MicroRNAs (miRNAs) are crucial regulators in tumor development, so accurately detecting and imaging them in living cells is vital for early cancer diagnosis. However, their low levels inside cells and...
Correction and removal of expression of concern for 'Total synthesis of the natural product EBC-329' by Raju S. Thombal et al., Org. Biomol. Chem., 2015, 13, 9485-9491, https://doi.org/10.1039/C5OB01276G.
The unprecedented C(sp2)–H functionalization of ethylidenemalonate in reaction with internal alkynes was discovered leading to substituted vinylcyclopentanes as trans,trans-isomers (dr > 15:1). The experiment with deuterated ethylidenemalonate showed that the...
A cationic AIE photosensitizer TTPy-PTSA preferentially accumulates in the mitochondria of HUVECs and generates ROS efficiently upon irradiation, triggering caspase-3-mediated apoptosis. It exhibits potent anti-angiogenic photodynamic activity in vitro and...
We report the water-soluble macrocycle ExBP3C, which binds 20 guests to form well-defined 1 : 1 complexes, with association constants in the range of 102-105 M-1. NMR studies, titration experiments and theoretical calculations clearly uncovered the binding stoichiometry, affinities, and complexation modes. This host holds promise for applications in neurotransmitter regulation, photosensitizer delivery, and antibacterial systems.
The development of citrullination detection methods has largely been driven by a fundamental chemical problem: distinguishing citrulline from its precursor arginine. Protein citrullination is a biologically relevant modification catalyzed by the peptidyl arginine deiminase (PAD) enzyme family. Dysregulated PAD activity has been implicated in several major human diseases, including rheumatoid arthritis, neurodegeneration, and cancer. In practice, studying this modification has long been difficult because the two amino acids, citrulline and arginine, are so chemically similar that most chemical reagents struggle to distinguish between them. This review highlights the evolution of citrullination detection, from colourimetric assays requiring harsh acidic conditions, through fluorescent probes that increased sensitivity, and to newer chemistries that can label citrulline at neutral pH. Alongside these citrulline-directed strategies, we also cover complementary approaches for profiling PAD enzyme activity, including antibody-based and activity-based protein profiling, as well as fluorogenic substrate assays.
Herein, we disclose an asymmetric alkylation of an α-C(sp3) bond of glycine derivatives proceeding through synergistic copper/photoredox catalysis. It is worth noting that this work represents the first example of an asymmetric transformation induced by the challenging 1,2-HAT process of amidyl radicals. This protocol is characterized by good yields, moderate to excellent enantioselectivities and simple operation procedures, providing an attractive strategy for the synthesis of biologically valuable α,β-diamino acids.
A new nitrosylation reaction for pyrroles, featuring tert-butyl nitrite as a mild nitrosylation agent, has been developed. Application to a variety of diaryl-substituted pyrroles resulted in moderate to good yields with significant improvement, in comparison to previous methods, for pyrroles featuring aryl groups appended with electron-donating groups. Isolation and characterisation of a nitrosopyrrole featuring tert-butyl functionality on the pyrrole ring was achieved in excellent yield, while attempts to nitrosylate other alkyl-functionalised pyrroles yielded trace amounts of promising oxime-containing products.
A visible-light-driven nickel-catalyzed cross-electrophile coupling of aryl halides with alkyl iodides has been developed using 9fluorenone (FLN) as an inexpensive organic photosensitizer. The readily available FLN/diisopropylethylamine system enables C(sp 2...
A series of unsymmetrical 1-(p-tolulyl)-5,6-di(p-tolyl)-10-(acyl)-dipyrroethenes were synthesized in two steps starting with 5,6-di(p-tolyl) dipyrroethene. In the first step, 5,6-di(p-tolyl) dipyrroethene was subjected to Grignard reaction with 4-methylbenzoyl chloride to afford...
Glycosides are crucial structural motifs in drug discovery and biology due to their enhanced metabolic stability and resistance to enzymatic hydrolysis compared to their O-glycoside counterparts. The synthesis of these...
The synthesis of chromenonitriles remains largely underexplored, primarily due to the limited availability of suitable substrates and the generally unsatisfactory yields of existing methods. Herein, we report a new method...
