- Novel Synthesis of 2-Amino-1,4-benzoquinone-4-phenylimides from Anilines via Dess-Martin Periodinane Oxidation
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A synthetic investigation on oxidation of anilines to 2-amino-1,4-benzoquinone-4-phenylimides via Dess-Martin periodinane (DMP) was carried out. This facile protocol offered the advantage of short reaction times, mild reaction conditions, high yields and compatibility with a wide range of functional groups.
- Ma, Heng Chang,Jiang, Xuan Zhen
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- Photocontrolled reversible morphology conversion of protein nanowires mediated by an azobenzene-cored dendrimer
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A novel strategy to construct photocontrolled protein nanowires with reversible morphology was reported through photoisomerizable azobenzene-cored dendrimer evoked protein self-assembly. Furthermore, the curvature of the protein nanowires could be switched by alternatively irradiating with visible light and ultraviolet light.
- Sun, Hongcheng,Zhao, Linlu,Wang, Tingting,An, Guo,Fu, Shuang,Li, Xiumei,Deng, Xiaoli,Liu, Junqiu
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- Interactions of 4,4′-diaminoazobenzene derivatives with telomeric G-quadruplex DNA
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The development of small molecules to stabilize the G-quadruplex structure has garnered significant attention for anticancer drug discovery. Herein, we report the synthesis of several 4,4′-diaminoazobenzene derivatives containing different substituent groups and their ability to bind and stabilize telomeric G-quadruplex DNA. Circular dichroism (CD) spectroscopy was performed to characterize the quadruplex topologies, measure stabilization effects, and evaluate their capabilities for conformational photoregulation. 4,4′-Diaminoazobenzene derivatives were found to moderately stabilize quadruplex structures but not affect conformational photoregulation. This work further develops the design and general understanding of the stabilization effects of small molecules with telomeric G-quadruplex DNA.
- McCallum, Jeremy E. B.,Coyle, Christopher W.,Elson, Ryan R.,Titterington, Blake A.
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- New thermotropic symmetrical and unsymmetrical azomethine with azobenzene unit and fluorinated alkyl chain: Synthesis and characterization
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A new thermotropic liquid crystals containing azobenzene unit and imine linkages were synthesized via condensation of 4-(4,4,5,5,6,6,7,7,8,8,9,9,10,10, 11,11,11-heptadecafluoroundecyloxy)benzaldehyde with 4-aminoazobenzene (AzoAz-1) and 4,4′-diaminoazobenzene (AzoAz-2). The structures of compounds were characterized by means of NMR, FTIR spectroscopy and elemental analysis; the results show an agreement with the proposed structure. The mesomorphic behavior of the unsymmetrical AzoAz-1 and symmetrical AzoAz-2 azobenzeneimines was investigated via differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Based on the POM and DSC measurements AzoAz-1 exhibited smectic phases (SmX, SmA), while AzoAz-2 showed smectic (SmX1, SmX2, SmA) and nematic (N) mesophases. Optical properties of the azobenzeneimines were tested by UV-vis and photoluminescence (PL) spectroscopy in various solvents. Preliminary investigations of electrical properties of the new compounds were carried out by current-voltage (I-V) measurements performed on ITO/compound/Al device.
- Hamryszak, Lukasz,Janeczek, Henryk,Schab-Balcerzak, Ewa
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- Conversion of anilines into azobenzenes in acetic acid with perborate and Mo(VI): correlation of reactivities
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Azobenzenes are extensively used to dye textiles and leather and by tuning the substituent in the ring, vivid colours are obtained. Here, we report preparation of a large number of azobenzenes in good yield from commercially available anilines using sodium perborate (SPB) and catalytic amount of Na2MoO4 under mild conditions. Glacial acetic acid is the solvent of choice and the aniline to azobenzene conversion is zero, first and first orders with respect to SPB, Na2MoO4 and aniline, respectively. Based on the kinetic orders, UV–visible spectra and cyclic voltammograms, the conversion mechanism has been suggested. The reaction rates of about 50 anilines at 20–50?°C and their energy and entropy of activation conform to the isokinetic or Exner relationship and compensation effect, respectively. However, the reaction rates, deduced by the so far adopted method, fail to comply with the Hammett correlation. The specific reaction rates of molecular anilines, obtained through a modified calculation, conform to the Hammett relationship. Thus, this work presents a convenient inexpensive non-hazardous method of preparation of a larger number of azobenzenes, and shows the requirement of modification in obtaining the true reaction rates of anilines in acetic acid and the validity of Hammett relationship in the conversion process, indicating operation of a common mechanism.
