The synthesis of 1,4-dihydropyridines (DHPs) 4 from three starting compounds, following Hantzsch’s protocol, was carried out in a one pot, under mild conditions (room temperature, a mixture solvent of ethanol and water), in the presence of a series of Keggin-type heteropolyacids (HPAs) of the formula H₃PMo₁₂O₄₀, H₃PW₁₂O₄₀, H₄SiW₁₂O₄₀,H4SiMo12O40, H₄PMo₁₁V₁O₄₀, H₅PMo₁₀V₂O₄₀ and H₆PMo₉V₃O₄₀ as catalysts. Among the tested HPAs, H₃PMo₁₂O₄₀, was found to be the most active catalyst with an excellent DHP yielding (ca. 80%). Various derivatives 4 were successfully synthesised and isolated, and subsequently identified by NMR, IR and UV-visible spectroscopies and mass spectrometry, as well as by measuring their melting points. A reaction mechanism was also proposed. Their antioxidant activity, assessed using DPPH radical scavenging assays, and their antibacterial activity against Gram-positive and Gram-negative bacterial strains were evaluated. Molecular docking studies were conducted with human peroxiredoxin 5 and Staphylococcus aureus DNA gyrase B to investigate possible modes of interaction between the ligand and the protein. The docking results revealed favorable hydrogen-bond, electrostatic, and hydrophobic interactions within the active sites of both targets, supporting the experimental biological observations. Preliminary in silico toxicity prediction suggested acceptable toxicity profiles for the most active derivatives.

Herein, we report a one-pot sequence to prepare 1,2-diazepine fused β-lactams under photochemical irradiation. Hence, α-diazoketones are readily converted to the corresponding ketenes in an additive-free Wolff rearrangement and react with isolated or in situ generated 1,2-diazepines to yield a rather uncommon β-lactam core. The operative mechanism follows the rules of the Staudinger [2 + 2] synthesis and involves a 4 π conrotatory ring closure. Key factors, both steric and electronic, governing the diastereoselectivity were identified. Postmodification of the substrates, including (hetero) Diels-Alder reactions on the residual diene, showcases the synthetic utility of the present work. Finally, the divergent reactivity of acyl ketenes, yielding oxazinone-fused 1,2-diazepines, was also established.

Robust organic cages featuring convergent hydrogen-bonding cavities constitute attractive platforms for confined molecular recognition. Here, we report a rapid four-step synthesis of a well-defined pyridyl hexa-amide cage based on a readily accessible benzylic tris-aniline platform. Microwave-assisted imine condensation enables fast cage assembly, while subsequent Pinnick oxidation converts the dynamic architecture into a permanently locked C3-symmetric host. Single-crystal x-ray diffraction reveals a rigid cavity lined with six inward-oriented N-H donors, generating a confined hydrogen-bonding environment suitable for anion recognition. In DMSO, mono- and dicarboxylate guests bind in a fast-exchange regime with comparable apparent affinities. In contrast, a symmetry-matched tricarboxylate (nitrilotripropionate, NTP) induces the formation of a discrete 1:1 host-guest complex displaying distinct titration behavior and confirmed crystallographically. Control experiments with a more rigid tricarboxylate (aluminon) revealed no detectable binding under comparable conditions, suggesting that guest conformational adaptability also contributes to complex formation. These observations highlight how rigidification and geometric complementarity within a confined cavity can influence host-guest recognition behavior in solution.

Herein, we report a one-pot sequence to prepare 1,2-diazepine fused b-lactams under photochemical irradiation. Hence, a-diazoketones are readily converted to corresponding ketenes in an additive-free Wolff rearrangement. The operative mechanism follows the rules of the Staudinger [2+2] synthesis and involves a 4 p conrotatory ring closure. Key factors, both steric and electronic, governing the diastereoselectivity were identified. Post-modification of the substrates, including a Diels-Alder reaction on the residual diene, showcase the synthetic utility of the present work. Finally, the divergent reactivity of acyl ketenes, yielding oxazinone-fused 1,2-diazepines was also established.

This study describes the synthesis of a new bioadsorbent from chitosan using ethylenediaminetetraacetic dianhydride (EDTAD) as a modifying agent and its successful application for removal of a cationic ion (copper (II) (Cu 2+ )) and oxyanions of chromium (VI) (Cr 6+ ) from single-component aqueous systems. The new multifunctionalised chitosan derivative (C1) was produced through chemical modification of the primary hydroxyl function of chitosan with EDTAD to introduce carboxylic and tertiary amine functional groups, maintaining the secondary amines on the chitosan surface. Such a transformation was important not only to increase the adsorptive potential of chitosan but also to allow C1 to be used in acidic media, thus solving the problem of solubility of most chitosan derivatives. C1 was characterised by spectroscopic methods. The effects of solution pH, contact time and initial solute concentration on the removal of copper (II) and chromium (VI) by C1 were investigated in aqueous solutions. C1 showed an experimental maximum adsorption capacity of 106 mg/g for copper (II) and 194 mg/g for chromium (VI).

