100-84-5Relevant articles and documents
An experimental and computational evaluation of the energetics of the isomeric methoxyphenylcarbenes generated in carbon atom reactions
Geise, C. Michael,Hadad, Christopher M.,Zheng, Fengmei,Shevlin, Philip B.
, p. 355 - 364 (2002)
Carbon atom reactions with anisole and methoxybenzaldehyde demonstrate the reversible ring expansion of methoxyphenylcarbene (CH3O-C6H4-C-H). Trapping with HBF4 yields the methoxytropylium ion, analogous to the
Reaction of triaryloxonium salts with bases via dehydroarenes
Tolstaya, Tatiana P.,Tsariev, Dmitry A.,Luzikov, Yury N.
, p. 4457 - 4458 (1997)
Tri-p-tolyloxonium tetrafluoroborate reacts with NaOH in water yielding a mixture of m- and p-cresls (1:1) use of MeOH as solvent rsults in a mixture of m- and p-crescols (1:1), use of MeOH as solvent results in a mixture of m- and p-methoxytoluenes (1:5:1). This result proves this reaction to proceed via 3,4-dehydrotoluene.
Design and Synthesis of Natural Product Inspired Libraries Based on the Three-Dimensional (3D) Cedrane Scaffold: Toward the Exploration of 3D Biological Space
Tajabadi, Fatemeh Mazraati,Pouwer, Rebecca H.,Liu, Miaomiao,Dashti, Yousef,Campitelli, Marc R.,Murtaza, Mariyam,Mellick, George D.,Wood, Stephen A.,Jenkins, Ian D.,Quinn, Ronald J.
, p. 6609 - 6628 (2018)
A chemoinformatic method was developed to extract nonflat scaffolds embedded in natural products within the Dictionary of Natural Products (DNP). The cedrane scaffold was then chosen as an example of a nonflat scaffold that directs substituents in three-dimensional (3D) space. A cedrane scaffold that has three orthogonal handles to allow generation of 1D, 2D, and 3D libraries was synthesized on a large scale. These libraries would cover more than 50% of the natural diversity of natural products with an embedded cedrane scaffold. Synthesis of three focused natural product-like libraries based on the 3D cedrane scaffold was achieved. A phenotypic assay was used to test the biological profile of synthesized compounds against normal and Parkinson's patient-derived cells. The cytological profiles of the synthesized analogues based on the cedrane scaffold revealed that this 3D scaffold, prevalidated by nature, can interact with biological systems as it displayed various effects against normal and Parkinson's patient-derived cell lines.
Iridium-catalyzed direct dehydroxylation of alcohols
Huang, Jian-Lin,Dai, Xi-Jie,Li, Chao-Jun
, p. 6496 - 6500 (2013)
Iridium-catalyzed direct dehydroxylation of alcohols with hydrazine was developed through a combination of the oxidation of alcohols and the Wolff-Kishner reduction. This protocol is simple to perform and highly efficient for a series of primary, benzylic and allylic alcohols. Iridium-catalyzed direct dehydroxylation of alcohols with hydrazine is developed through a combination of the oxidation of alcohols and Wolff-Kishner reduction. This protocol is simple to perform and highly efficient for a series of primary alcohols, especially benzylic and allylic ones. Copyright
Competitive homolytic and heterolytic dediazoniation mechanisms: Rate constants and product distribution of methoxy-, hydroxy-, and hydro-dediazoniation of 3- and 4-methylbenzenediazonium salts in acidic MeOH/H2O mixtures
Pazo-Llorente, Roman,Gonzalez-Romero, Elisa,Bravo-Diaz, Carlos
, p. 210 - 220 (2000)
The rates and product distribution for methoxy-, hydroxy- and hydro-dediazoniation and the rate constants for disappearance of 3- and 4-methylbenzenediazonium tetrafluoroborate in acidic MeOH/H2O mixtures, in the presence and absence of electrolytes like HCl, NaCl, and CuCl2, are reported. Data were obtained by using a combination of VIS-UV and HPLC techniques. The kinetics and product distributions are completely consistent with competitive homolytic and heterolytic mechanisms, the heterolytic one being predominant at any solvent composition. Heterolytic data are in agreement with the predictions of a DN+AN mechanism; that is, rate determining formation of an aryl cation that reacts immediately with available nucleophiles. Selectivity values, determined from product yields, are low and independent of solvent composition. Product formation is discussed in terms of a preassociation step between aryl cations and the nucleophile, which does not account for much of the trapping, and a nucleophilic attack on a `free' arenediazonium cation. Activation parameters were also determined at 99.5% MeOH: enthalpies of activation are high and entropies of activation are positive, and they are similar to those reported for pure water.
