Regioselectively <i>N</i>-Methylated Azacalix[8]arene Octamethyl Ether Prepared by Catalytic Aryl Amination Reaction Using a Temporal <i>N</i>-Silylation Protocol

Ishibashi, Koichi; Tsue, Hirohito; Tokita, Satoshi; Matsui, Kazuhiro; Takahashi, Hiroki; Tamura, Rui

doi:10.1021/ol062459p

Cited by 49 publications

(10 citation statements)

References 26 publications

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“…[15] To a ring-closing reaction of 5-fragment 5 with 1-fragment 6, [16] a Buchwald-Hartwig aryl amination reaction [17] with a temporal N-silylation protocol [18] was applied, which was demonstrated to be expedient for preparing the azacalixarene with no substituent on the bridging nitrogen atoms. From this macrocyclization reaction, regioselectively tetrabenzylated azacalix [6]arene 7 was successfully obtained in 32 % yield through the in-situ N,N'-bissilylation of 1-fragment 6 with tert-butyldimethylsilyl chloride (TBDMSCl) in the presence of tBuONa, followed by the one-pot Pd 0 -catalyzed aryl amination reaction with the 5-fragment 5 and by the subsequent cleavage of the N À Si bond in the workup process.…”

Section: Resultsmentioning

confidence: 99%

Azacalix[6]arene Hexamethyl Ether: Synthesis, Structure, and Selective Uptake of Carbon Dioxide in the Solid State

Tsue

Ishibashi

Tokita

et al. 2008

Chemistry A European J

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To investigate dynamic solid-state complexation hitherto unexplored in nitrogen-bridged calixarene analogues, azacalix[6]arene hexamethyl ether has been prepared in three steps by applying a 5+1 fragment-coupling approach by using a Buchwald- Hartwig aryl amination reaction with the aid of our previously devised temporal N-silylation protocol. X-ray crystallographic analysis and NMR spectroscopic measurements have revealed that the azacalix[6]arene is well endowed with hydrogen-bonding ability, by which both the molecular and crystal structures are controlled. The azacalix[6]arene is conformationally flexible in solution on the NMR time scale, whereas it adopts a definite 1,2,3-alternate conformation with S2 symmetry in the solid state as a result of intramolecular bifurcated hydrogen-bonding interactions. In the crystal, molecules of the azacalix[6]arene are mutually interacted by intermolecular hydrogen bonds to establish one-dimensional hexane-filled nanochannel crystal architecture. Although the single crystal was broken after desolvation, the resultant polycrystalline powder material was capable of selectively adsorbing CO2 among the four main gaseous components of the atmosphere. In contrast, carbocyclic p-tert-butylcalix[6]arene hexamethyl ether, the crystal structure of which was also elucidated for the first time in the present study, gave rise to almost no uptake of CO2. Additional solid-gas adsorption experiments for another three gases, such as N2, O2, and Ar, suggested that quadrupole/induced-dipole interactions and/or hydrogen-bonding interactions played an important role in permitting the observed selective uptake of CO2 by this new azacalix[6]arene in the solid state.

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Section: Resultsmentioning

confidence: 99%

Azacalix[6]arene Hexamethyl Ether: Synthesis, Structure, and Selective Uptake of Carbon Dioxide in the Solid State

Tsue

Ishibashi

Tokita

et al. 2008

Chemistry A European J

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“…In addition to the quest for the suitable linkage of polymacrocyclic oligoarylamines, the search for a more versatile synthetic methodology of the macrocyclic oligoarylamines is also important. In this line, there is ongoing active development [24][25][26][27][28]. The present multi-spin molecular systems based on macrocyclic oligoarylamines may afford the possibility for the extension to larger 2D molecular spin systems, and hence, further studies on the extended molecular systems based on 4 and 8 are still underway.…”

Section: Resultsmentioning

confidence: 99%

Macrocyclic oligoarylamine-based spin system

Ito

Tanaka

2010

Pure and Applied Chemistry

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Alternating meta-and para-phenylene-linked oligoarylamines are considered as promising molecular parts for the molecule-based electronics and/or spintronics due to their intriguing electronic and magnetic properties. From the magnetic viewpoint, a metaphenylene linker plays a crucial role in ensuring the effective ferromagnetic interaction, while para-phenylene linker plays an important part in stabilizing the spin-containing aminium radical cations. Of the meta-para and all-meta oligoarylamines prepared so far, the macrocyclic oligoarylamines are structurally defined, and therefore we can employ them as the component pieces to prepare the two-or three-dimensionally structured oligoarylamines. The spin electronic properties of polycationic species generated from two kinds of macrocyclic oligoarylamines, which will be able to be extended into the 2D multi-spin molecular systems, are described on the basis of the pulsed electron spin resonance (ESR) measurements.

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“…Similarly, thiacalixarenes, in which the methylene of the calixarene is replaced by a sulfur atom [ 4 , 5 , 6 , 7 , 8 ]; azacalixarenes, in which the methylene is replaced by a nitrogen atom [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]; and homoxacalixarenes, in which a -CH 2 O- unit is inserted [ 20 , 21 ], have been widely studied. However, in this review, only homoazacalixarenes are considered, referred to as azacalixarene, not homoazacalixarene, unless it is necessary.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Azacalixarenes and Development of Their Properties

Takemura

2021

Molecules

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This review focuses on the synthesis, structure, and interactions of metal ions, the detection of some weak interactions using the structure, and the construction of supramolecules of azacalixarenes that have been reported to date. Azacalixarenes are characterized by the presence of shallow or deep cavities, the simultaneous presence of a basic nitrogen atom and an acidic phenolic hydroxyl group, and the ability to introduce various side chains into the cyclic skeleton. These molecules can be given many functions by substituting groups on the benzene ring, modifying phenolic hydroxyl groups, and converting side chains. The author discusses the evidence of azacalixarene utilizing these characteristics.

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Regioselectively N-Methylated Azacalix[8]arene Octamethyl Ether Prepared by Catalytic Aryl Amination Reaction Using a Temporal N-Silylation Protocol

Cited by 49 publications

References 26 publications

Azacalix[6]arene Hexamethyl Ether: Synthesis, Structure, and Selective Uptake of Carbon Dioxide in the Solid State

Azacalix[6]arene Hexamethyl Ether: Synthesis, Structure, and Selective Uptake of Carbon Dioxide in the Solid State

Macrocyclic oligoarylamine-based spin system

Synthesis of Azacalixarenes and Development of Their Properties

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