6268-25-3Relevant academic research and scientific papers
Fe-Catalyzed Aerobic Oxidative C-CN Bond Cleavage of Arylacetonitriles Leading to Various Esters
Kong, Weiguang,Li, Bingnan,Xu, Xuezhao,Song, Qiuling
, p. 8436 - 8443 (2016/09/28)
Fe-catalyzed aerobic oxidative esterifications of arylacetonitriles with alcohols, tri alkoxsilanes, silicate esters, or borate esters have been developed. The acyl groups which were in situ generated via chemoselective C(CO)-CN bond cleavage were directly used as electrophiles, leading to corresponding aryl esters in good to excellent yields under molecular oxygen when attacked by alcohols or alcohol surrogates. Dioxygen serves as both oxidant and reactant in this protocol. The reaction has a very broad substrate scope. Cheap starting materials as well as environmentally benign and inexpensive iron catalyst and ideal oxidant O2 feature this transformation and make it a practical and sustainable protocol to afford esters.
A facile, one-pot procedure for the conversion of aromatic aldehydes to esters, as well as thioesters and amides, via acyl hydrazide intermediates
Maruani, Antoine,Lee, Maximillian T. W.,Watkins, George,Akhbar, Ahmed R.,Baggs, Henry,Shamsabadi, André,Richards, Daniel A.,Chudasama, Vijay
, p. 3372 - 3376 (2016/01/16)
Herein we present an efficient method for the synthesis of esters from aromatic aldehydes via readily accessible acyl hydrazides. The developed reaction protocol is shown to be tolerant of a range of aromatic aldehydes, bearing various functionalities, as well as being amenable to the synthesis of thioesters and amides.
Inclusion complex containing epoxy resin composition for semiconductor encapsulation
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, (2014/03/21)
The invention is an epoxy resin composition for sealing a semiconductor, including (A) an epoxy resin and (B) a clathrate complex. The clathrate complex is one of (b1) an aromatic carboxylic acid compound, and (b2) at least one imidazole compound represented by formula (II): wherein R2 represents a hydrogen atom, C1-C10 alkyl group, phenyl group, benzyl group or cyanoethyl group, and R3 to R5 represent a hydrogen atom, nitro group, halogen atom, C1-C20 alkyl group, phenyl group, benzyl group, hydroxymethyl group or C1-C20 acyl group. The composition has improved storage stability, retains flowability when sealing, and achieves an effective curing rate applicable for sealing delicate semiconductors.
Generally applicable and efficient esterification of aldehydes with alcohols catalyzed by cyclopalladated ferrocenylimine
Ma, Gaizhi,Leng, Yuting,Qiao, Huijie,Yang, Fan,Wang, Shiwei,Wu, Yangjie
, p. 44 - 47 (2014/01/06)
The palladacycle-catalyzed esterification of a variety of aldehydes with alcohols was developed. This reaction allows formation of esters in moderate to excellent yields not only for various aldehydes but also alcohols. In addition, the esterification could proceed well under mild conditions with a low catalyst loading of 0.0625 mol%. Copyright
Mechanistic investigation of oxidation of some substituted aromatic acetals with N-bromosuccinimide in acetonitrile medium - A kinetic approach
Mathiyalagan
, p. 1499 - 1506 (2013/02/23)
The oxidation of meta- and para-substituted aromatic acetals by N-bromosuccinimide (NBS) to the corresponding esters and alkyl bromide, is first-order in [NBS] and [acetal]. The effect of substituents in the aromatic ring of some aromatic acetals [X-C6H4CH(OBu-B) 2] {X = H, p-OMe, p-Me, p-Cl, p-NO2, m-OMe, m-CI, m-NO2} on the kinetics of above oxidation has been studied in acetonitrile medium at various temperatures by iodometric method. The rate of the reaction increases with the increase in the dielectric constant of the medium. The stoichiometry of the reaction is found to be 1 : 1. A primary kinetic isotopic effect kH/kD of 1.8 is observed, which indicates the C-H bond cleavage of the aldehydic carbon in the rate determining step. The Hammett reaction constant (a) for the reaction is found to be -1.38 and -1.42 at 313 K and 323 K respectively. The Exner plot is found to be linear with the isokinetic temperature 132 K. The kinetic and activation parameters Ea, A, ΔH≠, ΔG≠ and ΔS≠ have been calculated. A mechanism involving simultaneous loss of H+ from the aldehydic carbon and expulsion of bromide ion with the formation of carbonium ion intermediate is proposed.
