cas 623-11-0, P-NITROSOTOLUENE | Articles data

Articles about 623-11-0Total 75 be found

Article title
Article abstract
Author
Journal number and time
Download

Effect of Malt-PEG-Abz@RSL3 micelles on HepG2 cells based on NADPH depletion and GPX4 inhibition in ferroptosis
Ferroptosis is a regulated cell death pathway which depends on iron. Ferroptosis can be induced by limiting intracellular glutathione (GSH) synthesis, or inhibiting the activity of GPX4, or increasing intracellular accumulation of PE-AA-OOH, all of which involve NADPH. Therefore, NADPH depletion, excessive PE-AA-OOH, and GPX4 deficiency are generally considered to be the main characteristics of ferroptosis. In this research, the novel self-assembly nanomicelles modified by maltose ligand (Malt-PEG-Abz@RSL3) with superior nano characteristics were designed and fabricated. Malt-PEG-Abz@RSL3 micelles achieved active targeted drug delivery due to the high expression of glucose transporter (GLUT) and high uptake by HepG2 cells. Maltose-polyethylene glycol broke to release RSL3 for inhibiting GPX4 activity when Malt-PEG-Abz@RSL3 micelles entered the cells. Meanwhile, key coenzyme NADPH that participated in synthesis of GSH and Trx(SH)2 was depleted by azobenzene moiety, resulting in decreasing GSH and Trx(SH)2, which dually induced ferroptosis in tumour cells and promoted cell apoptosis.
Cheng, Xu,Gao, Chuya,Gong, Chen,Li, Wenhua,Liu, Xiaoying,Peng, Haisheng,Tang, Shukun,Tao, Haiquan,Yang, Bo,Zhang, Wenyuan
(2021)
Read Online

Rhodium(III)-catalyzed regioselective C–H nitrosation/annulation of unsymmetrical azobenzenes to synthesize benzotriazole N-oxides via a RhIII/RhIII redox-neutral pathway
A Rh(III)-catalyzed regioselective C–H nitrosation/annulation reaction of unsymmetrical azobenzenes with [NO][BF4] has been developed to achieve high-yielding syntheses of benzotriazole N-oxides with excellent functional group tolerance. Computational studies have revealed that this oxidative C–H functionalization reaction involves an interesting redox-neutral Rh(III)/Rh(III) pathway without the change of Rh oxidation state.
Zhang, Yuanfei,Chen, Zhe-Ning,Su, Weiping
supporting information

(2021/05/19)

Understanding Mechanistic Differences between 3-Diazoindolin-2-Imines and N-Sulfonyl-1,2,3-Triazoles in the Rh2(II)-Catalyzed Reactions with Nitrosoarenes
The employment of α-iminometallocarbenes to construct valuable N-containing compounds has attracted significant research interest. Herein, the nucleophilic addition of nitrosoarenes with the α-imino rhodium carbene species (I), which is derived from Rh2(II)-catalyzed denitrogenation of 3-diazoindolin-2-imines, to produce synthetically useful 2-iminoindolin-nitrones is described. Mechanistically, the N-attack of nitrosoarenes with the carbene site of I is proposed. For the analogous Rh2(II)-catalyzed reaction of nitrosoarenes with N-sulfonyl-1,2,3-triazoles reported by Li and co-workers (Org. Lett. 2014, 16, 6394), however, the O-attack of nitrosoarenes with the carbene site of α-imino rhodium carbene species (II) is more favorable to occur than the N-attack. The subsequent transformation to yield the product of N-acylamidines is rationalized based on computational studies. The mechanistic differences for the reactions of nitrosoarenes with α-imino rhodium carbene species I and II are discussed.
Bao, Xiaoguang,Fu, Rui,Gao, Ke,Kou, Luyao,Zhou, Shaofang
supporting information
p. 1565 - 1572
(2021/05/28)

Reversible Photoswitchable Inhibitors Generate Ultrasensitivity in Out-of-Equilibrium Enzymatic Reactions
Ultrasensitivity is a ubiquitous emergent property of biochemical reaction networks. The design and construction of synthetic reaction networks exhibiting ultrasensitivity has been challenging, but would greatly expand the potential properties of life-like materials. Herein, we exploit a general and modular strategy to reversibly regulate the activity of enzymes using light and show how ultrasensitivity arises in simple out-of-equilibrium enzymatic systems upon incorporation of reversible photoswitchable inhibitors (PIs). Utilizing a chromophore/warhead strategy, PIs of the protease α-chymotrypsin were synthesized, which led to the discovery of inhibitors with large differences in inhibition constants (Ki) for the different photoisomers. A microfluidic flow setup was used to study enzymatic reactions under out-of-equilibrium conditions by continuous addition and removal of reagents. Upon irradiation of the continuously stirred tank reactor with different light pulse sequences, i.e., varying the pulse duration or frequency of UV and blue light irradiation, reversible switching between photoisomers resulted in ultrasensitive responses in enzymatic activity as well as frequency filtering of input signals. This general and modular strategy enables reversible and tunable control over the kinetic rates of individual enzyme-catalyzed reactions and makes a programmable linkage of enzymes to a wide range of network topologies feasible.
Teders, Michael,Pogodaev, Aleksandr A.,Bojanov, Glenn,Huck, Wilhelm T. S.
supporting information
p. 5709 - 5716
(2021/05/07)

Photochromic controlled permeable small molecule cross-linked vesicle as well as preparation method and application thereof
The invention discloses a photochromic controlled-permeation small-molecule crosslinked vesicle CSMVs as well as a preparation method and application thereof. Belong to micromolecule self-assembly technical field. The invention firstly synthesizes an azobenzene amphiphilic compound, and then further cross-linking to prepare the photochromic controllable permeable small-molecule cross-linked vesicle. The controlled release system is simple to prepare, high in stability, intelligent in control, and capable of exhibiting real-time controllable permeability in time and space, CSMVs at the molecular level due to the molecular structure of the vesicle wall, and instantaneous controlled release is exhibited. In cancer. The method has wide application prospects in the accurate treatment of diseases such as diabetes and bacterial infection.
-
Paragraph 0033-0036

