Fluorine-a small magic bullet atom in the drug development: perspective to FDA approved and COVID-19 recommended drugs

Photo-induced decarboxylative radical cascade cyclization of unactivated alkenes: access to CF- and CF2-substituted ring-fused imidazoles

A mild and effective visible-light-induced decarboxylative radical cascade reaction of olefin-containing imidazoles with α-fluorinated carboxylic acids as building blocks containing CF or ArCF2 moieties, has been developed to afford a series of monofluoromethylated or aryldifluoromethylated polycyclic imidazoles in medium to excellent yields with features of simple operation, available raw materials, and wide substrate scopes. In addition, the mechanistic experiments indicated that the methodology involved a radical pathway.

Property-Based Design of Xanthine Derivatives as Potent and Orally Available TRPC4/5 Inhibitors for Depression and Anxiety

Transient receptor potential canonical channels 4 and 5 (TRPC4/5) are nonselective cation channels involved in emotional regulation, positioning them to be promising targets for treating mental disorders such as anxiety and depression. HC-070, a potent TRPC4/5 inhibitor, exhibits significant anxiolytic and antidepressant effects in animal models, though its drug-like properties require optimization. In this study, we applied a property-based drug design (PBDD) approach to optimize HC-070, leading to the discovery of compound 32, which shows improved LipE and Fsp3 values, reduced hERG blocking activity, enhanced metabolic stability, increased aqueous solubility, and superior oral bioavailability. Oral administration of compound 32 in mouse models demonstrates anxiolytic and antidepressant efficacy comparable to fluoxetine. This study supports the therapeutic potential of TRPC4/5 inhibitors for mental disorders and identifies compound 32 as a promising candidate for further investigation. Furthermore, our work underscores the value of PBDD in optimizing lead compounds during drug discovery process.

A Consecutive Two-Step Radical-Mediated Cyclization of gem-Difluorinated Diynes to Access gem-Difluorinated Cedrenes

A consecutive two-step radical-mediated cyclization of gem-difluoromethylenated bis(3-arylpropagyl)-indane-1,3-diones to access structurally unique gem-difluoromethylenated cedrenes is described. Substituents located on the aryl rings of the two propagyl units play an important role in governing the consecutive cyclization pattern. Upon treatment of gem-difluoromethylenated 1,3-diane with Bu3SnH/AIBN, a tributylstannyl radical-mediated radical cyclization between the two diyne units chemoselectively took place, leading to the corresponding gem-difluoromethylenated acoradienes in good yields, after removal of tributylstannyl group by TFA. Subsequently, Bu3SnH/AIBN promoted reductive cleavage of the phenylsulfanyl group leading to difluoroalkyl radicals which spontaneously underwent radical cyclization to give a series of gem-difluoromethylenated cedrenes.

Halogen-based quinazolin-4(3H)-one derivatives as MCF-7 breast cancer inhibitors: Current developments and structure-activity relationship

Currently, cancer is a serious health challenge with predominance beyond restrictions. Breast cancer remains one of the major contributors to cancer-related morbidity and mortality in women. Chemotherapy continues to be crucial in the treatment of all variants of cancer. Several antitumor drugs are presently in different phases of clinical trials, whereas many more have been approved for clinical use. However, these drugs have the potential to cause adverse effects, and certain individuals may become resistant to them, which would eventually reduce the drug's efficacy. Therefore, it is essential to discover, develop, and improve newer anticancer drug molecules that could potentially inhibit proliferative pathways. In recent years, quinazolinone derivatives, more specifically halogen-substituted 4(3H)-quinazolinone, have drawn attention as a promising new class of chemotherapeutic agents. In addition, these molecules showed significant inhibition in micromolar ranges when tested in vitro against the MCF-7 cell line. Therefore, this study aims to emphasize the intriguing versatility of halogen atoms, providing an in-depth summary and highlighting recent developments in the anticancer properties of halogenated 4(3H)-quinazolinones. It also features a detailed discussion of the structure-activity relationship (SAR) of various functional groups and their interaction with amino acid residues utilizing molecular docking studies. The intent is to foster novel discoveries that can inspire innovative investigations in this domain. Hence, this study simplifies the drug design and development strategies by prolonging the array of pharmacologically active candidates.