Steric Influences on Spin-Lattice Relaxation Rates of Methyl Protons in Substituted Aromatic Molecules
Chazin, Walter J.,Colebrook, Lawrence D.
, p. 597 - 604 (1985)
Proton spin-lattice relaxation rates (R1 values) have been measured at 400 MHz for a series of substituted aromatic compounds to determine the steric effects of ortho substituents on the R1 values of the methyl groups.These values have been interpreted on the basis of differences in the barriers to methyl group rotation caused by the substituent, resulting in changes in the contributions from the dipolar and the spin-rotation relaxation mechanisms.A significant dynamic range of methyl R1 values has been observed, showing that these measurements are sensitive to the steric environment.
Mechanistic Aspects of Hydrodeoxygenation of p-Methylguaiacol over Rh/Silica and Pt/Silica
Bouxin, Florent P.,Zhang, Xingguang,Kings, Iain N.,Lee, Adam F.,Simmons, Mark J. H.,Wilson, Karen,Jackson, S. David
, p. 1586 - 1589 (2018)
The mechanism of p-methylguaiacol (PMG) hydrodeoxygenation (HDO) has been examined over two Rh/silica catalysts and a Pt/silica catalyst at 300 °C and 4 barg hydrogen. Sequential conversion of PMG to 4-methylcatechol is followed by m- and p-cresol formation and finally toluene production, although direct conversion of PMG to p-cresol is favored over a commercial Rh/silica catalyst. Dehydroxylation and hydrogenation are shown to occur over metal functions, while demethylation and demethoxylation are favored over the fumed silica support. A mechanistic pathway for HDO of PMG is proposed.
En Route to a Practical Primary Alcohol Deoxygenation
Dai, Xi-Jie,Li, Chao-Jun
, p. 5433 - 5440 (2016)
A long-standing scientific challenge in the field of alcohol deoxygenation has been direct catalytic sp3 C-O defunctionalization with high selectivity and efficiency, in the presence of other functionalities, such as free hydroxyl groups and amines widely present in biological molecules. Previously, the selectivity issue had been only addressed by classic multistep deoxygenation strategies with stoichiometric reagents. Herein, we propose a catalytic late-transition-metal-catalyzed redox design, on the basis of dehydrogenation/Wolff-Kishner (WK) reduction, to simultaneously tackle the challenges regarding step economy and selectivity. The early development of our hypothesis focuses on an iridium-catalyzed process efficient mainly with activated alcohols, which dictates harsh reaction conditions and thus limits its synthetic utility. Later, a significant advancement has been made on aliphatic primary alcohol deoxygenation by employing a ruthenium complex, with good functional group tolerance and exclusive selectivity under practical reaction conditions. Its synthetic utility is further illustrated by excellent efficiency as well as complete chemo- and regio-selectivity in both simple and complex molecular settings. Mechanistic discussion is also included with experimental supports. Overall, our current method successfully addresses the aforementioned challenges in the pertinent field, providing a practical redox-based approach to the direct sp3 C-O defunctionalization of aliphatic primary alcohols.
The reduction of aromatic aldehydes to hydrocarbons with borohydride exchange resin (BER)-nickel acetate in methanol
Bandgar,Kshirsagar,Wadgaonkar
, p. 941 - 945 (1995)
Aromatic aldehydes were reduced to the corresponding hydrocarbons with borohydride exchange resin (BER)-nickel acetate in methanol in excellent yields.
Stepwise Reduction of Acetals to the Corresponding Hydrocarbons. A Mild and Effective Transformation via Carbinyl Bromides
Oriyama, Takeshi,Ichimura, Yuichi,Koga, Gen
, p. 2581 - 2582 (1991)
Stepwise reduction of two alkoxy groups in acetal was effected by the action of triethylsilane along with acetyl bromide and SnBr2 and then of tributyltinhydride (or lithium aluminium hydride) providing methyl or methylene compounds in good yields under very mild conditions.