(2021/09/01)

Azobenzene-Based Cross-Linked Small-Molecule Vesicles for Precise Oxidative Damage Treatments Featuring Controlled and Prompt Molecular Release
Precise therapy has become prevalent in clinical practice owing to its accurate and efficient targeting treatment of diseases. Such treatments involving polymersomes as carriers have great potential to lesion sites without damage to normal tissues. However, due to the inherent thick hydrophobic layer of polymersomes, an instantaneous release response to external stimuli remains a challenge. To tackle this challenge, here, we report on the synthesis and applications of azobenzene-containing photochromic vesicles as delivery vectors. These vesicles are assembled from small-molecule amphiphiles that have been developed to provide a fast response and promote instantaneous release due to molecular size reduction compared with macromolecular polymersomes. After cross-linking, the stability of vesicles under a physiological environment is notably enhanced. By varying UV and visible light irradiation, the “gate” of vesicles can be opened and closed reversibly for the controlled release of capsuled cargoes. In vitro experiments display that the vesicles can be applied to load cysteamine for eliminating excess reactive oxygen. The synthesized vesicles here show high performance in controlled and instantaneous release in cells both in time and space. By our approach, oxidative damage to cellular biomolecules can be substantially reduced.
Yao, Yongchao,Yu, Yunlong,Wan, Xiaohui,Yan, Daoping,Chen, Ying,Luo, Jianbin,Vancso, G. Julius,Zhang, Shiyong
p. 7357 - 7366
(2021/10/01)

Phenylimino Indolinone: A Green-Light-Responsive T-Type Photoswitch Exhibiting Negative Photochromism
Imines are photoaddressable motifs useful in the development of new generations of molecular switches, but their operation with low-energy photons and control over isomer stability remain challenging. Based on a computational design, we developed phenylimino indolinone (PIO), a green-light-addressable T-type photoswitch showing negative photochromism. The isomerization behavior of this photoactuator of the iminothioindoxyl (ITI) class was studied using time-resolved spectroscopies on time scales from femtoseconds to the steady state and by quantum-chemical analyses. The understanding of the isomerization properties and substituent effects governing these photoswitches opens new avenues for the development of novel T-type visible-light-addressable photoactuators based on C=N bonds.
Buma, Wybren Jan,Crespi, Stefano,Di Donato, Mariangela,Doria, Sandra,Feringa, Ben L.,Hilbers, Michiel F.,Kiss, Ferdinand L.,Simeth, Nadja A.,Stindt, Charlotte N.,Szymański, Wiktor,Toyoda, Ryojun,Wesseling, Sammo
supporting information
p. 25290 - 25295
(2021/10/25)

Selective Mild Oxidation of Anilines into Nitroarenes by Catalytic Activation of Mesoporous Frameworks Linked with Gold-Loaded Mn3O4 Nanoparticles
This work reports the synthesis and catalytic application of mesoporous Au-loaded Mn3O4 nanoparticle assemblies (MNAs) with different Au contents, i. e., 0.2, 0.5 and 1 wt %, towards the selective oxidation of anilines into the corresponding nitroarenes. Among common oxidants, as well as several supported gold nanoparticle platforms, Au/Mn3O4 MNAs containing 0.5 wt % Au with an average particle size of 3–4 nm show the best catalytic performance in the presence of tert-butyl hydroperoxide (TBHP) as a mild oxidant. In all cases, the corresponding nitroarenes were isolated in high to excellent yields (85–97 %) and selectivity (>98 %) from acetonitrile or greener solvents, such as ethyl acetate, after simple flash chromatography purification. The 0.5 % Au/Mn3O4 catalyst can be isolated and reused four times without a significant loss of its activity and can be applied successfully to a lab-scale reaction of p-toluidine (1 mmol) leading to the p-nitrotulene in 83 % yield. The presence of AuNPs on the Mn3O4 surface enhances the catalytic activity for the formation of the desired nitroarene. A reasonable mechanism was proposed including the plausible formation of two intermediates, the corresponding N-aryl hydroxylamine and the nitrosoarene.
Armatas, Gerasimos S.,Daikopoulou, Vassiliki,Koutsouroubi, Eirini D.,Lykakis, Ioannis N.,Skliri, Euaggelia
(2021/11/01)

Photochromic Evaluation of 3(5)-Arylazo-1 H-pyrazoles
The desire to photocontrol molecular properties ranging from materials to pharmacology using light as an external trigger with high spatiotemporal resolution led to the development of a broad range of photochromic scaffolds. Among them, azobenzenes are synthetically well accessible and show excellent fatigue resistance. Their photochromic properties vary with the substitution pattern and for different heteroarenes. However, the photochromism of 3(5)-substituted-1H-pryazoles has not yet been investigated, although this compound class offers interesting possibilities of metal ion coordination and hydrogen bond formation via its NH moiety. Herein, we present the results of an experimental and computational investigation of arylazo-3(5)-arylazo-1H-pyrazoles. To elucidate their properties, solvent and substitution effects on their light absorption, thermal half-lives, photostationary states, fatigue, and quantum yields were determined.
Rustler, Karin,Nitschke, Philipp,Zahnbrecher, Sophie,Zach, Julia,Crespi, Stefano,K?nig, Burkhard
p. 4079 - 4088
(2020/04/09)

Photoswitchable Conjugated Oligoelectrolytes for a Light-Induced Change of Membrane Morphology
The synthesis of a new conjugated oligoelectrolyte (COE), namely DSAzB, is described, which contains a conjugated core bearing a diazene moiety in the center of its electronically delocalized structure. Similar to structurally related phenylenevinylene-based COEs, DSAzB readily intercalates into model and natural lipid bilayer membranes. Photoinduced isomerization transforms the linear trans COE into a bent or C-shape form. It is thereby possible to introduce DSAzB into the bilayer of a cell and disrupt its integrity by irradiation with light. This leads to controlled permeabilization of membranes, as demonstrated by the release of calcein from DMPG/DMPC vesicles and by propidium iodide influx experiments on S. epidermidis. Both experiments support that the permeabilization is selective for the light stimulus, highly efficient, and repeatable. Target-selective and photoinduced actions demonstrated by DSAzB may have broad applications in biocatalysis and related biotechnologies.
Bazan, Guillermo C.,Leifert, Dirk,Limwongyut, Jakkarin,Mikhailovsky, Alexander A.,Moreland, Alex S.
supporting information
p. 20333 - 20337
(2020/09/07)