A Rapid, Mild and Direct Route to Sulfonimidoyl Fluoride from Sulfenamide

We develop a rapid and mild protocol to access sulfonimidoyl fluoride-[S(VI)] from sulfenamide-[S(II)] directly. The transformation occurs via the reaction of sulfenamide with NCS (N-chlorosuccinimide), water, and TBAF in acetonitrile. Water and TBAF act as the source for S═O bond formation and fluoride, respectively. The reaction takes a very short time (within 5 min). The drug molecules, such as Carbamazepine and Levetiracetam attached sulfonimidoyl fluorides are also achieved following this protocol. Furthermore, sulfonimidoyl fluoride is transformed into sulfonimidamide in the presence of AlCl3. To the best of our knowledge, it is the first report detailing the synthesis of sulfonimidoyl fluoride-[S(VI)] directly from S(II)-sulfenamide.

Insights into SARS-CoV-2: Small-Molecule Hybrids for COVID-19 Treatment

The advantages of a treatment modality that combines two or more therapeutic agents with different mechanisms of action encourage the study of hybrid functional compounds for pharmacological applications. Molecular hybridization, resulting from a covalent combination of two or more pharmacophore units, has emerged as a promising approach to overcome several issues and has also been explored for the design of new drugs for COVID-19 treatment. In this review, we presented an overview of small-molecule hybrids from both natural products and synthetic sources reported in the literature to date with potential antiviral anti-SARS-CoV-2 activity.

Enzyme (α-Glucosidase, α-Amylase, PTP1B & VEGFR-2) Inhibition and Cytotoxicity of Fluorinated Benzenesulfonic Ester Derivatives of the 5-Substituted 2-Hydroxy-3-nitroacetophenones

The prevalence of small multi-target drugs containing a fluorinated aromatic moiety among approved drugs in the market is due to the unique properties of this halogen atom. With the aim to develop potent antidiabetic agents, a series of phenylsulfonic esters based on the conjugation of the 5-substituted 2-hydroxy-3-nitroacetophenones 1a-d with phenylsulfonyl chloride derivatives substituted with a fluorine atom or fluorine-containing (-CF3 or -OCF3) group were prepared. Their structures were characterized using a combination of spectroscopic techniques complemented with a single-crystal X-ray diffraction (XRD) analysis on a representative example. The compounds were, in turn, assayed for inhibitory effect against α-glucosidase, α-amylase, protein tyrosine phosphatase 1 B (PTP1B) and the vascular endothelial growth factor receptor-2 (VEGFR-2) all of which are associated with the pathogenesis and progression of type 2 diabetes mellitus (T2DM). The antigrowth effect of selected compounds was evaluated on the human breast (MCF-7) and lung (A549) cancer cell lines. The compounds were also evaluated for cytotoxicity against the African Green Monkey kidney (Vero) cell line. The results of an in vitro enzymatic study were augmented by molecular docking (in silico) analysis. Their ADME (absorption, distribution, metabolism and excretion) properties have been evaluated on the most active compounds against α-glucosidase and/or α-amylase to predict their drug likeness.

Identification of Plant Peroxidases Catalyzing the Degradation of Fluorinated Aromatics Using a Peroxidase Library Approach

