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Polyurethanes (PUs) are very versatile and popular polymers that play a key role in the automotive, construction and non-food consumable sectors. In general, two-step polyurethane synthetic procedures involve the addition of catalysts also in the second phase of the reaction with problems of high environmental impact and disposal. In this work, an innovative eco-sustainable and very cheap procedure for the production of high-quality rigid polyurethane (PU) foams was developed, starting from polyethylene glycol (PEG 400) and diisocyanates as reagents and using common inorganic salts as catalysts, such as sodium chloride. In particular, our innovatory method is based on a single initial addition of a very cheap catalyst that is proved to be effective for both the prepolymer formation and polyurethane chain elongation. Moreover, simultaneous with the formation of final polyurethane, the salt was restored for a new catalytic cycle. Then, our strategy for polyurethane foam synthesis can surely represent a valid alternative as a very inexpensive and eco-compatible process, also for the industrial field. Finally, detailed mechanistic hypotheses were formulated and supported by DFT calculations.

The mitochondrial permeability transition pore (mPTP), a high-conductance channel triggered by a sudden Ca(2+)concentration increase, is composed of the F1FO-ATPase. Since mPTP opening leads to mitochondrial dysfunction, which is a feature of many diseases, a great pharmacological challenge is to find mPTP modulators. In our study, the effects of two 1,5-disubstituted 1,2,3-triazole derivatives, five-membered heterocycles with three nitrogen atoms in the ring and capable of forming secondary interactions with proteins, were investigated. Compounds3aand3bwere selected among a wide range of structurally related compounds because of their chemical properties and effectiveness in preliminary studies. In swine heart mitochondria, both compounds inhibit Ca2+-activated F1FO-ATPase without affecting F-ATPase activity sustained by the natural cofactor Mg2+. The inhibition is mutually exclusive, probably because of their shared enzyme site, and uncompetitive with respect to the ATP substrate, since they only bind to the enzyme-ATP complex. Both compounds show the same inhibition constant (KMODIFIER LETTER PRIMEi), but compound3ahas a doubled inactivation rate constant compared with compound3b. Moreover, both compounds desensitize mPTP opening without altering mitochondrial respiration. The results strengthen the link between Ca2+-activated F1FO-ATPase and mPTP and suggest that these inhibitors can be pharmacologically exploited to counteract mPTP-related diseases.

In the continuous effort to identify selective chelators towards bioavailable and toxic metal ions, the potential selectivity of a novel N,O chelating ligand, recently synthesized and claimed to be able to bind to Cu(II) ions forming stable complexes while leaving unaltered the level of essential metal ions, was scrutinized using a combined theoretical and experimental approach. A multistep synthetic procedure was used to synthesize the ligand, whose chelating properties along with the stability of the complexes formed binding Cu(II) and, for comparison, Fe(III) ions were evaluated using potentiometric measurements and UV-Vis spectroscopy. DFT analysis allowed to disclose the structural characteristics of the formed complexes. In the plethora of all the possible structures, a selection of the most reliable ones was achieved by means of a stringent comparison between experimental and simulated UV-Vis spectra. The outcomes of the present investigation demonstrate that the Cu(II) sequestering ability of the ligand is smaller than that towards Fe(III). The strategy used here should allow to check the propensity of ligands in selectively binding metal ions.

1,2,3-triazoles represent a functional heterocyclic core that has been at the center of modern organic chemistry since the beginning of click chemistry. Being a versatile framework, such an aromatic ring can be observed in uncountable molecules useful in medicine and photochemistry, just to name a few. This review summarizes the progress achieved in their synthesis from 2015 to today, with particular emphasis on the development of new catalytic and eco-compatible approaches. In doing so, we subdivided the report based on their degree of functionalization and, for each subparagraph, we outlined the role of the catalyst employed.

We thank the Italian Ministry of University and Scientific Research (MIUR) for a doctoral grant and the University of Calabria for financial support. We also acknowledge the MINECO and FEDER Program (Madrid, Spain, project CTQ2016‐76155‐R) and the Government of Aragon (Zaragoza, Spain. Biological & Computational Chemistry Group. E34_17R) cofunded with Feder 2014‐2020 “Constructing Europe from Aragon”.

In this study we evaluated the oil adsorption capacity of an aliphatic polyurethane foam (PU 1) and two of its composites, produced through surface coating using microparticles of silica (PU-Si 2) and activated carbon (PU-ac 3). The oil adsorption capacity in diesel was improved up to 36% using the composite with silica and up to 50% using the composite with activated carbon with respect to the initial PU 1. Excellent performances were retained in gasoline and motor oil. The adsorption was complete after a few seconds. The process follows a monolayer adsorption fitted by the Langmuir isotherm, with a maximum adsorption capacity of 29.50 g/g of diesel for the composite with activated carbon (PU-ac 3). These materials were proved to be highly oleophilic for oil removal from fresh water and sea water samples. Regeneration and reuse can be repeated up to 50 times by centrifugation, without a significant loss in adsorption capacity.

