Pseudo‐Ring Methodology to Control the Conformations of Macrocyclic Peptides

A pseudo-ring is a medium-sized cyclic structure, held together by a strong hydrogen bond, that can act as a mimetic of a covalently linked heterocycle. Molecules that contain pseudo-rings can switch between "open" and "closed" forms. This paper examines the utility of pseudo-ring constructs to control conformations and properties of macrocycles. The spectroscopic evidence suggests that the "open" and "closed" pseudo-ring-containing macrocycles differ in their three-dimensional characteristics, which results in markedly different lipophilicities. The dynamic nature of pseudo-rings has led to the emergence of tunable fluorescence that should be useful in environment-sensitive applications.