60498-68-2Relevant academic research and scientific papers
Room Temperature Coupling of Aryldiazoacetates with Boronic Acids Enhanced by Blue Light Irradiation
da Silva, Amanda F.,Afonso, Marco A. S.,Cormanich, Rodrigo A.,Jurberg, Igor D.
, p. 5648 - 5653 (2020/04/22)
A visible-light-promoted photochemical protocol is reported for the coupling of aryldiazoacetates with boronic acids. This photochemical reaction shows great enhancement compared to the same protocol performed in the absence of light. Except for a few cases, the room temperature coupling in the dark (thermal process) generally does not work. When it does, it is likely to also involve free carbenes as key intermediates. Alternatively, photochemical reactions show a broad scope, can be performed under air and tolerate a wide variety of functional groups. Reaction-evolution monitoring, DFT calculations and control experiments have been used to evaluate the main aspects of this intricate mechanistic scenario. Biologically active molecules Adiphenine, Benactyzine and Aprophen have been prepared as examples of synthetic applications.
Rhodium catalyzed arylation of diazo compounds with aryl boronic acids
Ghorai, Jayanta,Anbarasan, Pazhamalai
, p. 3455 - 3461 (2015/04/14)
A general and efficient synthesis of diarylacetate, a diarylmethine derivative, was accomplished through rhodium catalyzed direct arylation of diazo compounds with arylboronic acids. The reaction tolerates various boronic acid derivatives and functional groups. Notably, chemoselective arylation of diazo compounds over other electrophiles were demonstrated. The efficacy of the developed methodology is shown by the expeditious synthesis of the core structure of diclofensine.
Concave pyridines for selective acylations of polyols
Luening, Ulrich,Petersen, Soenke,Schyja, Wolfgang,Hacker, Wolfgang,Marquardt, Torsten,Wagner, Kerstin,Bolte, Michael
, p. 1077 - 1084 (2007/10/03)
Selectivity enhancements in the base-catalyzed acylation of polyols (1,2- or 1,3-alkanediol, partially protected glucoside) have been found with (bi)macrocyclic pyridines 2 and 9 as catalysts. The different selectivities obtained for concave pyridines of varying ring sizes (1 vs. 2) are probably caused by their different geometries as a number of X-ray analyses (1a, 1b, 2a, 2b, 2e, 9) indicate. The methyl glucoside 7 can selectively be acylated in 2-position.
Concave reagents, 21: Selective acylations of primary and secondary alcohols by ketenes
Schyja, Wolfgang,Petersen, Soenke,Luening, Ulrich
, p. 2099 - 2105 (2007/10/03)
Concave pyridines 1 were used to catalyze the addition of primary and secondary alcohols to ketenes 4, and the kinetic data of these catalyses were determined. In inter- and intramolecular competitions the use of 1e-g led to improved selectivities for the acylation of primary alcohols in comparison with secondary alcohols. All primary alcohols react at comparable rates. Observed rate constants were correlated with Taft's Es values. The starting materials and products were fully characterized. VCH Verlagsgesellschaft mbH, 1996.
A NEW GENERAL METHOD FOR THE PREPARATION OF CARBOXYLIC ACID ESTERS
Froeyen, Paul
, p. 145 - 152 (2007/10/02)
Esters can be generated directly in good yields under mild conditions from the corresponding carboxylic acid and alcohol in the presence of equivalent amounts of pyridine, triphenylphosphine and N-halosuccinimide.Key words: Carboxylic acids, esterification, triphenylphosphine, N-halo succinimides.
Pentaalkylguanidines as etherification and esterification catalysts
Barcelo, Gerard,Grenouillat, Denis,Senet, Jean-Pierre,Sennyey, Gerard
, p. 1839 - 1848 (2007/10/02)
Several pentaalkylguanidines have been prepared and found to be superior catalysts for the preparation of aryl and aralkyl ethers from carbonates and for the methylation of phenols with dimethylcarbonate.They also act as effective catalysts for esterification of acids with alkyl chloroformates but not for the acetylation of tertiary alcohols with acetic anhydride.
A Simple and Mild Esterification Method for Carboxylic Acids Using Mixed Carboxylic-Carbonic Anhydrides
Kim, Sunggak,Lee, Jae In,Kim, Youn Chul
, p. 560 - 565 (2007/10/02)
A simple and mild esterification method using mixed carboxylic-carbonic anhydrides has been developed.Simple aliphatic carboxylic esters are prepared in high yields by the reaction of acids with equimolar amounts of chloroformates (2,2,2-trichloroethyl chloroformate is an exception) and triethylamine in the presence of a catalytic amount of 4-(dimethylamino)pyridine.Although aromatic acids give a mixture of the ester, the acid anhydride, and the carbonate under normal conditions utilized in this study, it is found that increasing the amount of 4-(dimethylamino)pyridine drastically decreases the formation of the acid anhydride and the carbonate, affording a satisfactory yield of the ester.This method reaches a limit with sterically hindered acids and the formation of the acid anhydride and the carbonate is favored.
