Carbon isotopic labelling of carboxylic acids enabled by organic photoredox-catalysed cyanation.

The application of molecular imaging has advanced personalized medicine and generated a profound impact on patient care. Positron emission tomography and magnetic resonance imaging are among the most widely used imaging modalities, often requiring the isotopic labelling of bioactive molecules to generate the desired imaging probes. Unfortunately, radiochemistry often limits the development of novel agents due to complicated syntheses and the incompatibility of complex molecules.

Arene and Heteroarene Functionalization Enabled by Organic Photoredox Catalysis.

ConspectusAromatic functionalization reactions are some of the most fundamental transformations in organic chemistry and have been a mainstay of chemical synthesis for over a century. Reactions such as electrophilic and nucleophilic aromatic substitution (EAS and SAr, respectively) represent the two most fundamental reaction classes for arene elaboration and still today typify the most utilized methods for aromatic functionalization. Despite the reliable reactivity accessed by these venerable transformations, the chemical space that can be accessed by EAS and SAr reactions is inherently limited due to the electronic requirements of the substrate.

Difluoromethoxide Is a Strong Leaving Group in the Photoredox Deoxyradiofluorination of 2-Phenylpyridines.

A 2-phenyl-3-difluoromethoxy-pyridinyl moiety features in potent phosphodiesterase 4D inhibitors that are considered to be candidate radiotracers for positron emission tomography if they are labeled with fluorine-18. Fluorine-18 could be installed as desired at the 3'-phenyl position with acridinium-mediated photoredox radiodeoxyfluorination in homologues bearing variously substituted 3'-aryloxy groups. However, a distal 3-difluoromethoxide (-OCHF) group strongly competes as a leaving group, especially when an electron-deficient aryloxy group is present at position 3'.

First-in-Human Evaluation of [F]FDOPA Produced by Organo-Photoredox Reactions.

Photoredox is a powerful synthetic tool in organic chemistry and has been widely used in various fields, including nuclear medicine and molecular imaging. In particular, acridinium-based organophotoredox radiolabeling has significantly impacted the production and discovery of positron emission tomography (PET) agents. Despite their extensive use in preclinical research, no PET agents synthesized by acridinium photoredox labeling have been tested in humans.

Synthesis of Cu-, Co-, and Ga-Labeled Radiopharmaceuticals Targeting Neurotensin Receptor-1 for Theranostics: Adjusting In Vivo Distribution Using Multiamine Macrocycles.

The development of theranostic radiotracers relies on their binding to specific molecular markers of a particular disease and the use of corresponding radiopharmaceutical pairs thereafter. This study reports the use of multiamine macrocyclic moieties (MAs), as linkers or chelators, in tracers targeting the neurotensin receptor-1 (NTSR-1). The goal is to achieve elevated tumor uptake, minimal background interference, and prolonged tumor retention in NTSR-1-positive tumors.

Chelator boosted tumor-retention and pharmacokinetic properties: development of Cu labeled radiopharmaceuticals targeting neurotensin receptor.

Purpose: Accumulating evidence suggests that neurotensin (NTS) and neurotensin receptors (NTSRs) play key roles in lung cancer progression by triggering multiple oncogenic signaling pathways. This study aims to develop Cu-labeled neurotensin receptor 1 (NTSR1)-targeting agents with the potential for both imaging and therapeutic applications.

Method: A series of neurotensin receptor antagonists (NRAs) with variable propylamine (PA) linker length and different chelators were synthesized, including [Cu]Cu-CB-TE2A-iPA-NRA ([Cu]Cu-4a-c, i = 1, 2, 3), [Cu]Cu-NOTA-2PA-NRA ([Cu]Cu-4d), [Cu]Cu-DOTA-2PA-NRA ([Cu]Cu-4e, also known as [Cu]Cu-3BP-227), and [Cu]Cu-DOTA-VS-2PA-NRA ([Cu]Cu-4f).

Manufacturing 6-[F]Fluoro--DOPA via Flow Chemistry-Enhanced Photoredox Radiofluorination.

In this study, we introduce a practical methodology for the synthesis of PET probes by seamlessly combining flow chemistry with photoredox radiofluorination. The clinical PET tracer 6-[F]FDOPA was smoothly prepared in a 24.3% non-decay-corrected yield with over 99.

The BR signaling pathway regulates primary root development and drought stress response by suppressing the expression of and in .

