- Highly efficient reversible Z-E photoisomerization of a bridged azobenzene with visible light through resolved S1(nπ*) absorption bands
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(Graph Presented) The reversible Z-E photoswitching properties of the (Z) and (E) isomers of the severely constrained bridged azobenzene derivative 5,6-dihydrodibenzo[c,g][1,2]diazocine (1) were investigated quantitatively by UV/vis absorption spectroscop
- Siewertsen, Ron,Neumann, Hendrikje,Buchheim-Stehn, Bengt,Herges, Rainer,Naether, Christian,Renth, Falk,Temps, Friedrich
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- Incorporation of cyclic azobenzene into oligodeoxynucleotides for the photo-regulation of DNA hybridization
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Cyclic azobenzene carboxylic acid was synthesized using a shortened route. After reaction with d-threolinol, the resulting cyclic azobenzene-d-threolinol (cAB-Thr) building block was transformed into the corresponding DMTr-protected phosphoramidite, and incorporated into oligodeoxynucleotides at various positions and frequencies by solid phase synthesis. The melting temperatures of these modified oligonucleotides were determined by UV spectrometry. Photo-regulation of cAB-Thr-modified oligonucleotides with their complementary sequence was evaluated by Fluorescence Resonance Energy Transfer experiments using a fluorescein-Black Hole Quencher pair. Results suggest that while cis-cAB destabilizes DNA duplexes, trans-cAB can be accommodated in double stranded DNA.
- Eljabu, Fatma,Dhruval, Joshi,Yan, Hongbin
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- Preparation method of azobenzene oxide derivative
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The invention relates to a preparation method of an azobenzene oxide derivative. Nitrobenzene or a derivative thereof is used as a starting raw material, and is thoroughly reduced into the azobenzeneoxide derivative in an ethanol-water solution of an alka
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Paragraph 0022-0027
(2020/07/12)
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- Catalytic Selective Oxidative Coupling of Secondary N-Alkylanilines: An Approach to Azoxyarene
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Azoxyarenes are among important scaffolds in organic molecules. Direct oxidative coupling of primary anilines provides a concise fashion to construct them. However, whether these scaffolds can be prepared from secondary N-alkylanilines is not well explored. Here, we present a catalytic selective oxidative coupling of secondary N-alkylaniline to afford azoxyarene with tungsten catalyst under mild conditions. In addition, azoxy can be viewed as a bioisostere of alkene and amide. Several "azoxyarene analogues" of the corresponding bioactive alkenes and amides showed comparable promising anticancer activities.
- Ke, Lei,Zhu, Guirong,Qian, Hui,Xiang, Guangya,Chen, Qin,Chen, Zhilong
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p. 4008 - 4013
(2019/06/04)
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- Oxidative Approach Enables Efficient Access to Cyclic Azobenzenes
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Azobenzenes are versatile photoswitches that have found widespread use in a variety of fields, ranging from photopharmacology to the material sciences. In addition to regular azobenzenes, the cyclic diazocines have recently emerged. Although diazocines have fascinating conformational and photophysical properties, their use has been limited by their synthetic accessibility. Herein, we present a general, high-yielding protocol that relies on the oxidative cyclization of dianilines. In combination with a modular substrate synthesis, it allows for rapid access to diversely functionalized diazocines on gram scales. Our work systematically explores substituent effects on the photoisomerization and thermal relaxation of diazocines. It will enable their incorporation into a wide variety of functional molecules, unlocking the full potential of these emerging photoswitches. The method can be applied to the synthesis of a new cyclic azobenzene with a nine-membered central ring and distinct properties.
- Maier, Martin S.,Hüll, Katharina,Reynders, Martin,Matsuura, Bryan S.,Leippe, Philipp,Ko, Tongil,Sch?ffer, Lukas,Trauner, Dirk
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supporting information
p. 17295 - 17304
(2019/11/03)
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- Synthesis of cyclic azobenzene analogues
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Reaction of 2,20-dinitrodibenzyl with lead metal powder in the presence of a basic triethylammonium formate buffer gave a cyclic azoxybenzene, 11,12 dihydrodibenzo[c,g][1,2]diazocine-5-oxide. The latter compound was converted into cyclic azobenzene and analogues (chloro-, bromo-, and cyano-) through subsequent transformations. Hydrolysis of the cyano cyclic azobenzene gave the corresponding carboxylic acid. This carboxylic acid was finally reacted with D-threoninol to give the corresponding amide, which readily undergoes photoisomerization upon illumination with light.
