FDA-Approved Fluorinated Heterocyclic Drugs from 2016 to 2022

Synthetic approaches and application of representative clinically approved fluorine-enriched anti-cancer medications

Fluorine possesses distinctive chemical characteristics, such as its strong electron-withdrawing ability and small atomic size, which render it an invaluable asset in the design and optimization of pharmaceuticals. The utilization of fluorine-enriched medications for combating cancer has emerged as a prominent approach in medicinal chemistry and drug discovery, offering improved clinical outcomes and enhanced pharmacological properties. This comprehensive review explores the synthetic approaches and clinical applications of approved 22 representative fluorinated anti-cancer drugs from 2019 to present, shedding light on their historical development, brand names, drug target activity, mechanism of action, preclinical pharmacodynamics, clinical efficacy, and toxicity. Additionally, the review provides an extensive analysis of the representative synthetic techniques employed. Overall, this review emphasizes the significance of incorporating fluorine chemistry into anti-cancer drug research while highlighting promising future prospects for exploring compounds enriched with fluorine in the battle against cancer.

Synthesis of α,α-Difluoromethylene Amines from Thioamides Using Silver Fluoride

We developed a mild, rapid process employing AgF and thioamides to produce α,α-difluoromethylene amines efficiently. This method exhibited remarkable tolerance toward various functional groups present in N-sulfonylthioamides, thereby broadening the scope of difluoromethylene sulfonamides through a straightforward approach. Additionally, we applied this approach to synthesize various perfluoroalkyl amines, establishing practical synthetic routes for exploring these compounds in pharmaceutical chemistry and materials science.

Electrochemical Trifluoromethylthiolation/Cyclization of N-Arylacrylamides with AgSCF3: Access to SCF3-Containing Oxindoles

An environmentally friendly electrochemical strategy for the synthesis of SCF3-containing oxindoles was developed. This electrochemical transformation was accomplished through a cascade trifluoromethylthiolation/cyclization of N-acrylamides with AgSCF3, obviating the requirement for external oxidants. A variety of functional groups were well tolerated in this transformation.

Recent Advances: Heterocycles in Drugs and Drug Discovery

Interest and research focusing on the design of novel pharmaceutical agents is always growing [...].

Titanium in photocatalytic organic transformations: current applications and future developments

Titanium, as an important transition metal, has garnered extensive attention in both industry and academia due to its excellent mechanical properties, corrosion resistance, and unique reactivity in organic synthesis. In the field of organic photocatalysis, titanium-based compounds such as titanium dioxide (TiO2), titanocenes (Cp2TiCl2, CpTiCl3), titanium tetrachloride (TiCl4), tetrakis(isopropoxy)titanium (Ti(OiPr)4), and chiral titanium complexes have demonstrated distinct reactivity and selectivity. This review focuses on the roles of these titanium compounds in photocatalytic organic reactions, and highlights the reaction pathways such as photo-induced single-electron transfer (SET) and ligand-to-metal charge transfer (LMCT). By systematically surveying the latest advancements in titanium-involved organic photocatalysis, this review aims to provide references for further research and technological innovation within this fast-developing field.

Total Synthesis of Lipopeptide Bacilotetrin C: Discovery of Potent Anticancer Congeners Promoting Autophagy

A convergent strategy for the first total synthesis of the lipopeptide bacilotetrin C has been developed. The key features of this synthesis include Crimmins acetate aldol, Steglich esterification, and macrolactamization. Twenty-nine variants of the natural product were prepared following a systematic structure-activity relationship study, where some of the designed analogues showed promising cytotoxic effects against multiple human carcinoma cell lines. The most potent analogue exhibited a ∼37-fold enhancement in cytotoxicity compared to bacilotetrin C in a triple-negative breast cancer (MDA-MB-231) cell line at submicromolar doses. The study further revealed that some of the analogues induced autophagy in cancer cells to the point of their demise at doses much lower than those of known autophagy-inducing peptides. The results demonstrated that the chemical synthesis of bacilotetrin C with suitable improvisation plays an important role in the development of novel anticancer chemotherapeutics, which would allow future rational design of novel autophagy inducers on this template.

Parallel Minisci Reaction of gem-Difluorocycloalkyl Building Blocks

Parallel Minisci reactions of nonfluorinated and gem-difluorinated C4-C7 cycloalkyl building blocks (trifluoroborates and carboxylic acids) with a series of electron-deficient heterocycles were studied. A comparison of the reaction's outcome revealed better product yields in the case of carboxylic acids as the radical precursors in most cases, albeit these reagents were used with three-fold excess under optimized conditions. The nature of the heterocyclic core was found to be important for successful incorporation of the cycloalkyl fragment. The impact of the CF2 moiety on the oxidation potential of fluorinated cycloalkyl trifluoroborates and the reaction outcome, in general, was also evaluated.