Introduction: With the warming global climate, drought stress has become an important abiotic stress factor limiting plant growth and crop yield. As the most rapidly drought-sensing organs of plants, roots undergo a series of changes to enhance their ability to absorb water, but the molecular mechanism is unclear.

Results And Methods: In this study, we found that PLT1 and PLT2, two important transcription factors of root development in , are involved in the plant response to drought and are inhibited by BR signaling.

Development of [F]F-5-OMe-Tryptophans through Photoredox Radiofluorination: A New Method to Access Tryptophan-Based PET Agents.

Although various radiolabeled tryptophan analogs have been developed to monitor tryptophan metabolism using positron emission tomography (PET) for various human diseases including melanoma and other cancers, their application can be limited due to the complicated synthesis process. In this study, we demonstrated that photoredox radiofluorination represents a simple method to access novel tryptophan-based PET agents. In brief, 4-F-5-OMe-tryptophans (l/d-T) and 6-F-5-OMe-tryptophans (l/d-T) were easily synthesized.

C, C and C-Cyanation of Electron-Rich Arenes via Organic Photoredox Catalysis.

As a non-invasive imaging technology, positron emission tomography (PET) plays a crucial role in personalized medicine, including early diagnosis, patient screening, and treatment monitoring. The advancement of PET research depends on the discovery of new PET agents, which requires the development of simple and efficient radiolabeling methods in many cases. As bioisosteres for halogen and carbonyl moieties, nitriles are important functional groups in pharmaceutical and agrochemical compounds.

Bicyclol Alleviates Streptozotocin-induced Diabetic Cardiomyopathy By Inhibiting Chronic Inflammation And Oxidative Stress.

Purpose: Diabetic cardiomyopathy (DCM) is a common and severe complication of diabetes. Inflammation and oxidative stress play important roles in DCM development. Bicyclol is a hepatoprotective drug in China that exerts anti-inflammatory effects by inhibiting the MAPK and NF-κB pathways to prevent obesity-induced cardiomyopathy.

Direct C-H Radiocyanation of Arenes via Organic Photoredox Catalysis.

Innovative labeling methods to incorporate the short-lived positron emitter carbon-11(C) into bioactive molecules are attractive for positron emission tomography (PET) tracer discovery. Herein, we report a direct C-H radiocyanation method that incorporates [C]cyanide (CN) to a series of functional electron-rich arenes via photoredox catalysis. This photoredox-mediated radiocyanation can proceed in an aerobic environment and is not moisture sensitive, which allows for ease of reaction setup and for scalable synthesis of C-aryl nitriles from readily available precursors.

ERECTA regulates seed size independently of its intracellular domain via MAPK-DA1-UBP15 signaling.

Seed size is determined by the coordinated growth of the embryo, endosperm, and integument. Growth of the integument is initiated by signal molecules released from the developing endosperm or embryo. Although recent studies have identified many components that regulate seed size by controlling integument growth, the upstream signals and the signal transduction pathway that activate these components after double fertilization are unclear.

The Synthesis and Initial Evaluation of MerTK Targeted PET Agents.

MerTK (Mer tyrosine kinase), a receptor tyrosine kinase, is ectopically or aberrantly expressed in numerous human hematologic and solid malignancies. Although a variety of MerTK targeting therapies are being developed to enhance outcomes for patients with various cancers, the sensitivity of tumors to MerTK suppression may not be uniform due to the heterogeneity of solid tumors and different tumor stages. In this report, we develop a series of radiolabeled agents as potential MerTK PET (positron emission tomography) agents.

Heat Shock-Induced Accumulation of the Glycogen Synthase Kinase 3-Like Kinase BRASSINOSTEROID INSENSITIVE 2 Promotes Early Flowering but Reduces Thermotolerance in .

Brassinosteroids (BRs) are essential plant growth- and development-regulating phytohormones. When applied exogenously, BRs ameliorate heat shock (HS)-induced cell damage and enhance plant thermotolerance; however, the molecular mechanism by which BRs regulate plant thermotolerance is unknown. In this study, by analyzing the thermotolerance of a series of BR signaling mutants and plants that overexpressed different BR signaling components, we obtained comprehensive data showing that BRASSINOSTEROID INSENSITIVE 2 (BIN2) plays a major role in mediating the crosstalk between BR signaling and plant HS responses.

