19082-49-6Relevant academic research and scientific papers
Mechanism of reaction of an arenediazonium ion in aqueous solutions of acetamide, N-methylacetamide, and N,N-dimethylacetamide. A potential method for chemically tagging peptide bonds at aggregate interfaces
Romsted, Laurence S.,Zhang, Jianbing,Zhuang, Lanzhen
, p. 10046 - 10054 (1998)
The mechanism of dediazoniation of 2,4,6-trimethylbenzenediazonium ion, 1-ArN2+, in concentrated aqueous solutions of acetamide, N-methylacetamide, and N,N-dimethylacetamide (peptide bond models) was probed by a combination of techniques including HPLC, GC/MS, and H218O isotopic labeling. The kinetics and product distributions are completely consistent with the heterolytic dediazoniation mechanism, i.e., rate-determining loss of N2 followed by trapping of the aryl cation intermediate, 1-Ar+, by H2O and the oxygens and nitrogens of the amides. Aryl imidates formed from trapping by amide O hydrolyze rapidly into aryl ester/amine and amide/phenol product pairs. The results were used to estimate the selectivity of 1-Ar+ toward the amide oxygens and nitrogens versus H2O. 1-Ar+ is only 10-40% more selective toward H2O than amide O, but it is more than 10 times more selective toward H2O than the amide N. 1-Ar+ is slightly more selective toward the N of acetamide than N-methylacetamide. However, within the HPLC detection limit, 1-At+ does not give a product from reaction with the N,N-dimethylacetamide nitrogen. The selectivities are interpreted by using a preassociation model, i.e., selective solvation by the different nucleophiles of the reactive diazonio group in the ground state. These results indicate that chemical tagging (trapping by N) and cleaving (trapping by O) of the peptide bonds and the weakly basic side chains of polypeptides and proteins bound to association colloids, vesicles and biomembranes, and emulsions may provide new information on their topologies and orientations at the aggregates' interfaces.
OXIDATION OF MESITYLENE BY HYDROGEN PEROXIDE IN AcOH-Ac2O-H2SO4
Kholdeeva, O. A.,Kozhevnikov, I. V.
, p. 2462 - 2466 (1990)
By the oxidation of mesitylene by hydrogen peroxide in AcOH-Ac2O-H2SO4 one can obtain mesitol (2,4,6-trimethylphenol) with a selectivity of 57-69percent at a mesitylene conversion of 22-16percent and the acetate of mesitol with a selectivity of 72-85percent at 25-22percent conversion.The peroxide responsible for the oxidation of mesitylene in this system is in the form of peracetic acid, formed in situ.Over the concentration range studied, the reaction is first order in AcOOH, mesitylene, and H2SO4.Hydroxylation of mesitylene by AcOOH proceeds by an electrophilic substitution mechanism, the limiting step being the formation of the ?-complex.
Structure–activity comparison in palladium–N–heterocyclic carbene (NHC) catalyzed arene C[sbnd]H activation- functionalization
Mondal, Moumita,Choudhury, Joyanta
, p. 451 - 457 (2016/12/16)
A simple and efficient C[sbnd]H activation catalyst was identified through a model structure-activity screening applied to a noncooperative, nonsymmetric bimetallic palladium(II)-N-heterocyclic carbene complex. Mechanistic studies based on kinetics and DOSY NMR spectroscopy provided the origin of the higher efficiency of the identified catalyst.
Gold-catalyzed C-H oxidative polyacyloxylation reaction of hindered arenes
Pradal, Alexandre,Faudot Dit Bel, Pierre,Toullec, Patrick Y.,Michelet, Veronique
experimental part, p. 2463 - 2468 (2012/09/08)
The synthesis of polyacyloxylated aromatic derivatives was achieved in moderate yields using a gold-catalyzed C-H activation strategy and di(acetoxy)iodobenzene as an oxidant. Georg Thieme Verlag Stuttgart · New York.