Bioactive Oxadiazoles 3.0

Heterocycles are fundamental moieties for the construction of new compounds with perspective applications ranging from drugs to materials [...].

Fluorine in the pharmaceutical industry: Synthetic approaches and application of clinically approved fluorine-enriched anti-infectious medications

The strategic integration of fluorine atoms into anti-infectious agents has become a cornerstone in the field of medicinal chemistry, owing to the unique influence of fluorine on the chemical and biological properties of pharmaceuticals. This review examines the synthetic methodologies that enable the incorporation of fluorine into anti-infectious drugs, and the resultant clinical applications of these fluorine-enriched compounds. With a focus on clinically approved medications, the discussion extends to the molecular mechanisms. It further outlines the specific effects of fluorination, which contribute to the heightened efficacy of anti-infective therapies. By presenting a comprehensive analysis of current drugs and their developmental pathways, this review underscores the continuing evolution and significance of fluorine in advancing anti-infectious treatment options. The insights offered extend valuable guidance for future drug design and the development of next-generation anti-infectious agents.

Design, Synthesis, and In Silico and In Vitro Cytotoxic Activities of Novel Isoniazid-Hydrazone Analogues Linked to Fluorinated Sulfonate Esters

Cancer is a life-threatening disease, and significant efforts are still being made to treat it. In this study, we synthesized and characterized novel hybrid molecules (10-18) containing hydrazone and sulfonate moieties and tested their cell growth inhibitory effect on human colon cancer cells (DLD-1), human prostate cancer cells (PC3), and human embryonic kidney cells (HEK-293T) using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method for 72 h. In cell culture studies, all tested hybrid molecules except for 12 and 13 showed significant cytotoxic activities at a micromolar level with IC50 values in the range of 10.28-214.0 μM for the PC3 cell line and 13.49-144.30 μM for the DLD-1 cell line. Compounds 4 (10.28 μM) and 5 (11.22 μM) demonstrated the highest cytotoxicity against the PC3 cell line. Against the DLD-1 cell line, compounds 1 (22.53 μM), 4 (13.49 μM), 5 (19.33 μM), 6 (17.82 μM), 8 (24.71 μM), 9 (17.56 μM), and 10 (17.90 μM) in the series showed anticancer activity at lower micromolar levels compared to cisplatin (26.70 μM). Moreover, the study was handled computationally, and molecular docking studies were performed for compounds 1, 4, and 5 for PC3-FAK and PC3-Scr and compounds 4, 6, and 9 for the DLD-1-TNKS target. In this study, compound 4 was found to be the most effective and promising molecule for both targets.

Molecular dynamics and NMR reveal the coexistence of H-bond-assisted and through-space JFH coupling in fluorinated amino alcohols

The JFH coupling constants in fluorinated amino alcohols were investigated through experimental and theoretical approaches. The experimental JFH couplings were only reproduced theoretically when explicit solvation through molecular dynamics (MD) simulations was conducted in DMSO as the solvent. The combination of MD conformation sampling and DFT NMR spin-spin coupling calculations for these compounds reveals the simultaneous presence of through-space (TS) and hydrogen bond (H-bond) assisted JFH coupling between fluorine and hydrogen of the NH group. Furthermore, MD simulations indicate that the hydrogen in the amino group participates in both an intermolecular bifurcated H-bond with DMSO and in transmitting the observed JFH coupling. The contribution of TS to the JFH coupling is due to the spatial proximity of the fluorine and the NH group, aided by a combination of the non-bonding transmission pathway and the hydrogen bonding pathway. The experimental JFH coupling observed for the molecules studied should be represented as 4TS/1hJFH coupling.

