Highly selective N-Alkylation of amines promoted on silica: An efficient and recyclable surface
作者:Basudeb Basu、Susmita Paul、Ashis K. Nanda
DOI:10.1039/b905878h
日期:——
N-Alkylation of amines suffers from competing over alkylations. At the same time, use of strong base and other harsh conditions greatly limits providing a practical, generalized and selective procedure. Activated silica gel has been found to promote N-alkylations of amines. Here, we studied N-alkylation of amines with various types of alkyl halides, which finally constitute practical, highly selective and eco-friendly conditions for mono- or bis-alkylated amines at ambient temperature with recyclability of silica.
Synthesis of <i>N</i>-Substituted 3-Amino-4-halopyridines: A Sequential Boc-Removal/Reductive Amination Mediated by Brønsted and Lewis Acids
作者:Christopher A. Wilhelmsen、Alexandre D.C. Dixon、John D. Chisholm、Daniel A. Clark
DOI:10.1021/acs.joc.7b02966
日期:2018.2.2
readily provide access to imidazopyridines and similar heterocyclic systems. The direct synthesis of N-substituted 3-amino-4-halopyridines is problematic, as reductive aminations and base-promoted alkylations are difficult in these systems. A high yielding deprotection/alkylation protocol mediated by trifluoroacetic acid and trimethylsilyl trifluoromethanesulfonate is described, providing access to a wide