In this work, the degradation of mono- and polyfluorinated phenolic compounds was demonstrated by a series of crude plant peroxidases, including horseradish root (HRP) and six members of the Cucurbita genus. Highly active samples were identified using a library screening approach in which more than 50 crude plant samples were initially evaluated for defluorination activity toward 4-fluorophenol. The highest concentrations were observed in the HRP, pumpkin skin (PKS), and butternut squash skin (BNS), which consistently gave the highest intrinsic rates of decomposition for all the substrates tested. Although HRP exhibited a significant decrease in activity with increased fluorination of the phenolic substrate, PKS showed only minor reductions. Furthermore, in silico studies indicated that the active site of HRP poorly accommodates the steric bulk of additional fluorines, causing the substrate to dock farther from the catalytic heme and thus slowing the catalysis rate. We propose that the PKS active site might be larger, allowing closer access to the perfluorinated substrate, and therefore maintaining higher activity compared to the HRP enzyme. However, detailed kinetic characterization studies of the peroxidases are recommended. Conclusively, the high catalytic activity of PKS and its high yield per gram of tissue make it an excellent candidate for developing environmentally friendly biocatalytic methods for degrading fluorinated aromatics. Finally, the success of the library approach in identifying highly active samples for polyfluorinated aromatic compound (PFAC) degradation suggests the method may find utility in the quest for other advanced catalysts for PFAS degradation.

Attentive graph neural network models for the prediction of blood brain barrier permeability

The blood brain barrier's (BBB) unique endothelial cells and tight junctions selectively regulate passage of molecules to the central nervous system (CNS) to prevent pathogen entry and maintain neural homeostasis. Various neurological conditions and neurodegenerative diseases benefit from small molecules capable of BBB penetration (BBBP) to elicit a therapeutic effect. Predicting BBBP often involves in silico assessment of molecular properties such as lipophilicity (log P ) and polar surface area (PSA) using the CNS multiparameter optimization (MPO) method. This study curated an open-source dataset to benchmark rigorously machine learning (ML) and neural network (NN) models with each other and with MPO for predicting BBBP. Our analysis demonstrated that AI models, especially attentive NNs using stereochemical features, significantly outperform MPO in predicting BBBP. An attentive graph neural network (GNN), we refer to as CANDID-CNS™, achieved a 0.23-0.26 higher AUROC score than MPO on full test sets, and a 0.17-0.19 higher score on stereoisomers filtered subsets. Regarding stereoisomers that differ in BBBP, which MPO cannot distinguish, attentive GNNs correctly classify these with AUROC and MCC metrics comparable to or better than MPO's AUROC and MCC on less difficult test molecules. These findings suggest that integrating attentive GNN models into pharmaceutical drug discovery processes can substantially improve prediction rates, and thereby reduce the timeline, cost, and increase probability of success of designing brain penetrant therapeutics for the treatment of a wide variety of neurological and neurodegenerative diseases.

Synthesis and photodynamic activity of new 5-[(E)-2-(3-alkoxy-1-phenyl-1H-pyrazol-4-yl)ethenyl]-2-phenyl-3H-indoles

A series of new indole-pyrazole hybrids 8a-m were synthesized through the palladium-catalyzed ligandless Heck coupling reaction from easily accessible unsubstituted, methoxy- or fluoro-substituted 4-ethenyl-1H-pyrazoles and 5-bromo-3H-indoles. These compounds exerted cytotoxicity to melanoma G361 cells when irradiated with blue light (414 nm) and no cytotoxicity in the dark at concentrations up to 10 µM, prompting us to explore their photodynamic effects. The photodynamic properties of the example compound 8d were further investigated in breast cancer MCF-7 cells. Evaluation revealed comparable anticancer activities of 8d in both breast and melanoma cancer cell lines within the submicromolar range. The treatment induced a massive generation of reactive oxygen species, leading to different types of cell death depending on the compound concentration and the irradiation intensity.

Micromolar fluoride contamination arising from glass NMR tubes and a simple solution for biomolecular applications

Fluorine (19F) NMR is emerging as an invaluable analytical technique in chemistry, biochemistry, structural biology, material science, drug discovery, and medicine, especially due to the inherent rarity of naturally occurring fluorine in biological, organic, and inorganic compounds. Here, we revisit the under-reported problem of fluoride leaching from new and unused glass NMR tubes. We characterised the leaching of free fluoride from various types of new and unused glass NMR tubes over the course of several hours and quantify this contaminant to be at micromolar concentrations for typical NMR sample volumes across multiple glass types and brands. We find that this artefact is undetectable for samples prepared in quartz NMR tubes within the timeframes of our experiments. We also observed that pre-soaking new glass NMR tubes combined with rinsing removes this contamination below micromolar levels. Given the increasing popularity of 19F NMR across a wide range of fields, increasing popularity of single-use screening tubes, the long collection times required for relaxation studies and samples of low concentrations, and the importance of avoiding contamination in all NMR experiments, we anticipate that our simple solution will be useful to biomolecular NMR spectroscopists.

