Nielsen, Daniel S. published the artcileImproving on Nature: Making a Cyclic Heptapeptide Orally Bioavailable, Recommanded Product: (S)-2-((((9H-Fluoren-9-yl)methoxy)carbonyl)(methyl)amino)-3-phenylpropanoic acid, the publication is Angewandte Chemie, International Edition (2014), 53(45), 12059-12063, database is CAplus and MEDLINE.
The use of peptides in medicine is limited by low membrane permeability, metabolic instability, high clearance, and negligible oral bioavailability. The prediction of oral bioavailability of drugs relies on physicochem. properties that favor passive permeability and oxidative metabolic stability, but these may not be useful for peptides. Here we investigate effects of heterocyclic constraints, intramol. hydrogen bonds, and side chains on the oral bioavailability of cyclic heptapeptides. NMR-derived structures, amide H-D exchange rates, and temperature-dependent chem. shifts showed that the combination of rigidification, stronger hydrogen bonds, and solvent shielding by branched side chains enhances the oral bioavailability of cyclic heptapeptides in rats without the need for N-methylation.
Angewandte Chemie, International Edition published new progress about 77128-73-5. 77128-73-5 belongs to ethers-buliding-blocks, auxiliary class Inhibitor, name is (S)-2-((((9H-Fluoren-9-yl)methoxy)carbonyl)(methyl)amino)-3-phenylpropanoic acid, and the molecular formula is C25H23NO4, Recommanded Product: (S)-2-((((9H-Fluoren-9-yl)methoxy)carbonyl)(methyl)amino)-3-phenylpropanoic acid.
Referemce:
https://en.wikipedia.org/wiki/Ether,
Ether | (C2H5)2O – PubChem