Unnatural Amino Acid: 4-Aminopyrazolonyl Amino Acid Comprising -Peptides Forms Organogel With Co-Solvent (EtOAc:Hexane).

Ampyrone is an amino-functionalized heterocyclic pyrazolone derivative that possesses therapeutic values such as analgesic, anti-inflammatory, and antipyretics. The chemical structure of ampyrone exhibits excellent hydrogen bonding sites and is considered as the potential scaffold of supramolecular self-assembly. Recently, this molecule has been derived into unnatural amino acids such as aminopyrazolone amino acid and its peptides.

Instability of Amide Bond with Trifluoroacetic Acid (20%): Synthesis, Conformational Analysis, and Mechanistic Insights into Cleavable Amide Bond Comprising β-Troponylhydrazino Acid.

The instability of an amide bond with dilute trifluoroacetic acid (TFA) is a rare chemical event. The native amide bonds are stable even in the neat TFA, which is one of the reagents that releases the peptides from the solid support in the solid-supported peptide synthesis method. In the repertoire of unnatural peptidomics, α-/β-hydrazino acids and their peptides are explored for the synthesis of -amino peptide derivatives, and their amide bonds are stable in TFA (∼100%) as natural amide bonds.