crude oils from the Okha, Katangli (Sakhalin) and Dorokhovsk (Urals-Volga) fields.With the aid of the individual compounds synthesized, for the first time 2-ethylanthracene and 1,3- and 2,3-dimethylanthracene have been identified in crude oils, and the retention indices have also been calculated for certain C2- and C3-substituted anthracene hydrocarbons for chromatographic phase SE-54.
- Ivanov, V. I.,Golovko, A. K.
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p. 504 - 512
(2007/10/02)
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