The synthetic potentialities of cerium(III) chloride are demonstrated by the synthesis of a nine-membered ring heterocycle component of Griseoviridin (3) in optically active form. The key step ...involves the stereospecific formation of the alpha-carbalkoxy alkenyl sulfide moiety using a combination system of cerium(III) chloride heptahydrate and sodium iodide.
Readily preparable morpholine amides hitch in good yields with organocerium reagents to produce ketones. Even in the presence of substrates and reagents with high steric hindrance, the organometallic ...compounds prepared from dry cerium(III) chloride and organomagnesium or organolithium compounds at -78 degrees C add cleanly to morpholine amides. The low cost of starting materials makes this new scheme of synthesis very interesting for the preparation of biologically important pheromones.
π-Facial diastereoselectivity effects of the substituent in 4-position on the nucleophilic addition of substituted adamantan-2-ones were observed for the methylation reaction of ...4-chloroadamantan-2-ones. NMR study revealed that when chlorine atom is in axial stereochemical position, exclusively
anti-addition occurs, whereas selective preference for
syn-addition was observed with stereochemical equatorial position for chloro substituent. The success of this strategy can be attributed to the important role that CeCl
3 plays in increasing the nucleophilicity and decreasing the basicity of the methylorganometallic reagent.
DESs were profitably investigated as solvents and promoters of the conjugate reaction addition of cyclic and acyclic α‐nitroketones to a variety of electron‐poor alkenes. The best results were ...obtained conducing the reaction in betaine:1,2‐propanediol (1 : 5 molar ratio) DES at room temperature, and enones were demonstrated to be the most effective Michael acceptors. The same reaction conducted by using different molar ratios of the components in this DES showed the eutectic point to be the most effective in terms of the yields observed.
The conjugate addition reaction of cyclic and acyclic α‐nitroketones to a variety of electron‐poor alkenes was successfully accomplished in 1,2‐propanediol:betaine deep eutectic solvent (DES). Enones resulted the most effective Michael acceptors, however satisfactory results were also obtained using acrylates, nitriles, nitroalkenes, and pull‐pull alkenes.
Among many, poly(lactic acid) (PLA) has received significant consideration. The striking price and accessibility of
l
-lactic acid, as a naturally occurring organic acid, are important reasons for ...poly-(
l
)-lactic acid (PLLA) improvement. PLLA is a compostable and biocompatible/bioresorbable polymer used for disposable products, for biomedical applications, for packaging film, in the automotive industry, for electronic device components, and for many other applications. Formerly, titanium and other metals have been used in different orthopaedic screws and plates, but they are not degradable and therefore remain in the body. So, the development of innovative and eco compatible catalysts for polyester synthesis is of great interest. In this study, an innovative and eco sustainable catalyst was employed for PLLA synthesis. The combined CeCl
3
·7H
2
O-NaI system has been demonstrated to be a very valuable and nontoxic catalyst toward PLLA synthesis, and it represents a further example of how to exploit the antibacterial properties of cerium ions in biomaterials engineering. A novel synthesis of poly-(
l
)-lactic acid was developed in high yields up to 95% conversion and with a truly valuable molecular weight ranging from 9000 to 145 000 g mol
−1
, testing different synthetic routes.
The combined CeCl
3
·7H
2
O-NaI system has demonstrated to be a very valuable and nontoxic catalyst toward PLLA synthesis.
A new procedure for the sulfenylation of indoles and pyrroles based on an aromatic substitution with α‐acylthiones used as electrophiles is described. The sulfenylating species were obtained, under ...very mild reaction conditions, from N‐thiophthalimides, using a weak base (pyridine or triethylamine) as promoter. The overall yields obtained are comparable with those obtained by other known sulfenylation protocols, which typically require harsher reaction conditions and/or metal‐containing Lewis acids as promoters.
A simple procedure for the sulfenylation of indoles and pyrroles through hetero‐aromatic substitution with α‐acylthiones acting as electrophiles is presented. The reaction occurs under mild basic conditions that are particularly suitable for the derivatization of aza‐aromatics. However, such conditions are quite uncommon.