- Karunakaran,Venkataramanan
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p. 375 - 385
(2019/02/14)
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- PHOTOCHROMIC COMPOUNDS FOR USE IN THE TREATMENT OF EYE DISORDERS
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The present patent application relates to compounds of formula (1) wherein Y and Z are independently O, N, P; R, R1, R2, R3, where present, are independently H, optionally substituted C1-C12 alkyl, O, or R and R1 and/or R2 and R3 form, together with the atom Y and/or Z to which they are attached, a 3-14 membered ring, optionally containing one or more additional heteroatoms selected from O, N, and S, optionally substituted, compositions comprising such compounds and the medical use of such compounds.
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Page/Page column 23
(2019/12/28)
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- A Natural Glycyrrhizic Acid-Tailored Light-Responsive Gelator
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The construction of stimuli-responsive materials by using naturally occurring molecules as building blocks has received increasing attention owing to their bioavailability, biocompatibility, and biodegradability. Herein, a symmetrical azobenzene-functionalized natural glycyrrhizic acid (trans-GAG) was synthesized and could form stable supramolecular gels in DMSO/H2O and MeOH/H2O. Owing to trans–cis isomerization, this gel exhibited typical light-responsive behavior that led to a reversible gel–sol transition accompanied by a variation in morphology and rheology. Additionally, this trans-GAG gel displayed a distinct injectable self-healing property and outstanding biocompatibility. This work provides a simple yet rational strategy to fabricate stimuli-responsive materials from naturally occurring, eco-friendly molecules.
- Fang, Heshu,Zhao, Xia,Lin, Yuan,Yang, Song,Hu, Jun
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p. 1192 - 1198
(2018/04/02)
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- A promising catalyst for exclusive: Para hydroxylation of substituted aromatic hydrocarbons under UV light
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Herein, we describe a waterborne polymer/carbon dot nanocomposite system as an efficient, resourceful and sustainable photocatalyst for para-selective hydroxylation of substituted aromatic compounds using H2O2 under UV light. The polymer matrix and carbon dot generate a synergistic catalytic system. A unique structural attribute of the functionalities in this catalytic system attracts the aromatic substrates into close proximity and activates them. Additionally, the flexible molecular box-like structure of the hyperbranched polymer provides the ability for favorable three-point interaction with several substrates having various sizes by means of their multiple force networks and the increased accessibility of the active sites. The catalyst can be stored on the bench top for months and is reusable without considerable loss in its activity. The reaction was exclusively selective toward para hydroxylation irrespective of the nature of the substituents (electron donating or electron withdrawing) in the aromatic hydrocarbons. Hence, it is one of the most promising catalysts for selective hydroxylation of substituted aromatic hydrocarbons.
- Das, Vijay Kumar,Gogoi, Satyabrat,Choudary, Boyapati Manoranjan,Karak, Niranjan
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p. 4278 - 4283
(2017/09/29)
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- Facile, mild and convenient preparation and characterization of some novel schiff base ligands from synthetic diamines and salicylaldehyde
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Some novel Schiff base ligands have been prepared through condensation of salicylaldehyde with synthetic various primary diamines under mild reaction conditions. The used aromatic diamines were synthesized in good yields starting from low-cost commercially available materials. In these reactions, the Schiff base products have been afforded with excellent yields and appropriate reaction times. The structure of these ligands has been characterized by IR, 1H NMR and 13C NMR techniques.
- Naeimi, Hossein,Heidarnezhad, Arash
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p. 117 - 122
(2015/01/30)
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- Variable noninnocence of substituted azobis(phenylcyanamido)diruthenium complexes
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The synthetic chemistry of substituted 4,4′-azobis(phenylcyanamide) ligands was investigated, and the complexes [{Ru(tpy)(bpy)}2( μ-L)][PF6]2, where L = 2,2′:5,5′-tetramethyl-4,4′-azobis(phenylcyanamido) (Me4adpc2-), 2,2′-dimethyl-4,4′-azobis(phenylcyanamido) (Me2adpc2-), unsubstituted (adpc2-), 3,3′-dichloro-4,4′-azobis(phenylcyanamido) (Cl2adpc2-), and 2,2′:5,5′-tetrachloro-4,4′-azobis(phenylcyanamido) (Cl4adpc2-), were prepared and characterized by cyclic voltammetry and vis-near-IR (NIR) and IR spectroelectrochemistry. The room temperature electron paramagnetic resonance spectrum of [{Ru(tpy)(bpy)}2( μ-Me4adpc)]3+ showed an organic radical signal and is consistent with an oxidation-state description [RuII, Me4adpc?-, RuII]3+, while that of [{Ru(tpy)(bpy)}2( μ-Cl2adpc)]3+ at 10 K showed a low-symmetry RuIII signal, which is consistent with the description [RuIII, Cl2adpc2-, RuII]3+. IR spectroelectrochemistry data suggest that [{Ru(tpy)(bpy)}2( μ-adpc)]3+ is delocalized and [{Ru(tpy)(bpy)}2( μ-Cl2adpc)]3+ and [{Ru(tpy)(bpy)}2( μ-Cl4adpc)]3+ are valence-trapped mixed-valence systems. A NIR absorption band that is unique to all [{Ru(tpy)(bpy)}2( μ-L)]3+ complexes is observed; however, its energy and intensity vary depending on the nature of the bridging ligand and, hence, the complexes oxidation-state description.