Calcium supplementation attenuates fluoride-induced bone injury via PINK1/Parkin-mediated mitophagy and mitochondrial apoptosis in mice

Excessive consumption of fluoride can cause skeletal fluorosis. Mitophagy has been identified as a novel target for bone disorders. Meanwhile, calcium supplementation has shown great potential for mitigating fluoride-related bone damage. Hence, this study aimed to elucidate the association between mitophagy and skeletal fluorosis and the precise mechanisms through which calcium alleviates these injuries. A 100 mg/L sodium fluoride (NaF) exposure model in Parkin knockout (Parkin-/-) mice and a 100 mg/L NaF exposure mouse model with 1% calcium carbonate (CaCO3) intervention were established in the current study. Fluoride exposure caused the impairment of mitochondria and activation of PTEN-induced putative kinase1 (PINK1)/E3 ubiquitin ligase Park2 (Parkin)-mediated mitophagy and mitochondrial apoptosis in the bones, which were restored after blocking Parkin. Additionally, the intervention model showed fluoride-exposed mice exhibited abnormal bone trabecula and mechanical properties. Still, these bone injuries could be effectively attenuated by adding 1% calcium to their diet, which reversed fluoride-activated mitophagy and apoptosis. To summarize, fluoride can activate bone mitophagy through the PINK1/Parkin pathway and mitochondrial apoptosis. Parkin-/- and 1% calcium provide protection against fluoride-induced bone damage. Notably, this study provides theoretical bases for the prevention and therapy of animal and human health and safety caused by environmental fluoride contamination.

Synthesis of Substituted Pentafluorosulfanylpyrazoles Under Flow Conditions

The development of flow conditions for the synthesis of pentafluorosulfanylpyrazoles is reported. A range of alkyl- and aryl-substituted SF5-alkynes were used in combination with different diazoacetates for this transformation. The corresponding substituted SF5-pyrazoles were obtained in up to 90% yield (average of 74% for 21 examples) as a mixture of isomers (up to 73:27 ratio). Synthetic transformations starting from an SF5-containing pyrazole were also demonstrated.

Synthesis and biological evaluation of novel benzenesulfonamide incorporated thiazole-triazole hybrids as antimicrobial and antioxidant agents

A library of 20 novel benzenesulfonamide incorporating thiazole tethered 1,2,3-triazoles 1-4a-e was synthesized and screened for their antimicrobial, antioxidant, and cytotoxicity studies. Amoxicillin and fluconazole were used as reference antibacterial and antifungal drugs, respectively. Further, energies of frontier molecular orbitals were calculated for all the synthesized target compounds 1-4a-e to correlate electronic parameters with the observed biological results. Global reactivity descriptors, including highest occupied molecular orbitals-lowest unoccupied molecular orbitals energy gap, electronegativity, chemical hardness, chemical softness, and electrophilicity index, were also calculated for the synthesized molecules. All the tested compounds possessed moderate to excellent antibacterial potency; however, 3d and 4d exhibited the overall highest antibacterial effect (minimum inhibitory concentration [MIC] values 5-11 µM) while 2c showed the highest antifungal effect (MIC value 6 µM). Compound 3c exhibited the highest antioxidant activity with a % radical scavenging activity value of 95.12. The cytotoxicity of the compounds 1-4a-e was also checked against an animal cell line and a plant seed germination cell line, and the compounds were found to be safe against both the tested cell lines.

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.

Divergent [2 + n] Heteroannulation of β-CF3-1,3-enynes with Alkyl Azides via Hydrogen Atom Transfer and Radical Substitution

A copper-promoted divergent intermolecular [2 + n] heteroannulation of β-CF3-1,3-enynes with alkyl azides via alkyl radical-driven HAT and radical substitution (C-C bond formation) to form four- to ten-membered saturated N-heterocycles is developed. This method enables the aryl-induced or kinetically controlled site selective functionalization of the remote C(sp3)-H bonds at positions 2, 3, 4, 5, 6, 7, or 8 toward the nitrogen atom through triplet nitrene formation, radical addition across the C═C bond, HAT and radical substitution cascades, and features a broad substrate scope, excellent site selectivity, and facile late-stage derivatization of bioactive molecules. Initial deuterium-labeling and control experiments shed light on the reaction mechanism via nitrene formation and HAT.

Aza-Heterocyclic Building Blocks with In-Ring CF2 -Fragment

Modern organic chemistry is a titan supporting and reinforcing pharmaceutical, agricultural, food and material science products. Over the past decades, the organic compounds market has been evolving to meet all the research demands. In this regard, medicinal chemistry is especially dependent on available chemical space as subtle tuning of the molecule structure is required to create a drug with relevant physicochemical properties and a remarkable activity profile. The recent rapid evolution of synthetic methodology to deploy fluorine has brought fluorinated compounds to the spotlight of MedChem community. And now unique properties of fluorine still keep fascinating more and more as its justified installation into a molecular framework has a beneficial impact on membrane permeability, lipophilicity, metabolic stability, pharmacokinetic properties, conformation, pKa , etc. The backward influence of medicinal chemistry on organic synthesis has also changed the landscape of the latter towards new fluorinated topologies as well. Such complex relationships create a flexible and ever-changing ecosystem. Given that MedChem investigations strongly lean on the ability to reach suitable building blocks and the existence of reliable synthetic methods in this review we collected advances in the chemistry of respectful, but still enigmatic gem-difluorinated aza-heterocyclic building blocks.