In the last decades, there is more awareness on the impact on human health of pollutants emitted during cooking processes, both from commercial and from domestic activities. In this study, a new ...method exploiting solid‐phase microextraction and gas chromatography coupled to mass spectrometry (SPME‐GC–MS) was developed to analyse the volatile organic compounds (VOCs) emitted during cooking. The air above the cooking plate was sampled using a polyethylene terephthalate olfactometric bag that allows to transport the sample to the instrument location and to perform the SPME extraction of the sampled air. The efficiency of different extraction systems and different extraction times (1, 8, 16, and 24 h) was evaluated in order to obtain sufficient sensitivity. Thus, the proposed system, combining the use of olfactometric bags and SPME‐GC–MS, was applied for the first time to study VOCs emitted during cooking allowing to perform the analysis, even on samples produced in sites far from the instrument location, in an easy way and with instrumentations available in most of laboratories. Then, the method was applied to assess the efficiency of odour filters used in common kitchen hoods, using deep frying of potatoes in sunflower oil as cooking model system. VOCs were analysed in the air before and after passage through the filter, calculating then percentages of dejection for the different classes of VOCs that resulted to be in the range 31–77%.
Electron‐rich aza‐aromatic compounds such as indoles and pyrroles are structures of particular interest and importance in organic chemistry. A useful methodology for the regioselective introduction ...of the sulfenyl group into electron‐rich aza‐aromatics using S‐alkyl‐ and S‐arylthiophthalimides as sulfenylating agents is described. Catalytic amounts of CeCl3·7H2O/NaI are crucial to the promotion of this regioselective carbon–sulfur‐bond‐forming electrophilic aromatic substitution reaction. The reaction occurred under mild conditions, and the products were obtained in good to excellent yields. The method represents an efficient preparation of sulfenyl aza‐aromatics, which are useful intermediates for important organic transformations, due to the great importance of functionalized indoles among natural compounds and pharmaceutical products.
A useful method for the regioselective introduction of the sulfenyl group into electron‐rich aza‐aromatics using S‐alkyl‐ and S‐arylthiophthalimides as sulfenylating agents is described. Catalytic amounts of CeCl3·7H2O/NaI are crucial to the promotion of this regioselective carbon–sulfur‐bond‐forming electrophilic aromatic substitution reaction.
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Several modern drugs, including those for cancer therapy, have been isolated from natural sources, are based on natural products and its derivatives, or mime natural products. Some of ...them are in clinical use, others in clinical trials. The success of natural products in drug discovery is related to their biochemical characteristics and to the technologic methods used to study their feature. Natural compounds may acts as chemo-preventive agents and as factors that increase therapeutic efficacy of existing drugs, thus overcoming cancer cell drug resistance that is the main factor determining the failure in conventional chemotherapy.
Water environment, because of its physical and chemical conditions, shows an extraordinary collection of natural biological substances with an extensive structural and functional diversity. The isolation of bioactive molecules has been reported from a great variety of aquatic organisms; however, the therapeutic application of molecules from eukaryotic microorganisms remains inadequately investigated and underexploited on a systematic basis.
Herein we describe the biological activities in mammalian cells of selected substances isolated from ciliates, free-living protozoa common almost everywhere there is water, focusing on their anti-tumour actions and their possible therapeutic activity. In particular, we unveil the cellular and molecular machine mediating the effects of cell type-specific signalling protein pheromone Er-1 and secondary metabolites, i.e. euplotin C and climacostol, in cancer cells. To support the feasibility of climacostol-based approaches, we also present novel findings and report additional mechanisms of action using both in vitro and in vivo models of mouse melanomas, with the scope of highlighting new frontiers that can be explored also in a therapeutic perspective.
The high skeletal chemical difference of ciliate compounds, their sustainability and availability, also through the use of new organic synthesis/modifications processes, and the results obtained so far in biological studies provide a rationale to consider some of them a potential resource for the design of new anti-cancer drugs.
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