Chloroimidazolium Deoxyfluorination Reagent with H2F3- Anion as a Sole Fluoride Source

In the study, we introduce an air-stable NHC-based deoxyfluorination reagent ImCl[H2F3], offering a promising avenue for deoxyfluorination across various substrates. Reagent efficiently fluorinates benzyl alcohols, carboxylic acids, and P(V) compounds without external fluoride sources. A mechanistic study reveals a two-step process involving benzyl chloride as an intermediate, shedding light on the two-step reaction pathway. The Hammet plot provides insights into reaction mechanisms with different substrates, enhancing our understanding of this versatile deoxyfluorination method.

Visible Light-Induced Radical Cascade Difluoromethylation/Cyclization of Unactivated Alkenes: Access to CF2H-Substituted Polycyclic Imidazoles

An efficient and mild protocol for the visible light-induced radical cascade difluoromethylation/cyclization of imidazoles with unactivated alkenes using easily accessible and bench-stable difluoromethyltriphenylphosphonium bromide as the precursor of the -CF2H group has been developed to afford CF2H-substituted polycyclic imidazoles in moderate to good yields. This strategy, along with the construction of Csp3-CF2H/C-C bonds, is distinguished by mild conditions, no requirement of additives, simple operation, and wide substrate scope. In addition, the mechanistic experiments have indicated that the difluoromethyl radical pathway is essential for the methodology.

Selective Defluorination of Trifluoromethyl Substituents by Conformationally Induced Remote Substitution

The selective reduction of an aromatic trifluoromethyl substituent to a difluoromethyl substituent may be achieved by base-promoted elimination to form a difluoro-p-quinomethide which is trapped by an intramolecular nucleophile. High yields are obtained when the nucleophilic trap entails the conformationally favoured cyclisation of an aminoisobutyric acid (Aib) derivative. The resulting cyclised difluoromethyl-substituted arylimidazolidinone products are readily converted to versatile difluoromethyl-substituted aldehydes by reduction and hydrolysis. Defluorination is successful on a range of benzenoid (both para and ortho CF3-substituted) and heterocyclic substrates. Double defluorination may likewise be achieved sequentially, or in a single step, from an Aib dipeptide derivative.

Synthesis, crystal structure and Hirshfeld surface analysis of (3Z)-4-[(4-amino-1,2,5-oxa-diazol-3-yl)amino]-3-bromo-1,1,1-tri-fluoro-but-3-en-2-one

In the title compound, C6H4BrF3N4O2, the oxa-diazole ring is essentially planar with a maximum deviation of 0.003 (2) Å. In the crystal, mol-ecular pairs are connected by N-H⋯N hydrogen bonds, forming dimers with an R 2 2(8) motif. The dimers are linked into layers parallel to the (10) plane by N-H⋯O hydrogen bonds. In addition, C-O⋯π and C-Br⋯π inter-actions connect the mol-ecules, forming a three-dimensional network. The F atoms of the tri-fluoro-methyl group are disordered over two sites in a 0.515 (6): 0.485 (6) ratio. The inter-molecular inter-actions in the crystal structure were investigated and qu-anti-fied using Hirshfeld surface analysis.

Design, Synthesis, and Activity Evaluation of Fluorine-Containing Scopolamine Analogues as Potential Antidepressants

This study aimed to develop novel rapid-acting antidepressants with sustained efficacy and favorable safety profiles. We designed and synthesized a series of fluorine-containing scopolamine analogues and evaluated their antidepressant potential. In vitro cytotoxicity assays showed that most of these compounds exhibited minimal toxicity against neuronal and non-neuronal mammalian cell lines (IC50 > 100 μM). The antidepressant activities of the compounds were evaluated using the tail suspension test, and S-3a was identified as a lead compound with potent and sustained antidepressant effects. Behaviorally, S-3a alleviated depressive symptoms in mice and displayed a higher cognitive safety margin than scopolamine. Toxicological assessments confirmed S-3a's safety, while pharmacokinetics showed a rapid clearance (half-life: 16.6 min). Mechanistically, S-3a antagonized M1 receptors and elevated BDNF levels, suggesting its potential as an antidepressant for further exploration.

