9-Amino Acridines Undergo Reversible Amine Exchange Reactions in Water: Implications on Their Mechanism of Action in Vivo

Composition processing property relationship of vitrimers Based on polyethyleneimine

An innovative use of characterization methods to establish correlation between chemical composition and material properties in imine based RCBPs, and a novel understanding of chemical processes that occur during heating\ processing of such polymers.

Configurational and Constitutional Dynamics of Enamine Molecular Switches

Dual configurational and constitutional dynamics in systems based on enamine molecular switches has been systematically studied. pH-responsive moieties, such as 2-pyridyl and 2-quinolinyl units, were required on the "stator" part, also providing enamine stability through intramolecular hydrogen-bonding (IMHB) effects. Upon protonation or deprotonation, forward and backward switching could be rapidly achieved. Extension of the stator π-system in the 2-quinolinyl derivative provided a higher E-isomeric equilibrium ratio under neutral conditions, pointing to a means to achieve quantitative forward/backward isomerization processes. The "rotor" part of the enamine switches exhibited constitutional exchange ability with primary amines. Interestingly, considerably higher exchange rates were observed with amines containing ester groups, indicating potential stabilization of the transition state through IMHB. Acids, particularly BiIII , were found to efficiently catalyze the constitutional dynamic processes. In contrast, the enamine and the formed dynamic enamine system showed excellent stability under basic conditions. This coupled configurational and constitutional dynamics expands the scope of dynamic C-C and C-N bonds and potentiates further studies and applications in the fields of molecular machinery and systems chemistry.

Primary aminomethyl derivatives of kaempferol: hydrogen bond-assisted synthesis, anticancer activity and spectral properties

Primary aminomethyl derivatives of kaempferol with anticancer activity were synthesized by a combination strategy involving a hydrogen bond-assisted process.

Recent advances in dynamic covalent chemistry

Dynamic covalent chemistry (DCvC) has been strongly integrated into diverse research fields, and has enabled easy access to a variety of combinatorial libraries, 2-D macrocycles, and 3-D molecular cages that target many important applications, such as drug discovery, biotechnology, molecular separation, light harvesting, etc. DCvC relies on the reversible formation and breaking of rather strong covalent bonding within molecules. Therefore it combines the error-correction capability of supramolecular chemistry and the robustness of covalent bonding. Compared to those supramolecular interactions, dynamic covalent reactions usually have slower kinetics and require the assistance of catalysts to achieve rapid equilibrium. Although the scope of dynamic covalent reactions is rapidly expanding, the reversible reactions suitable for DCvC are still very limited. The identification and development of new dynamic reactions and catalysts would be critical for the further advancement of DCvC. This review covers the recent development of dynamic covalent reactions as well as their applications.

Two-in-one: a pH-sensitive, acridine-based, fluorescent probe binds G-quadruplexes in oncogene promoters

We report the synthesis of an acridine-containing cyanine dye and demonstrate its potential as a pH-responsive colorimetric indicator and fluorescent probe.

Reversible covalent chemistries compatible with the principles of constitutional dynamic chemistry: new reactions to create more diversity

An approach to make chemical diversity space more manageable is to search for smaller molecules, or fragments, and then combine or elaborate these fragments. Dynamic Combinatorial Chemistry (DCC) is a powerful approach whereby a number of molecular elements each with binding potential can be reversibly combined via covalent or noncovalent linkages to generate a dynamic library of products under thermodynamic equilibrium. Once a target molecule has been added, the distribution of products can be shifted to favor products that bind to the target. Thus the approach can be employed to identify products that selectively recognize the target. Although the size of the repertoire of reversible covalent reactions suitable for DCC has increased significantly over the past 5-10 years, the discovery of new reactions that satisfy all the criteria of reversibility and biocompatibility remains an exciting challenge for chemists. Increasing the number of chemical reactions will enable the engineering of larger and more diverse DCLs, which remains a key step toward a broader use of DCC. In this review, we aim to provide a nonexhaustive list of reversible covalent reactions that are compatible with the concept of DCC, focusing mainly on the most recent examples that were reported in the literature in the past 5 years.