- Joshi, Dhruval K.,Mitchell, Matthew J.,Yan, Hongbin,Bruce, Doug,Lough, Alan J.
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p. 8670 - 8676,7
(2012/12/11)
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- Synthesis of cyclic azobenzene analogues
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Reaction of 2,20-dinitrodibenzyl with lead metal powder in the presence of a basic triethylammonium formate buffer gave a cyclic azoxybenzene, 11,12 dihydrodibenzo[c,g][1,2]diazocine-5-oxide. The latter compound was converted into cyclic azobenzene and analogues (chloro-, bromo-, and cyano-) through subsequent transformations. Hydrolysis of the cyano cyclic azobenzene gave the corresponding carboxylic acid. This carboxylic acid was finally reacted with D-threoninol to give the corresponding amide, which readily undergoes photoisomerization upon illumination with light.
- Joshi, Dhruval K.,Mitchell, Matthew J.,Bruce, Doug,Lough, Alan J.,Yan, Hongbin
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p. 8670 - 8676
(2013/01/14)
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- ELECTROLYTIC REDUCTION OF o-NITROBENZYL THIOCYANATE IN BUFFERED SOLUTIONS ON MERCURY
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The o-nitrobenzyl thiocyanate (I) behaves differently on the DME and on a large mercury pool electrode.Polarography did not give a sufficiently clear explanation of the reaction mechanism, only the preparative experiments yielded useful results.Whereas polarographic curves in solutions of Britton-Robinson buffer system with 50percent by vol. ethanol exhibit two cathodic waves within the pH region 1-12, corresponding according to their height ratio to an uptake of 4 e and 2 e respectively, the controlled potential preparation electrolysis (CPE) and coulometry results indicate a more complicated reaction path.In the CPE carried out at the concentration of I 1.10-2 mol/l the electroreductive splitting of CH2-SCN occurs as the first step.Nitrobenzyl radicals so formed react in the follow-up dimerization resulting in dibenzyl or toluene structures.Simultaneously or at a later stage the completion of the electrolytic reduction of the nitro group proceeds to the hydroxylamino group.In solution of 9>pH>1 the CPE of nitro compounds I takes place by an ECEC mechanism yielding dibenzodiazocine III, its N-oxide IV and 2,2'-dimethylazoxybenzene (V).In course of preparative electrolysis in strongly acidic medium 2-amino-benzo(1,3)-thiazine-1-oxide (II) is formed by an EC mechanism.
- Hlavaty, Jaromir
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- Cyclic Azo Dioxides. Synthesis and Properties of Bis(o-nitrosobenzyl) Derivatives
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Several cyclic azo dioxides have been prepared by oxidation of the corresponding diamines with sodium tungstate-hydrogen peroxide in ethanol-water: 4 (related to o,o'-dinitrosobibenzyl), 8 (related to bis(o-nitrosobenzyl)ether), 14 (related to bis(o-nitrosobenzyl)amine), 13 (the trifluoroacetate salt of 14), 12a and 12b (the N-carbomethoxy and N-carbo-tert-butoxy derivatives of 14).In solution the azo dioxides are in equilibrium (Ke) with the corresponding dinitroso forms: Ke increases with decreasing polarity of solvent and with increasing temperature.For azo dioxide 4 in dioxane at 25 deg C Ke = 0.18, Δ H0 = 7.09 +/- 0.47 kcal mol-1, and Δ S0 = 20.4 cal mol-1 deg-1.The azo dioxides decompose at elevated temperatures (>100 deg C); azo dioxide 14 is converted to 2-(o-nitrosobenzyl)indazole (15) in refluxing methylene chloride.
- Smith, Mark A.,Weinstein, Barry,Greene, Frederick D.
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p. 4597 - 4602
(2007/10/02)
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