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Nickel Boride Catalyzed Reductions of Nitro Compounds and Azides: Nanocellulose-Supported Catalysts in Tandem Reactions
Nickel boride catalyst prepared in situ from NiCl2 and sodium borohydride allowed, in the presence of an aqueous solution of TEMPO-oxidized nanocellulose (0.01 wt%), the reduction of a wide range of nitroarenes and aliphatic nitro compounds. Here we describe how the modified nanocellulose has a stabilizing effect on the catalyst that enables low loading of the nickel salt pre-catalyst. Ni-B prepared in situ from a methanolic solution was also used to develop a greener and facile reduction of organic azides, offering a substantially lowered catalyst loading with respect to reported methods in the literature. Both aromatic and aliphatic azides were reduced, and the protocol is compatible with a one-pot Boc-protection of the obtained amine yielding the corresponding carbamates. Finally, bacterial crystalline nanocellulose was chosen as a support for the Ni-B catalyst to allow an easy recovery step of the catalyst and its recyclability for new reduction cycles.
Proietti, Giampiero,Prathap, Kaniraj Jeya,Ye, Xinchen,Olsson, Richard T.,Dinér, Peter
p. 133 - 146
(2021/11/04)

Selective Carbon-Carbon Bond Amination with Redox-Active Aminating Reagents: A Direct Approach to Anilines?
Amines are among the most fundamental motifs in chemical synthesis, and the introduction of amine building blocks via selective C—C bond cleavage allows the construction of nitrogen compounds from simple hydrocarbons through direct skeleton modification. Herein, we report a novel method for the preparation of anilines from alkylarenes via Schmidt-type rearrangement using redox-active amination reagents, which are easily prepared from hydroxylamine. Primary amines and secondary amines were prepared from corresponding alkylarenes or benzyl alcohols under mild conditions. Good compatibility and valuable applications of the transformation were also displayed.
Qiu, Xu,Wang, Yachong,Su, Lingyu,Jin, Rui,Song, Song,Qin, Qixue,Li, Junhua,Zong, Baoning,Jiao, Ning
p. 3011 - 3016
(2021/09/13)

Manganese Catalyzed Hydrogenation of Azo (N=N) Bonds to Amines
We report the first example of homogeneously catalyzed hydrogenation of the N=N bond of azo compounds using a complex of an earth-abundant-metal. The hydrogenation reaction is catalyzed by a manganese pincer complex, proceeds under mild conditions, and yields amines, which makes this methodology a sustainable alternative route for the conversion of azo compounds. A plausible mechanism involving metal-ligand cooperation and hydrazine intermediacy is proposed based on mechanistic studies. (Figure presented.).
Ben-David, Yehoshoa,Das, Uttam Kumar,Diskin-Posner, Yael,Kar, Sayan,Milstein, David
supporting information
p. 3744 - 3749
(2021/07/09)

Palladium supported on metal–organic framework as a catalyst for the hydrogenation of nitroarenes under mild conditions
Sustainable development demands an environmentally friendly and efficient method for the hydrogenation of organic molecules, including the hydrogenation of functionalized nitroarenes. In this study, a highly active and selective metal–organic framework-supported palladium catalyst was prepared for the catalytic hydrogenation of nitroarenes. High selectivity (>99%) and excellent yield (98%) of aniline were realized after 2 hours in ethanol under hydrogen (1 atm) at room temperature. The reductions were successfully carried out in the presence of a wide range of other reducible functional groups. More importantly, the catalyst was very stable without the loss of its catalytic activity after five cycles.
Bao, Lingxiang,Fei, Teng,Li, Jiazhe,Pang, Siping,Sun, Chenghui,Yan, Zhiyuan,Yu, Zongbao
(2020/03/24)

