Electrochemical amination. synthesis of aniline in aqueous–acetonitrile solutions of sulfuric acid

Lisitsyn, Yu. A.; Сухов, А. В.

doi:10.1134/s1023193515110099

Cited by 9 publications

(10 citation statements)

References 9 publications

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“…Extensive optimization revealed that several factors have a favorable impact on the rate and yield of the reaction (Figure ). These include the use of (1) sulfuric acid as an additive, (2) high concentration of the arene, (3) acetonitrile or acetic acid as solvent, and (4) slow addition of Ti III (as a solution in HCl). Overall, the optimal conditions were found to involve the slow addition of TiCl 3 to a mixture of arene substrate (1 equiv), hydroxylamine hydrochloride (2 equiv), and sulfuric acid (10 equiv) in acetonitrile at room temperature.…”

supporting

confidence: 85%

“…Mechanistically, we propose that hydroxylamine interacts with the oxophilic Ti III via the free hydroxyl group (Figure B). − This proposal is supported by control studies with O -substituted hydroxylamines and/or hydrazine, which show no consumption of the starting material nor formation of any aminated products (Figure C). Inner-sphere electron transfer then likely occurs, resulting in N–O bond homolysis.…”

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confidence: 77%

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C–H Amination of Arenes with Hydroxylamine

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Sanford

2020

Org. Lett.

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This Letter describes the development of a Ti IIImediated reaction for the C−H amination of arenes with hydroxylamine. This reaction is applied to a variety of electronrich (hetero)arene substrates, including a series of natural products and pharmaceuticals. It offers the advantages of mild conditions (room temperature), fast reaction rates (<30 min), compatibility with ambient moisture and air, scalability, and the use of inexpensive commercial reagents.A niline derivatives (ArNH 2 ) appear in a wide variety of specialty chemicals, materials, natural products, and pharmaceuticals. 1 As such, synthetic methods for the formation of ArNH 2 are highly sought-after in organic synthesis. In general, the most common approaches involve transition-metal catalyzed cross-coupling, 2 arene nitration/reduction, 3 and arene C−H amination protocols. 4−6 However, due to high reagent/catalyst costs as well as reactivity concerns, processscale preparations of ArNH 2 still largely rely on nitration of the corresponding aromatic precursor followed by hydrogenation to yield the aniline products (Figure 1A). 7 We sought to develop a practical alternative to nitration/ reduction that enables the direct conversion of arenes (Ar−H) to ArNH 2 . Recent reports have shown that O-protected hydroxylamine derivatives (e.g., A−D in Figure 1B) are effective reagents for Fe-catalyzed arene C−H amination. 4−6 A key step of these reactions involves Fe-mediated N−O bond cleavage to release an aminyl radical (H 2 N • ). This radical (and/or its conjugate acid H 3 N •+ ) then reacts with the arene substrate, ultimately affording an aniline product. 8 While this is a conceptually attractive approach, in practice current methods are limited by the requirement for an electron-withdrawing substituent on oxygen to facilitate N−O bond scission. 9 These functionalized hydroxylamine derivatives can be expensive and/or require multistep synthesis, thus rendering them less practical for larger scale applications. Herein, we develop a method that accesses an analogous reaction manifold using the commodity chemical hydroxylamine as the aminating reagent (Figure 1C). This transformation is high yielding, inexpensive, and scalable and thus offers a complement to existing C−H amination methods as well as more traditional nitration/ reduction sequences.Pioneering early work by Keller, Kovacic, and Minisci demonstrated the feasibility of the Ti III -mediated amination of electron-rich arenes using hydroxylamine. 10−13 However, these early examples were very limited due to their narrow substrate scope, low yields, formation of side products, and the requirement for large excesses of arene substrate. 14 For

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confidence: 85%

supporting

confidence: 77%

C–H Amination of Arenes with Hydroxylamine

See

Sanford

2020

Org. Lett.