A novel series of bio-based polyurethane composite foams was prepared, employing a cellulose-derived polyol for chain extension and cellulose-citrate as a thickener additive. The utilized polyol was obtained from the reduction reaction of cellulose-derived bio-oil through the use of sodium borohydride and iodine. Primarily, we produced both rigid and flexible polyurethane foams through chain extension of the prepolymers. Secondly, we investigated the role of cellulose citrate as a polyurethane additive to improve the mechanical properties of the realized composite materials. The products were characterized by FT-IR spectroscopy and their morphologies were analysed by SEM. Mechanical tests were evaluated to open new perspectives towards different applications.

In the present work, we proved the efficacy of cellulose citrate to remove methylene blue (MB) from artificially contaminated water. MB is a widely used dye, but because of its chemical aromatic structure, it is significantly stable with quite slow biodegradation, causing consequent serious health problems for people and significant environmental pollution. Cellulose citrate, the bio-adsorbent proposed and studied by us to remediate water polluted by MB, is produced by a green, cheap and fast procedure that makes use of two abundant natural products, cellulose and citric acid. The average of two citrate groups for each glucose unit of cellulose chains allows this material to have many carboxylic groups available for interaction with the cationic dye. The characterization was carried out through FT-IR, SEM, specific surface area, pore structure parameters and zeta potential. The negative value of the zeta potential at neutral pH is consistent with the affinity of this material for the adsorption of cationic compounds like MB. The activity of the adsorbent at different times, temperatures, pH and concentrations was investigated. The process followed monolayer adsorption typical of the Langmuir model, with a maximum adsorption capacity of 96.2 mg g−1, while for the kinetic studies the process followed a pseudo-second order model. The highest levels of adsorption were reported using solutions of dye with concentrations under 100 mg L−1. The adsorbent can be regenerated several times without a significant loss in the adsorption capacity, and it is not strongly affected by temperature and pH, giving rise to a simple and eco-sustainable procedure for water remediation. Therefore, we conclude that cellulose citrate can be considered as a promising bio-adsorbent for the removal of MB and other cationic pollutants from the environment.

Nanocellulose (NC) is a biomaterial with growing interest in the field of nanocomposites and sustainable materials. NC has various applications including biodegradable materials, reinforcing agents, packaging films, transpiring membranes and medical devices. Among the many applications, the use of NC functionalized with organic and inorganic groups has found wide use as a catalyst in chemical transformations. The goal of this review is to collect the current knowledge on its catalytic applications for chemical groups conversion. We have chosen to organize the manuscript according to subdivision of NC into Bacterial Nanocellulose (BNC), Cellulose Nanocrystals (CNCs), and Cellulose Nanofibers (CNFs) and their role as inorganic- and organic-functionalized NC-catalysts in organic synthesis. However, in consideration of the fact that the literature on this field is very extensive, we have decided to focus our attention on the scientific productions of the last five years.

The simultaneous transformation of crystalline or amorphous cellulose into a furan-based bio-oil and cellulose citrate was realized avoiding the use of strong inorganic acids, drastic conditions, enzymatic treatments or microorganism fermentation. This innovative method is very eco-friendly and involves the use of molten citric acid under solvent free conditions at atmospheric pressure. An accurate discussion on chemical composition of the bio-oil enriched in bioprivileged molecules as well as structural and morphological characterization of cellulose citrate was reported. Moreover, mechanistic hypotheses were formulated on the basis of experimental findings and detailed DFT quantum-mechanical simulations were carried out to confirm, step by step, the proposed reaction paths.

A series of ketonitrones derived from isatin and indanone (INs) were synthesized and evaluated for their antiproliferative activities against several human cancer cell lines. Then, the antioxidant properties of these substrates were measured by the DPPH test to report their biological activity in terms of their spin trapping action. In particular, one substrate has showed very high biological and scavenging activity, probably due to the strong correlation between its spin trapping activity and structure.

A simple procedure to obtain 1,5-disubstituted 1,2,3-triazoles, using the Er(OTf)3/[mpy]OTf/H2O catalytic system is described. The reaction proceeds through an eliminative azide–olefin cycloaddition (EAOC) offering a highly regioselective approach and good yields (81–94%). The advantages of this method include simple operations of work-up and the ability of the catalytic system to be re-used five times without an evident loss in yield. The role of IL and water were speculated, invoking also a probable ionic self-assembly (ISA) effect.