One-Pot Generation of Benzynes from Phenols: Formation of Primary Anilines by the Deoxyamination of Phenols
Benzynes were selectively generated in situ from phenols and trapped regioselectively with potassium hexamethyldisilazide to form primary anilines following acidic workup. The direct conversion of a phenolic hydroxyl group into a free amino group is a useful method for the preparation of primary aryl amines that are hard to synthesize by using coupling reactions involving phenol derivatives with ammonia. Whereas reactions of ortho- and meta-substituted phenols produced meta-substituted anilines exclusively, those of para-substituted phenols provided ortho-silylanilines.
Akai, Shuji,Ikawa, Takashi,Masuda, Shigeaki
(2020/03/23)

Discovery and characterization of an acridine radical photoreductant
Photoinduced electron transfer (PET) is a phenomenon whereby the absorption of light by a chemical species provides an energetic driving force for an electron-transfer reaction1–4. This mechanism is relevant in many areas of chemistry, including the study of natural and artificial photosynthesis, photovoltaics and photosensitive materials. In recent years, research in the area of photoredox catalysis has enabled the use of PET for the catalytic generation of both neutral and charged organic free-radical species. These technologies have enabled previously inaccessible chemical transformations and have been widely used in both academic and industrial settings. Such reactions are often catalysed by visible-light-absorbing organic molecules or transition-metal complexes of ruthenium, iridium, chromium or copper5,6. Although various closed-shell organic molecules have been shown to behave as competent electron-transfer catalysts in photoredox reactions, there are only limited reports of PET reactions involving neutral organic radicals as excited-state donors or acceptors. This is unsurprising because the lifetimes of doublet excited states of neutral organic radicals are typically several orders of magnitude shorter than the singlet lifetimes of known transition-metal photoredox catalysts7–11. Here we document the discovery, characterization and reactivity of a neutral acridine radical with a maximum excited-state oxidation potential of ?3.36 volts versus a saturated calomel electrode, which is similarly reducing to elemental lithium, making this radical one of the most potent chemical reductants reported12. Spectroscopic, computational and chemical studies indicate that the formation of a twisted intramolecular charge-transfer species enables the population of higher-energy doublet excited states, leading to the observed potent photoreducing behaviour. We demonstrate that this catalytically generated PET catalyst facilitates several chemical reactions that typically require alkali metal reductants and can be used in other organic transformations that require dissolving metal reductants.
MacKenzie, Ian A.,Wang, Leifeng,Onuska, Nicholas P. R.,Williams, Olivia F.,Begam, Khadiza,Moran, Andrew M.,Dunietz, Barry D.,Nicewicz, David A.
p. 76 - 80
(2020/04/17)

Deacetylative Amination of Acetyl Arenes and Alkanes with C-C Bond Cleavage
The Br?nsted acid-catalyzed synthesis of primary amines from acetyl arenes and alkanes with C-C bond cleavage is described. Although the conversion from an acetyl group to amine has traditionally required multiple steps, the method described herein, which uses an oxime reagent as an amino group source, achieves the transformation directly via domino transoximation/Beckmann rearrangement/Pinner reaction. The method was also applied to the synthesis of γ-aminobutyric acids, such as baclophen and rolipram.
Hyodo, Kengo,Hasegawa, Genna,Maki, Hiroya,Uchida, Kingo
supporting information
p. 2818 - 2822
(2019/04/25)

From alkylarenes to anilines via site-directed carbon–carbon amination
Anilines are fundamental motifs in various chemical contexts, and are widely used in the industrial production of fine chemicals, polymers, agrochemicals and pharmaceuticals. A recent development for the synthesis of anilines uses the primary amination of C–H bonds in electron-rich arenes. However, there are limitations to this strategy: the amination of electron-deficient arenes remains a challenging task and the amination of electron-rich arenes has a limited control over regioselectivity—the formation of meta-aminated products is especially difficult. Here we report a site-directed C–C bond primary amination of simple and readily available alkylarenes or benzyl alcohols for the direct and efficient preparation of anilines. This chemistry involves a novel C–C bond transformation and offers a versatile protocol for the synthesis of substituted anilines. The use of O2 as an environmentally benign oxidant is demonstrated, and studies on model compounds suggest that this method may also be used for the depolymerization of lignin.
Liu, Jianzhong,Qiu, Xu,Huang, Xiaoqiang,Luo, Xiao,Zhang, Cheng,Wei, Jialiang,Pan, Jun,Liang, Yujie,Zhu, Yuchao,Qin, Qixue,Song, Song,Jiao, Ning
p. 71 - 77
(2018/11/10)

