How Does Nucleophilic Aromatic Substitution Really Proceed in Nitroarenes? Computational Prediction and Experimental Verification

Błaziak, Kacper; Danikiewicz, Witold; Mąkosza, Mieczysław

doi:10.1021/jacs.5b13365

Cited by 76 publications

(69 citation statements)

References 36 publications

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“…Nukleophile aromatische Substitutionen wurden mindestens seit den 1870er Jahren studiert . Der seit langem anerkannte Mechanismus – dargestellt in Schema für das Dinitroaren 1 – umschreibt einen zweistufigen Prozess mit einem Meisenheimer‐Intermediat 2 . In diesen Substitutionsreaktionen ist das Aren durch elektronenziehende Substituenten in der ortho ‐ oder para ‐Position – relativ zur Position der Substitution – stark aktiviert, wobei die Nitrogruppe der bevorzugte Substituent dafür ist.…”

Section: Aromatische Substitutionenunclassified

Konzertierte nukleophile aromatische Substitutionen

Rohrbach¹,

Sutherland-Smith²,

Pang

et al. 2019

Angewandte Chemie

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Jüngste Entwicklungen in der experimentellen und theoretischen Chemie haben zur Identifizierung einer schnell wachsenden Klasse von nukleophilen aromatischen Substitutionsreaktionen geführt, die einem konzertierten Mechanismus (cSNAr) folgen, und nicht dem klassischen, zweistufigen SNAr‐Mechanismus. Während klassische SNAr‐Reaktionen auf die substantielle Aktivierung des aromatischen Ringes durch elektronenziehende Substituenten angewiesen sind, ist eine solche Aktivierung für den konzertierten Reaktionsverlauf nicht zwingend nötig.

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Section: Aromatische Substitutionenunclassified

Konzertierte nukleophile aromatische Substitutionen

Rohrbach¹,

Sutherland-Smith²,

Pang

et al. 2019

Angewandte Chemie

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“…Compound 4 was successfully synthesized by employing compound 3 as a common precursor. Compound 3 was prepared by using a similar synthetic route in a single step by reacting 1,5‐difluoro‐2,4‐dinitrobenzene and resorcinol under basic conditions (Scheme ) . First, 1,3‐dichlorobenzene was transformed into 1,5‐difluoro‐2,4‐dinitrobenzene in 93 % yield.…”

Section: Resultsmentioning

confidence: 99%

“…It is believed that the amination of compound 4 proceeds in accordance with the VNS mechanism . In the presence of a strong base, deprotonation of 4‐amino‐4 H ‐1,2,4‐triazole (ATA) occurs, resulting in the formation of 4‐amino‐4 H ‐1,2,4‐triazole imide (ATAI).…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Detonation Properties of 5‐Amino‐2,4,6‐trinitro‐1,3‐dihydroxy‐benzene

et al. 2017

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Abstract5‐Amino‐4,6‐dinitro‐1,3‐dihydroxy‐benzene (6) was synthesized through the ring‐opening reaction of macrocyclic compound 4 with the aid of VNS (vicarious nucleophilic substitution of hydrogen) reaction conditions. The mechanism of ring opening of macrocyclic compound 4 was studied. 5‐Amino‐2,4,6‐trinitro‐1,3‐dihydroxy‐benzene (8) was obtained after the nitration of 6 in KNO3 and concentrated sulfuric acid. The thermal stability, sensitivity, and other detonation performances of 6 or 8 were compared to commercially used 1,3,5‐triamino‐2,4,6‐trinitrobenzene (TATB) or 1,3,5‐trinitrotriazacyclohexane (RDX), respectively. All target compounds were characterized by using single‐crystal X‐ray diffraction, NMR spectroscopy, elemental analysis, and differential scanning calorimetry. The sensitivities were determined by using BAM methods (drop‐hammer and friction tests). Performance parameters, including heats of formation and detonation properties, were calculated by using Gaussian 03 and EXPLO5 v6.01 programs, respectively. It is worth pointing out that compound 8 has a remarkable measured density of 2.078 g cm−3 at 298 K. In addition, compound 8 is more insensitive than RDX (compound 8: IS=11 J; RDX: IS=7 J; IS is the impact sensitivity).

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“…an addition–elimination pathway with the formation of a zwitterionic intermediate. The formation of σ H adducts can be a competing pathway and the reaction outcome is the result of numerous factors including solvation, which makes this class of reactions extremely sensitive to the choice of reaction medium . It is well known that the reaction is particularly sensitive to the choice of solvents and the choice of an appropriate solvent has been widely used synthetic strategy to improve the yield and selectivity of nucleophilic substitution reactions ,…”

Section: Introductionmentioning

confidence: 99%

“Zero VOC” Synthetic Strategy – Aromatic Amination Reactions in Deep Eutectic Solvents

Valvi

Tiwari

2018

Eur J Org Chem

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Rising concern for environment hazards resulting from the use of volatile organic compounds (VOCs) is prompting many chemists to use “green” solvents like water, polyethylene glycol, ionic liquids and deep eutectic solvents (DES). With a few notable exceptions, many of these processes still need to use volatile organic solvents for the workup and isolation of products. In the present report, we demonstrate a “zero VOC” protocol which eliminates the need to use organic solvents for any stage of the reaction. As a proof of concept, nucleophilic aromatic substitution reactions of 1‐halo‐2,4‐dinitrobenzene with secondary amines were carried out in deep eutectic solvents. The reaction workup involved the addition of water for separating the product from the DES. Evaporation of water led to recovery of the DES, which exhibited good recyclability. The reaction in deep eutectic solvents was much faster than that in many other solvents, as confirmed by the kinetic studies. An attempt was made to elucidate the origin of this rate enhancement based on analysis activation parameters and correlation with the polarity parameters. The results show that use of deep eutectic solvents can take chemists a step closer towards the “zero VOC” synthetic strategy.

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How Does Nucleophilic Aromatic Substitution Really Proceed in Nitroarenes? Computational Prediction and Experimental Verification

Cited by 76 publications

References 36 publications

Konzertierte nukleophile aromatische Substitutionen

Konzertierte nukleophile aromatische Substitutionen

Synthesis and Detonation Properties of 5‐Amino‐2,4,6‐trinitro‐1,3‐dihydroxy‐benzene

“Zero VOC” Synthetic Strategy – Aromatic Amination Reactions in Deep Eutectic Solvents

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