Polyhydroxy containing compounds, in particular those derived from monoterpenoids, have attracted attention as biologically active compounds, but a key limitation in their synthesis is the need for regio- and stereoselective hydroxylation. Here, the synthesis of two dihydroxy derivatives and potential metabolites of the antiparkinsonian agent Prottremine, which is a monoterpenoid diol with a para-menthene scaffold, was carried out using an epoxy ester-orthoester rearrangement as the key step. The isomerization of epoxyacetate derivative of Prottremine to corresponding orthoester proceeded stereoselectively, as a result, two new stereoisomeric tetraols were obtained in yields of 22% and 3%. Using a similar approach directly and in combination with the Mitsunobu reaction, three stereoisomeric triols based on (-)-isopulegol and (+)-neoisopulegol were synthesized in yields ranging from 13% to 36%, thus demonstrating the potential to expand the approach to other compounds. Isomerization of the epoxyacetate derivative in the presence of superacids was accompanied by aromatization of cyclohexene ring with the formation of the dioxolane cation, which then, upon longer storage at room temperature, was completely converted into a mixture of protonated ketones, one of which was a dimeric form (dication).
We report the stereoselective synthesis of β,β-diborylalanine (AlaBB), a compact amino acid scaffold designed to introduce a gem-diboronic acid motif as a branched connector in peptides. Pinacol-protected AlaBB derivatives, denoted...
An efficient method for the synthesis of tetrazolo[1,5-a]quinolines from N-aryltetrazoles and alkynes has been developed. The reaction proceeds through double C-H activation under chelation-controlled Rh(III)-catalysis and tolerates various functional groups. The obtained tetrazolo[1,5-a]quinolines exhibit fluorescence over a wide range (320-480 nm) with quantum yields of up to 58%.
Tat trimers are superior carriers for the delivery of exogenous biomolecules into living cells. We synthesized three Tat trimers carrying the same number of positive charges but with different arrangements of mono-Tat on the scaffold. We investigated the structure-uptake relationship of the three Tat trimers and found that tri-Tat 3 formed by mono-Tat arranged in the same orientation on the scaffold had lower cytotoxicity and better cellular uptake. We hope that this study will provide insight into the structural design and optimization of cell-penetrating peptides.
Kobayashi's fluoride-mediated approach to aryne generation remains the dominant strategy in aryne chemistry and has been widely applied in aryne-capture reactions involving both nucleophiles and electrophiles. However, many electrophile-trapping variants are limited by the presence of acidic protons, which compete with the desired electrophilic quench. Accordingly, considerable effort has been devoted to the development of anhydrous fluoride sources to enable efficient interception of the aryne intermediate. In this context, we recently reported a CsF/diglyme system that outperformed commonly used methods. Here, we describe the application of this CsF/diglyme protocol in an aryne-arylamine-aldehyde three-component reaction that efficiently furnishes 2-aminobenzyl ether products through a tandem aryne capture, electrophile quench, and Smiles-type rearrangement cascade. Importantly, these conditions enable the efficient use of aliphatic aldehydes, providing access to amino analogues of biologically active molecules.
We report herein a mild and selective cleavage of N-(2-hydroxyalkyl)amides based on sequential O-(1-imidazolyl)carboxylation, cyclization to an oxazolidinone, and nucleophilic disconnection. We found that sodium imidazolide enabled temperature-dependent control in the reaction sequence. Application of the method to poecillastrin C at the nmol scale led to successful LC-MS detection of the C39-C54 fragment retaining seven stereogenic centres whose configurations remain unassigned. This fragment will facilitate further studies toward the complete configurational assignment of poecillastrin C.
Energy-transfer (EnT) photocatalysis has rapidly emerged as a powerful platform in synthetic organic chemistry, enabling diverse molecular transformations with high selectivity. Consequently, it has unlocked reaction pathways that are inaccessible or challenging under conventional thermal conditions. These advantages have stimulated considerable interest in the development of sustainable methods based on EnT photocatalysis. The present review highlights recent (2022-2025) advances in photocycloadditions beyond the EnT-enabled [2 + 2] manifold. The discussion is organized according to reaction type, encompassing EnT-based [4 + 2] cycloadditions, [3 + 2] cycloadditions, 6π-photocyclizations, Norrish-Yang-type cyclizations, and miscellaneous cyclization reactions. Plausible mechanistic rationales are presented to provide insight into the underlying reaction pathways.
Systematic comparison of hydroxy-, amino-, amide-, sulfonamide-, and phosphinamide-substituted C4N4 fluorophores revealed that fluorescence is modulated not simply by hydrogen-bond donor strength, but by positional, geometrical, and conformational accessibility of intramolecular hydrogen bonding to the pyrimidine core. This insight was translated into an acetylation-responsive turn-on probe, providing a design basis for responsive C4N4 fluorophores.