Tungstate-supported silica-coated magnetite nanoparticles: a novel magnetically recoverable nanocatalyst for green synthesis of nitroso arenes
Tungstate ion was heterogenized on the silica-coated magnetite nanoparticles and applied for the selective oxidation of anilines to nitroso arenes—with hydrogen peroxide/urea as oxidant in dimethyl carbonate as solvent—in moderate–good yields (40–96%). The catalyst was characterized using different techniques including Fourier-transform infrared spectroscopy, X-ray powder diffraction, vibrating sample magnetometry, scanning electron microscopy, energy dispersive X-ray and inductively coupled plasma atomic emission spectroscopy (ICP-AES). The catalyst was easily recovered using an external magnet and reused for six times.
Jadidi Nejad, Masoume,Yazdani, Elahe,Kazemi Miraki, Maryam,Heydari, Akbar
p. 1575 - 1583
(2019/09/09)

A Photoswitchable Agonist for the Histamine H3 Receptor, a Prototypic Family A G-Protein-Coupled Receptor
Spatiotemporal control over biochemical signaling processes involving G protein-coupled receptors (GPCRs) is highly desired for dissecting their complex intracellular signaling. We developed sixteen photoswitchable ligands for the human histamine H3 receptor (hH3R). Upon illumination, key compound 65 decreases its affinity for the hH3R by 8.5-fold and its potency in hH3R-mediated Gi protein activation by over 20-fold, with the trans and cis isomer both acting as full agonist. In real-time two-electrode voltage clamp experiments in Xenopus oocytes, 65 shows rapid light-induced modulation of hH3R activity. Ligand 65 shows good binding selectivity amongst the histamine receptor subfamily and has good photolytic stability. In all, 65 (VUF15000) is the first photoswitchable GPCR agonist confirmed to be modulated through its affinity and potency upon photoswitching while maintaining its intrinsic activity, rendering it a new chemical biology tool for spatiotemporal control of GPCR activation.
Hauwert, Niels J.,Mocking, Tamara A. M.,Da Costa Pereira, Daniel,Lion, Ken,Huppelschoten, Yara,Vischer, Henry F.,De Esch, Iwan J. P.,Wijtmans, Maikel,Leurs, Rob
supporting information
p. 4531 - 4535
(2019/03/07)

Fluorination of Photoswitchable Muscarinic Agonists Tunes Receptor Pharmacology and Photochromic Properties
Red-shifted azobenzene scaffolds have emerged as useful molecular photoswitches to expand potential applications of photopharmacological tool compounds. As one of them, tetra-ortho-fluoro azobenzene is well compatible for the design of visible-light-responsive systems, providing stable and bidirectional photoconversions and tissue-compatible characteristics. Using the unsubstituted azobenzene core and its tetra-ortho-fluorinated analogue, we have developed a set of uni- and bivalent photoswitchable toolbox derivatives of the highly potent muscarinic acetylcholine receptor agonist iperoxo. We investigated the impact of the substitution pattern on receptor activity and evaluated the different binding modes. Compounds 9b and 15b show excellent photochemical properties and biological activity as fluorination of the azobenzene core alters not only the photochromic behavior but also the pharmacological profile at the muscarinic M1 receptor. These findings demonstrate that incorporation of fluorinated azobenzenes not just may alter photophysical properties but can exhibit a considerably different biological profile that has to be carefully investigated.
Agnetta, Luca,Bermudez, Marcel,Riefolo, Fabio,Matera, Carlo,Claro, Enrique,Messerer, Regina,Littmann, Timo,Wolber, Gerhard,Holzgrabe, Ulrike,Decker, Michael
supporting information
p. 3009 - 3020
(2019/05/08)

Rhodium-Catalyzed Reaction of Azobenzenes and Nitrosoarenes toward Phenazines
A rhodium-catalyzed annulative reaction between azobenzenes and nitrosoarenes has been developed, leading to a series of phenazines in moderate to good yields. This procedure proceeds with sequential chelation-assisted addition of aryl C-H to nitrosoarenes and ring closure by electrophilic attack of azo group to aryl. During this transformation, the azo group served as not only a traceless directing group but also a building block in the final products.
Xiao, Yan,Wu, Xiaopeng,Wang, Hepan,Sun, Song,Yu, Jin-Tao,Cheng, Jiang
supporting information
p. 2565 - 2568
(2019/04/30)

Substrate-Controlled Divergent Synthesis of Enaminones and Pyrroles from Indolizines and Nitroso Compounds
It is imperative to learn new synthetic transformations to succeed in drug discovery and development. We report the substrate-driven synthesis of β-enaminones and N-aryl pyrroles from indolizines and nitrosoarenes; aryl-substituted indolizines lead to β-enaminones in a regio- and diastereoselective manner, whereas alkyl-substituted indolizines produce tetrasubstituted pyrroles. All products contain a pyridine unit, the second most abundant ring (after phenyl) in the FDA Orange Book. In both cases, the reactions proceed at room temperature without any catalyst. Moreover, both types of products can be obtained in one pot from commercial materials as well as at a gram scale. It is worthy of note that the regioselectivity of the β-enaminones is inaccessible by the standard literature methods and their utility has been exemplified in the synthesis of diverse heterocycles. We have made every endeavor to put forward the corresponding reaction mechanisms based on thorough experimental work. (Figure presented.).
González-Soria, María José,Alonso, Francisco
supporting information
p. 5005 - 5017
(2019/11/03)

