Reaction of organic anions. Part 108. On the mechanism of the vicarious nucleophilic substitution of hydrogen in nitroarenes

Mąkosza, Mieczysław; Glinka, Tomasz

doi:10.1021/jo00169a067

Cited by 62 publications

(18 citation statements)

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“…1-Methyl-4-nitropyrazole (7) was exclusively attacked at position 5 to give 5-benzenesulfonylmethyl)-1-methyl-4nitro-1 H-pyrazole (7 o) in 86 % yield (Scheme 3), in analogy to previously reported reactions of 7 with other carbanions. [27,28] In contrast to the regioselectivity of the reaction of 5 a with 1 À (see above), 2-nitrothiophene (8) is selectively attacked at the 3-position by 1 À (Scheme 3).…”

Section: Introductionmentioning

confidence: 55%

“…After final protonation, the substituted nitroarene or -heteroarene is obtained (Scheme 1). [7][8][9][10] It has been reported that the solvent, the nature and concentration of the base, and the steric demand of the carbanion have a considerable influence on the ratio of isomeric products. [11] When there is a high excess of the base, H À X elimination is faster than the retroaddition of the s H -adduct, and the formation of the s H -adducts becomes irreversible.…”

Section: Introductionmentioning

confidence: 99%

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Reactions of Nitroheteroarenes with Carbanions: Bridging Aromatic, Heteroaromatic, and Vinylic Electrophilicity

Seeliger

Błażej

Bernhardt

et al. 2008

Chemistry A European J

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The relative rate constants for the vicarious nucleophilic substitution (VNS) of the anion of chloromethyl phenyl sulfone (1-) with a variety of nitroheteroarenes, for example, nitropyridines, nitropyrroles, nitroimidazoles, 2-nitrothiophene, and 4-nitropyrazole, have been determined by competition experiments. It was shown that nitropyridines are approximately four orders of magnitude more reactive than nitrobenzene. Among the five-membered heterocycles 2-nitrothiophene is the most active followed by nitroimidazoles and 4-nitropyrazole. Nitropyrroles are the least electrophilic nitroheteroarenes with reactivities comparable to nitrobenzene. Quantum chemically calculated methyl anion affinities (B3LYP/6-311G(d,p)//B3LYP/6-31G(d)) of the nitroarenes correlated only moderately with the partial relative rate constants. The correlation of these activities with the LUMO energies of nitroarenes is even worse. By measuring the second-order rate constants of the addition of 1- to nitroarenes and to diethyl arylidenemalonates 10, it was possible to link the electrophilic reactivities of nitroheteroarenes with the comprehensive electrophilicity scale based on the linear-free-energy-relationship log k(20 degrees C)=s(N+E).

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Section: Introductionmentioning

confidence: 55%

Section: Introductionmentioning

confidence: 99%

Reactions of Nitroheteroarenes with Carbanions: Bridging Aromatic, Heteroaromatic, and Vinylic Electrophilicity

Seeliger

Błażej

Bernhardt

et al. 2008

Chemistry A European J

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“…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%

“…It is believed that the amination of compound 4 proceeds in accordance with the VNS mechanism. [9][10][11][12] In the presence of as trongb ase, deprotonation of 4-amino-4 H-1,2,4-triazole (ATA)o ccurs, resulting in the formation of 4-amino-4 H-1,2,4-triazole imide (ATAI). The latter is added onto the aromatic ring of compound 4 in the middle of the two nitro groups to give the corresponding ó-adduct.…”

Section: Reaction Mechanism Of Compoundmentioning

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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“…[7][8][9][10] This two-step reaction proceeds via addition of carbanions containing leaving groups X at the carbanionic center to the nitroaromatic ring followed by the base-induced β-elimination of HX from intermediate σ-adducts. 11 The products of VNS reactions are key intermediates in the synthesis of useful and new heterocyclic compounds. 12 The nitro derivatives of furan, pyrrole, thiophene, 13 imidazole, 14 pyridine, 15 indole, 16,17 quinoline 18 and benzimidazole 19 undergo VNS cyanomethylation with a variety of cyanoalkylating agents such as the carbanions of chloroacetonitrile, aryloxyacetonitriles, 20 arylthioacetonitrile, cyanomethyl dithiocarbamates 13 or trialkylammonium cyanomethylides.…”

mentioning

confidence: 99%

Vicarious nucleophilic substitution in nitro derivatives of imidazo[1,2-a]pyridine

Rahimizadeh

Pordel

Bakavoli

et al. 2009

Mendeleev Communications

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Reaction of organic anions. Part 108. On the mechanism of the vicarious nucleophilic substitution of hydrogen in nitroarenes

Cited by 62 publications

References 0 publications

Reactions of Nitroheteroarenes with Carbanions: Bridging Aromatic, Heteroaromatic, and Vinylic Electrophilicity

Reactions of Nitroheteroarenes with Carbanions: Bridging Aromatic, Heteroaromatic, and Vinylic Electrophilicity

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

Vicarious nucleophilic substitution in nitro derivatives of imidazo[1,2-a]pyridine

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