Transformation of lignin model compounds to: N -substituted aromatics via Beckmann rearrangement
Here we present the highly effective cleavage of C-C bonds in lignin model compounds for the production of N-substituted aromatics in up to 96% total yield, including benzonitriles and amides, via oxime formation followed by Beckmann rearrangement (BR). The amides could be further hydrolyzed to anilines (>92% yield) and carboxylic acids (>90% yield), respectively. In addition, the employment of a substrate with a γ-OH group will lead to the formation of C-2 monosubstituted oxazole. A one-pot process involving the BR reaction and hydrolysis has also been developed to directly afford an up to 96% total yield of benzonitriles, benzamides, and anilines. This strategy enabled us to successfully apply the BR reaction to the degradation of lignin model compounds to N-functionalized aromatic products under mild conditions.
Wang, Yinling,Du, Yiman,He, Jianghua,Zhang, Yuetao
supporting information
p. 3318 - 3326
(2018/07/29)

Catalytic Reductions and Tandem Reactions of Nitro Compounds Using in Situ Prepared Nickel Boride Catalyst in Nanocellulose Solution
A mild and efficient method for the in situ reduction of a wide range of nitroarenes and aliphatic nitrocompounds to amines in excellent yields using nickel chloride/sodium borohydride in a solution of TEMPO-oxidized nanocellulose in water (0.01 wt %) is described. The nanocellulose has a stabilizing effect on the catalyst, which increases the turnover number and enables low loading of nickel catalyst (0.1-0.25 mol % NiCl2). In addition, two tandem protocols were developed in which the in situ formed amines were either Boc-protected to carbamates or further reacted with an epoxide to yield β-amino alcohols in excellent yields.
Prathap, Kaniraj Jeya,Wu, Qiong,Olsson, Richard T.,Dinér, Peter
supporting information
p. 4746 - 4749
(2017/09/23)

Fe-Catalyzed Amination of (Hetero)Arenes with a Redox-Active Aminating Reagent under Mild Conditions
A novel and efficient Fe-catalyzed direct C?H amination (NH2) of arenes is reported using a new redox-active aminating reagent. The reaction is simple, and can be performed under air, mild, and redox-neutral conditions. This protocol has a broad substrate scope and could be used in the late-stage modification of bioactive compounds. Mechanistic studies demonstrate that a radical pathway could be involved in this transformation.
Liu, Jianzhong,Wu, Kai,Shen, Tao,Liang, Yujie,Zou, Miancheng,Zhu, Yuchao,Li, Xinwei,Li, Xinyao,Jiao, Ning
supporting information
p. 563 - 567
(2017/01/18)

Cubical Palladium Nanoparticles on C@Fe3O4 for Nitro reduction, Suzuki-Miyaura Coupling and Sequential Reactions
Cubical Pd nanoparticles incorporated magnetically recyclable nanoreactor (Pd cNPs/C@Fe3O4) are found to be efficient catalysts for the hydrogenation or aromatic nitrocompounds, Suzuki-Miyaura coupling and the sequential reaction of [Formula presented] coupling followed by reduction of nitrobiphenyl substrates. A variety of aryl iodides, bromides and chlorides were coupled with phenylboronic acids to form corresponding biaryl products and variety of nitro aromatic compounds was hydrogenated with excellent yield and high TON. The catalytic activity of palladium cubical nanoparticles (Pd cNPs) embedded with excess of {100} surface facets are superior compared to Pd spherical nanoparticles (Pd sNPs) embedded with mixed surface facets. The catalytic efficiency remains unaltered even after five repeated cycles. The observed enhanced catalytic activity is attributed to the high density of low-coordinated Pd {100} atoms present at the surface of the Pd cNPs/C@Fe3O4 catalyst, confirmed by HR-TEM studies. Also, the catalyst is truly heterogeneous, highly stable, does not require any toxic ligands, has wide substrate scope in both nitroreduction and Suzuki-Miyaura coupling reaction along with the ability to catalyse in a sequential manner, magnetically separable from the reaction mixture and can be reused.
Kumar, Basuvaraj Suresh,Amali, Arlin Jose,Pitchumani, Kasi
p. 511 - 519
(2016/08/15)