- Choudhuri, Mohommad M. R.,Behzad, Mahdi,Al-Noaimi, Mousa,Yap, Glenn P. A.,Kaim, Wolfgang,Sarkar, Biprajit,Crutchley, Robert J.
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supporting information
p. 1508 - 1517
(2015/06/16)
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- Anion-tunable control of thermal Z→E isomerisation in basic azobenzene receptors
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Herein, we report that thermal Z→E isomerisation of simple azobenzene urea derivatives is selectively and predictably controlled by anion binding. The rate of this process depends strictly on the anion concentration and its binding affinity to the Z-isomer of the azobenzene host, i.e. increased rate constants are observed for higher anion concentration as well as for more strongly bound guests. The origin of this phenomenon is attributed to the electron density transfer from the anion to the host π-system, resulting in increased repulsion between the lone electron pairs in the NN bond.
- Dbrowa, Kajetan,Niedbala, Patryk,Jurczak, Janusz
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supporting information
p. 15748 - 15751
(2015/02/19)
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- Dynamic photo-control of kinesin on a photoisomerizable monolayer - Hydrolysis rate of ATP and motility of microtubules depending on the terminal group
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The reversibly and repeatedly altered gliding motility of microtubules driven by kinesin on the photoresponsive monolayer surface is studied. It was confirmed that an azobenzene monolayer surface needs to have free amino terminal groups for the successful dynamic control of the motility of microtubule. The surface of the azobenzene monolayer with terminal amino groups can dynamically control the ATP hydrolysis activity of kinesin which resulted in the change in motility of the microtubules.
- Rahim, M. K. Abdul,Kamei, Takashi,Tamaoki, Nobuyuki
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p. 3321 - 3331
(2012/06/04)
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- Organocatalytic oxidative dehydrogenation of aromatic amines for the preparation of azobenzenes under mild conditions
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(Diacetoxyiodo)benzene used as stoichiometrically and catalytically in the preparation of azobenzenes under mild reaction conditions was developed. The metal-free oxidation systems demonstrated wide substituents tolerance, alkyls, halogens, and several versatile functional groups, such as amino, ethynyl, and carboxyl substituents are compatible well, and the corresponding products could be formed with good to excellent yields. In this disclosed method, the more large scale formation of azo compounds also could be carried out successfully. Of note that 3-ethynylbenzenamine applied as a very useful cross dehydrogenative partner, which coupled with different anilines, providing asymmetrical azo compounds with acceptable yields in one step under very mild reaction conditions.
- Ma, Hengchang,Li, Wenfeng,Wang, Jian,Xiao, Guanghai,Gong, Yuan,Qi, Chunxuan,Feng, Yunpeng,Li, Xiufang,Bao, Zhikang,Cao, Wei,Sun, Qiangsheng,Veaceslav, Caraus,Wang, Feng,Lei, Ziqiang
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experimental part
p. 8358 - 8366
(2012/09/21)
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- Fast synthesis of hydrazine and Azo derivatives by oxidation of rare-earth-metal-nitrogen bonds
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A novel N-N coupling reaction was developed through the oxidation of rare-earth-metal-nitrogen bonds produced by treatment of the easily available rare-earth-metal amides [(Me3Si)2N]3RE(μ-Cl) Li(THF)3 with aromatic primary or secondary amines. The reaction provides the symmetrical or unsymmetrical azo compounds and hydrazine derivatives in good to high yields within a very short time under mild conditions.
- Zhang, Lijun,Xia, Jing,Li, Qinghai,Li, Xihong,Wang, Shaowu
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scheme or table
p. 375 - 378
(2011/03/21)
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- Synthesis of azo compounds by nanosized iron-promoted reductive coupling of aromatic nitro compounds
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Treatment of a variety of aromatic nitro compounds with the active-iron based reducing system composed of FeCl2·4H2O, an excess of lithium powder and a catalytic amount of 4,4′-di-tert-butylbiphenyl (DTBB, 5 mol %) in THF at room temperature, led to the formation of the corresponding symmetrically substituted azo compounds in good yield, resulting from a reductive coupling process. Some other functionalities including carbonyl, halogen, amino and hydroxyl groups, demonstrated to be compatible with the reaction conditions, giving none reduced or coupled by-products. In all cases, the azo compounds formed have not experienced over-reduction to the corresponding hydrazo or amino derivatives even upon prolonged heating or using an excess of the reducing system.
