Copolymerization of an indazole ligand into the self-polymerization of dopamine for enhanced binding with metal ions

Abstract

Synthesis and mussel-inspired polymerization of a new catechol monomer. The generated copolymer exhibits enhanced metal binding, due to the ligand nature of the new monomer, compared to polydopamine homopolymer.

Chemistry of polydopamine analogues

“…Oxidation of 5,6‐dihydroxy‐1H‐indazole as an aza‐analogue of DHI by air in Tris buffer led to a dark material useful for the coating of silica particles and the production of polymeric capsules after removal of the silica core (Scheme ) . The polymerization was slower than in the case of DA polymerization.…”

“…Oxidative copolymerization of DA with N‐substituted DA (top), 5,6‐dihydroxyindazole (middle) and 5‐hydroxyindole (bottom) …”

“…Copolymers of PDA with 5,6‐dihydroxy‐1H‐indazole were investigated in order to obtain coated silica particles and polymeric capsules after HF etching (Scheme , copolymer II) . The pyrazole ring, incorporated into the structure of PDA, extends the availability of ligands for metal ions beyond the catechol group and is attractive for biomedical applications.…”

The modulation of melanin‐like materials: methods, characterization and applications

“…A concerted effect of redox reactions, redox‐dependent differential cation binding affinity and nanoscale architecture collectively facilitates the insertion and removal of multivalent cations in melanin. Fan et al reported that the copolymerization of 5,6‐dihydroxy‐1H‐indazole with dopamine will enhance the binding with metal ions . The 1:3 copolymer (indazole‐to‐dopamine ratio) has adequate structural stability as a polymer coating.…”

A Suitable Functionalization of Nitroindazoles with Triazolyl and Pyrazolyl Moieties via Cycloaddition Reactions

“…The corresponding nitroindazole-pyrazoline derivatives were obtained in good to excellent yields.Molecules 2020, 25, 126 2 of 18 antipyretic, antioxidant, antiparasitic, antimicrobial, antitumoral and anti-inflammatory activities, among others [5][6][7][21][22][23].Indazoles are another important group of N-heterocycles with significant biological activities as nitric oxide synthase (NOS) inhibitors, kinase inhibitors, anti-inflammatory, anticancer, antimicrobial, antifungal, antimalarial, and antileishmanial agents, among others.Some anticancer and anti-inflammatory drugs based in indazole scaffolds are commercially available [24][25][26][27][28][29][30]. Besides the biological properties presented by indazole derivatives, this family of N-heterocycles also showed potential to be used in other fields as corrosion inhibitors, components for OLEDs and battery applications, and as copolymerizing molecules for new materials [31][32][33][34].Following our interest on developing synthetic approaches to functionalize the indazole core [35,36], we decided to follow the 1,3-dipolar cycloaddition methodology to substitute nitroindazoles with triazole or pyrazoline moieties, aiming in such way to obtain new compounds with improved biological features for different applications. In the strategy envisaged it was considered that the alkylation of indazole with 1,2-dibromoethane using liquid-liquid phase transfer catalysis, could afford not only the N-1and N-2-bromoethylindazoles, but also the corresponding N-1and N-2-vinylindazoles [37].…”