A triazine-phosphite polymeric ligand bearing cage-like P,N-ligation sites: An efficient ligand in the nickel-catalyzed amination of aryl chlorides and phenols
A novel P,N-ligand was introduced for efficient Ni-catalyzed amination of aryl chlorides. Reaction of cyanuric acid (1,3,5-triazine-2,4,6-triol) and trichlorophosphine (PCl3) resulted in the production of a new porous material (TPPM) containing triazine rings with phosphite moieties in a sheet morphology. Cavities in the prepared compound create sites on the surface of the material with appropriate ligation character to coordinate with metals for catalytic purposes. The nickel-catalyzed amination of aryl chlorides and of phenols in their 2,4,6-triaryloxy-1,3,5-triazine (TAT) protected form were efficiently accomplished in the presence of this easily prepared and reusable P,N-ligand under mild reaction conditions. More importantly, TPPM was reusable for 5 iterations following this protocol without significantly decreasing in its activity.
Panahi, Farhad,Roozbin, Fatemeh,Rahimi, Sajjad,Moayyed, Mohammadesmaeil,Valaei, Aria,Iranpoor, Nasser
supporting information
p. 80670 - 80678
(2016/10/12)

Photo-Fries rearrangement of aryl acetamides: Regioselectivity induced by the aqueous micellar green environment
Photochemical reactions tend to give more than one photoproduct. However, such a reaction can be a powerful synthetic tool when it is possible to conduct it in regioselective conditions yielding a single photoproduct. Water-surfactant solutions as reaction media can be considered as an approach in this context because they show products with different features than those from isotropic solutions. Here we describe results obtained from studying the effect on the prototypical photoreaction, known as the photo-Fries reaction of several substituted acetanilides and α-naphthyl acetamide within surfactant micelles (ionic and non-ionic micelles). This reaction involves homolytic cleavage of a C-N bond to yield a singlet radical pair. The surfactant micelles control the rotational and translational mobility of the radical pair, resulting in noticeable photoproduct selectivity.
Iguchi, Daniela,Erra-Balsells, Rosa,Bonesi, Sergio M.
p. 105 - 116
(2016/01/20)

Direct metal-free synthesis of diarylamines from 2-nitropropane via the twofold C-H functionalization of arenes
Synthesis of symmetric diarylamines via a twofold intermolecular electrophilic C-H functionalization of electron-rich arenes by umpolung-activated nitroalkane in polyphosphoric acid is demonstrated.
Aksenov, Alexander V.,Aksenov, Nicolai A.,Orazova, Naila A.,Aksenov, Dmitrii A.,Dmitriev, Maksim V.,Rubin, Michael
p. 84849 - 84855
(2015/10/28)

Reductive ring cleavage of nonconjugated Δ2-isoxazolines to β-hydroxy ketones with aluminum and copper(II) chloride
A facile, economic, and efficient protocol for the reduction of nonconjugated Δ2-isoxazolines to the corresponding β-hydroxy ketones using Al/CuCl2 as the reducing agent has been developed. The method is both rapid and complete requiring less than ten minutes to attain total ring cleavage. This is the first example of using an in situ prepared Al/Cu couple in organic synthesis. Georg Thieme Verlag Stuttgart · New York.
Karpaviiene, Ieva,Lapinskaite, Ringailé,Bruktus, Algirdas,Cikotiene, Inga
experimental part
p. 381 - 384
(2012/03/27)

Organophosphorus-catalysed Staudinger reduction
The first Staudinger reduction that is catalytic in phosphine has been developed, showing excellent yields and functional group selectivity. To this end we utilised dibenzophosphole catalysts and mild in situ reduction of the intermediate iminophosphoranes. We could avoid the necessity of water during the reduction, obtained no phosphine oxides as waste and thus enabled facile purification of the product. A range of azides was converted into amines with good to excellent yields and high functional group tolerance. Copyright
Van Kalkeren, Henri A.,Bruins, Jorick J.,Rutjes, Floris P. J. T.,Van Delft, Floris L.
supporting information; experimental part
p. 1417 - 1421
(2012/07/03)

