Ruthenium-centred btp glycoclusters as inhibitors for Pseudomonas aeruginosa biofilm formation

Generating water/MeOH-soluble and luminescent polymers by grafting 2,6-bis(1,2,3-triazol-4-yl)pyridine (btp) ligands onto a poly(ethylene-alt-maleic anhydride) polymer and cross-linking with terbium(III)

The synthesis of two new polymers made from P(E-alt-MA) (poly(ethylene-alt-maleic anhydride) and possessing 2,6-bis(1,2,3-triazol-4-yl)pyridine (btp) ligand side chains in 3 and 6 mol%, respectively (P1 and P2, respectively) is described. These polymers were shown to be soluble in MeOH solution and, in the case of P1, also in water, while P2 needed prolonged heating to enable water dissolution. Btp ligands are known for coordinating both d- and f-metal ions and so, herein, we demonstrate by using both UV-Vis absorption, fluorescence emission, as well as time-gated phosphorescence spectroscopies, that both P1 and P2 can bind to Tb(III) ions to give rise to luminescent polymers. From the analysis of the titration data, which demonstrated large changes in the emission intensity properties of the polymer upon Tb(III) binding (ground state changes were also clearly observed, with the absorption being red-shifted at lower energy), we show that the dominant stoichiometry in solution is 1 : 2 (M : L; Tb(III) : btp ratio) which implies that two btp ligands from the polymer background are able to crosslink through lanthanide coordination and that the backbone of the polymer is very likely to aid in coordinating the ions.

Structural considerations for building synthetic glycoconjugates as inhibitors for Pseudomonas aeruginosa lectins

Pseudomonas aeruginosa is a pathogenic bacterium, responsible for a large portion of nosocomial infections globally and designated as critical priority by the World Health Organisation. Its characteristic carbohydrate‐binding proteins LecA and LecB, which play a role in biofilm‐formation and lung‐infection, can be targeted by glycoconjugates. Here we review the wide range of inhibitors for these proteins (136 references), highlighting structural features and which impact binding affinity and/or therapeutic effects, including carbohydrate selection; linker length and rigidity; and scaffold topology, particularly for multivalent candidates. We also discuss emerging therapeutic strategies, which build on targeting of LecA and LecB, such as anti‐biofilm activity, anti‐adhesion and drug‐delivery, with promising prospects for medicinal chemistry.

A Therapeutic Journey of Pyridine-Based Heterocyclic Compounds as Potent Anticancer Agents: A Review (From 2017 to 2021)

Pyridine derivatives are the most common and significant heterocyclic compounds, which show their fundamental characteristics to various pharmaceutical agents and natural products. Pyridine derivatives possess several pharmacological properties and a broad degree of structural diversity that is considered most valuable to explore the novel therapeutic agents. These compounds have an extensive range of biological activities such as antifungal, antibacterial, anticancer, anti-obesity, anti-inflammatory, antitubercular, antihypertensive, antineuropathic, antihistaminic, antiviral activities, and antiparasitic. The potent therapeutic properties of pyridine derivatives allow medicinal chemists to synthesize novel and effective chemotherapeutic agents. Consequently, the imperative objective of this comprehensive review is to summarize and investigate the literature regarding recent advancements in pyridine-based heterocycles to treat several kinds of cancer. Furthermore, the performances of pyridine derivatives were compared with some standard drugs including etoposide, sorafenib, cisplatin, and triclosan against different cancer cell lines. We hope this study will support the new thoughts to pursue the most active and less toxic rational designs.

Macrocyclic vs. [2]catenane btp structures: influence of (aryl) substitution on the self templation of btp ligands in macrocyclic synthesis

The synthesis of four 2,6-bis(1,2,3-triazol-4-yl)pyridine (btp) olefin based ligands 3, 4, 11 and 12 is described and their attempted use to form mechanically interlocked molecules using ring closing metatheses (RCM) reactions. The btp ligands were modified in two ways, in 3 and 4 the aryl substitution pattern was changed from 4^th position to 3^rd position and in the case of 11 and 12, the arms were replaced with aliphatic chains. Our study demonstrates that for all four ligands, the RCM reactions only result in the formation of macrocyclic structures, which in three of the cases, were structurally characterised in both solution (using NMR and HRMS) and in the solid-state using X-ray crystallography. NMR studies were also carried out to investigate if these ligands could preorganise in solution via hydrogen bonding interactions. This study provides a handle of how such precursor substitution can be used to direct the formation of macrocycles or mechanically interlocked structures.