Niobium oxide prepared through a novel supercritical-CO2-assisted method as a highly active heterogeneous catalyst for the synthesis of azoxybenzene from aniline
High-surface area Nb2O5 nanoparticles were synthesised by a novel supercritical-CO2-assisted method (Nb2O5-scCO2) and were applied for the first time as a heterogeneous catalyst in the oxidative coupling of aniline to azoxybenzene using the environmentally friendly H2O2 as the oxidant. The application of scCO2 in the synthesis of Nb2O5-scCO2 catalyst resulted in a significantly enhanced catalytic activity compared to a reference catalyst prepared without scCO2 (Nb2O5-Ref) or to commercial Nb2O5. Importantly, the Nb2O5-scCO2 catalyst achieved an aniline conversion of 86% (stoichiometric maximum of 93% with the employed aniline-to-H2O2 ratio of 1?:?1.4) with an azoxybenzene selectivity of 92% and with 95% efficiency in H2O2 utilisation in 45 min without requiring external heating (the reaction is exothermic) and with an extremely low catalyst loading (weight ratio between the catalyst and substrate, Rc/s = 0.005). This performance largely surpasses that of any other heterogeneous catalyst previously reported for this reaction. Additionally, the Nb2O5 catalyst displayed high activity also for substituted anilines (e.g. methyl or ethyl-anilines and para-anisidine) and was reused in consecutive runs without any loss of activity. Characterisation by means of N2-physisorption, XRD, FTIR and TEM allowed the correlation of the remarkable catalytic performance of Nb2O5-scCO2 to its higher surface area and discrete nanoparticle morphology compared to the aggregated larger particles constituting the material prepared without scCO2. A catalytic test in the presence of a radical scavenger proved that the reaction follows a radical pathway.
Tao, Yehan,Singh, Bhawan,Jindal, Vanshika,Tang, Zhenchen,Pescarmona, Paolo P.
p. 5852 - 5864
(2019/11/11)

A novel synthesis of N-hydroxy-3-aroylindoles and 3-aroylindoles
A straightforward indole synthesis via annulation of C-nitrosoaromatics with conjugated terminal alkynones was realised achieving a simple, highly regioselective, atom- and step economical access to 3-aroylindoles in moderate to good yields. Further functionalizations of indole scaffolds were investigated and an easy way to JWH-018, a synthetic cannabinoid, was achieved.
Ieronimo, Gabriella,Palmisano, Giovanni,Maspero, Angelo,Marzorati, Alessandro,Scapinello, Luca,Masciocchi, Norberto,Cravotto, Giancarlo,Barge, Alessandro,Simonetti, Marco,Ameta, Keshav Lalit,Nicholas, Kenneth M.,Penoni, Andrea
supporting information
p. 6853 - 6859
(2018/10/20)

Copper-catalyzed pyrrole synthesis from 3,6-dihydro-1,2-oxazines
Highly-functionalized pyrroles could be effectively synthesized from 3,6-dihydro-1,2-oxazines using a heterogeneous copper on carbon (Cu/C) under neat heating conditions. Furthermore, the in situ formation of 3,6-dihydro-1,2-oxazines via the hetero Diels-Alder reaction between nitroso dienophiles and 1,3-dienes and the following Cu/C-catalyzed pyrrole synthesis also provided the corresponding pyrrole derivatives in a one-pot manner.
Yasukawa, Naoki,Kuwata, Marina,Imai, Takuya,Monguchi, Yasunari,Sajiki, Hironao,Sawama, Yoshinari
supporting information
p. 4409 - 4413
(2018/10/17)

Reversible Laser-Induced Bending of Pseudorotaxane Crystals
This study investigated the dynamic photoresponse of pseudorotaxane crystals with azobenzene and ferrocenyl groups in the axle component. X-ray crystallography showed pseudorotaxanes with a methylazobenzene group and a dibromophenylene ring in the cyclic component to exhibit twisting of the trans-azobenzene groups at torsion angles of 17° and 38°, respectively. Repeated alternating laser irradiation of the crystals at 360 and 445 nm produced bending of 20-30° in opposite directions, with no evidence of decay. Under 445 nm irradiation, bending took place within 0.3 s. A crystal of nonsubstituted pseudorotaxane showed bending of only 2° under 360 nm irradiation due to multiple π-π interactions between the planar trans-azobenzene groups. The pseudorotaxane crystals have two chromophores, bent rapidly and reversibly on irradiation at rates depending on the molecular structure.
Cheng, Shao-Chi,Chen, Kai-Jen,Suzaki, Yuji,Tsuchido, Yoshitaka,Kuo, Ting-Shen,Osakada, Kohtaro,Horie, Masaki
supporting information
p. 90 - 93
(2018/01/17)

Coupling of N -Nosylhydrazones with Nitrosoarenes: Transition-Metal-Free Approach to (Z)- N -Arylnitrones
An efficient and transition-metal-free protocol for the synthesis of (Z)- N -arylnitrones from the direct coupling of N -nosylhydrazones with nitrosoarenes under mild conditions is described. The protocol is compatible with a wide range of functional groups placed on both the reagents and provided the corresponding nitrones in good to excellent yields by simple recrystallization process. The use of these 1,3-dipoles for the synthesis of substituted indoles is elaborated for 2,3-diphenyl-1 H -indole.
Liu, Tingting,Liu, Zhaohong,Liu, Zhenhua,Hu, Donghua,Wang, Yeming
supporting information
p. 1728 - 1736
(2018/02/14)

Synthesis of Nitrosobenzene Derivatives via Nitrosodesilylation Reaction
The electrophilic ipso-substitution of trimethylsilyl-substituted benzene derivatives into nitrosobenzene derivatives is reported. The optimization of the reaction conditions was performed for moderately electron-deficient, electron-rich, and sterically hindered starting materials by varying reaction time, temperature, and equivalents of NOBF4. Also, a stable intermediate of the nitrosation reaction could be characterized by 19F NMR which can be assigned to a NO+ adduct with the nitrosobenzene derivative. This complex decomposes upon aqueous workup and liberates the desired nitrosobenzene derivative.
Kohlmeyer, Corinna,Klüppel, Maike,Hilt, Gerhard
p. 3915 - 3920
(2018/04/14)