An efficient copper-catalyzed synthesis of anilines by employing aqueous ammonia
Under the catalysis of CuI/2-carboxylic acid-quinoline-N-oxide, the cross coupling reactions between aryl iodides or bromides and aqueous ammonia proceed very well to afford N-unprotected aniline derivatives in excellent yields. This inexpensive catalytic system shows great functional group tolerance and excellent reaction selectivity. The Royal Society of Chemistry 2011.
Zeng, Xin,Huang, Wenming,Qiu, Yatao,Jiang, Sheng
supporting information; experimental part
p. 8224 - 8227
(2012/04/04)

A convenient one-pot synthesis of aryl amines from aryl aldoximes mediated by Koser's reagent
A simple and convenient procedure has been developed for the synthesis of aromatic amine by a one-pot reaction of aromatic aldoxime with hypervalent iodine(III) reagent [hydroxy(tosyloxy)iodo]benzene (HTIB, Koser's reagent), in an alkaline medium. The aldoxime reacts with Koser's reagent to form an intermediate hydroxamic acid, which then undergoes Lossen type rearrangement to produce the desired amine. Several amines have been prepared which otherwise are difficult to prepare, by the reduction of corresponding nitro compounds. The scopes and limitations of this transformation have been discussed. ARKAT-USA, Inc.
Ghosh, Harisadhan,Baneerjee, Arghya,Rout, Saroj Kumar,Patel, Bhisma K.
experimental part
p. 209 - 216
(2011/05/30)

Nitroethane in polyphosphoric acid: A new reagent for acetamidation and amination of aromatic compounds
A new method of acetamidation of aromatic compounds based on their reaction with nitroethane in polyphosphoric acid has been developed. Upon the hydrolysis of acetamides during the reaction mixture workup, the corresponding amines can be obtained. Georg Thieme Verlag Stuttgart New York.
Aksenov, Alexander V.,Aksenov, Nicolai A.,Nadein, Oleg N.,Aksenova, Inna V.
experimental part
p. 2628 - 2630
(2010/12/18)

A highly active heterogeneous palladium catalyst supported on a synthetic adsorbent
A method to prepare heterogeneous palladium catalyst highly dispersed in a synthetic adsorbent DIAION HP20, has been demonstrated. Heterogeneous palladium catalyst are suitable for organic synthetic chemistry due to their high air-stability, reconverability, reusability, and non-residual property. The catalyst was obtained by adding DIAION HP20 into a rust-colored solution of Pd(OAc)2 in MeOH at room temperature. The resulting products was collected by filtration, washed with H2O and MeOH, and dried in vacuo to give a palladium-DIAION HP20 complex as a grey powder. The products was made from a physical interaction between the orbitals of the palladium species and π-electrons of the benzene rings of the adsorbents. The thermogravimetry- differential thermal analysis of the complex showed that the complex has no volatiles.
Monguchi, Yasunari,Fujita, Yuki,Endo, Koichi,Takao, Shinobu,Yoshimura, Masatoshi,Takagi, Yukio,Maegawa, Tomohiro,Sajiki, Hironao
scheme or table
p. 834 - 837
(2009/06/25)

tGENTS AND METHODS FOR THE TREATMENT OF DISORDERS ASSOCIATED WITH OXIDATIVE STRESS
The invention provides a method for preventing or reducing the effects of oxidative stress on a substrate. The method includes the step of treating the substrate with a compound of formula (I), or a pharmaceutically acceptable salt thereof, wherein: R1 is one or more substituents selected from -H, -alkyl, -alkoxy, -aryl, -aryloxy, -halogen, -amino (mono-, di- and tri-substituted), -alkylthio, -NO2, -COOH, -COOAlkyl, -CO-alkyl, -CN; R2 is one or more substituents selected from -H, -alkyl, -(CH2CH2O)n-R5, a sugar moiety; R3 is -H, -alkyl, -aryl, -alkylOR6 , -alkylC(O)R6; R5 is selected from -H, -alkyl, -aryl; and R4 and R6 are independently selected from -OH, -O-alkyl, -O-polyalkyleneoxy, -O-aryl, -OC(O)O-alkyl, -S-alkyl and -amino.
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Page 24-25

