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  • Open access
  • 61 Reads
A one-pot synthesis of fluoro α-acylamino amides-xanthates via IMCR coupled -SN2 strategy

A series of six novel Ugi-xanthates products containing several fluorine atoms were prepared in moderate to good yields (40-92%) via a MCR of-5CR followed by SN2 in one pot process. The design of molecules with fluorine atoms is of interest in medicinal chemistry and a research line of our interest. The role of fluorine atoms in biological properties is well documented, improving bioavailability, lipophilicity and metabolic resistance in bioactive molecules. These compounds could be synthetic platforms for later transformations via free radical cyclization toward the synthesis of molecules containing heterocycle peptidomimetics.

  • Open access
  • 96 Reads
Two symmetrical squarylium cyanine dyes: synthesis, photophysics and antifungal activity in Saccharomyces cerevisiae

Squarylium cyanine dyes are compounds 1,3-disubstituted that have a central four-carbon ring, derived from squaric acid, attached to aromatic or heterocyclic rings. These compounds have a zwiteronic structure, that typically absorbs in the visible to near-infrared region and, normally, present high molar absorption coefficient, high photochemical stability, and good photoconductivity. Considering these properties and depending on the potential application of this class of compounds, changes in their structure can be made.
In this work, two squarylium cyanine dyes were synthesized and characterized by the usual analytical techniques, including by UV-Vis-NIR absorption and emission spectroscopy. Their antifungal activity was evaluated, through the obtention of MIC values, using yeasts of the species Saccharomyces cerevisiae as a biological model and the results will be presented.

  • Open access
  • 110 Reads
Thiomonosaccharide derivatives from D-mannose

Sulfur-containing monosaccharide derivatives can be highly valuable for obtaining compounds with biological activities. In this work, a synthetic route starting from D-mannose has been designed. After a convenient hydroxyl protection and anomeric carbon functionalization in a ciano group, a new carbohydrate analogous has been obtained with sulfur in the ring. The heteroatoms have been introduced by an SN2 mechanism, with subsequent cyclization. Structural identification has been performed by different spectroscopic techniques.

  • Open access
  • 102 Reads
Synthesis of Epoxyisoindolinones Via Microwave-assisted Ugi-4C/Intramolecular-Diels-Alder Reaction

A series of Epoxyisoindolinones were synthesized by microwave-assisted domino Ugi-4C/Intramolecular-Diels-Alder (U-4C/IMDA) under eco-friendly conditions (free solvent, free catalyst, short time) and using orthogonal-bifunctional components. Epoxyisoindolinones are a privileged core of high interest in medicinal chemistry mainly for its anticancer activity in several cell lines.

  • Open access
  • 101 Reads
One-pot synthesis of janusene N-methyl-5a,11a-dicarboximide employing 2,3-dibromo-N-methylmaleimide as acetylene equivalent

Synthesis of janusene (5,5a,6,11,11a,12-hexahydro-5,12:6,11-di-o-benzenonaphthacene) requires several reaction steps starting from anthracene. In this account, one-pot, three steps synthesis of janusene N-methyl-5a,11a-dicarboximide employing 2,3-dibromo-N-methylmaleimide as acetylene equivalent is described. This thermal reaction is simple synthetic procedure in comparison to sequential-multi step [4+2] cycloaddition routes. Here 2,3-dibromo-N-methylmaleimide acts effectively as ' molecular glue ' bridging two anthracene molecules.

