4H-Azepin-4-ones from 4-azidophenols in low-temperature matrices

Dunkin, Ian R.; Gallivan, Sean L.; Lynch, Michael

doi:10.1039/a701595j

Cited by 16 publications

(17 citation statements)

References 33 publications

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“…4‐Hydroxyphenylazide: 1 H: δ =6.75 (H b AB, 2 H, 3 J H,H =8.8 Hz), 6.83 ppm (H a AB, 2 H, 3 J H,H =8.8 Hz); 13 C: δ =131.5 (s, C i ), 120.4 (s, C o ), 116.9 (s, C m ), 155.3 ppm (s, C p ), 15 N: δ =−136.6 (s, N2), −149.1 ppm (s, N3); 15 N: δ =−141.2 (s, N2), −152.5 ppm (s, N3). Literature values 40: 1 H: δ =6.83 (H b d, 2 H, J =9 Hz), 6.92 ppm (H a d, 2 H, J =9 Hz).…”

Section: Methodsmentioning

confidence: 99%

Experimental Detection of the Pentaazacyclopentadienide (Pentazolate) Anion, cyclo-N5â This work was funded predominantly by the Defense Advanced Research Projects Agency, with additional support from the Air Force Office of Scientific Research and the National Science Foundation. The mass spectrometer instrumentation at UCSB was supported under the Army Research Office Award no. DAAD19-00-1-0026. We thank Dr. Robert Corley, Dr. Arthur Morrish, Dr. Don Woodbury, Dr. Michael Berman, and Prof. W. Kaska for

et al. 2002

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Dedicated to Professor George Olah on the occasion of his 75th birthday Nitrogen and oxygen are unique among the chemical elements. In contrast to the other elements, their homonuclear single-bond energies are significantly less than one third of their triple-or one half of their double-bond energies. Consequently, homonuclear polynitrogen and polyoxygen species are thermodynamically highly unstable and the number of known compounds is very limited. Owing to the highly endothermic heats of formation, their syntheses and handling present great challenges. It is, therefore, no surprise that for oxygen only one metastable allotrope, that is, ozone, is known and for nitrogen none are known that can be isolated in bulk, while most other elements can exist in the form of many stable allotropes.Polynitrogen compounds have been studied extensively for the last two decades. In view of the great experimental difficulties, most of the efforts have been limited to theoretical studies. [1±9] The first major breakthrough in the synthesis area was achieved in 1999 with the synthesis of the N 5 þ ion in the form of a marginally stable AsF 6 À salt. [10] Subsequently, the thermally more stable N 5 þ SbF 6 À was synthesized, and the crystal structure of N 5 þ Sb 2 F 11 À was determined.[11] Based on Born±Haber cycle considerations, the stability of an ionic salt is governed by three factors: the lattice energy, the electron affinity of the cation, and the first ionization potential of the anion. Furthermore, each ion must possess a sufficiently high activation energy barrier toward decomposition. For the successful combination of N 5 þ with a poly-nitrogen anion in the form of a stable salt, an anion with a high first ionization potential is required. Theoretical calculations from our and other [1, 5, 8, 12±18] research groups predict that the unknown pentazolate anion (see Figure 1) has a first ionization potential and activation energy barrier toward decomposition that might be high enough for the formation of stable N 5 þ N 5 À . As a result, the synthesis of the N 5 À ion is hotly pursued in numerous laboratories.Although the existence and stability of substituted pentazole ring compounds have been demonstrated successfully more than 40 years ago by Huisgen and Ugi [19±22] and substituted pentazoles have been well characterized, [23±28] all attempts to prepare either the parent HN 5 molecule [29,30] or its anion, N 5 À , have so far been unsuccessful. Herein, we report the first experimental detection of this important anion.In our pursuit of the N 5 À ion, the following strategy was employed: a) the use of Ugi±Huisgen-type, substituted phenylpentazoles as starting materials; b) the transfer of maximum negative charge to the pentazole ring by the use of highly electron-donating substituents on the phenyl ring in para-position to the pentazolyl substituent to increase the aromaticity and stability of the pentazole ring, while at the same time weakening the connecting CÀN bond; c) the selective cleavage of the CÀN bond, whil...