The ability of perfluorinated terephthalonitrile to act as an anion-pi donor fragment in anion receptors is evaluated. New receptors combining an urea and a perfluorinated terephthalonitrile motif into a single architecture have been designed and synthesized. Their molecular recognition properties towards Cl-, Br- and I-, have been studied in solution by means of H-1 and F-19 NMR as well as photophysical experiments. A complementary electrospray ionization-tandem mass spectrometry study confirmed the ranking of recognition properties between the receptors. A further theoretical evaluation of binding properties confirmed the association constant trend and suggests a main contribution of the urea motif weakly complemented by a eta(2)-type anion-pi interaction.

We report a general remote tribromo- and trichloromethylation process using CBr4 and CBrCl3 as ready available sources of trihalomethyl radicals. This method operates under mild and metal-free photocatalyzed conditions and enables the access to γ-trihalomethylated enals with complete regioselectivity in up to 71 % isolated yield. Importantly, this protocol is easily adapted to the selective one-pot synthesis of the corresponding γ-dihalomethylidenated enals in up to 49 % overall yield. Mechanistic studies are in favor of a radical chain propagation initiated by an oxidative quenching of the photocatalyst.

In this report, we developed a unified and standardized one-pot sequence that converts pyridine derivatives into 1,2-diazepines by inserting a nitrogen atom. This skeletal transformation capitalizes on the in situ generation of 1-aminopyridinium ylides, which rearrange under UV light irradiation. A thorough evaluation of the key parameters (wavelength, reaction conditions, activating agent) allowed us to elaborate on a simple, mild, and user-friendly protocol. The model reaction was extrapolated to more than 40 examples, including drug derivatives, affording unique 7-membered structures. Mechanistic evidence supports the transient presence of a diazanorcaradiene species. Finally, pertinent transformations of the products, including ring contraction reactions to form pyrazoles, were conducted and paved the way to a broad application of the developed protocol.

This study describes the synthesis of a new bioadsorbent from chitosan using ethylenediaminetetraacetic dianhydride (EDTAD) as modifying agent and its successful aplication for removal of cationic ion (Cu(II)) and oxyanion (Cr(VI)) from single component aqueous systems. The new multifunctionalized chitosan derivative (C1) was produced through chemical modification of primary hydroxyl function of chitosan with EDTAD to introduce carboxylic and tertiary amine functional groups, maintaining the secondary amines on the chitosan surface. Such a transformation was important to increase the adsorptive potential of chitosan but also to allow C1 to be used in acidic media, thus solving the problem of solubility of most chitosan derivatives. C1 was characterized by spectroscopic methods. The effects of solution pH, contact time, and initial solute concentration on removal of Cu(II) and Cr(VI) by C1 were investigated in aqueous solutions. C1 showed experimental maximum adsorption capacity of 106 mg g(-1) for Cu(II) and 194 mg g(-1) for Cr(VI).

Although used for one century in billions of people as the vaccine adjuvant with the best benefit/side-effect balance, aluminium salts/gels have drawbacks of rapid leakage of antigens from the injection site and indefinite persistence. Herein, we propose an alternative to canonical Al-adjuvant. Proteins, nucleic acids, and bacteria were successfully encapsulated within an Al-based Metal-Organic Framework (MOF), namely Al-fumarate, using a synthesis process in water and room temperature, compatible with bio-entities preservation. Mice immunizations demonstrated antigenicity preservation of tetanus toxoid and inactivated E. coli, and a stronger adjuvant effect of Al-fumarate than benchmark Al-adjuvant (Alhydrogel) with an initial slow antigen release and a protective effect. The Al-fumarate vaccine formulation was fully resorbable in vivo, disappearing from the injection site, was not exhibiting any toxicity, and was stable for two years. The limitation of Al adjuvants as eliciting only antibody responses was also overcome by co-immobilisation of CpG 1018 with tetanus toxoid.

We report herein a general and highly selective γ-functionalization protocol under visible light irradiation. This mild radical approach enables the expansion of the scope of application to unbiased enals and the introduction of a wide variety of alkoxy, amino and alkyl functionalities in the γ position with complete regioselectivity.