The use of eco-compatible synthetic procedures in organic reactions and, in particular, in 1,3-dipolar cycloaddition reactions, has recently received a great deal of attention and considerable progress has been achieved in this area in the last years. This review summarizes the approaches currently employed to synthesize heterocyclic compounds by catalyzed 1,3-dipolar cycloadditions in green solvents in the last six years. Our choice to do a selection of the literature from 2014 to 2019 was made considering the absence of a recent review about this period, to our knowledge. Several examples to construct heterocycles by 1,3-dipolar cycloadditions will be discussed in this work subdivided in function of the most important class of non-conventional and green solvents, i.e., ionic liquids (ILs), deep eutectic solvents (DES), and water.

A simple procedure to obtain 1,5-disubstituted 1,2,3-triazoles, using the catalytic system erbium(III) trifluoromethanesulfonate, 1-methyl pyridinium trifluoromethanesulfonate and water is described. The reaction proceeds through an eliminative azide–olefin cycloaddition (EAOC) offering a highly regioselective approach and good yields (81–94%). The advantages of this method include simple operations of work-up and the ability of the catalytic system to be re-used five times without an evident loss in yield.

Nucleobase-containing isoxazolidines spiro-bonded to an indane core have been synthesized in very good yields by regio- and diastereoselective 1,3-dipolar cycloaddition starting from indanyl nitrones and N-vinylnucleobases by using environmentally benign microwave technology. The contemporary presence of various structural groups that are individually active scaffolds of different typology of drugs, has directed us to speculate that these compounds may act as inhibitors of MDM2-p53 interaction. Therefore, both computational calculations and antiproliferative screening against A549 human lung adenocarcinoma cells and human SH-SY5Y neuroblastoma cells were carried out to support this hypothesis., We thank the Italian Ministry of University and Scientific Research (MIUR) for a doctoral grant and the University of Calabria for financial support. We also acknowledge the MINECO and FEDER Program (Madrid, Spain, project CTQ2016-76155-R) and the Gobierno de Aragon (Zaragoza, Spain. Biological & Computational Chemistry Group. E34_R17).

Post-translational lipid modifications farnesylation and geranylgeranylation of proteins (protein prenylation) have been identified to mediate critical events in cancer, cardiovascular disorders, malaria and bone disorders like osteoporosis. To date eight compounds are commercialized for the treatment of bone disorders, and there are considerable efforts to develop selective small molecules that inhibit protein prenylation. This review summarizes the approaches currently employed to synthesize new inhibitors of isoprenoid biosynthesis. Bisphosphonates are mainly prepared through reaction of carboxylic acids with phosphorus reagents, Michael addition to tetraethylvinylidenebisphosphonate and alkylation of tetralkylmethyl bisphosphonate. Approaches to non-bisphosphonate derivatives include a variety of methodologies depending on the structure of the target compound., This work was supported by the MINECO and FEDER Program (Madrid, Spain, project CTQ2016-76155-R) and the Gobierno de Aragon (Zaragoza, Spain. Bioorganic Chemistry Group. E-10). We thank the Italian Ministry of University and Scientific Research (MIUR) for a doctoral grant and the University of Calabria for financial support.

This work was supported by the Ministerio de Ciencia e Innovacion (MICINN) and FEDER Program (Madrid, Spain, project CTQ2013-44367-C2-1-P) and the Gobierno de Aragon (Zaragoza, Spain. D.R.-L. thanks the Spanish Ministry of Education (MEC) for a pre-doctoral grant (FPU program). We thank the Italian Ministry of University and Scientific Research (MIUR) for a doctoral grant and the University of Calabria for financial support.

The synthesis, characterization and evaluation of a new highly efficient organocatalyst, namely (5S)-2,2,3-trimethyl-5-thiobenzylmethyl-4-imidazolidinone hydrochloride has been achieved. The catalyst possesses important structural features that should increase the catalytic efficiency and solubility in polar media. The application of ionic liquid-supported imidazolidinone catalyst in enantioselective Diels–Alder reactions was investigated. The Diels–Alder reactions of several dienes and dienophiles proceeded efficiently in the presence of the catalyst to provide the desired products in a range from moderate to good yields and from good to excellent enantioselectivities. The conformational study confirms that in the transition state the Re face is completely shielded by phenyl ring preferring approach on less hindered Si face. Particularly remarkable is the fact that the entire system IL/HCl 0.01 M/Catalyst can be recovered and reused for up to six runs without appreciable loss of catalytic activity., This work was supported by the Ministerio de Ciencia e Innovación (MICINN) and FEDER Program (Madrid, Spain, project CTQ2013-44367-C2-1-P) and the Gobierno de Aragón (Zaragoza, Spain. D.R.-L. thanks the Spanish Ministry of Education (MEC) for a pre-doctoral grant (FPU program). We thank the Italian Ministry of University and Scientific Research (MIUR) for a doctoral grant and the University of Calabria for financial support.