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Section: Methodsmentioning

confidence: 99%

Experimental Detection of the Pentaazacyclopentadienide (Pentazolate) Anion, cyclo-N5â This work was funded predominantly by the Defense Advanced Research Projects Agency, with additional support from the Air Force Office of Scientific Research and the National Science Foundation. The mass spectrometer instrumentation at UCSB was supported under the Army Research Office Award no. DAAD19-00-1-0026. We thank Dr. Robert Corley, Dr. Arthur Morrish, Dr. Don Woodbury, Dr. Michael Berman, and Prof. W. Kaska for

et al. 2002

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“…16 As expected, 8 showed no fluorescence due to the quenching effect of the electron-rich azido group 13. In the presence of catalytic Cu(I) and ascorbic acid 8 reacts readily at room temperature with 1-ethynylcyclohexene ( 9a ) in DMF/4-methylpiperidine (8:2) to afford the cycloaddition product 10a in excellent yield.…”

Section: Resultsmentioning

confidence: 56%

Synthesis of Red-Shifted 8-Hydroxyquinoline Derivatives Using Click Chemistry and Their Incorporation into Phosphorylation Chemosensors

González‐Vera¹,

Luković²,

Imperiali

2009

J. Org. Chem.

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Protein phosphorylation is a ubiquitous post-translational modification and protein kinases, the enzymes that catalyze the phosphoryl transfer, are involved in nearly every aspect of normal, as well as aberrant, cell function. Here we describe the synthesis of novel, red-shifted 8-hydroxyquinolinebased fluorophores and their incorporation into peptidyl kinase activity reporters. Replacement of the sulfonamide group of the sulfonamido-oxine (1, Sox) chromophore, which has been previously used in kinase sensing, by a 1,4-substituted-triazole moiety, via click chemistry, resulted in a significant bathochromic shift in the fluorescence excitation (15 nm) and emission (40 nm) maxima for the Mg 2+ chelate. Furthermore, when a click derivative was incorporated into a chemosensor for MK2, the kinase accepted the new substrate as efficiently as the previously reported Sox-based sensor. Taken together, these results extend the utility range of kinase sensors that are based on chelation-enhanced fluorescence (CHEF).

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“…DMA was distilled under reduced pressure and the pure DMA was collected below 135 8C. BICDT, [31] CPDB, [32] methacryloyl chloride, [33] and 4-azidophenol [34] were synthesized according to the references, respectively.…”

Section: Experimental Part Materialsmentioning

confidence: 99%

A Facile Strategy for the Preparation of Azide Polymers via Room Temperature RAFT Polymerization by Redox Initiation

Zheng

Bai

2009

Macromol. Rapid Commun.

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A new vinyl aryl azide monomer, 4-azidophenyl methacrylate (APM), has been synthesized and characterized by (1) H NMR and FT-IR spectroscopy. The thermal stability of APM has been investigated by temperature-dependent FT-IR spectroscopy and (1) H NMR, and the monomer has been demonstrated to be quite stable at ambient temperature. Reversible addition-fragmentation chain transfer (RAFT) homopolymerization and copolymerizations of APM with methyl acrylate, methyl methacrylate, and styrene have been carried out at room temperature using a redox initiator, benzoyl peroxide (BPO)/N,N-dimethylaniline (DMA). The results show that the polymerizations bear all the characteristics of controlled/living free-radical polymerizations. Moreover, the cycloaddition of azido group to carbon-carbon double bond can be avoided in the polymerization process at room temperature.

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4H-Azepin-4-ones from 4-azidophenols in low-temperature matrices

Cited by 16 publications

References 33 publications

Synthesis of Red-Shifted 8-Hydroxyquinoline Derivatives Using Click Chemistry and Their Incorporation into Phosphorylation Chemosensors

A Facile Strategy for the Preparation of Azide Polymers via Room Temperature RAFT Polymerization by Redox Initiation

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