Palladium-catalyzed annulation of 2-(aryldiazenyl) aniline with dimethyl sulfoxide to access N-aryl-1H-benzo[d]imidazol-1-amine
A palladium-catalyzed annulation of 2-(aryldiazenyl) aniline and dimethyl sulfoxide was developed to access N-aryl-1H-benzo[d]imidazol-1-amine in moderate to good yields. Activated by 1,4-diazabicyclo[2.2.2]octane bis(sulfur dioxide) adduct (DABSO), DMSO served as a “[dbnd]CH[sbnd]” fragment during this procedure. It represents a facile pathway leading to benzimidazoles.
Wang, Hepan,Sun, Song,Cheng, Jiang
supporting information
p. 3875 - 3878
(2017/09/15)

Titania-Supported Gold Nanoparticles Catalyze the Selective Oxidation of Amines into Nitroso Compounds in the Presence of Hydrogen Peroxide
In this article, the catalytic activity of titania-supported gold nanoparticles (Au/TiO2) was studied for the selective oxidation of amines into nitroso compounds using hydrogen peroxide (H2O2). Gold nanoparticles deposited on Degussa P25 polymorphs of titania (TiO2) have been found to promote the selective formation of a variety of nitroso arenes in high yields and selectivities, even in a large-scale synthesis. In contrast, alkyl amines are oxidized to the corresponding oximes under the examined conditions. Kinetic studies indicated that aryl amines substituted with electron-donating groups are oxidized faster than the corresponding amines bearing an electron-withdrawing functionality. A Hammett-type kinetic analysis of a range of para-X-substituted aryl amines implicates an electron transfer (ET) mechanism (ρ=-1.15) for oxidation reactions with concomitant formation of the corresponding N-aryl hydroxylamine as possible intermediate. We also show that the oxidation protocol of aryl amines in the presence of 1,3-cyclohexadiene leads in excellent yields to the corresponding hetero Diels-Alder adducts between the diene and the in situ formed nitrosoarenes.
Fountoulaki, Stella,Gkizis, Petros L.,Symeonidis, Theodoros S.,Kaminioti, Eleni,Karina, Athanasia,Tamiolakis, Ioannis,Armatas, Gerasimos S.,Lykakis, Ioannis N.
supporting information
p. 1500 - 1508
(2016/05/19)

Azopyridine-imidacloprid derivatives as photoresponsive neonicotinoids
A series of imidacloprid derivatives containing an azopyridine motif as a photoswitchable functional group were designed and synthesized. The new version of photoresponsive imidacloprid analogues showed improved solubility in comparison with their azobenzene analogues. 1.2 to 2-fold activity difference was observed for these azopyridine-imidacloprids against house fly (Musca domestica) and cowpea aphid (Aphis craccivora) upon irradiation.
Li, Shen,Song, Run-Jiang,Wang, Dong-Hui,Tian, Xue,Shao, Xu-Sheng,Li, Zhong
p. 635 - 639
(2016/05/19)

Formal [4+2] cycloaddition of 3-ethoxycyclobutanones with azo compounds
Azobenzenes reacted with 3-ethoxycyclobutanoes to give 2,3-dihydro-pyridazin-4(1H)-ones by using EtAlCl2as a Lewis acid. Thus, ring cleavage of 3-ethoxycyclobutanones took place to form a zwitterionic intermediate by activation with EtAlCl2, and intermolecular formal [4+2] cycloaddition of the zwitterionic intermediate proceeded with azobenzenes to give 2,3-dihydro-pyridazin-4(1H)-ones after elimination of ethanol. Regioselectivity for cycloaddition of unsymmetrical azobenzenes, ring contraction and chemoselective reduction of 2,3-dihydro-pyridazin-4(1H)-ones, and [4+2] cycloaddition to 4-phenyl-1,2,4-triazolin-3,5-dione are also described.
Shima, Yusuke,Matsuo, Jun-ichi
supporting information
p. 4066 - 4069
(2016/08/18)

Enantioselective Nitroso Aldol Reaction Catalyzed by a Chiral Phosphine–Silver Complex
A catalytic asymmetric O-nitroso aldol reaction of alkenyl trifluoroacetates with nitrosoarenes was achieved by using QuinoxP*·AgOAc [(R,R)-QuinoxP* = (–)-(R,R)-2,3-bis(tert-butylmethylphosphino)quinoxaline] as the chiral precatalyst and N,N-diisopropylethylamine as the base precatalyst in the presence of methanol. Optically active α-aminooxy ketones with up to 99 % ee were regioselectively obtained in moderate to high yields by the in situ generated chiral silver enolates.
Yanagisawa, Akira,Lin, Yuqin,Takeishi, Akihiro,Yoshida, Kazuhiro
supporting information
p. 5355 - 5359
(2016/11/22)

In situ formation of gold nanoparticles on magnetic halloysite nanotubes via polydopamine chemistry for highly effective and recyclable catalysis?
In this study, we present a simple and green approach to fabricate a magnetic halloysite nanotube (MHNT) supported Au nanoparticle (NP) composite (MHNTs–PDA–Au) with a polydopamine functional coating for highly effective and recyclable catalysis. The fabrication of MHNTs–PDA–Au involves decoration of Fe3O4 NPs on HNTs via a one-step co-precipitation method, deposition of a polydopamine layer on the MHNTs and subsequent in situ reduction of Au NPs via polydopamine chemistry. All the processes are simple and eco-friendly without use of additional toxic reagents and complicated treatment. The obtained MHNTs–PDA–Au composite exhibits excellent and versatile catalytic activity toward the reduction of various nitrobenzene derivatives and methylene blue dye when only trace amounts of Au catalyst are used. In addition, the catalytic system can be easily recycled for several cycles based on its good magnetic properties. The synergistic combination of MHNTs, polydopamine coating and metal NPs offers a versatile platform for design of natural HNT based composite materials and will expand the applications of HNTs in heterogeneous catalysis, water purification and green chemistry.
Wei, Qiangbing,Shi, Ruirong,Lu, Dedai,Lei, Ziqiang
p. 29245 - 29253
(2018/05/31)

