81375-37-3Relevant academic research and scientific papers
Mechanism of Alkyl Chloroformate-Mediated Esterification of Carboxylic Acids in Aqueous Media
Opekar, Stanislav,Kví?ala, Jaroslav,Moos, Martin,Pejchal, Vladimír,?imek, Petr
, p. 16293 - 16299 (2021/10/12)
The protection of carboxyl groups by esterification has been the most common method in macroscale and microscale chemistries. The esterification is usually conducted under anhydrous conditions; however, in biological chemistry and related fields, the reaction is of major concern in aqueous environments. Immediate esterification of the carboxyl in aqueous alcoholic media driven by an alkyl chloroformate and pyridine has been such a method which has found widespread use in many research and industrial laboratories. Nevertheless, the reaction mechanism has not yet been investigated, to our knowledge, and is not well understood. Herein, we describe the reaction intermediates and demonstrate that the reaction proceeds via a continual formation of the N-acylpyridinium intermediate decomposed by several reaction channels to the final ester. The understanding of the mechanism could encourage novel laboratory applications of this important esterification method.
Organocatalytic Enantioselective Addition of α-Aminoalkyl Radicals to Isoquinolines
Liu, Xiangyuan,Liu, Yang,Chai, Guobi,Qiao, Baokun,Zhao, Xiaowei,Jiang, Zhiyong
supporting information, p. 6298 - 6301 (2018/10/09)
With a dual organocatalytic system involving a chiral phosphoric acid and a dicyanopyrazine-derived chromophore (DPZ) photosensitizer and under the irradiation with visible light, an enantioselective Minisci-type addition of α-amino acid-derived redox-active esters (RAEs) to isoquinolines has been developed. A variety of prochiral α-aminoalkyl radicals generated from RAEs were successfully introduced on isoquinolines, providing a range of valuable α-isoquinoline-substituted chiral secondary amines in high yields with good to excellent enantioselectivities.
DIISOPROPYLETHYLAMINE ELIMINATES DIPEPTIDE FORMATION DURING THE ACYLATION OF AMINO ACIDS USING BENZOYL CHLORIDE AND SOME ALKYL CHLOROFORMATES
Chen, Francis M. F.,Benoiton, N. Leo
, p. 1224 - 1227 (2007/10/02)
Acylation of amino acids using benzoyl chloride in aqueous alkali leads to benzoylamino acids containing one percent of benzoyldipeptide.Use of diisopropylethylamine instead of sodium hydroxide as base eliminates the side reaction responsible for the contaminant.Ethoxycarbonylamino acids are advantageously prepared in the same manner using ethyl chloroformate or diethyl dicarbonate.The latter gives rise to some N-substituted dipeptide when used in aqueous alkali.The method is unsatisfactory for the benzyloxycarbonylation of amino acids.Use of 9-fluorenylmethyl chloroformate and diisopropylethylamine gives the pure derivative of leucine in moderate yield.
