Synthesis and conformational analysis of a coumarinic acid‐based cyclic prodrug of an opioid peptide with modified sensitivity to esterase‐catalyzed bioconversion

Abstract
The coumarinic acid‐based cyclic DADLE (H‐Tyr‐D‐Ala‐Gly‐Phe‐D‐Leu‐OH) prodrug 1a exhibited more favorable physicochemical properties than did DADLE for permeation across the intestinal muco...