Dual photo- and pH-responsive supramolecular nanocarriers based on water-soluble pillar[6]arene and different azobenzene derivatives for intracellular anticancer drug delivery
Two novel types of supramolecular nanocarriers fabricated by the amphiphilic host-guest inclusion complex formed from water-soluble pillar[6]arene (WP6) and azobenzene derivatives G1 or G2 have been developed, in which G1 is structurally similar to G2 but has an extra phenoxy group in its hydrophobic region. Supramolecular micelles can be initially formed by WP6 with G1, which gradually transform into layered structures with liquid-crystalline properties, whereas stable supramolecular vesicles are obtained from WP6 and G2, which exhibit dual photo- and pH-responsiveness. Notably, the resulting WP6a??G2 vesicles can efficiently encapsulate anticancer drug mitoxantrone (MTZ) to achieve MTZ-loaded vesicles, which maintain good stability in a simulated normal physiological environment, whereas in an acid environment similar to that of tumor cells or with external UV irradiation, the encapsulated drug is promptly released. More importantly, cytotoxicity assay indicates that such vesicles have good biocompatibility and the MTZ-loaded vesicles exhibit comparable anticancer activity to free MTZ, especially with additional UV stimulus, whereas its cytotoxicity for normal cells was remarkably reduced. Flow cytometric analysis further confirms that the cancer cell death caused by MTZ-loaded vesicles is associated with apoptosis. Therefore, the dual pH- and UV-responsive supramolecular vesicles are a potential platform for controlled release and targeted anticancer drug delivery.
Hu, Xiao-Yu,Jia, Keke,Cao, Yu,Li, Yan,Qin, Shan,Zhou, Fan,Lin, Chen,Zhang, Dongmei,Wang, Leyong
supporting information
p. 1208 - 1220
(2015/03/05)

A Twist-Bend Nematic (NTB) Phase of Chiral Materials
New chiral dimers consisting of a rod-like and cholesterol mesogenic units are reported to form a chiral twist-bend nematic phase (NTB) with heliconical structure. The compressibility of the NTB phase made of bent dimers was found to be as large as in smectic phases, which is consistent with the nanoperiodic structure of the NTB phase. The atomic force microscopy observations in chiral bent dimers revealed a periodicity of about 50 nm, which is significantly larger than the one reported previously for non-chiral compounds (ca. 10 nm).
Gorecka, Ewa,Vaupoti, Nataa,Zep, Anna,Pociecha, Damian,Yoshioka, Jun,Yamamoto, Jun,Takezoe, Hideo
supporting information
p. 10155 - 10159
(2015/09/01)

High-Yield Lithiation of Azobenzenes by Tin-Lithium Exchange
The lithiation of halogenated azobenzenes by halogen-lithium exchange commonly leads to substantial degradation of the azo group to give hydrazine derivatives besides the desired aryl lithium species. Yields of quenching reactions with electrophiles are therefore low. This work shows that a transmetalation reaction of easily accessible stannylated azobenzenes with methyllithium leads to a near-quantitative lithiation of azobenzenes in para, meta, and ortho positions. To investigate the scope of the reaction, various lithiated azobenzenes were quenched with a variety of electrophiles. Furthermore, mechanistic 119Sn NMR spectroscopic studies on the formation of lithiated azobenzenes are presented. A tin ate complex of the azobenzene was detected and characterized at low temperature.
Strueben, Jan,Lipfert, Matthias,Springer, Jan-Ole,Gould, Colin A.,Gates, Paul J.,S?nnichsen, Frank D.,Staubitz, Anne
supporting information
p. 11165 - 11173
(2015/11/10)

NOVEL BIS-CHROMONE DERIVATIVES, METHODS FOR THEIR PREPARATION AND USES THEREOF
The invention relates to novel bis-chromone derivatives, methods for their preparation and their therapeutic application, especially in the treatment or prevention of disease involving mast cell activation, such as allergic disease. Provided is a compound according to the general Formula (I).
-
Page/Page column 20

(2014/07/08)

Azobenzene-functionalized metal-organic polyhedra for the optically responsive capture and release of guest molecules
Stimuli-responsive metal-organic polyhedra (srMOPs) functionalized with azobenzene showed UV-irradiation-induced isomerization from the insoluble trans-srMOP to the soluble cis-srMOP, whereas irradiation with blue light reversed this process. Guest molecules were trapped and released upon cis-to-trans and trans-to-cis isomerization of the srMOPs, respectively. This study provides a new direction in the ever-diversifying field of MOPs, while laying the groundwork for a new class of optically responsive materials. Lock in the guests, later set them free: Stimuli-responsive metal-organic polyhedra (srMOPs) functionalized with azobenzene showed UV-light-induced isomerization from insoluble srMOPs substituted with trans-azobenzene to soluble srMOPs with cis-azobenzene units; irradiation with blue light reversed this process (see picture). Guest molecules were trapped upon cis-to-trans and released upon trans-to-cis isomerization of the azobenzene units.
Park, Jinhee,Sun, Lin-Bing,Chen, Ying-Pin,Perry, Zachary,Zhou, Hong-Cai
supporting information
p. 5842 - 5846
(2014/06/10)

Trifluoromethylation of arenediazonium salts with fluoroform-derived CuCF3 in aqueous media
A new protocol has been developed for trifluoromethylation of arenediazonium salts with moisture-sensitive CuCF3 (from fluoroform) in aqueous media. The reaction is governed by a radical mechanism, tolerates a broad variety of functional groups, and is applicable to the synthesis of complex, polyfunctionalized molecules. This journal is the Partner Organisations 2014.
Lishchynskyi, Anton,Berthon, Guillaume,Grushin, Vladimir V.
supporting information
p. 10237 - 10240
(2014/08/18)

Design, synthesis, and inhibitory activity of potent, photoswitchable mast cell activation inhibitors
Allergic reactions affect millions of people worldwide. The need for new and effective antiallergic agents is evident, and insight into the underlying mechanisms that lead to allergic events is necessary. Herein, we report the design, synthesis, and activity of photoswitchable mast cell activation inhibitors. In mast cell degranulation assays, these inhibitors possess significantly greater potency than an original, chromone-based antiallergic agent. Furthermore, one of the photoswitchable inhibitors shows a significant difference in inhibitory activity between its two photoisomeric forms. Further optimization could ultimately lead to a photoswitchable compound suitable for studying mechanisms involved in allergic reactions in a novel manner, with activity addressable by light and with precise spatiotemporal control over events at the molecular level.
Velema, Willem A.,Van Der Toorn, Marco,Szymanski, Wiktor,Feringa, Ben L.
supporting information
p. 4456 - 4464
(2013/07/19)

