1004-66-6Relevant articles and documents
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Brieger et al.
, p. 581 (1968)
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Wittmann,H. et al.
, p. 1619 - 1623 (1969)
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Brown et al.
, p. 4339 (1958)
Fraser
, p. 2226,2227 (1960)
Selective catalytic conversion of guaiacol to phenols over a molybdenum carbide catalyst
Ma, Rui,Cui, Kai,Yang, Le,Ma, Xiaolei,Li, Yongdan
, p. 10299 - 10301 (2015)
An activated carbon supported α-molybdenum carbide catalyst (α-MoC1-x/AC) showed remarkable activity in the selective deoxygenation of guaiacol to substituted mono-phenols in low carbon number alcohol solvents. Combined selectivities of up to 85% for phenol and alkylphenols were obtained at 340°C for α-MoC1-x/AC at 87% conversion in supercritical ethanol. The reaction occurs via consecutive demethylation followed by a dehydroxylation route instead of a direct demethoxygenation pathway.
AGGREGATION OF LITHIUM PHENOLATES IN WEAKLY POLAR APROTIC SOLVENTS.
Jackman,DeBrosse
, p. 4177 - 4184 (1983)
The aggregation of lithium phenolate, 3,5-dimethylphenolate, 2,6-dimethylphenolate, and 2,6-di-tert-butylphenolate in dioxalane, dimethoxyethane, and pyridine has been investigated by a variety of methods including studies of vapor pressure barometry, **1**3C chemical shifts, **7Li nuclear quadrupole coupling constants, and **1**3C spin-lattice relaxation times. The phenolates with no ortho substituents from tetramers under most conditions. In pyridine at low concentrations and temperature the tetramers coexist with dimers. Lithium 2,6-dimethylphenolate forms dimers under all conditions studied, and lithium 2,6-di-tert-butylphenolate exists as a monomer or an oligomer depending on conditions. Attempts to establish solvation numbers for the aggregates from solvent **1**3C relaxation times have not been successful, and the reason for the failure, very fast solvent exchange, is discussed. The kinetics and thermodynamics of exchange between dimers and tetramers of lithium 3,5-dimentylphenolate in pyridine have been investigated, and the mechanism of interconversion is shown to involve additional solvation of the tetramer prior to dissociation.
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Dewar et al.
, p. 2455,2457, 2459 (1974)
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Trialkylammonium salt degradation: Implications for methylation and cross-coupling
Assante, Michele,Baillie, Sharon E.,Juba, Vanessa,Leach, Andrew G.,McKinney, David,Reid, Marc,Washington, Jack B.,Yan, Chunhui
, p. 6949 - 6963 (2021/06/02)
Trialkylammonium (most notably N,N,N-trimethylanilinium) salts are known to display dual reactivity through both the aryl group and the N-methyl groups. These salts have thus been widely applied in cross-coupling, aryl etherification, fluorine radiolabelling, phase-transfer catalysis, supramolecular recognition, polymer design, and (more recently) methylation. However, their application as electrophilic methylating reagents remains somewhat underexplored, and an understanding of their arylation versus methylation reactivities is lacking. This study presents a mechanistic degradation analysis of N,N,N-trimethylanilinium salts and highlights the implications for synthetic applications of this important class of salts. Kinetic degradation studies, in both solid and solution phases, have delivered insights into the physical and chemical parameters affecting anilinium salt stability. 1H NMR kinetic analysis of salt degradation has evidenced thermal degradation to methyl iodide and the parent aniline, consistent with a closed-shell SN2-centred degradative pathway, and methyl iodide being the key reactive species in applied methylation procedures. Furthermore, the effect of halide and non-nucleophilic counterions on salt degradation has been investigated, along with deuterium isotope and solvent effects. New mechanistic insights have enabled the investigation of the use of trimethylanilinium salts in O-methylation and in improved cross-coupling strategies. Finally, detailed computational studies have helped highlight limitations in the current state-of-the-art of solvation modelling of reaction in which the bulk medium undergoes experimentally observable changes over the reaction timecourse. This journal is
