A "fat" Streptomycete strain overproduces antibiotics

Photochemical synthesis of pyrene perfluoroalkyl derivatives and their embedding in a polymethylmethacrylate matrix: a spectroscopic and structural study

A photochemical, alternative and eco-compatible approach to perfluoroalkyl derivatives of pyrene is presented. The perfluoroalkyl chain is regiospecifically introduced at the 1 position of pyrene. The synthesized products have been embedded in a polymethylmethacrylate matrix by photocuring at 365 nm. Both the photochemical reactions can be considered a “green tool” for the synthetic chemist in order to obtain materials with prospective optoelectronic applications. The so-obtained composites have been the object of a study by UV and fluorescence spectroscopy in order to explore their luminescence properties. The small angle X-ray scattering and the transmission electron microscopy techniques…

Characterization of the bacterial community isolated from a High Middle Age soil sample dated since 980 AD

Perfluorocarbon functionalized hyaluronic acid derivatives as oxygenating systems for cell culture

A set of new hyaluronic acid (HA) derivatives was obtained by binding fluorinated oxadiazole (OXA) moieties to an amino derivative of the polysaccharide (HA-EDA). The obtained HA-EDA-OXA biomaterials are potentially able to improve oxygenation into a scaffold for tissue engineering purposes. The oxygen solubility in aqueous dispersions of the obtained derivatives showed that polymers were able to improve oxygen uptake and maintenance in the medium. The HA-EDA-OXA was employed to form a hydrogel in situ by reaction with a vinyl sulphone derivative of inulin, under physiological conditions. The influence of the presence of OXA moieties on the mechanical properties of the obtained hydrogels as…

Synthesis of Fluorinated Bent-Core Mesogens (BCMs) Containing the 1,2,4-Oxadiazole Ring

New fluorinated bent-core mesogens containing the 1,2,4-oxadiazole or 1,2,4-triazole nucleus have been synthesized taking advantage of the ANRORC (Addition of Nucleophile, Ring-Opening, Ring-Closure) reactivity of 5-perfluoroalkyl-1,2,4-oxadiazoles. Physical state changes of the obtained compounds were characterized through DSC, POM, and SAXS. Besides the formation of a smectic mesophase, a novel behavior as organic molecular glass was evidenced for some 1,2,4-oxadiazole derivatives.

The Boulton-Katritzky Reaction: A Kinetic Study of the Effect of 5-Nitrogen Substituents on the Rearrangement of Some (Z)-phenylhydrazones of 3-Benzoyl-1,2,4-oxadiazoles

The kinetics of the ring-into-ring conversion of some new (Z)-phenylhydrazones of 3-benzoyl-1,2,4-oxadiazole containing different nitrogen-substituents at C-5 (3b-d; X = NHMe, NMe2, and NHCOMe) into the relevant triazoles 4b-d have been examined in a wide range of pS+ (0.1-11.9) in 1:1 (v/v) dioxane/water solution. The obtained results have been compared with previous data concerning the (Z)-phenyl-hydrazone of 5-amino-3-benzoyl-1,2,4-oxadiazole (3a; X = NH2). All of the studied (Z)-phenylhydrazones rearrange through three different pathways (specific acid-catalysed, uncatalysed and general base-catalysed). The different effects of the substituents on the course of the rearrangement in the …

Quaternary structures of GroEL and naïve-Hsp60 chaperonins in solution: a combined SAXS-MD study

The quaternary structures of bacterial GroEL and human naïve-Hsp60 chaperonins in physiological conditions have been investigated by an innovative approach based on a combination of synchrotron Small Angle X-ray Scattering (SAXS) in-solution experiments and molecular dynamics (MD) simulations. Low-resolution SAXS experiments over large and highly symmetric oligomers are analyzed on the basis of the high-resolution structure of the asymmetric protein monomers, provided by MD. The results reveal remarkable differences between the solution and the crystallographic structure of GroEL and between the solution structures of GroEL and of its human homologue Hsp60.

Extended Investigation of the Aqueous Self-Assembling Behavior of a Newly Designed Fluorinated Surfactant

The physicochemical behavior of the newly synthesized fluorinated 5-hydroxyamino-3-perfluoroheptyl-1,2,4-oxadiazin-6-one (PFHO) surfactant was investigated. Thermal analysis showed that the pure surfactant is thermally stable under an inert atmosphere to 135 degrees C, which is several degrees higher than the melting point (99 degrees C). PFHO is rather active at the water/air interface where it assumes a standing up configuration. It exhibits an enhanced self-assembling behavior; accordingly, the critical micellar concentrations at some temperatures are 2 orders of magnitude lower than those of a similar surfactant having the same phobicity, such as sodium perfluorooctanoate. Even in the d…

Synthesis of a fluorinated graphene oxide-silica nanohybrid: Improving oxygen affinity

An easy method to achieve a fluorinated graphene oxide–silica nanohybrid (GOSF) is presented. Graphene oxide (GO) was synthesized by Hummer's modified method, the GO–silica nanohybrid (GOS) was obtained via Fischer esterification, the fluorinated moiety (3-pentadecafluoroheptyl-5-perfluorophenyl-1,2,4-oxadiazole) was introduced by nucleophilic substitution operated by the hydroxyl functionalities onto the GOS surface. Full characterization of the new materials confirmed the formation of covalent bonds between the graphene oxide/silica hybrid matrix and the fluorinated moieties. The proposed methodology offers an easy way to get fluorinated carbon/silica hybrid nanomaterials avoiding the har…

A NEW WATER-SOLUBLE FLUORINATED POLYMER BASED ON A POLYASPARTAMIDE AND OXADIAZOLE UNITS AS A POTENTIAL ARTIFICIAL OXYGEN (O2) CARRIER

Concise asymmetric synthesis of Linezolid through catalyzed Henry reaction

A new asymmetric synthesis of the antibiotic Linezolid was performed through a copper-catalyzed Henry reaction as the key step. The use of camphor-derived aminopyridine ligands helped to improve the yields of the chiral precursor and to obtain Linezolid in good overall yield and enantiomeric excess.