Reversible switching between self-assembled homomeric and hybrid capsules
We present here the reversible, guest-controlled disproportionation of homomeric and hybrid capsules using photochemistry. The supramolecular containers are self-assembled from shallow and deep cavitand modules.
Lux, Jacques,Rebek, Julius
supporting information
p. 2127 - 2129
(2013/03/28)

Control of the equilibrium between 2-phosphinoazobenzenes and inner phosphonium salts by heat, solvent, acid, and photoirradiation
Several 2-phosphinoazobenzenes, which are in equilibrium with inner phosphonium salts, were synthesized. Effects of substituents, solvents, and acidic additives on their equilibria are described. Thermodynamic parameters of the equilibria in various solvents suggest that the acceptor character of the solvents is mainly responsible for the solvent effects. Addition of phenols changed the equilibria depending on their acidity. Substituents at the 4- and 4′-positions of the azobenzene also affected the equilibrium constants, which shifted the equilibrium toward the phosphonium salt in the order of their electron-withdrawing ability. Photoisomerization of the 2-phosphinoazobenzenes bearing electron-donating substituents at the 4- and 4′-positions, which shifted the equilibrium toward the 2-phosphinoazobenzene, proceeded successfully. While the phosphonium salt in equilibrium with the (E)-isomer of the 2-phosphinoazobenzene was protonated by perchlorophenol, the (Z)-isomer did not react with a proton source because it could not take on the form of an inner phosphonium salt. Thus, the properties and reactivity of the inner phosphonium salts in equilibrium with the phosphines can be successfully controlled by photoirradiation.
Yamamura, Masaki,Kano, Naokazu,Kawashima, Takayuki
experimental part
p. 110 - 123
(2012/03/07)

Mechanosynthesis of nitrosobenzenes: A proof-of-principle study in combining solvent-free synthesis with solvent-free separations
Mechanochemical Oxone oxidation of selected para-substituted anilines was used as a rapid and solvent-free route to nitrosobenzenes; besides avoiding bulk solvents and short reaction times, this method exploits high vapour pressures of nitrosobenzenes for the solvent-free separation of the product by sublimation, demonstrating an entirely solvent-free route to chemical synthesis and product isolation. The Royal Society of Chemistry.
Huskic, Igor,Halasz, Ivan,Friscic, Tomislav,Vancik, Hrvoj
supporting information
p. 1597 - 1600
(2013/02/23)

NO2/H3BO3 as an effective nitrosonium source for electrophilic aromatic nitrosation under MW-promoted solvent-free conditions
[Bmim]NO2/H3BO3 was used as a nitrosonium source for the efficient synthesis of nitrosoarenes. The reaction was accomplished under MW irradiation at 60 W in a solventless system. Side processes such as oxidation or dealkylation were not observed during the nitrosation of alkyl phenyl ethers in the presence of this new reagent. The satisfactory results were obtained with very short reaction time, simplicity in the experimental procedure and good to excellent yields.
Valizadeh, Hassan,Gholipour, Hamid
experimental part
p. 963 - 966
(2012/04/23)

New nitrite ionic liquid (IL-ONO) and nanoparticles of organosilane-based nitrite ionic liquid immobilized on silica as nitrosonium sources for electrophilic aromatic nitrosation
An improved method for the synthesis of nitrosoarenes has been developed using a new nitrite ionic liquid (IL-ONO) and immobilized nitrite ionic liquid. These ionic liquids play as nitrosonium sources for electrophilic aromatic nitrosation of active aromatics at 0-5 °C. Their action was accomplished in water and the satisfactory results were obtained under the mild conditions in short reaction time.
Valizadeh, Hassan,Amiri, Mohammad,Shomali, Ashkan
experimental part
p. 1103 - 1108
(2012/03/10)

Reduction of nitrosobenzenes to azoarenes with SmI2
A novel method was developed to synthesise azoarenes from nitrosobenzenes under mild conditions. Samarium (II) iodine was used to achieve the N-N coupling. The method also provides evidence for the proposed mechanism involved in the reduction of nitro compounds to the amines with SmI2.
Ye, Wei,Ding, Wenbo,Hu, Zhang,Yu, Yongping,Zou, Hongbin
body text
p. 214 - 215
(2010/07/08)

Nitrosobenzene cross-dimerization: Structural selectivity in solution and in solid state
Possibility of nitrosobenzenes to form dimeric molecular structures (azodioxides) is used as a model for intermolecular selectivity investigations in solution as well as in solid state. Cross-dimerization of different combinations of p- and m-substituted nitrosobenzene pairs was studied by variable temperature 1H NMR, solid-state NMR (CP MAS), IR, and ab initio calculations. It is evident that p-nitronitrosobenzene behaves nonselectively because it forms dimers with all the studied nitrosobenzene partners. In contrast, p-methoxynitrosobenzene in most cases does not form dimers. The evidence that ability to form dimers is different in solution than in the solid state can be explained by influence of molecular arrangements in the crystal lattice.
Biljan, Ivana,Cvjetojevic, Gorana,Smrecki, Vilko,Novak, Predrag,Mali, Gregor,Plavec, Janez,Babic, Darko,Mihalic, Zlatko,Vancik, Hrvoj
body text
p. 22 - 26
(2010/09/16)

Synthesis of functionalized triazatriangulenes for application in photo- Switchable self-assembled monolayers
Various triazatriangulenes are synthesized by nucleophilic attack at the central C atom of triazatriangulenium ions. The molecular functions, especially azobenzenes, are fixed via an ethynyl linker by in situ deprotection of trimethylsilylalkynes. The structure of two of these molecules is further investigated by X-ray crystallography. The photo-inducedtrans/cis-isomerization of the azobenzene substituted derivatives is analyzed in solution and shows great promise for the preparation of switchable functionalized monolayers, as the triazatriangulenes are known for their self-assembly on gold surfaces. [1].
Kubitschke, Jens,Naether, Christian,Herges, Rainer
experimental part
p. 5041 - 5055
(2010/11/05)