(2008/06/13)

Phenylureas. Part 2. Mechanism of the acid hydrolysis of phenylureas
The mechanism of the hydrolytic decomposition of phenylureas in acid media is investigated. It includes, in part, knowledge already present in the literature. Over the investigated pH range the occurrence of a rate maximum in the pH curves due to the strongly reduced water activity at higher acid strengths is observed. An addition-elimination mechanism with rate-determining attack of water at the N-protonated substrate is proposed. The reversion of the substituent influence on the reaction rate with increasing acidity of the reaction medium points to a change of the hydrolytic decomposition mechanism in strongly acidic media.
Laudien, Robert,Mitzner, Rolf
p. 2230 - 2232
(2007/10/03)

Phenylureas. Part 1. Mechanism of the basic hydrolysis of phenylureas
The mechanism of the hydrolytic decomposition of phenylureas in basic media in the pH range 12 to 14 is investigated. In this pH range a levelling of the rate-pH curve is observed as well as a change of the substituent influence on the hydrolysis rate. These experimental findings suggest the formation of an unreactive side product of the phenylurea in a parasitic side equilibrium at sufficiently high pH. The urea dissociates at the aryl-NH group to give its conjugate base. For the hydrolytic decomposition of phenylureas an addition-elimination mechanism is proposed as has been established for the alkaline hydrolysis of carboxylic acid esters and amides.
Laudien,Mitzner
p. 2226 - 2229
(2007/10/03)

MCM-silylamine Pd(II)complex: A heterogeneous catalyst for selective azide reductions
Palladium complex immobilized on MCM-41 catalyses the reduction of alkyl, aryl and arylsulfonyl azides to the corresponding amines in excellent yields under mild conditions.
Kantam, M. Lakshmi,Chowdari, N. Srcenivasa,Rahman, Ateeq,Choudary
p. 1413 - 1414
(2007/10/03)

Synthesis of nonsubstituted anilines from molecular nitrogen via transmetalation of arylpalladium complex with titanium-nitrogen fixation complexes
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Hori,Mori
p. 7651 - 7652
(2007/10/03)

Gas-chromatographic studies using glass capillary columns with crown-ether type stationary phases. I β-naphthol-azo-crown ethers and related compounds: Synthesis and properties
Azoderivatives containing residues of benzo-15-crown-5 or benzo-18-crown-6 and 2-naphthol were synthesised in order to be employed as stationary phase in GC studies with glass capillary columns. Analogous azo compounds containing anisole, veratrole and phenyl residues were used for comparison. The compounds were characterised by UV-VIS, NMR and DSC measurements.
Luca, Constantin,Spafiu, Florica,Cǎproiu, Miron Teodor,Tudor, Ecaterina,Ioni?ǎ, Petre,Constantinescu, Titus,Dǎnescu, Mihaela,Stǎnciuc, Andreea
p. 287 - 293
(2007/10/03)

Effect of Topologically Controlled Coulombic Interactions on the Dynamic Behavior of Photoexcited Nitrophenyl Alkyl Ethers in the Presence of Tertiary Amines with Limited Motion Freedom
Time-resolved electronic absorption spectroscopy has been successfully applied to clarify the mechanism of the "abnormal" photochemical cleavage of 4-nitrophenyl piperidinoaikyl ethers induced by controlled Coulombic disturbance of the "normal" electronic distribution of the radical anion intermediate. Thus, photolysis of 1-piperidino-2-(2-methoxy-4-nitrophenoxy)ethane (a system with an amine with limited freedom of motion) in acetonitrile leads to C-O bond photocleavage in a relatively slow process (k ≈ 4 × 105 s-1) from intermediate species that show radical-ion pair behavior. Systems with higher freedom of motion of the amine moiety, such as 1-piperidino-5-(2-methoxy-4-nitrophenoxy)pentane or 4-nitroveratrole 4- triethylamine, show the intermediate radicalion pairs mainly evolving to reduction products, probably a result of intermediates with geometries not allowed for the system with limited freedom of motion of the amine.
Gonzalez-Blanco, Roberto,Bourdelande, Jose L.,Marquet, Jordi
p. 6903 - 6910
(2007/10/03)

