Facile amidation of esters with aromatic amines promoted by lanthanide tris (amide) complexes
The development of catalysts capable of catalyzing amidation of esters with amines to construct amides under mild conditions is of great importance. Compared to aliphatic amines, the direct catalytic amidation of esters with less nucleophilic aromatic amines is rather difficult. Employing simple lanthanide tris (amide) complexes Ln[N (SiMe3)2]3(μ-Cl)Li (THF)3 as the catalysts, it was found a broad range of aromatic amines and esters were efficiently converted into various amides in good yields under mild conditions. A plausible mechanism for this transformation was experimentally supported as starting from an amide exchange reaction between the lanthanide tris (amide) complex and the substrate amine.
Stereochemistries of aromatic N-methylamides in crystal and solution. Temperature-dependent conformational conversion and attracting aromatic-aromatic interactions
Crystal structures and dynamic behavior in solution of some aromatic N-methylanilides were analyzed. Every N-methylamide examined was in cis form in the crystal, and exhibited cis-preference in solution. Among them, meta-substituted amides, such as N,N',N