Site-selective trifluoromethylation of silyl dienol ethers derived from α,β-unsaturated aldehydes, ketones, and amides was achieved for the first time in the remote γ position. This photoredox catalyzed process is quite general to compounds bearing many functionalities and is applicable to the late-stage functionalization of biorelevant molecules. The use of S-perfluoroalkyl sulfoximines as ·RF radical sources enables the generalization of the reaction to other perfluoroalkyl groups (RF = CF2H, C4F9). Importantly, an unprecedented enantioselective C(sp3)-H perfluoroalkylation process is disclosed.

Modulation and fine-tuning of the strength of weak interactions to bind anions are described in a series of synthetic receptors. The general design of the receptors includes both a urea motif and a tetrazine motif. The synthetic sequence towards three receptors is detailed. Impacts of H-bond strength and linker length between urea and tetrazine on chloride complexation are studied. Binding properties of the chloride anion are examined in both the ground and excited states using a panel of analytical methods (NMR spectroscopy, mass spectrometry, UV/Visible spectroscopies, and fluorescence). A ranking of the receptors by complexation strength has been determined, allowing a better understanding of the structure-properties relationship on these compounds.

This work describes the application of raw and chemically modified cellulose and sugarcane bagasse for ipso-hydroxylation of aryl boronic acids in environmentally friendly reaction conditions. The catalytic efficiency of five support-[Cu] materials was compared in forming phenols from aryl boronic acids. Our investigation highlights that the CEDA-[Cu] material (6-deoxy-6-aminoethyleneamino cellulose loaded with Cu) leads to the best results under very mild reaction conditions. The optimized catalytic sequence, allowing a facile transformation of boronic acids to phenols, required the mandatory and joint presence of the support, Cu2O, and KOH at room temperature. CEDA-[Cu] was characterized using 13C solid-state NMR, ICP, and FTIR. The use of CEDA-[Cu] accounts for the efficacious synthesis of variously substituted phenol derivatives and presents very good recyclability after five catalytic cycles.

Due to the high reactivity of alkoxyl (RO·) radicals and their propensity to easily undergo β-scission or Hydrogen Atom Transfer (HAT) reactions, intermolecular alkoxylations involving RO· radicals are barely described. We report herein for the first time the efficient intermolecular trapping of alkoxyl radicals by silyl enol ethers. This photoredox-mediated protocol enables the introduction of both structurally simple and more complex alkoxy groups into a wide range of ketones and amides.

The synthesis of molecules bearing (trifluoromethylselenyl)methylchalcogenyl groups is described via an efficient two-step strategy based on a metal-free photoredox catalyzed decarboxylative trifluoromethylselenolation with good yields up to 88 %, which raised to 98 % in flow chemistry conditions. The flow methods allowed also to scale up the reaction. The mechanism of this key reaction was studied. The physicochemical characterization of these emerging groups was performed by determining their Hansch-Leo lipophilicity parameters with high values up to 2.24. This reaction was also extended to perfluoroalkylselenolation with yields up to 95 %. Finally, this method was successfully applied to the functionalization of relevant bioactive molecules such as tocopherol or estrone derivatives.

We designed monodisperse and perfectly shaped core/shell AuNP@Mo(4)Zol(2)Mn nanohybrids consisting of gold nanoparticles (AuNPs) functionalized by an antitumoral polyoxometalate (POM) incorporating the biologically active zoledronate ligand. After incubation, the nanoparticles were readily confined in the endosomal compartments of PC3 human prostate adenocarcinoma cells. Under photothermal treatment, the metabolic activity drastically decreased at concentrations where the nanohybrids exhibited no anticancer activity in the dark, and almost all cancer cells were killed at concentrations at which zoledronate alone was totally inactive. This study evidences for the first time that AuNPs capped by POMs can represent excellent candidates for combined chemotherapy and photothermal cancer therapy.

A novel decahydrodecaborate-functionalized Anderson type polyoxometalate has been synthesized and characterized in solution by ESI-MS, various NMR techniques and electrochemical methods. DFT studies provide strong support to understand the properties of this hybrid system.

A metal‐free visible‐light‐promoted regioselective trifluoromethylselenolation of electron‐rich heteroarenes has been developed using C–H functionalization. This eco‐friendly, atom‐economical, and easy‐to‐operate protocol provides direct access to a wide range of functionalized SeCF3‐containing heteroarenes in high yields, and is amenable to continuous flow techniques. A radical mechanism was supported by EPR experiments.