A New Cyclization Involving the Diazonium and ortho-(tert-Butyl)-NNO-azoxy Groups − Synthesis of 1,2,3,4-Benzotetrazine 1-Oxides

Lipilin, Dmitry L.; Smirnov, O. Yu.; Churakov, A. M.; Strelenko, Yuri A.; Ioffe, Sema L.; Tartakovsky, Vladimir A.

doi:10.1002/1099-0690(200210)2002:20<3435::aid-ejoc3435>3.0.co;2-z

Cited by 11 publications

(10 citation statements)

References 13 publications

(27 reference statements)

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“…Aromatic 1,2,3,4‐tetrazines are represented in the literature only by annulated compounds,1 especially triazolo‐annulated 1,2,3,4‐tetrazine2 and benzo‐annulated 1,2,3,4‐tetrazine N 1 ‐oxides 3. The question of ring‐chain tautomerism is of considerable importance in the chemistry of these compounds 4.…”

Section: Introductionsupporting

confidence: 90%

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2‐Alkyl‐1,2,3,4‐benzotetrazinium Tetrafluoroborates: Their Reaction with Nucleophiles

et al. 2004

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Section: Introductionsupporting

confidence: 90%

“…The closely related 1,2,3,4‐benzotetrazinium N 4 ‐oxide 26 reacts with water3 or primary amines15 in another way — replacement of bromine to give the quinoid structures 27 (Scheme ).…”

Section: Resultsmentioning

confidence: 99%

2‐Alkyl‐1,2,3,4‐benzotetrazinium Tetrafluoroborates: Their Reaction with Nucleophiles

et al. 2004

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“…Moreover, given its unstable nature, the 1,2,3,4-tetrazine-1-oxide ring was inferred to involve ring–chain isomerization with formation of unstable or highly reactive open-chain isomers. , In this study, we infer that this opening tendency of the 1,2,3,4-tetrazine ring to release thermodynamically stable N 2 results from the fairly weak interaction between p orbitals in a delocalized π orbital on the ring. Such tendency can hardly be prevented by one N + –O – bond alone.…”

Section: Resultsmentioning

confidence: 72%

Influence of N-Oxide Introduction on the Stability of Nitrogen-Rich Heteroaromatic Rings: A Quantum Chemical Study

2016

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N-Oxidization is an important strategy for enhancing the density and energy of energetic materials. Nevertheless, the influence of N-O introduction on molecular stability remains relatively unknown. Thus, the present work comprehensively studied 102 basic N-rich ring structures, including azoles, furazans, and azines, as well as their N-oxides by quantum chemical calculations. The introduction of N-O weakens molecular stability in most cases because the process elongates chemical bonds, decreases ring aromaticity, narrows the gaps between the highest occupied and lowest unoccupied molecular orbitals, and increases the photochemical reactivity. Besides, the easy H transfer to the neighboring O atom, which forms a N-OH isomer in azoles, renders the stabilization by N-oxide introduction ineffective. However, N-oxide introduction can enhance the molecular stability of 1,2,3,4-tetrazine-1,3-dioxide and tetrazino-tetrazine 1,3,6,8-tetraoxide by promoting σ-π separation and relieving lone-pair repulsion. Moreover, the alternate arrangement of positive and negative charges is another factor stabilizing the 1,2,3,4-tetrazine ring by 1,3-dioxidation. Finally, we assess the accessibility of N-oxidized azoles and azines by regarding NO and HO as oxidizers. We find that all the oxidations were exothermic, thermodynamically spontaneous, and kinetically feasible. After an overall evaluation, we propose 19 N-oxides as basic structures for high-energy materials with considerable stability.

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“…With regard to the significance of these unique furazan scaffolds, unremitting investigations have been conducted with respect to new synthetic protocol development. Traditional methods of preparing arylated/arene-fused furazans are the dehydration of prefunctionalized 1,2-dioximes and using simple furazans as primitive substrates, − as well as lengthy, multistep, and in particular sequential reactions using anilines or o -halonitroarene compounds as early starting materials. − …”

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confidence: 99%

Assembly of Furazan-Fused Quinolines via an Expeditious Metal-Free [2+2+1] Radical Tandem Cyclization Process

et al. 2021

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A [2+2+1]-NO-segment-incorporating heteroannulative cascade is described. This versatile method, particularly using modular cyanoarylated ketimine substrates, allows efficient access to structurally diversified quinolines embedded with an oxadiazole core. This metal-free protocol proceeds smoothly at 30 °C, offers easy manipulation of substituents on the quinoline moiety, and tolerates a spectrum of functional groups. Density functional theory calculation revealed that the cyano moiety is crucial to facilitate the early cyclization step in this heteroannulation process and is different from the previously established late cyclization mechanistic interpretation.

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A New Cyclization Involving the Diazonium and ortho-(tert-Butyl)-NNO-azoxy Groups − Synthesis of 1,2,3,4-Benzotetrazine 1-Oxides

Cited by 11 publications

References 13 publications

2‐Alkyl‐1,2,3,4‐benzotetrazinium Tetrafluoroborates: Their Reaction with Nucleophiles

2‐Alkyl‐1,2,3,4‐benzotetrazinium Tetrafluoroborates: Their Reaction with Nucleophiles

Influence of N-Oxide Introduction on the Stability of Nitrogen-Rich Heteroaromatic Rings: A Quantum Chemical Study

Assembly of Furazan-Fused Quinolines via an Expeditious Metal-Free [2+2+1] Radical Tandem Cyclization Process

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