Synthesis of 9-Substituted Triptycene Building Blocks for Solid-Phase Diversification and Nucleic Acid Junction Targeting

Beyond symmetric self-assembly and effective molarity: unlocking functional enzyme mimics with robust organic cages

The bespoke environments in enzyme active sites can selectively accelerate chemical reactions by as much as 1019. Macromolecular and supramolecular chemists have been inspired to understand and mimic these accelerations and selectivities for applications in catalysis for sustainable synthesis. Over the past 60+ years, mimicry strategies have evolved with changing interests, understanding, and synthetic advances but, ubiquitously, research has focused on use of a molecular "cavity". The activities of different cavities vary with the subset of features available to a particular cavity type. Unsurprisingly, without synthetic access to mimics able to encompass more/all of the functional features of enzyme active sites, examples of cavity-catalyzed processes demonstrating enzyme-like rate accelerations remain rare. This perspective will briefly highlight some of the key advances in traditional cavity catalysis, by cavity type, in order to contextualize the recent development of robust organic cage catalysts, which can exploit stability, functionality, and reduced symmetry to enable promising catalytic modes.

Selective recognition of A/T-rich DNA 3-way junctions with a three-fold symmetric tripeptide

Non-canonical DNA structures, particularly 3-Way Junctions (3WJs) that are transiently formed during DNA replication, have recently emerged as promising chemotherapeutic targets. Here, we describe a new approach to target 3WJs that relies on the cooperative and sequence-selective recognition of A/T-rich duplex DNA branches by three AT-Hook peptides attached to a three-fold symmetric and fluorogenic 1,3,5-tristyrylbenzene core.

Design, Synthesis, and Anticancer Activity of Triptycene-Peptide Hybrids that Induce Paraptotic Cell Death in Cancer Cells

We report on the design and synthesis of triptycene-peptide hybrids (TPHs), 5, syn-6, and anti-6, which are conjugates of a triptycene core unit with two or three cationic KKKGG peptides (K: lysine and G: glycine) through a C₈ alkyl chain. It was discovered that syn-6 and anti-6 induce paraptosis, a type of programmed cell death (PCD), in Jurkat cells (leukemia T-lymphocytes). Mechanistic studies indicate that these TPHs induce the transfer of Ca²⁺ from the endoplasmic reticulum (ER) to mitochondria, a loss of mitochondrial membrane potential (ΔΨ_m), tethering of the ER and mitochondria, and cytoplasmic vacuolization in the paraptosis processes.

BiCl3-Facilitated removal of methoxymethyl-ether/ester derivatives and DFT study of –O–C–O– bond cleavage

An experimental and DFT study of the cleavage of the MOM group mediated by an eco-friendly reagent, bismuth trichloride.

Chiral Triptycenes in Supramolecular and Materials Chemistry

Triptycenes are an intriguing class of organic molecules with several unusual characteristics, such as a propeller-like shape, saddle-like cavities around a symmetrical scaffold, a rigid π-framework. They have been extensively studied and proposed as key synthons for a variety of applications in supramolecular chemistry and materials science. When decorated with an appropriate substitution pattern, triptycenes can be chiral, and, similarly to other popular chiral π-extended synthons, can express chirality robustly, efficiently, and with relevance to chiroptical spectroscopies. This minireview highlights and encompasses recent advances in the synthesis of chiral triptycenes and in their introduction as molecular scaffolds for the assembly of functional supramolecular materials.

The Emerging Role of RNA as a Therapeutic Target for Small Molecules

Recent advances in understanding different RNAs and unique features of their biology have revealed a wealth of information. However, approaches to identify small molecules that target these newly discovered regulatory elements have been lacking. The application of new biochemical screening and design-based technologies, coupled with a resurgence of interest in phenotypic screening, has resulted in several compelling successes in targeting RNA. A number of recent advances suggest that achieving the long-standing goal of developing drug-like, biologically active small molecules that target RNA is possible. This review highlights advances and successes in approaches to targeting RNA with diverse small molecules, and the potential for these technologies to pave the way to new types of RNA-targeted therapeutics.

Aryne Compatible Solvents are not Always Innocent

Arynes are important and versatile intermediates in a variety of transformations. Commonly used solvents for aryne chemistry include acetonitrile and dichloromethane. Although rarely reported, the reactive nature of aryne intermediates makes them prone to side reactions, which sometimes involve solvent participation. Acetonitrile and dichloromethane are not always innocent solvents and can participate in aryne-based reactions. These results are presented in the context of ongoing mechanistic investigations of the triple aryne-tetrazine reaction.

Modulation of the E. coli rpoH Temperature Sensor with Triptycene-Based Small Molecules

Regulation of the heat shock response (HSR) is essential in all living systems. In E. coli, the HSR is regulated by an alternative σ factor, σ(32) , which is encoded by the rpoH gene. The mRNA of rpoH adopts a complex secondary structure that is critical for the proper translation of the σ(32) protein. At low temperatures, the rpoH gene transcript forms a highly structured mRNA containing several three-way junctions, including a rare perfectly paired three-way junction (3WJ). This complex secondary structure serves as a primitive but highly effective strategy for the thermal control of gene expression. In this work, the first small-molecule modulators of the E. coli σ(32) mRNA temperature sensor are reported.

Bridgehead-Substituted Triptycenes for Discovery of Nucleic Acid Junction Binders

Recently, the utility of triptycene as a scaffold for targeting nucleic acid three-way junctions was demonstrated. A rapid, efficient route for the synthesis of bridgehead-substituted triptycenes is reported, in addition to solid-phase diversification to a new class of triptycene peptides. The triptycene peptides were evaluated for binding to a d(CAG)·(CTG) repeat DNA junction exhibiting potent affinities. The bridgehead-substituted triptycenes provide new building blocks for rapid access to diverse triptycene ligands with novel architectures.