Selenium-Containing (Hetero)Aryl Hybrids as Potential Antileishmanial Drug Candidates: In Vitro Screening against L. amazonensis

Leishmaniasis remains a significant global health concern, with current treatments relying on outdated drugs associated with high toxicity, lengthy administration, elevated costs, and drug resistance. Consequently, the urgent need for safer and more effective therapeutic options in leishmaniasis treatment persists. Previous research has highlighted selenium compounds as promising candidates for innovative leishmaniasis therapy. In light of this, a library of 10 selenium-containing diverse compounds was designed and evaluated in this study. These compounds included selenium-substituted indole, coumarin, chromone, oxadiazole, imidazo[1,2-a]pyridine, Imidazo[2,1-b]thiazole, and oxazole, among others. These compounds were screened against Leishmania amazonensis promastigotes and intracellular amastigotes, and their cytotoxicity was assessed in peritoneal macrophages, NIH/3T3, and J774A.1 cells. Among the tested compounds, MRK-106 and MRK-108 displayed the highest potency against L. amazonensis promastigotes with reduced cytotoxicity. Notably, MRK-106 and MRK-108 exhibited IC50 values of 3.97 µM and 4.23 µM, respectively, and most of the tested compounds showed low cytotoxicity in host cells (CC50 > 200 µM). Also, compounds MRK-107 and MRK-113 showed activity against intracellular amastigotes (IC50 18.31 and 15.93 µM and SI 12.55 and 10.92, respectively). In conclusion, the identified selenium-containing compounds hold potential structures as antileishmanial drug candidates to be further explored in subsequent studies. These findings represent a significant step toward the development of safer and more effective therapies for leishmaniasis, addressing the pressing need for novel and improved treatments.

From Conventional to Sustainable Catalytic Approaches for Heterocycles Synthesis

Synthesis of heterocyclic compounds is fundamental for all the research area in chemistry, from drug synthesis to material science. In this framework, catalysed synthetic methods are of great interest to effective reach such important building blocks. In this review, we will report on some selected examples from the last five years, of the major improvement in the field, focusing on the most important conventional catalytic systems, such as transition metals, organocatalysts, to more sustainable ones such as photocatalysts, iodine-catalysed reaction, electrochemical reactions and green innovative methods.

Monofluoromethylation of N-Heterocyclic Compounds

The review focuses on recent advances in the methodologies for the formation or introduction of the CH2F moiety in N-heterocyclic substrates over the past 5 years. The monofluoromethyl group is one of the most versatile fluorinated groups used to modify the properties of molecules in synthetic medical chemistry. The review summarizes two strategies for the monofluoromethylation of N-containing heterocycles: direct monofluoromethylation with simple XCH2F sources (for example, ICH2F) and the assembly of N-heterocyclic structures from CH2F-containing substrates. The review describes the monofluoromethylation of pharmaceutically important three-, five- and six-membered N-heterocycles: pyrrolidines, pyrroles, indoles, imidazoles, triazoles, benzothiazoles, carbazoles, indazoles, pyrazoles, oxazoles, piperidines, morpholines, pyridines, quinolines and pyridazines. Assembling of 6-fluoromethylphenanthridine, 5-fluoromethyl-2-oxazolines, C5-monofluorinated isoxazoline N-oxides, and α-fluoromethyl-α-trifluoromethylaziridines is also shown. Fluoriodo-, fluorchloro- and fluorbromomethane, FCH2SO2Cl, monofluoromethyl(aryl)sulfoniummethylides, monofluoromethyl sulfides, (fluoromethyl)triphenylphosphonium iodide and 2-fluoroacetic acid are the main fluoromethylating reagents in recent works. The replacement of atoms and entire functional groups with a fluorine atom(s) leads to a change and often improvement in activity, chemical or biostability, and pharmacokinetic properties. The monofluoromethyl group is a bioisoster of -CH3, -CH2OH, -CH2NH2, -CH2CH3, -CH2NO2 and -CH2SH moieties. Bioisosteric replacement with the CH2F group is both an interesting task for organic synthesis and a pathway to modify drugs, agrochemicals and useful intermediates.