  • Open access
  • 78 Reads

Confocal laser scanning microscopy (CSLM) is a powerful microscopic tool that gives valuable morphological and functional information within cells and tissues. CLSM is non-invasive, with high-contrast scanning, a simple and fast sample preparation procedure as well as easy operation. The aim of this paper was to study the intracellular uptake of polymeric nanoparticles loaded with cardiovascular drugs using confocal laser scanning microscopy. Polymeric nanoparticles were prepared via nanoprecipitation method using poly(lactide-co-glycolide) (PLGA) as biodegradable polymeric matrix and Pluronic F127 as a stabilizer. A mixture of two cardiovascular drugs - valsartan (an angiotensin II receptor antagonist drug) and amlodipine besylate (a calcium channel blocker) - was loaded in polymeric nanoparticles. The prepared polymeric nanoparticles had sizes lower than 300 nm and narrow dispersity. The cellular uptake of polymeric nanoparticles was investigated by incubating adherent mouse embryo fibroblasts (NIH 3T3) with a suspension of nanoparticles (stained previously with phthalocyanine) at three different time points. Targeted cell compartments were labeled with two fluorophores: Rhodamine B (membrane stain) and Hoechst (nucleic acid stain). Live cell imaging was performed using a confocal microscope Zeiss LSM710 with Zeiss PALM microdissection system. The intracellular uptake of polymeric nanoparticles was revealed by confocal laser scanning microscopy for each incubation time. The results suggest a possible mechanism of endocytosis and clearly a vesicular-based accumulation of the nanoparticles in the cytoplasmatic compartments .

  • Open access
  • 89 Reads

The objective of this paper is to develop polymeric nanoparticles loaded with a cardiovascular drug, an angiotensin II receptor antagonist drug, valsartan. Polymeric nanoparticles were prepared via nanoprecipitation method using pullulan acetate as biodegradable polymeric matrix and Pluronic F127 as a stabilizer. Pullulan acetate was obtained by chemical modification of pullulan (produced through a fermentation process by Aureobasidium pullulans strain) with dimethylformamide, pyridine, and acetic anhydride. Obtained nanoparticles were characterized in terms of entrapment efficiency, size, and polydispersity index using spectrophotometric and dynamic light scattering techniques. The valsartan-loaded nanoparticles showed a good entrapment efficiency of valsartan, nano-metric sizes (lower than 200 nm), and a narrow dispersity (polydispersity index below 0.2). This research revealed that pullulan and pullulan derivatives showed great potential for the production of nanoparticles with application in cardiovascular agents delivery (NUCLEU PN 1941-04 01).

  • Open access
  • 72 Reads

Polyhydroxyalkanoates (PHAs) are microbial homo- and copolymers of [R]-β-hydroxyalkanoic acids, produced by a wide variety of bacteria as an intracellular carbon and energy reserve. To obtain mcl-PHAs of microbial origin we used a Pseudomonas spp. strain (from the National Institute for Chemical-Pharmaceutical Research and Development (ICCF) culture collection of micro-organisms), by varying the carbon sources and the precursors.

In this work, assays were performed with fermentation media seeded with inoculum cultures of strain Pseudomonas putida in a proportion of 10%.

The influence on mcl -PHA production of carbon sources for strain development, hexanoic (C6), heptanoic (C7), octanoic (C8) and nonanoic (C9) acids, as polymers precursors, were analyzed. Due to their properties, similar to those of conventional plastics and to their biodegradability, PHAs are suitable for many applications and for biomedical materials useful in surgical sutures, tissue engineering and drugs carriers, which leads us to the deepening of the study of obtaining micro/nanofibers by the electrospinning method.

  • Open access
  • 98 Reads
Fluorescent chiral nanostructures based on poly(diphenylacetylene)s

In nature, helical structure is present in a lot of biomolecules such as proteins, nucleic acids or polysaccharides. It’s also known this secondary structure is directly related with the properties of those molecules. For this reason, scientific community has expended time and effort to obtain new molecules that can adopt the helical structure to be able of emulating the functions and properties of biomolecules. Thus, helical polymers born.

Dynamic helical polymers have been widely studied due to the potential of these materials to act as sensors, chiral stationary phases to chromatographic separation or chiral catalyst because of the helical sense control via external stimuli.

Metals are one of the most employed external stimuli for modifying the structure of helical polymers. In poly(phenylacetylene)s it’s known that can act as crosslinking agent among polymer chains, inverse the helical sense or enhance the initial helicity. Finally, nanostructures like nanospheres, nanorods, etc, can be obtained.

In order to find new structures and new functions in helical polymers, this work addressed the synthesis of a novel family of materials denominated poly(diphenylacetylene)s. These polymers are a special class of conjugated polymers that present the abilities of fluorescence emission and a high thermal stability.

In this work, we analyze the chiroptical properties of the synthetized polymers and how the addition of different metals can modify them. Also, fluorescent chiral nanostructures are