The Butylation of Guaiacol

Rosenwald, R. H.

doi:10.1021/ja01138a047

Cited by 18 publications

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“…To increase the solubility of the Eu 3+ complexes in organic solvents, the methyl groups at the terphenyl ring were replaced by tert -butyl groups, starting from p-tert -butylphenol ( 12 ) as depicted in Scheme . The compounds 13 , 14 , 15 , and 16 were prepared according to literature procedures. Dibromination of 16 with Br 2 in chloroform at room temperature gave 17 in 88% yield.…”

Section: Resultsmentioning

confidence: 99%

Novel Preorganized Hemispherands To Encapsulate Rare Earth Ions: Shielding and Ligand Deuteration for Prolonged Lifetimes of Excited Eu³⁺ Ions

et al. 1997

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Quenching of the luminescent excited state of Eu3+ ions by C−H high-vibrational modes was studied by deuteration of the encapsulating ligand and the solvent. Novel polydentate hemispherands providing nine donor atoms, which form overall neutral complexes with rare earth ions, were synthesized in nine steps, allowing the easy incorporation of deuterium atoms (11a−d·Eu 3+ ). The introduction of tert-butyl groups at the aromatic rings of the ligand further increased the solubility of the complexes in organic solvents (29·Eu 3+ and 34·Eu 3+ ). Photophysical studies, viz., luminescence spectra and lifetime measurements, revealed that significant quenching of the Eu3+ excited state is induced by nearby C−H vibrational modes. Substitution of these quenching C−H modes for C−D bonds in the azacrown bridge leads to an enhancement of the luminescent lifetime by a factor of 1.5. C−H high-vibrational modes of the pendant arms which are at a larger distance to the Eu3+ ion than the azacrown bridge hydrogen atoms (determined from the MD calculations) are less efficient quenchers. The number of coordinating methanol molecules to 11a·Eu 3+ , 29·Eu 3+ , and 34·Eu 3+ estimated by the “Horrocks equation” is 0.9, 1.2, and 1.9, respectively, as was predicted by MD calculations. Moreover, the experimental data show that quenching of the excited state of well-shielded Eu3+ ions by the C−H modes of the ligand is of the same order of magnitude as quenching by one O−H mode.

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Section: Resultsmentioning

confidence: 99%

Novel Preorganized Hemispherands To Encapsulate Rare Earth Ions: Shielding and Ligand Deuteration for Prolonged Lifetimes of Excited Eu³⁺ Ions

et al. 1997

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“…The model compounds, 4-f-butylsyringoI (1) and 4-f-butyIguaiacol (2), were synthesized according to known methods (Rosenwald 1952;Ley and M ller 1956;Adderley and Hewgill 1968) and the structure and purity were confirmed by HPLC, GC-MS and NMR. Milli-Q (Millipore) filtered water was used s solvent.…”

Section: Methodsmentioning

confidence: 99%

On the Significance of the Superoxide Radical () in Oxidative Delignification, Studied with 4-t-Butylsyringol and 4-t-Butylguaiacol. Part I. The Mechanism of Aromatic Ring Opening

Gierer¹,

Yang²,

Reitberger³

1994

HFSG

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“…Firstly, 3 was treated with tert-butanol and 85% H 3 PO 4 at 75 °C to give a colorless oil 4 in 83% yield. 9 …”

Section: Figurementioning

confidence: 99%

Regioselective Oxidative Coupling Approach to the Synthesis of (±)-Matairesinol and (±)-Secoisolariciresinol

Zhu¹,

Li²,

Wang³

et al. 2006

Synlett

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The Butylation of Guaiacol

Cited by 18 publications

References 0 publications

Novel Preorganized Hemispherands To Encapsulate Rare Earth Ions: Shielding and Ligand Deuteration for Prolonged Lifetimes of Excited Eu³⁺ Ions

Novel Preorganized Hemispherands To Encapsulate Rare Earth Ions: Shielding and Ligand Deuteration for Prolonged Lifetimes of Excited Eu³⁺ Ions

On the Significance of the Superoxide Radical () in Oxidative Delignification, Studied with 4-t-Butylsyringol and 4-t-Butylguaiacol. Part I. The Mechanism of Aromatic Ring Opening

Regioselective Oxidative Coupling Approach to the Synthesis of (±)-Matairesinol and (±)-Secoisolariciresinol

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The Butylation of Guaiacol

Cited by 18 publications

References 0 publications

Novel Preorganized Hemispherands To Encapsulate Rare Earth Ions: Shielding and Ligand Deuteration for Prolonged Lifetimes of Excited Eu3+ Ions

Novel Preorganized Hemispherands To Encapsulate Rare Earth Ions: Shielding and Ligand Deuteration for Prolonged Lifetimes of Excited Eu3+ Ions

On the Significance of the Superoxide Radical () in Oxidative Delignification, Studied with 4-t-Butylsyringol and 4-t-Butylguaiacol. Part I. The Mechanism of Aromatic Ring Opening

Regioselective Oxidative Coupling Approach to the Synthesis of (±)-Matairesinol and (±)-Secoisolariciresinol

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Novel Preorganized Hemispherands To Encapsulate Rare Earth Ions: Shielding and Ligand Deuteration for Prolonged Lifetimes of Excited Eu³⁺ Ions

Novel Preorganized Hemispherands To Encapsulate Rare Earth Ions: Shielding and Ligand Deuteration for Prolonged Lifetimes of Excited Eu³⁺ Ions