- Moglie, Yanina,Vitale, Cristian,Radivoy, Gabriel
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p. 1828 - 1831
(2008/09/18)
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- Synthesis and photoresponsive properties of a molecularly imprinted polymer
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A photoresponsive molecularly imprinted polymer was prepared from a di(ureidoethylenemethacrylate)azobenzene monomer, using a methotrexate analogue as template. Photoisomerization of the 3D crosslinked polymer matrix allowed switching the substrate affinity by altering the geometry and spatial arrangement of the receptor binding sites. As a result, controlled release and uptake of the template (or analogous ligands) were obtained.
- Gomy, Christophe,Schmitzer, Andreea R.
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p. 3865 - 3868
(2008/02/12)
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- Rates of thermolysis of azidobenzenes in solution: Large stabilizations of transition states by charge transfer from electron-donor substituents
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Introduction of +R type para substituents into azidobenzenes causes very large increases in rate of thermolysis, up to 225-fold. The rates of nitrobenzene solutions at 120°C follow a Hammett-type linear free energy relationship log k = -5.44 - 2.33σ1 - 1.48R+ which indicates conjugative stabilization of a nitrene-like transition state. ortho-Substituents of the +R type causes still larger rate enhancements, up to 456-fold for 2-amino, which identify a special resonance proximity effect. It is suggested that the very high rates reported for such α-azidoheterocycles as 2-azidothiophene are due to similar resonance stabilizations and not to ring-opening concerted with nitrogen loss.
- Dyall, Leonard K.,L'abbe, Gerrit,Dehaen, Wim
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p. 971 - 975
(2007/10/03)
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- Chemoselective reductive coupling of nitroarenes with magnesium in methanol via single electron transfer
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A chemoselective reductive coupling of nitroarenes using magnesium in methanol has been reported at ambient temperature. While the cyano, formyl, methoxycarbonyl, methyl, methoxy, phenyl, amino, and chloro groups are unaffected, iodo and bromo groups undergo dehalogenation but in a slower reaction than the coupling of nitro group. The coupling is believed to be proceeding via SET from Mg to nitroarenes.
- Khurana, Jitender M.,Ray, Abhijit
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p. 407 - 410
(2007/10/03)
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- Basic azo dyestuffs of the 3-cyano-2,4,6-triamino pyridine series
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The new basic azo dyestuffs of the formula STR1 wherein the symbols have the meaning given in the description, are suitable for dyeing synthetic and naturally occurring substrates which can be dyed with basic dyestuffs.
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- Reduction of Nitroarenes Using an Activated Catalyst Prepared by the Reduction of Nickel Nitrate with Excess Zinc in the Presence of Hydrazine Monohydrate
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An activated catalyst prepared from a mixture of nickel nitrate hexahydrate with zinc in dry ethanol under reflux showed exceptional catalytic activity for the reduction of nitroarenes to the corresponding azoxy compounds exclusively in the presence of hydrazine monohydrate.However when nickel nitrate hexahydrate was replaced by nickel chloride dihydrate with zinc, only the aminoarenes were formed in high yields.With unactivated catalyst, the reduction reaction from a mixture of nitroarenes, nickel nitrate or chloride, excess zinc and hydrazine monohydrate gave the corresponding azo, azoxy and amino compounds in much lower yields.
- Yun, Tae Ho,Park, Moon Keu,Han, Byung Hee
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p. 2774 - 2788
(2007/10/02)
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- Insecticide evaporator comprising a stabilizer
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Insecticide evaporator comprising at least one volatile phosphoric ester insecticide, an agent for stabilizing the said ester against decomposition by protonization and used in an amount of 0.2 to 20% based on the weight of phosphoric ester, characterized in that the stabilizing agent contains at least one compound selected from the compounds of the chemical class of 1,3-benzodioxoles and at least one diazene.
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- Evaporator system comprising a stabilized pesticidal phosphoric acid ester and method for stabilizing such ester enclosed in an evaporator
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An evaporator system adapted for emitting insect killing vapors of an insecticide therefrom and comprising a liquid or solid composition enclosed therein, said insecticide consisting in at least one volatile phosphoric acid ester which is stabilized by at least one diazene compound.
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