Gold-catalyzed oxidative acyloxylation of arenes
Pradal, Alexandre,Toullec, Patrick Y.,Michelet, Veronique
supporting information; experimental part, p. 6086 - 6089 (2011/12/22)
A variety of nonactivated hindered aromatic rings are acyloxylated (22 examples, up to 83% yield) in the presence of PPh3AuCl as the catalyst and di(acetoxy)iodobenzene as the oxidant. The reaction proceeds at 110 °C in an acid media and allows the formation of both hindered acetoxy and acyloxy derivatives. This methodology nicely complements the Pd-catalyzed arene acyloxylation reaction, which is not operating on hindered substrates and allows the Au-catalyzed unprecedented acyloxylation reaction of arenes, implying various carboxylic acids.
Gold(III)-catalyzed direct acetoxylation of arenes with iodobenzene diacetate
Qiu, Di,Zheng, Zhitong,Mo, Fanyang,Xiao, Qing,Tian, Yu,Zhang, Yan,Wang, Jianbo
, p. 4988 - 4991 (2011/11/13)
AuCl3-catalyzed direct acetoxylation of electron-rich aromatic compounds has been achieved with iodobenzene diacetate as the acetoxylation reagent.
Iodonium salts are key intermediates in Pd-catalyzed acetoxylation of pyrroles
Lubriks, Dmitrijs,Sokolovs, Igors,Suna, Edgars
body text, p. 4324 - 4327 (2011/10/05)
A mild, room-temperature Pd-catalyzed acetoxylation of pyrroles with phenyliodonium acetate is described. The acetoxylation was found to proceed via the initial formation of pyrrolyl(phenyl)iodonium acetates, which were converted to acetoxypyrroles in the presence of Pd(OAc)2. The acetoxylation could also be carried out as a one-pot sequential procedure without the isolation of the intermediate iodonium salts.
Counterattack mode differential acetylative deprotection of phenylmethyl ethers: Applications to solid phase organic reactions
Chakraborti, Asit K.,Chankeshwara, Sunay V.
experimental part, p. 1367 - 1370 (2009/07/04)
A counterattack protocol for differential acetylative cleavage of phenylmethyl ether has been developed. The phenylmethyl moiety is liberated as benzyl bromide that is isolated and reused providing advantages in terms of waste minimization/utilization and atom economy. The applicability of this methodology has been extended for solid phase organic reactions with the feasibility of reuse of the solid support.
Samarium trifluoromethanesulfonate: An efficient moisture tolerant acylation catalyst under solvent-free condition
Roy, Bimalendu,Dasgupta, Somnath,Kumar Rajput, Vishal,Mukhopadhyay, Balaram
, p. 1 - 9 (2008/09/21)
Samarium trifluoromethanesulfonate catalyzed the acylation of phenols, alcohols, thiols, free reducing sugars, and glycosides in excellent yields at ambient temperature under solvent-free condition using stoichiometric amounts of various anhydrides. (Chemical Equation Presented). Copyright Taylor & Francis Group, LLC.
Widely useful DMAP-catalyzed esterification under auxiliary base- and solvent-free conditions
Sakakura, Akira,Kawajiri, Kimio,Ohkubo, Takuro,Kosugi, Yuji,Ishihara, Kazuaki
, p. 14775 - 14779 (2008/09/17)
With regard to atom economy and E-factor, catalytic condensation of carboxylic acids with equimolar amounts of alcohols is the most desirable. Although several highly active dehydration catalysts have been reported, more efficient alternatives are still strongly needed because the dehydrative esterification of tertiary alcohols, phenols, acid-sensitive alcohols, amino acids, and hardly soluble alcohols has never proceeded satisfactorily. Here we report new insights into the classical DMAP-catalyzed acylation of alcohols: surprisingly, only a 0.05-2 mol % of DMAP can efficiently promote acylation of alcohols with acid anhydrides under auxiliary base- and solvent-free conditions to give the corresponding esters in high yields. Furthermore, we achieved the recovery and reuse of commercially available polystyrene-supported DMAP without using any solvents. These serendipitous findings provide widely useful and environmentally benign esterification methods, which might be more practical and reliable than catalytic dehydrative condensation methods, in particular, for the less reactive alcohols which hardly condense with carboxylic acid directly.