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“…Lysitin and co‐workers used hydroxylamine (Scheme , 23b ) as a reagent for the amination of aromatic compounds . They successfully aminated anisole ( 23a ), benzene, chlorobenzene, and anilines . In all cases, strong acidic conditions were mandatory for the reactions to take place.…”

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confidence: 99%

Recent Advances in the Electrochemical Reduction of Substrates Involving N−O Bonds

2020

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In this review,t he versatile and rich chemistry for the electrochemical reductiono fs ubstrates involving N À Ob onds is surveyed. By the cathodic treatment of nitro,n itroso and other oxygenated organic nitrogen substrates,v ersatile andr eactive intermediates are formed which can be subsequently converted to high value-added products. In many examples,n itrogen heterocycles are selectively formed, but, also depending on the electrolytic conditions, free oximes,n itrones,a mines and other entities can be obtained as well. Ther ecent decades have witnessed twom ajor advances-(i)g oing directly to more complext arget molecules and (ii)c onductingt he electrolysesi nm uch simpler set-ups.Both improvements make the cathodic access of the target compoundsm uch more practical and scalable. 1I ntroduction 2N itro Derivatives 2.1 IntermolecularReactions 2.2 IntramolecularReactions:Synthesis of Heterocycles 3O ximes 4O ther Functionalities 5C onclusions

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“…Materials and Methods: This study was an empirical-lab study which the Jar tests and DAF were used in laboratory scale. After determination of the optimal condition of pH and the optimum of concentration of poly-aluminum chloride by Jar test, the effect of the effective parameters including the concentration of the coagulant (10, 20, 30, 40, 60 mg/L), coagulation time (5, 10, 15 and 20 min), flotation time (5, 10, 15 and 20 sec), saturation pressure ( 3, 3.5, 4 and 4,5 atm) and turbidity ( 10,20 , 30, 40, 60 NTU) on the removal efficiency of COD, BOD 5 and TSS by DAF were studied. Results: Results of this study showed that the DAF process can treatment COD, BOD 5 and TSS up to85.7%, 80.68% and 95.6%, respectively.…”

mentioning

confidence: 99%

“…The textile wastewater must be properly treated before their discharge to the water resources and the environment (6). There are several methods for the elimination of textile wastewaters, including the application of photo decomposition (7), electrolysis (8), adsorption (9), oxidation (10), biodegradation (11) and other processes. Flotation is a physical approach in which the solid particles are transported to the surface layer from the liquid phase.…”

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confidence: 99%

Treatment of Textile Wastewater Using a Combined Coagulation and DAF Processes, Iran, 2016

Ahmadi

Mostafapour

2017

Arch Hyg Sci

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Background & Aims of the Study: There are three different types of fibers used in the manufacture of various textile products: cellulose fibers, protein fibers and synthetic fibers. Textile wastewater discharge into the environment leads to irreparable damages. The main purpose of this study was treatment of textile wastewater, using a combined coagulation and dissolved air flotation (DAF) processes, Iran in 2016. Materials and Methods: This study was an empirical-lab study which the Jar tests and DAF were used in laboratory scale. After determination of the optimal condition of pH and the optimum of concentration of poly-aluminum chloride by Jar test, the effect of the effective parameters including the concentration of the coagulant (10, 20, 30, 40, 60 mg/L), coagulation time (5, 10, 15 and 20 min), flotation time (5, 10, 15 and 20 sec), saturation pressure ( 3, 3.5, 4 and 4,5 atm) and turbidity ( 10,20 , 30, 40, 60 NTU) on the removal efficiency of COD, BOD 5 and TSS by DAF were studied. Results: Results of this study showed that the DAF process can treatment COD, BOD 5 and TSS up to85.7%, 80.68% and 95.6%, respectively. The appropriate condition was as follows: pH=6, initial concentration of aniline= 200 mg/L, flocculation time = 10 min, flotation time= 20 sec and the air pressure= 4 atm. Also, this study indicates that the DAF process to conclusion requires a lower dosage of poly-aluminum chloride. Conclusion:The coagulation and DAF processes can be effective to treat textile wastewater from industries.

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Electrochemical amination. synthesis of aniline in aqueous–acetonitrile solutions of sulfuric acid

Cited by 9 publications

References 9 publications

C–H Amination of Arenes with Hydroxylamine

C–H Amination of Arenes with Hydroxylamine

Recent Advances in the Electrochemical Reduction of Substrates Involving N−O Bonds

Treatment of Textile Wastewater Using a Combined Coagulation and DAF Processes, Iran, 2016

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