Potassium Iodide Nanoparticles Enhance Radiotherapy against Breast Cancer by Exploiting the Sodium-Iodide Symporter.

Iodine has shown promise in enhancing radiotherapy. However, conventional iodine compounds show fast clearance and low retention inside cancer cells, limiting their application as a radiosensitizer. Herein, we synthesize poly(maleic anhydride--1-octadecene) coated KI nanoparticles (PMAO-KI NPs) and evaluate their potential for enhancing radiotherapy.

Development of Novel F-PET Agents for Tumor Hypoxia Imaging.

Tumor hypoxia is a major factor responsible for tumor progression, metastasis, invasion, and treatment resistance, leading to low local tumor control and recurrence after radiotherapy in cancers. Here,F-positron emission tomography (PET) probes are developed for visualizing viable hypoxic cells in biopsies. Pimonidazole derivatives and nitroimidazole-based agents bearing sulfonyl linkers were evaluated.

Enantioselective Sensing in the Fluorous Phase for Catalyst Screening: Application of a Racemic Fluorescent Probe.

A perfluoroalkyl ketone-based molecular probe was found to show highly enantioselective fluorescent enhancement in the fluorous phase when treated with an amino alcohol generated from the asymmetric reaction of a -epoxide with an alkyl amine. The two enantiomeric probes ()- and ()- were used to screen catalysts for this asymmetric reaction. The use of the probe in the fluorous phase allowed the fluorescent sensing of the products to be conducted away from the other reaction components with minimized interference.

Determining the concentration and enantiomeric composition of histidine using one fluorescent probe.

A chemoselective as well as enantioselective fluorescent probe has been developed to determine both the concentration and enantiomeric composition of the biologically important amino acid histidine by measuring the fluorescence responses when excited at two different wavelengths.

A near-IR Fluorescent Probe for Enantioselective Recognition of Amino Acids in Aqueous Solution.

A novel BINOL-based near-IR fluorescent probe was designed and synthesized by incorporating a rhodamine-like dye. In the presence of Zn(II), this compound was found to exhibit highly enantioselective fluorescence enhancement at λ > 730 nm and λ = 690 nm when treated with 14 common amino acids in aqueous solution. An enantioselective fluorescence enhancement ratio up to 163 was observed.

Mechanistic Study on a BINOL-Coumarin-Based Probe for Enantioselective Fluorescent Recognition of Amino Acids.

A detailed investigation was conducted on the reaction of a 1,1'-bi-2-naphthol-coumarin-based fluorescent probe with amino acids. On the basis of the studies, including fluorescence spectroscopy, H NMR, UV-vis, mass spectroscopy, single-crystal X-ray analysis, and molecular modeling, it was found that the distinctively different fluorescent responses of the probe toward the amino acid at the two excitation wavelengths are due to two different reaction pathways that generate different intermediates and products.

Sulfonation of 3,3'-Diformyl-BINOL for Enantioselective Fluorescent Recognition of Amino Acids in Water.

Reaction of (R)-3,3'-diformyl-1,1'-bi-2-naphthol with concentrated sulfuric acid gives the corresponding 6,6'-disulfonated compound (R)-2 selectively. This provides a simple and efficient method to convert a water-insoluble compound to a water-soluble fluorescent probe. It is found that (R)-2 in combination with Zn shows a highly enantioselective fluorescent response toward various amino acids in the aqueous HEPES buffer solution at pH 7.

Excitation of One Fluorescent Probe at Two Different Wavelengths to Determine the Concentration and Enantiomeric Composition of Amino Acids.

When a novel fluorescent probe made of BINOL and coumarin is excited at λ = 365 nm in a neutral buffer solution, it shows fluorescence enhancement at 465 nm in the presence of an amino acid with a very small difference between the two enantiomers. When excited at λ = 467 nm, it shows highly enantioselective fluorescence enhancement at 534 nm. This allows the determination of both concentration and enantiomeric composition of amino acids.

Design and synthesis of sinomenine isoxazole derivatives 1,3-dipolar cycloaddition reaction.

A novel structure of sinomenine isoxazole derivatives is synthesised from sinomenine hydrochloride and aromatic aldehydes and requires six steps. 19 target compounds have been obtained in good yields. The sinomenine hydrochloride transforms to 4-alkynyl sinomenine, which is a key intermediate product to synthesise the target sinomenine isoxazole compounds, after a neutralisation reaction with ammonia and substitution reaction with 3-chloropropyne.