Preparation of azobenzenealkanethiols for self-assembled monolayers with photoswitchable properties
A series of azobenzenealkanethiol compounds with the structure p-RC 6H4N=NC6H4(CH2) nSH (n = 3, 4) was synthesized using a divergent strategy with the two anilines H2NC6H4(CH2) nSAc as central compounds. This strategy provides fast access to a broad variety of the respective azobenzenethiols without (note!) an oxygen atom in the alkyl chain, thus permitting the self-assembly of these compounds onto gold in a predictable conformation, also taking advantage of the previously found odd-even effect in aromatic-aliphatic hybrid systems. Initial experiments indicate that all of these molecules indeed form dense monolayers, in which the orientation of the azobenzene unit is determined by the number of methylene groups in the aliphatic part of the molecules. CSIRO 2010.
Krakert, Simone,Terfort, Andreas
body text
p. 303 - 314
(2011/06/23)

N-Oxidation of arylamines to nitrosobenzenes using chloroperoxidase purified from Musa paradisiaca stem juice
N-Oxidation of arylamines to their corresponding nitrosobenzenes using a new chloroperoxidase purified from Musa paradisiaca stem juice has been examined. The enzymatic characteristics of the stem chloroperoxidase using 4-chloroaniline as substrate were determined. The Km values for 4-chloroaniline and H2O2 were 770 μM and 154 μM respectively, while the pH and temperature optima were 4.4 and 30°C respectively. The substrate specificities of the enzyme for the arylamines 3,4-dichloroamine, p-aminobenzoic acid, p-toluidine, p-anisidine, m-anisidine, p-aminophenol, o-aminophenol and m-aminophenol have been characterized. The feasibility of using concentrated M. paradisiaca stem juice for the specific conversion of 4-chloroaniline to 4-chloronitrosobenzene has been demonstrated. This enzyme can be used for the N-oxidation of other arylamines.
Yadav, Pratibha,Sharma, Jitendra K.,K. Singh, Vinod,Yadav, Kapil D. S.
body text
p. 222 - 226
(2011/12/04)

Influence of 1,3-dichloroacetone on the regularities of decay of arylnitroso oxides
The decay kinetics of isomeric forms of a series of arylnitroso oxides in the presence of 1,3-dichloroacetone in acetonitrile was studied by the flash photolysis technique. The regularities observed are explained by the complex formation between the molecules of nitroso oxide and additive.
Chainikova,Safiullin
p. 2437 - 2442
(2014/05/06)

Selective N-oxidation of aromatic amines to nitroso derivatives using a molybdenum acetylide oxo-peroxo complex as catalyst
The molybdenum acetylide oxo-peroxo complex obtained in situ by the treatment of the corresponding molybdenum acetylide carbonyl complex, CpMo(CO)3(C{triple bond, long}CPh); Cp = η5-C5H5 with H2O2, has been used as an efficient catalyst for selective N-oxidation of primary amines to nitroso derivatives. Excellent amine conversion (up to 100%) and very high selectivity for nitroso compounds (99%) have been obtained using 30% hydrogen peroxide as an oxidant. The oxo peroxo Mo(VI) complex has also been found to be very active for the oxidation of various substituted primary aromatic amines with electron donating as well as electron withdrawing substituents on the aromatic ring.
Biradar, Ankush V.,Kotbagi, Trupti V.,Dongare, Mohan K.,Umbarkar, Shubhangi B.
p. 3616 - 3619
(2008/09/19)

A highly stereoselective organocatalytic tandem aminoxylation/aza-Michael reaction for the synthesis of tetrahydro-1,2-oxazines
(Chemical Equation Presented) A facile stereoselective synthesis of multifunctionalized tetrahydro-1,2-oxazines (THOs) has been achieved by the organocatalyzed asymmetric tandem α-aminoxylation/aza-Michael reaction for the C-O/C -N bond formations in moderate to good yields with excellent diastereo- (>99:1 dr) and enantioselectivities (92% to >99% ee).
Zhu, Di,Lu, Min,Chua, Pei Juan,Tan, Bin,Wang, Fei,Yang, Xinhao,Zhong, Guofu
supporting information; experimental part
p. 4585 - 4588
(2009/05/13)

Multiphase oxidation of aniline to nitrosobenzene with hydrogen peroxide catalyzed by heteropolyacids
Keggin-type heteropolyacids have been used as catalyst for high-yielding oxidation reactions in multiphase conditions. This simple and efficient procedure promoted the conversion of anilines to the corresponding nitroso and nitro derivatives. In comparison with homogeneous system the oxidation from anilines to nitroso compounds and nitro compounds were more effective and the solvents used were not toxic. Georg Thieme Verlag Stuttgart.
Tundo,Romanelli,Vázquez,Loris,Aricò
experimental part
p. 967 - 970
(2009/04/06)

Tungsten- and molybdenum-based coordination polymer-catalyzed N-oxidation of primary aromatic amines with aqueous hydrogen peroxide
Recyclable tungsten- and molybdenum-based coordination polymers efficiently catalyzed the oxidation of primary aromatic amines to the corresponding nitroso derivatives with 30% aqueous hydrogen peroxide in high yields at room temperature.
Bordoloi, Ankur,Halligudi
p. 2085 - 2088
(2008/09/18)

Water as an efficient solvent for oxygenation transformations with 34% hydrogen peroxide catalyzed by some heteropolyoxometalates
A highly efficient, selective, fast, and cheap protocol is developed for oxidation of aromatic amines and alcohols utilizing 34% hydrogen peroxide in water catalyzed by some W- and Mo-based heteropolyoxometalates. Findings showed that dodecatungstophosphoric acid, H3PW12O40, was the most efficient catalyst in the examined oxidation reactions. This methodology may prove to be a valuable alternative for eco-friendly green oxidation. Inherent simplicity, easy work up, and using regenerable catalysts were other key aspects of this oxidation protocol.
Tayebee, Reza,Alizadeh, Mohammad H.
p. 763 - 769
(2008/02/09)