Chemistry of amide-based axial chirality: Elucidation of the active conformation recognized by enzymes and receptors

Abstract

Axial chirality caused by an sp 2 -sp2 axis at Ar-N(C=O) (a conformational stereogenic axis) in pharmaceutically important seven-membered-ring benzolactams (I) and N-acyl-benzazepines and related nuclei (II) was investigated to verify the importance of the atropisomerism in the biologically active molecules. Anilide derivatives with the seven-membered-ring benzolactams (derivatives of I: 6-8) and the N-benzoyl derivatives of 1,5-benzodiazepines (derivatives of II: 11-ii-14-ii) were successfully synthesized as new, highly potent acyl-CoA:cholesterol acyltransferase inhibitors and the vaptan class of vasopressin receptor ligands, respectively. By freezing the atropisomerism at the scaffold regions, we succeeded in separating and isolating the atropisomers. The biological activities of the atropisomers were examined to reveal that the axial chirality is recognized by the enzyme and receptor when the molecules exert their activity. © 2013 The Pharmaceutical Society of Japan.