16837-06-2Relevant academic research and scientific papers
Tropylium salts as efficient organic Lewis acid catalysts for acetalization and transacetalization reactions in batch and flow
Lyons,Crocker,Enders,Nguyen
supporting information, p. 3993 - 3996 (2017/09/08)
Acetalization reactions play significant roles in the synthetically important masking chemistry of carbonyl compounds. Herein we demonstrate for the first time that tropylium salts can act as organic Lewis acid catalysts to facilitate acetalization and transacetalization reactions of a wide range of aldehyde substrates. This metal-free method works efficiently in both batch and flow conditions, prompting further future applications of tropylium organocatalysts in green synthesis.
Synthesis of pinacol acetals catalyzed by (2-carboxyphenyl)diphenylphosphonium bromide
Huang, Wenhua,Xu, Ning
supporting information, p. 2133 - 2138 (2017/10/31)
(2-Carboxyphenyl)diphenylphosphonium bromide that is readily prepared from commercial 2-(diphenylphosphino)benzoic acid and HBr is an efficient catalyst for the synthesis of pinacol acetals from a variety of aldehydes at room temperature.
Highly efficient and chemoselective acetalization and thioacetalization of aldehydes catalyzed by propylphosphonic anhydride (T3P) at room temperature
Augustine, John Kallikat,Bombrun, Agnes,Sauer, Wolfgang H.B.,Vijaykumar, Pujari
, p. 5030 - 5033 (2012/11/07)
Propylphosphonic anhydride (T3P), a low toxic peptide coupling agent, has been demonstrated to be an efficient catalyst for the chemoselective acetalization and thioacetalization of aldehydes in the presence of ketones. Cyclic and acyclic acetals of diverse aldehydes were obtained in good to excellent yields at room temperature in the presence of a catalytic amount of T3P.
Structure-based design of novel boronic acid-based inhibitors of autotaxin
Albers, Harald M. H. G.,Hendrickx, Loes J. D.,Van Tol, Rob J. P.,Hausmann, Jens,Perrakis, Anastassis,Ovaa, Huib
supporting information; experimental part, p. 4619 - 4626 (2011/09/14)
Autotaxin (ATX) is a secreted phosphodiesterase that hydrolyzes the abundant phospholipid lysophosphatidylcholine (LPC) to produce lysophosphatidic acid (LPA). The ATX-LPA signaling axis has been implicated in inflammation, fibrosis, and tumor progression
Aromatic Nitration under Neutral Conditions Using Nitrogen Dioxide and Ozone as the Nitrating Agent. Application to Aromatic Acetals and Acylal
Suzuki, Hitomi,Yonezawa, Shuji,Mori, Tadashi
, p. 1535 - 1544 (2007/10/03)
Cyclic acetals derived from aromatic carbonyl compounds can be nitrated smoothly with nitrogen dioxide in ice-cooled dichloromethane or acetonitrile in the presence of ozone and magnesium oxide to give ortho- and para-nitro derivatives as the major product in good combined yields, the acetal ring as a protective group remaining almost intact.An acylal derived from benzaldehyde similarly undergoes nitration on the aromatic ring to give an isomeric mixture of three nitro compounds, in which the ortho and meta isomers predominate, while aromatic orthoesters are rapidly decomposed to give simply the parent esters.Ring nitration under neutral conditions has been interpreted in terms of a nonclassical mechanism, in which nitrogen trioxide is involved as the initial electrophile.
ELECTRONIC EFFECT OF 1,3-DIOXACYCLANE SUBSTITUENTS IN NITROBENZALDEHYDE ACETALS
Ovchinnikov, V. V.,Evstaf'eva, Yu. G.,Latypova, V. Z.,Bogoveeva, G. A.,Cherkasov, R. A.
, p. 196 - 199 (2007/10/02)
The electronic effect of 1,3-dioxacyclane substituents in p- and m-nitrobenzaldehyde acetals was studied by IR spectroscopy and electrochemical reduction.In the investigated compounds the electron-withdrawing effect of the 1,3-dioxolane fragments is more
Observation of a Stable Hemiortho Ester Anion. Acidity Constant for a Tetrahedral Intermediate
McClelland, Robert A.,Seaman, N. Esther,Cramm, David
, p. 4511 - 4515 (2007/10/02)
Pinacol mono-p-nitrobenzoate (POH) undergoes a rapid, reversible cyclization in base producing an anionic tetrahedral intermediate (TO-), the conjugate base of 2-(p-nitrophenyl)-2-hydroxy-4,4,5,4-tetramethyl-1,3-dioxolane (TOH).Presence of the anion is established by changes in UV spectra and by the rate behavior exhibited in the hydrolysis of the ester to pinacol and p-nitrobenzoate.Rate constants in base do not rise as rapidly as expected as the ester form is converted to the unreactive TO-.Interconversion of POH and TO- occurs in a typical acid:base manner, and UV spectral analysis in base provides Kb= ->/->=0.7.The equilibrium constant K0=/ for cyclization of the pinacol ester to the neutral hemiortho ester TOH is 8*10-4, this has been measured as the ratio of forward and reverse rate constants.Combination of Kb and K0 provides a value Ka=->+>/ for the acidity constant of the tetrahedral intermediate of 10-10.4.This number is compared with estimates of tetrahedral intermediate acidity based on substituent effects and free energy correlations, and excellent agreement is noted.
