Rate constants for 1,n-hydrogen transfer reactions in some amino acid derived radicals
作者:Le Zeng、Talbi Kaoudi、Carl H. Schiesser
DOI:10.1016/j.tetlet.2006.09.010
日期:2006.11
Absolute rateconstants for 1,n-hydrogen atom transfers in some substituted amino acid derivedradicals have been determined in benzene through the use of competitive kinetic experiments. Radicalsderivedfrom methyl N-(2-iodobenzoyl)-N-(tert-butyloxycarbonyl)glycinate, -alaninate, -leucinate, -tert-leucinate and -phenylglycinate undergo intramolecular 1,5-hydrogen atom transfer to afford the corresponding
通过使用竞争动力学实验,已经确定了苯中某些取代的氨基酸衍生基团中n氢原子转移的1的绝对速率常数。由N-(2-碘苯甲酰基)-N-(叔丁氧基羰基)甘氨酸甲酯,-丙氨酸酯,-亮氨酸酯,-叔亮氨酸酯和-苯基甘氨酸酯衍生的自由基经历分子内的1,5-氢原子转移以提供相应的α-氨基在80°C时速率常数在1.0-4.3×10 7 s -1范围内的酸酯基。如果氨基酸侧链中存在可抽象的氢原子,则1,6-和1,7-易位是竞争过程。
[EN] PROCESS FOR MAKING BETA 3 ANGONISTS AND INTERMEDIATES<br/>[FR] PROCÉDÉ POUR LA FABRICATION D'AGONISTES BÊTA 3 ET D'INTERMÉDIAIRES ASSOCIÉS
申请人:MERCK SHARP & DOHME
公开号:WO2013062878A1
公开(公告)日:2013-05-02
The present invention is directed to a process for preparing a compound of formula I-11 through multiple-step reactions:.
本发明涉及通过多步反应制备化合物I-11的过程。
Ball-milling enables highly selective solvent-free N-tert-butoxycarbonylation for activation of amides
作者:Weijia Shi、Guoping Sun、Gang Zou
DOI:10.1016/j.tetlet.2020.152140
日期:2020.7
chemoselective activation of amides via N-tert-butoxycarbonylation catalyzed by 4-dimethylaminopyridine is described undersolvent-freeconditions. High chemoselectivity with respect to NH acidity of amides has been observed. A one-pot two-step procedure for selective esterification of amides has been demonstrated in model reaction of benzamides with p-cresol and benzylalcohol.
A Pd-catalyzed enantio selective synthesis of quaternary alpha-amino acid derivatives using a phenylalanine-derived P-chirogenic diaminophosphine oxide is described. Asymmetric allylic substitution using acyclic beta-keto esters with a nitrogen functional group at the alpha-carbon as prochiral nucleophiles proceeded in the presence of 5 mol % of Pd catalyst, 10 mol % of chiral diaminophosphine oxide 1j, BSA, and appropriate additives, affording the corresponding quaternary alpha-amino acid derivatives in excellent yield and in up to 92% ee. (c) 2007 Elsevier Ltd. All rights reserved.