Synthesis, Molecular Structure, and Properties of 2‐(2‐Hydroxyphenyl)‐1‐azaazulene

Oda, Mitsunori; Sugiyama, Ayumi; Takeuchi, Rie; Fujiwara, Yoshitaka; Miyatake, Ryuta; Abe, Takako; Kuroda, Shigeyasu

doi:10.1002/ejoc.201101831

Cited by 13 publications

(26 citation statements)

References 30 publications

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“…1-Azaazulene with a phenol functional group at the 2-position has been synthesized by Oda et al 26 This structure is similar to 8-hydroxyquinoline, which is an important chelating agent. 27 , 28 Thus, 2-(2-hydroxyphenyl)-1-azaazulene ( 2OHPhAZ ) has the potential to be used as a chelating ligand through the imino nitrogen atom and the phenolic oxygen atom.…”

Section: Introductionmentioning

confidence: 99%

Structures, Energetics, and Spectra of (NH) and (OH) Tautomers of 2-(2-Hydroxyphenyl)-1-azaazulene: A Density Functional Theory/Time-Dependent Density Functional Theory Study

et al. 2022

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Tautomerization of 2-(2-hydroxyphenyl)-1-azaazulene ( 2OHPhAZ ) in the gas phase and ethanol has been studied using B3LYP, M06-2X, and ωB97XD density functional theory (DFT) with different basis sets. For more accurate data, energies were refined at CCSD(T)/6-311++G(2d,2p) in the gas phase. Nuclear magnetic resonance (NMR), aromaticity, Fukui functions, acidity, and basicity were also calculated and compared with experimental data. Time-dependent density functional theory (TDDFT)-solvation model based on density (TDDFT-SMD) calculations in acetonitrile have been utilized for the simulation of UV–vis electronic spectra. In addition, electronic structures of the investigated system have been discussed. The results reveal that the enol form ( 2OHPhAZ ) is thermodynamically and kinetically stable relative to the keto tautomer ( 2OPhAZ ) and different rotamers ( 2OHPhAZ–R1:R3 ) in the gas phase and ethanol. A comparison with the experiment illustrates a good agreement and supports the computational findings.

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Section: Introductionmentioning

confidence: 99%

Structures, Energetics, and Spectra of (NH) and (OH) Tautomers of 2-(2-Hydroxyphenyl)-1-azaazulene: A Density Functional Theory/Time-Dependent Density Functional Theory Study

et al. 2022

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“…The combined organic layers were washed with brine (5 mL), and dried over anhydrous MgSO4. Filtration was concentrated in vacuo, and the residue was purified by column chromatography (silica gel, 90% EtOAc in hexane) to provide 14 (11…”

Section: -Phenylcyclohepta[b]pyrrol-4(1h)-one (14)mentioning

confidence: 99%

“…1 Of the many azaazulenes, 1-azaazulenes have attracted considerable attention from chemists because of their stabilities and pharmacological activities. [2][3][4] While many examples of 1-azaazulene syntheses have been reported, [5][6][7][8][9][10][11] in most cases, troponoid compounds were used as starting materials. For example, Nitta and co-workers successfully synthesized various 1-azaazulene derivatives 3 from tropones 1 using the aza-Wittig reaction followed by the oxidation of the bicyclic intermediates 2 (Scheme 1, A).…”

mentioning

confidence: 99%

Synthesis of 1-Azaazulenes Using Ring-Opening Cyclization of Spirocyclopropane with Amine