Transition-metal-free aerobic oxidative cleavage of C-C bonds in α-hydroxy ketones and mechanistic insight to the reaction pathway
Liu, Hui,Dong, Chao,Zhang, Zeguang,Wu, Peiyu,Jiang, Xuefeng
supporting information, p. 12570 - 12574 (2013/02/22)
Clear cut: For the title reaction, O2, the ideal oxidant, was used as the only oxidizing reagent. The dimer intermediate (see scheme) and isotopic labeling control experiments with 18O2 partially disclosed the reaction mec
Correlation analysis in the study of oxidation kinetics of aromatic acetals with N-bromosuccinimide in acetonitrile medium
Mathiyalagan
scheme or table, p. 865 - 868 (2012/04/10)
An attempt has been made to correlate the rate constants of substituted acetals with the chemical shifts of the benzylic proton of the acetals (log k2 vs δ). This correlation is similar to that of which is obtained between σ vs δ. The benzylic proton chemical shift in acetals is found to be the characteristics of acetals. The benzylic proton does not couple with other protons and hence appears as a singlet, which would ensure effective correlation.
Regioselective nitration of deactivated mono-substituted benzenes using acyl nitrates over reusable acidic zeolite catalysts
Smith, Keith,Ajarim, Mansour D.,El-Hiti, Gamal A.
experimental part, p. 270 - 278 (2010/12/19)
Nitration of benzonitrile was investigated using a nitric acid/acid anhydride/zeolite catalyst system under different reaction conditions. Trifluoroacetic and chloroacetic anhydrides were found to be the most active among the anhydrides tried. Also, zeolites Hβ and Fe3+β (Si/ Al = 12.5) were found to be the most active catalysts. For example, nitration of benzonitrile with trifluoroacetyl nitrate under reflux conditions in dichloromethane gave 3- and 4-nitrobenzonitriles in quantitative yield, of which the para-isomer represented 24-28%. The yield of para-isomer was improved to 33% when passivated Hβ was used under similar reaction conditions. This is easily the most para-selective nitration of benzonitrile ever recorded. Also, no ortho-isomer was formed under the conditions tried. The zeolite can be easily recovered, regenerated by heating and reused up to six times to give results similar to those obtained with a fresh sample of the catalyst. The nitration system was applied successfully to a range of deactivated mono-substituted benzenes to give para-isomers in significantly higher proportions than in the corresponding traditional nitration reactions.
Alumina sulfuric acid as a novel heterogeneous system for esterification of carboxylic acids in solvent free conditions
Sharghi, Hashem,Sarvari, Mona Hosseini,Eskandari, Razieh
, p. 488 - 491 (2007/10/03)
Neat chlorosulfonic acid reacts with alumina to give alumina sulfuric acid (ASA) in which sulfuric acid is immobilised on the surface of alumina via a covalent bond. Carboxylic acids can be readily converted to their corresponding esters with a combination of ASA and alcohols in solvent free conditions.
Linear free energy relationship and conformational effects on oxidation of aromatic acetals by pyridinium fluorochromate
Ramakrishnan,Nambi
, p. 232 - 234 (2007/10/03)
Kinetics of oxidation of aromatic acetals by pyridiniumfluorochromate (PFC) in aqueous acetic acid medium reveal that the reactions are second order, first order each in [acetal] and [PFC]. The presence of electron- withdrawing substituents in the benzene ring enhances the rate of oxidation while that of opposite one retards it. The small ρ value suggests a mechanism with little charge separation. The rate of oxidation depends on the nature of alkyl group and conformational effects.
