Selective Recognition of G-Quadruplex by Structural Tuning of Heteroaromatic Scaffolds and Side Chains.

In this study, carbazole () and dibenzofuran () derivatives were synthesized to examine their effect on the biomolecular recognition of G-quadruplex (G4) targets. Biophysical studies revealed that , a carbazole derivative, exhibits a specific affinity and effectively stabilizes the G4. Molecular modeling suggests a stable interaction of with the terminal G-tetrad of G4.

Guanosine-based hydrogel as a supramolecular scaffold for template-assisted macrocyclization.

The G-quartet-like supramolecular assembly present in guanosine hydrogel templates macrocyclization between bis-azide and bis-alkyne fragments. The resulting macrocycle enhances viscoelastic properties, and strengthens the hydrogel network. This approach holds potential for the synthesis of drugs and their simultaneous delivery in a stimuli-responsive manner.

Expanding the Toolbox of Target Directed Bio-Orthogonal Synthesis: In Situ Direct Macrocyclization by DNA Templates.

Herein, we demonstrate for the first time that noncanonical DNA can direct macrocyclization-like challenging reactions to synthesize gene modulators. The planar G-quartets present in DNA G-quadruplexes (G4s) provide a size complementary reaction platform for the bio-orthogonal macrocyclization of bifunctional azide and alkyne fragments over oligo- and polymerization. G4s immobilized on gold-coated magnetic nanoparticles have been used as target templates to enable easy identification of a selective peptidomimetic macrocycle.

Cycloaddition of -sulfonyl and -sulfamoyl azides with alkynes in aqueous media for the selective synthesis of 1,2,3-triazoles.

The cycloaddition of -sulfonyl and -sulfamoyl azides with terminal alkynes generally produces amide derivatives via ketenimine intermediates. We herein delineate a Cu(I) catalyzed method using a prolinamide ligand that selectively generate sulfonyl and sulfamoyltriazoles in aqueous media by inhibiting the cleavage of the N-N bond of 5-cuprated triazole intermediates. The present method is mild and tolerant to air, moisture and a wide range of functional groups thereby providing an easy access to a variety of triazole products.

A Competitive Pull-Down Assay Using G-quadruplex DNA Linked Magnetic Nanoparticles To Determine Specificity of G-quadruplex Ligands.

Herein, we develop a competitive screening method in which G-quadruplex DNA linked magnetic nanoparticles pull down selective ligands for a particular quadruplex topology from a series of small molecules. The screening strategy is first optimized with known G-quadruplex ligands and then used with a new series of G-quadruplex interactive bis-triazolyl ligands that are synthesized by Cu(I)-catalyzed azide-alkyne cycloaddition. The assay enables the identification of c-MYC and BCL2 G-quadruplex selective bis-triazole ligands that specifically target promoter G-quadruplexes in cancer cells.

Chemically synthesized butein and butin: Optical, structure and electrochemical redox functionality at electrode interface.

Progress in the development of phytochemistry has delivered advancement in materials functionality for range of inter/trans-disciplinary application. Here, we investigated the structural functionality of chemically synthesized phytoconstitutent, chalcone (butein) and flavanone (butin). Photoactive and electroactive behavior of butein and butin were comprehensively studied using UV-vis absorbance, photoluminescence and cyclic voltammetric techniques.