Nambu¹,

Onuki²,

Yamazaki³

et al. 2021

HETEROCYCLES

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Synthesis of 1-azaazulenes using ring-opening cyclization of spirocyclopropane with a primary amine was accomplished. The reaction of cycloheptane-1,3-dione-2-spirocyclopropane with 2,4-dimethoxybenzylamine in refluxing acetonitrile resulted in a 94% yield of 1,2,3,6,7,8hexahydrocyclohepta[b]pyrrol-4(5H)-one. The obtained product was successfully converted into 1-azaazulenes by deprotecting the amino-protecting group followed by oxidation.Azaazulenes, aza-analogues of azulene, have intriguing physical and chemical properties and potential biological activities. 1 Of the many azaazulenes, 1-azaazulenes have attracted considerable attention from chemists because of their stabilities and pharmacological activities. [2][3][4] While many examples of 1-azaazulene syntheses have been reported, [5][6][7][8][9][10][11] in most cases, troponoid compounds were used as starting materials. For example, Nitta and co-workers successfully synthesized various 1-azaazulene derivatives 3 from tropones 1 using the aza-Wittig reaction followed by the oxidation of the bicyclic intermediates 2 (Scheme 1, A). 8 Narasaka and co-workers reported the synthesis of 1-azaazulenes 3 from cycloheptatrienylmethyl ketone O-pentafluorobenzoyloximes 4 by palladium(0)-catalyzed cyclization and sequential oxidation (Scheme 1, A). 9 Although these synthetic methods are direct and efficient, tropone derivatives are expensive and difficult to prepare.Meanwhile, we have developed a synthetic method of indole employing the ring-opening cyclization of cyclohexane-1,3-dione-2-spirocyclopropanes 5 with primary amines 6 to provide 2,3,6,7-tetrahydro-1Hindol-4(5H)-ones 7 followed by its oxidation into indole 8 (Scheme 1, B). 12 Based on this approach, we envision that the use of cycloheptane-1,3-dione-derived spirocyclopronane instead of a cyclohexane-1,3-dione derivative can construct a 1-azaazulene skeleton. Herein, we report the synthesis

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“…Slight difference between two spectra may be attributed to its conformational change by hydrogen bond in the protic solvent, as seen in 1. [12] a) 7 (X=I) was added to the reaction mixture in portions during a time of 6 hr. b) 7 (X=I) was added to the reaction mixture in portions during a time of 9 hr.…”

Section: Scheme 1 Synthesis Ofmentioning

confidence: 99%

“…1, and studied ability of 1-azaazulenes [6][7][8][9] as a ligand for metal ions and as a base for Brønsted acids. [10][11][12] It was found that 2-(pyrid-2-yl)-1-azaazulene (1) chelated with metal ions and bound with proton and, then, showed the enhanced emission upon photoexcitation. [10] During a course of our study, we have been interested in a pincer ligand having 1-azaazulenyl groups.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Properties of 2,6-Bis(1-Azaazulen-2-yl)-Pyridine

Oda

Yamaga²,

Kumai³

et al. 2015

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The title compound, 2,6-bis(1-azaazulen-2-yl)pyridine (5), was synthesized by condensation between tropone (6) and 2,6-bis(pyridinioacetyl)pyridinium salt (7) in the presence of ammonium acetate. By slow addition of an acetic acid solution of the pyridinium salt 7 to a mixture of 6 and ammonium acetate the yield of 5 was improved. Physical properties of 5 were investigated. It is worthy to note that upon irradiation 5 shows strong emission in acidic media in contrast to very weak emission in neutral media.

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Synthesis, Molecular Structure, and Properties of 2‐(2‐Hydroxyphenyl)‐1‐azaazulene

Cited by 13 publications

References 30 publications

Structures, Energetics, and Spectra of (NH) and (OH) Tautomers of 2-(2-Hydroxyphenyl)-1-azaazulene: A Density Functional Theory/Time-Dependent Density Functional Theory Study

Structures, Energetics, and Spectra of (NH) and (OH) Tautomers of 2-(2-Hydroxyphenyl)-1-azaazulene: A Density Functional Theory/Time-Dependent Density Functional Theory Study

Synthesis of 1-Azaazulenes Using Ring-Opening Cyclization of Spirocyclopropane with Amine

Synthesis and Properties of 2,6-Bis(1-Azaazulen-2-yl)-Pyridine

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