Synthesis and conformational behaviour of tetra-anthranilides

The tetra-anthranilide derivatives ($\text{5}$)–($\text{7}$) have been synthesised. X-Ray crystallography shows that $\text{N}$,$\text{N}$′,$\text{N}$″-trimethyltetra-anthranilide ($\text{5}$) adopts a conformation with three $\text{trans}$ - and one $\text{cis}$-amide linkages in the solid state. Dynamic ¹H n.m.r. spectroscopy indicates that $\text{N}$-benzyl-$\text{N}$′,$\text{N}$″,$\text{N}$′″-trimethyltetra-anthranilide ($\text{7}$) exists as an interconverting ternary mixture of chiral non-planar conformational diastereoisomers in solution.