Amoebicidal effect of synthetic indoles against Acanthamoeba spp.: a study of cell death

Organic and synthetic chemistry plays a crucial role in drug discovery fields. Moreover, chemical modifications of available molecules to enhance their efficacy, selectivity and safety have been considered as an attractive approach for the development of new bioactive agents. Indoles, a versatile group of natural heterocyclic compounds, have been widely used in pharmaceutical industry due to their broad spectrum of activities including antimicrobial, antitumoral and anti-inflammatory among others. Herein, we report the amoebicidal activity of different indole analogs on Acanthamoeba castellanii Neff. Among the 40 tested derivatives, eight molecules were able to inhibit this protistan parasite. The structure-activity relationship (SAR) analysis of their anti-Acanthamoeba activity would suggest that a carboxylation of C-3 position and the incorporation of halogen as chlorine/fluorine would enhance their biological profile, presumably by increasing their lipophilicity and therefore their ability to cross the cell membrane. Fluorescence image base system was used to investigate the effect of indole 6o c-6 on the cytoskeleton network and various programmed cell death features. We were able to highlight that the methyl 6-chloro-1H-indole-3-carboxylate could induce program cell death by the mitochondrial dysfunction.

Polymer-Based Drug Delivery Systems for Cancer Therapeutics

Chemotherapy together with surgery and/or radiotherapy are the most common therapeutic methods for treating cancer. However, the off-target effects of chemotherapy are known to produce side effects and dose-limiting toxicities. Novel delivery platforms based on natural and synthetic polymers with enhanced pharmacokinetic and therapeutic potential for the treatment of cancer have grown tremendously over the past 10 years. Polymers can facilitate selective targeting, enhance and prolong circulation, improve delivery, and provide the controlled release of cargos through various mechanisms, including physical adsorption, chemical conjugation, and/or internal loading. Notably, polymers that are biodegradable, biocompatible, and physicochemically stable are considered to be ideal delivery carriers. This biomimetic and bio-inspired system offers a bright future for effective drug delivery with the potential to overcome the obstacles encountered. This review focuses on the barriers that impact the success of chemotherapy drug delivery as well as the recent developments based on natural and synthetic polymers as platforms for improving drug delivery for treating cancer.

The Role of Small Molecules Containing Fluorine Atoms in Medicine and Imaging Applications

The fluorine atom possesses many intrinsic properties that can be beneficial when incorporated into small molecules. These properties include the atom's size, electronegativity, and ability to block metabolic oxidation sites. Substituents that feature fluorine and fluorine-containing groups are currently prevalent in drugs that lower cholesterol, relieve asthma, and treat anxiety disorders, as well as improve the chemical properties of various medications and imaging agents. The dye scaffolds (fluorescein/rhodamine, coumarin, BODIPY, carbocyanine, and squaraine dyes) reported will address the incorporation of the fluorine atom in the scaffold and the contribution it provides to its application as an imaging agent. It is also important to recognize radiolabeled fluorine atoms used for PET imaging in the early detection of diseases. This review will discuss the many benefits of incorporating fluorine atoms into small molecules and give examples of fluorinated molecules used in the pharmaceutical industry and imaging techniques.

Expanded Access to Fluoroformamidines via a Modular Synthetic Pathway

Fluoroformamidines are an underutilized and understudied functional group despite combining two of the most highly prized elements in drug design: nitrogen and fluorine. We report a practical and modular synthesis of fluoroformamidines via the rearrangement of in situ-generated amidoximes. High yields in just 60 s at room temperature highlight the efficiency of this protocol. Furthermore, fluoroformamidines proved to be useful intermediates in the synthesis of diverse ureas and carbamimidates.