Topologically Controlled Coulombic Interactions, a New Tool in the Developing of Novel Reactivity. Photochemical and Electrochemical Cleavage of Phenyl Alkyl Ethers
The hypothesis that a specific placement of a positive charge would dramatically alter the behavior of a charged intermediate has been tested.Phenyl ethers substituted by electron-attracting groups do not undergo reductive fragmentation.However, related α-piperidino-ω-(4-substituted-phenoxy)alkanes give alkyl ether photocleavage when the linker between the redox centers is short, or the usual substitution-reduction photochemistry when it is long.Mechanistic experiments suggest that the photofragmentation process operates through space intramolecular electron transfer to the triplet aromatic chromophore and that a coplanar relative orientation of the alkyl ether bond and the phenyl ring is compulsory for the photofragmentation to be observed.Configuration interaction AM1 calculations justify the described facts, indicating that the fragmentation process is only operative when a Coulombic stabilization of a ?* intramolecular electron transfer excited state is produced.Electrochemical studies carried out with the corresponding quaternary salts (intermolecular generation of the phenyl ether radical anion) confirm the conclusions derived from the photochemical experiments.
Marquet, Jorge,Cayon, Eduard,Martin, Xavier,Casado, Francisco,Gallardo, Iluminada,et al.
p. 3814 - 3825
(2007/10/02)

Synthesis of aromatic amines from electron-rich arenes and bis(2,2,2-trichloroethyl) azodicarboxylate
Electron-rich arenes react with bis(2,2,2-trichloroethyl) azodicarboxylate in 3 M lithium perchlorate-diethylether or acetone solution to produce para-substituted aryl hydrazides in high yields. The corresponding aromatic amines are readily obtained by reducing the hydrazides with zinc in acetic acid.
Zaltsgendler,Leblanc,Bernstein
p. 2441 - 2444
(2007/10/02)

The synthesis of dimethoxy- and trimethoxy[1]benzothieno[2,3-c]quinolines
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Stuart,Khora,McKenney Jr.,Castle
p. 1589 - 1594
(2007/10/02)

Tellurolate-Induced Deprotection of 2,2,2-Trichloro-tert-butyloxycarbonyl (TCBOC) Derivatives
Sodium-2-thiophenetellurolate efficiently regenerates amines from their 2,2,2-trichloro-tert-butyloxycarbonyl (TCBOC) and 2,2,2-trichloroethoxycarbonyl derivatives.
Lakshmikantham, M.V.,Jackson, Yvette A.,Jones, Robert J.,O'Malley, Gerard J.,Ravichandran, K.,Cava, Michael P.
p. 4687 - 4688
(2007/10/02)

Polar Effects in Free Radical Reactions. Homolytic Aromatic Amination by the Amino Radical Cation, +NH3: Reactivity and Selectivity
Small amounts of Fe(II) salt initiate redox chains with hydroxyamino-O-sulfonic acid (HSA) and aromatic compounds leading to the amination of the aromatic ring.The positional and substrate selectivity with a variety of substituted benzenes show the important role of the electrophilic character of the radical +NH3.Hammett relationships with ? and ?+ are roughly observed.The lower sensitivity to polar effects of the radical +NH3 compared with (CH3)2+NH is explained by the different reaction enthalpies.The different positional selectivity obtained with anisole and the redox system +NH3OH/Ti(III) is discussed.
Citterio, Attilio,Gentile, Anna,Minisci, Francesco,Navarrini, Valter,Serravalle, Marco,Ventura, Susanna
p. 4479 - 4482
(2007/10/02)