An efficient method for Pd-catalyzed site-selective C(sp 2 )–H chalcogenation of α-amino acids/peptides with disulfides and diselenides in moderate to good yields is presented.

Kynurenine metabolites are derived from the aromatic amino acid, tryptophan, and their chemical synthesis has been sought to understand tryptophan-kynurenine-based biochemical reactions that could provide opportunities for exploring therapeutic values. This report describes of kynurenine (kyn) derivatives tryptophan-containing peptides using versatile hypervalent iodine reagent, phenyliodine(III)diacetate (PIDA), through C-C bond fragmentation tryptophan's indole ring. However, BocNH-Trp-OH...

This report describes a Pd-catalyzed picolinamide-directed site-selective C(sp

Study of self-assembly PNA TC8 monitored by UV thermal transition at 295 nm indicates formation a C–C+ tetraplex (i-motif) in acidic pH, with higher stability than the analogous dTC8

Isopentenyl diphosphate isomerase (IDI) catalyzes the interconversion of isopentenyl (IPP) and dimethylallyl (DMAPP), basic five-carbon building blocks isoprenoid molecules. Two structurally unrelated classes IDIs are known. Type I IPP (IDI-1) utilizes a divalent metal in protonation-deprotonation reaction. In contrast, type II enzyme (IDI-2) requires reduced flavin, raising possibility that reaction catalyzed by IDI-2 involves net addition or abstraction hydrogen atom. As part our studies...

This report describes the Pd-catalyzed late-stage chalcogenation of tryptophan-containing peptides with disulfides/diselenides in moderate to good yields. It comprises broad substrate scope, functional group diversity, modification drug molecules, and various valuable synthetic transformations, including room temperature easy removal picolinamide auxiliary, which could be applicable tune structure function peptides.

An unusual hydrolysis/solvolysis of the classical acyclic amide bond, derived from N-troponylaminoethylglycine (Traeg) and α-amino acids, is described under mild acidic conditions. The reactivity this bond possibly owed to protonation troponyl carbonyl functional group. results suggest that Traeg amino acid a potential candidate for protecting caging amine group bioactive molecules via cleavable bond.

An organic acid, salicylic and its derivatives are constituents of various natural products possessing remarkable bioactivity. O-Acetyl salicylate (aspirin) is a well-known life-saving drug. Its peptide derivative salicylamide has also been explored in the designing peptide-based therapeutic drugs. base, picolylamine recently for diagnostic probes. However, both acid base have common features as metal chelating with coordinating metals. Thus, these scaffolds could be used inhibitors...

Mono-ortho-arylated arylamines are constituents of various natural products but their syntheses challenging. This report describes a new synthetic methodology for the ortho-arylation and α-aromatic amino acids (phenylglycine phenylalanine) through Pd-catalyzed C(sp2)-H activation using transient directing group diethoxyethyl-L-proline (DEP). A catalytic amount is sufficient to form mono-arylated as major aryliodides. method could be useful synthesis biphenyl amines novel peptidomimetics.

Boron-dipyrromethene (BODIPY) fluorophore derivatives were prepared from a Pyrromethene scaffold and di-fluoroboron. To add to the range of biocompatible fluorophores, this report describes synthesis photophysical studies carboxylate-functionalized BODIPY analogues natural products, Tropolone α-amino acids, through N,O-chelation. The structure few was confirmed by single crystal X-ray studies. UV/fluorescence revealed their fluorescence behaviors in organic solvents with quantum yield...

This report presents a silver-mediated site-selective chalcogenation of tryptophan-containing peptides with various dichalcogenides (disulfides/diselenides) at room temperature in good to excellent yields. The significant features include broad substrate scope, functional group diversity, late-stage modification drug molecules (Dopamine and Levodopa), valuable postsynthetic transformations under mild conditions.

1 H and 13 C nmr results for 1,2-oxathiane 2-oxide eight derivatives are reported. It is concluded that these molecules have a high preference chair forms with axial S=O groups, even when sterically bulky group such as phenyl substituted in syn-axial orientation to the exocyclic oxygen.

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

New PNA analogues derived from aminoethylpyrrolidin-5-one backbone show stabilization of aepone-PNA:DNA hybrids and destabilization the corresponding RNA compared to unmodified PNA.

Nucleic (DNA) acids having contiguous stretch of G sequence form quadruplex structure, which is very critical to control cell division. Recently the existence G-quadruplex in RNA also reported presence monovalent metal ion. PNA a promising DNA analogue binds strongly PNA:DNA duplex or PNA(2):DNA triplex. forms quadruplexes such and i-motif C-rich sequences respectively. aep-PNA containing prolyl ring one several analogues that provide rigidity chirality backbone has binding affinity natural...

The conversion of troponyl alkylglycinate acid/ester/amide derivatives (Trag acid/ester/amide) into cationic lactones (CTLs) in the presence trifluoroacetic acid and their amidation with amines is described. reversible Trag amides, that is, cleavage reformation amide bond via CTLs demonstrated. direct esters amino group esters/peptide achieved. amine hydroxyl selective over esterification. stable under basic ester hydrolysis Fmoc removal conditions. Hence, alkylglycinates could be applicable...

Abstract Tropolone (2‐hydroxycyclohepta‐2,4,6‐triene‐1‐one and tautomer) is a non‐benzenoid bioactive natural chromophore with pH‐dependent fluorescence character extraordinary metal binding affinities, especially transition‐metal ions Cu 2+ /Zn /Ni . This report describes the syntheses biophysical studies of new tropolonyl thymidine [(4(5)‐hydroxy‐5(4)‐oxo‐5(4) H ‐cyclohepta‐1,3,6‐trienyl)thymidine] ( tr ‐T) nucleoside corresponding tropolone‐conjugated DNA oligonucleotides that form B‐form...

The cleavage of amide bonds under mild acidic conditions is a rare chemical event. N-Acetamide bond peptides extremely stable even the strongest organic acid trifluoromethanesulfonic acid. This report mechanistically describes new cleavable in 4-aminopyrazolyloxy acetamide peptide analogues such as trifluoroacetic (10–20%) or HCl (0.1–4.0 N) at room temperature, and formation unusual lactam from acetic after evaporation solvent. event bond, which could be explored acid-sensitive protecting...

The scarcity of novel bioactive molecules against multidrug-resistant (MDR) bacterial strains like Pseudomonas aeruginosa is alarming. This virulence regulated via Quorum sensing (QS), a cell-cell communication process. Disabling QS circuits (las, pqs, rhl) with small has been proposed as potential strategy to prevent pathogenicity. focuses on interruption virulence, rather than killing them tackle the drug resistance problem. Herein, we describe synthesis rationally designed...

<italic>N</italic>-arylated peptides as peptoids influence the structural and conformational changes of small that lead to unique foldamers, even in di-/tri-peptides.