Synthesis of 2-Substituted Azulenes by Nucleophilic Substitution Reactions of 2-Haloazulene Derivatives

Nozoe, Tetsuo; Seto, Shûichi; Matsumura, Shingo

doi:10.1246/bcsj.35.1990

Cited by 89 publications

(40 citation statements)

References 6 publications

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“…Pd 0 -catalysed alkynylation with trimethylsilylacetylene (TMSA) under Sonogashira [22][23][24] conditions furnished the protected monoethynyl-or diethynylazulenes 2a,b and 5a,b, respectively, which afforded the 1-ethynyl-and 1,3-diethynylazulenes 3a,b and 6a,b, respectively, as blue crystals in 38-99 % yield, upon treatment with potassium hydroxide in methanol. In a similar reaction sequence, 2-ethynylazulene (9) could be prepared from 2-iodoazulene (7) [25] via the trimethylsilyl-protected derivative 8.…”

Section: Synthesis Of Mono- Di-and Triethynylazulenesmentioning

confidence: 99%

Ethynylazulenes — Building Blocks for Novel Oligoazulenes with Ethynyl and Butadiynyl Bridges

2006

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The azulenes 3a,b, 6a,b, 9, 12 and 15 ethynylated in the fivemembered ring were prepared by Pd-catalysed cross-coupling of the corresponding iodoazulenes 1a,b, 4a,b, 7, 10 and 13, respectively, with trimethylsilylacetylene and subsequent desilylation. The synthesis of some acyclic oligomers 23-30, 32-36 and 38-40 from these ethynylazulenes could be accomplished by oxidative Eglinton coupling as well as Pd/Cu-

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Section: Synthesis Of Mono- Di-and Triethynylazulenesmentioning

confidence: 99%

Ethynylazulenes — Building Blocks for Novel Oligoazulenes with Ethynyl and Butadiynyl Bridges

2006

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“…To a flask charged with Pd(dppf)Cl 2 (0.03 mmol), KOAc (3.0 mmol) and bis(pinacolato)diboron (1.1 mmol) was added DMSO (6 mL) and then haloazulene (3 or 7) 9 (1.0 mmol). The mixture was stirred at 80°C for 5 h, the reaction was quenched with H 2 O (20 mL), and the resulting mixture was extracted with benzene (3 ´ 5 mL).…”

Section: Preparation Of Azulenyl-4455-tetramethyl-132-dioxaborolmentioning

confidence: 99%

Coupling Reaction of Azulenyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolanes with Haloazulenes

Kurotobi¹,

Tochihara²,

Miyauchi³

et al. 2002

Synthesis

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“…Precursors of the S N Ar reaction, i.e., 2-chloroazulenes 1 and 2, were readily prepared by Nozoe's procedure by using 2amino-1,3-diethoxycarbonylazulene as a starting material with a two-step procedure (Scheme 2). 10 Previously, Nozoe and co-workers have reported the reaction of 1 with several amines in EtOH at 80 °C giving the corresponding 2-aminoazulenes in 42−81% yields. 10 To improve the yield of products, we investigated the S N Ar reaction of 1 and 2 with several amines without the solvent.…”

Section: Synthesis Of 2-aminoazulenesmentioning

confidence: 99%

“…10 Previously, Nozoe and co-workers have reported the reaction of 1 with several amines in EtOH at 80 °C giving the corresponding 2-aminoazulenes in 42−81% yields. 10 To improve the yield of products, we investigated the S N Ar reaction of 1 and 2 with several amines without the solvent. The yield and structure of 2-aminoazulene derivatives obtained by the reaction were summarized in Table 1.…”

Section: Synthesis Of 2-aminoazulenesmentioning

confidence: 99%

“…In the pioneering work of Nozoe et al, the nucleophilic aromatic substitution (S N Ar) reaction of 2-chloro-1,3-diethoxycarbonylazulene (1) is examined with several nucleophiles to give the corresponding 2-substituted azulenes. 10 They investigate the preparation of some 2-aminoazulenes by the S N Ar reaction, but the scope and limitation of amine formation are not examined extensively. Moreover, the reaction of 2-chloroazulene (2) with amines have never been investigated to prepare the 2-aminoazulenes without the electron-withdrawing groups that should accelerate the S N Ar reaction.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of 2-amino- and 2-arylazoazulenes via nucleophilic aromatic substitution of 2-chloroazulenes with amines and arylhydrazines

et al. 2017

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The SAr reaction of 2-chloroazulene derivative 1 with ethoxycarbonyl groups at the 1,3-positions of the azulene ring with several amines afforded the corresponding 2-aminoazulenes 3-9 in excellent yields. 2-Chloroazulene (2) without the electron-withdrawing groups reacted with highly nucleophilic cyclic amines (i.e., morpholine, piperidine and pyrrolidine) under the high-temperature conditions in a sealed tube to produce the corresponding 2-aminoazulenes 10-12 in good yields. 2-Aminoazulenes 10-14 without the electron-withdrawing groups were also obtained in good yields by the treatment of compounds 3-7 with 100% HPO, but in the cases of the reaction of 8 and 9 with a secondary amine function, the decomposition of the products resulted. The synthesis of 2-arylazoazulenes 15-18 was also established via the SAr reaction of 1 with arylhydrazines. The optical and electrochemical properties of the 2-arylazoazulene derivatives were examined by UV/Vis spectroscopy, theoretical calculations and voltammetric experiments.

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Synthesis of 2-Substituted Azulenes by Nucleophilic Substitution Reactions of 2-Haloazulene Derivatives

Cited by 89 publications

References 6 publications

Ethynylazulenes — Building Blocks for Novel Oligoazulenes with Ethynyl and Butadiynyl Bridges

Ethynylazulenes — Building Blocks for Novel Oligoazulenes with Ethynyl and Butadiynyl Bridges

Coupling Reaction of Azulenyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolanes with Haloazulenes

Synthesis of 2-amino- and 2-arylazoazulenes via nucleophilic aromatic substitution of 2-chloroazulenes with amines and arylhydrazines

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