https://www.selleckchem.com/products/bay-293.html Disulfide-rich peptides (DRPs) are a class of peptides that are constrained through two or more disulfide bonds. Though natural DRPs have been extensively exploited for developing protein binders or potential therapeutics, their synthesis and re-engineering to bind new targets are not straightforward due to difficulties in handling the disulfide pairing problem. Rationally designed DRPs with an intrinsically orthogonal disulfide pairing propensity provide an alternative to the natural scaffolds for developing functional DRPs. Herein we report the use of tandem CXPen/PenXC motifs ((C) cysteine; (Pen) penicillamine; (X) any residue) for directing the oxidative folding of peptides. Diverse tricyclic peptides were designed and synthesized by varying the pattern of C/Pen residues and incorporating a tandem CXPen/PenXC motif into peptides. The folding of these peptides was determined primarily by C/Pen patterns and tolerated to sequence manipulations. The applicability of the designed C/Pen-DRPs was demonstrated by designing protein binders using an epitope grafting strategy. This study thus demonstrates the potential of using orthogonal disulfide pairing to design DRP scaffolds with new structures and functions, which would greatly benefit the development of multicyclic peptide ligands and therapeutics.The high demand for new and efficient routes toward synthesis of nitrogen-containing heterocyclic scaffolds has inspired organic chemists to discover several methodologies over recent years. This Perspective highlights one standout approach, which involves the use of pyridotriazoles and related compounds in denitrogenative transformations. Readily available pyridotriazoles undergo ring-chain isomerization to produce uniquely reactive α-diazoimines. Such reactivity, enabled by metal catalysts, additives, or visible-light irradiation, can be applied in transannulation, insertion, cyclopropanation, and many other transformatio