4257-83-4Relevant academic research and scientific papers
Rearrangement of Benzylic Trichloroacetimidates to Benzylic Trichloroacetamides
Adhikari, Arijit A.,Suzuki, Tamie,Gilbert, Reesheda T.,Linaburg, Matthew R.,Chisholm, John D.
, p. 3982 - 3989 (2017/04/11)
The rearrangement of allylic trichloroacetimidates is a well-known transformation, but the corresponding rearrangement of benzylic trichloroacetimidates has not been explored as a method for the synthesis of benzylic amines. Conditions that provide the tr
Hafnium-catalyzed direct amide formation at room temperature
Lundberg, Helena,Adolfsson, Hans
, p. 3271 - 3277 (2015/06/16)
Herein, the first example of a metal-catalyzed protocol for direct amidation of nonactivated carboxylic acids at ambient temperature (26 °C) is presented. The mild reaction conditions give rise to high yields of a range of amides in reaction times as short as 90 min, employing a commercial hafnium complex, [Hf(Cp)2Cl2], as catalyst. Amino acids are transformed into their corresponding amides without racemization, and the catalyst displays full selectivity for the amidation of carboxylic acids over esters. Electronic properties of the carboxylic acids were found to have a strong influence on the rate of the amidation reaction, and the need for a balanced amount of molecular sieves was observed to be highly important for optimal reaction outcome.
Steric and Electronic Effects in the Synthesis and Regioselective Hydrolysis of Unsymmetrical Imides
Shang, Jing,Pourvali, Aysa,Cochrane, James R.,Hutton, Craig A.
, p. 1854 - 1858 (2015/12/26)
The AgI-promoted coupling reaction of thioamides and carboxylic acids is shown to be a useful method for the generation of unsymmetrical imides. The reaction proceeds efficiently with unhindered and electron-rich or neutral coupling partners, but not with hindered thioamides (such as thiopivalamides) or electron deficient thioamides (such as trifluorothioacetamides). Intriguingly, thioformamides are also ineffective coupling partners, despite having minimal steric or electronic influence. Hindered carboxylic acid coupling partners (such as pivalic acid) are tolerated, but electron deficient acids, such as trifluoroacetic acid, are ineffective coupling partners. Furthermore, an interplay of both steric and electronic effects is observed in the subsequent hydrolysis of unsymmetrical imides. Imides with a dimethoxybenzoyl group give high regioselectivity upon hydrolysis, favouring cleavage of the distal acyl group. Imides with a p-nitrobenzoyl or pivaloyl group give reversed selectivity, favouring cleavage of the proximal acyl group.
Asymmetric synthesis of unnatural (Z,Z,E)-octadecatrienoid and eicosatrienoid by lipoxygenase-catalyzed oxygenation
Nanda,Yadav
, p. 1799 - 1806 (2007/10/03)
The asymmetric synthesis of unnatural 13-hydroxy-(6Z,9Z,11E,13S)-octadecatrienoid and 15-hydroxy-(8Z,11Z,13E,15S)-eicosatrienoid is described using a biomimetic oxidation route. The main highlights of this synthesis are the asymmetric hydroxylation of the substrate with soybean lipoxygenase and cis selective Wittig olefination.
Kinetics and mechanism of aminolysis of aliphatic esters in aprotic solvents
Talvik, Agu-Tonis,Tuulmets, Ants,Vaino, Evi
, p. 747 - 750 (2007/10/03)
Kinetic studies were carried out on the aminolysis reactions of substituted aliphatic esters in a variety of aprotic solvents. The reaction rate is strongly affected by inductive and steric effects of substituents in the acyl group, rising more than 104-fold from cyanoacetate to trifluoroacetate. The quantitative treatment of solvent effects revealed a rate decrease by the polarity and π-basicity of the solvents, and also an accelerating effect of the polarizability of solvents. Cyclic transition states were assumed for both the first and second-order (in amine) reactions. Copyright
NEW PROCEDURES FOR THE SYNTHESIS OF SYMMETRICAL BISBENZYLATED UREAS BASED ON N-BENZYLTRICHLOROACETAMIDES
Atanassova, I.A.,Petrov, J.S.,Mollov, N.M.
, p. 147 - 154 (2007/10/02)
Treatment of N-benzylated trichloroacetamides 4, obtained by three different procedures, with potassium carbonate in dimethylsulfoxide affords simmetrical bisbenzylated ureas 5.
Formation of N-Substituted Trichloroacetamides from Amines and Hexachloroacetone
Bew, Clive,Joshi, Virginia Otero de,Gray, Jim,Kaye, Perry T.,Meakins, G. Denis
, p. 945 - 948 (2007/10/02)
Procedures are described for converting primary amines into their well-crystalline trichloroacetyl-derivatives by treatment with hexachloroacetone under mild conditions.Although secondary aromatic N-methylamines are unaffected by hexachloroacetone, saturated heterocyclic amines react vigorously.A mechanistic study using 2-amino-4-t-butylthiazole showed that the reaction is first order in hexachloroacetone, second order in amine, and base-catalysed; there is no appreciable kinetic isotope (H/D) effect nor accumulation of intermediates during the reaction.A sequence which accommodates these results is suggested.
