Search results for "Dioxolane"

Nucleophilic benzoylation using a mandelic acid dioxolanone as a synthetic equivalent of the benzoyl carbanion. Oxidative decarboxylation of α-hydrox…

2004

The synthesis of alkyl aryl ketones using a mandelic acid dioxolanone as a synthetic equivalent (Umpolung) of the benzoyl carbanion is reported. The methodology involves alkylation of the mandelic acid dioxolanone, hydrolysis of the dioxolanone moiety in the alkylated products and oxidative decarboxylation of the resulting alpha-hydroxyacids. The last step is carried out in a catalytic aerobic way using a Co (III) complex in the presence of pivalaldehyde under very mild conditions.

1974

The temperature dependences of the absolute small angle X-ray scattering powers and of the unit cell spacings of a series of 1,3,5-trioxane—1,3-dioxolane copolymers were measured. From a comparison of these data and of the specific volume values measured by Wilski it is concluded that values of crystallinity calculated in a conventional manner provide meaningful parameters when discussing the microstructure of these materials. The measurements were made on annealed samples. At temperatures below the original annealing temperatures changes in small angle scattering power, long periods and crystallinities of the samples were observed. These changes were reversible with temperature and were to…

Identification of highly effective antitrypanosomal compounds in essential oils from the Apiaceae family

2018

The Apiaceae family encompasses aromatic plants of economic importance employed in foodstuffs, beverages, perfumery, pharmaceuticals and cosmetics. Apiaceae are rich sources of essential oils because of the wealth of secretory structures (ducts and vittae) they are endowed with. The Apiaceae essential oils are available on an industrial level because of the wide cultivation and disposability of the bulky material from which they are extracted as well as their relatively cheap price. In the fight against protozoal infections, essential oils may represent new therapeutic options. In the present work, we focused on a panel of nine Apiaceae species (Siler montamon, Sison amomum, Echinophora spi…

5′-Benzylidene-1′′-methyl-4′′-phenyltrispiro[1,3-dioxolane-2,1′-cyclohexane-3′,3′′-pyrrolidine-2′′,3′′′-indole]-4′,2′′′-dione

2017

In the title compound, C32H30N2O4, two spiro links connect the methyl-substituted pyrrolidine ring to the oxindole and cyclohexanone rings. The cyclohexanone ring is further connected to the dioxalane ring by a third spiro junction. Both the pyrrolidine and dioxalane rings adopt a twist conformation. The indole ring is nearly planar, with a maximum deviation of 0.0296 (7) Å, and the cyclohexanone ring adopts a distorted boat conformation. In the crystal, C—H...O and N—H...N hydrogen-bonding interactions connect molecules into chains running parallel to thebaxis, which are further linked into layers parallel to theabplane by C—H...O hydrogen bonds.

An experimental and kinetic modeling study on the oxidation of 1,3-dioxolane

2021

International audience; The modern catalytic or enzymatic advances allow the production of novel biofuel. Among them, 1,3dioxolane can be produced from formaldehyde and ethylene glycol, both can be obtained from biomass. In this study, the oxidation of 1,3-dioxolane is studied at stoichiometric conditions. The ignition delay times of 1,3-dioxolane/O 2 /inert mixtures were measured in a shock tube and in a rapid compression machine at pressures of 20 to 40 bar and temperatures ranging from 630 to 1300 K. The pressure profiles recorded in the rapid compression machine show a first stage of ignition enlightening the influence of the low temperature chemistry of combustion. Furthermore, mole fr…

Activation of metabotropic glutamate receptors induces propagating network oscillations in the intact cerebral cortex of the newborn mouse.

2006

Activation of metabotropic glutamate receptors (mGluRs) with (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid (ACPD) elicited in the frontal or occipital pole of the intact cerebral cortex preparation of the newborn mouse (P0-P3) a transient oscillatory field potential activity in the frequency range of 11-14Hz. These oscillations propagated over the whole cortical hemisphere and were blocked by tetrodotoxin, indicating that action potentials are required for the generation of this activity. Blockade of GABA-A receptors with gabazine did not influence the ACPD-induced network activity, but the glycine antagonist strychnine caused a significant decrease in the frequency, amplitude and durat…

Phenguignardic acid and guignardic acid, phytotoxic secondary metabolites from Guignardia bidwellii.

2012

Bioactivity-guided isolation led to the identification of phenguignardic acid (2), a new phytotoxic secondary metabolite from submerged cultures of grape black rot fungus, Guignardia bidwellii. The compound is structurally related to guignardic acid (1), a dioxolanone moiety-containing metabolite isolated previously from Guignardia species. However, in contrast to guignardic acid, which is presumably synthesized from deamination products of valine and phenylalanine, the biochemical precursor for the biosynthesis of the new phytotoxin appears to be exclusively phenylalanine. Guignardic acid was also found in extracts of cultures from Guignardia bidwellii. The phytotoxic activities of both co…

Theoretical prediction of structural, vibrational and NMR parameters of plastic optical fiber (POF) material precursors. Cis and trans perhydro- and …

2014

Abstract Density functional theory (DFT) prediction of cis and trans perhydro- and perfluoro-2-methylene-4,5-dimethyl-1,3-dioxolanes structure, supported by vibrational analysis and calculation of multinuclear isotropic nuclear magnetic resonance (NMR) shieldings and indirect spin–spin couplings (SSCCs) was performed. The performance of the used methodology was verified on 1,3-dioxolane selected as model compound. The structures of hydrogenated and fluorinated monomers of POF materials were calculated using B3LYP and BLYP density functionals combined with 6-311 ++ G(3df,2pd) basis set. The BLYP/6-311++G(3df,2pd) level of theory was suggested for vibrational analysis. Gauge independent atomi…

Phytotoxic dioxolanone-type secondary metabolites from Guignardia bidwellii.

2012

Phenguignardic acid was recently described as a phytotoxic secondary metabolite from submerged cultures of the grape black rot fungus Guignardia bidwellii. Since the production rate of this natural product in submerged culture is very low, fermentation optimisation was carried out. The optimisation of cultivation conditions led to the identification of seven secondary metabolites, structurally related to guignardic acid, a known secondary metabolite from Guignardia species containing a dioxolanone moiety. All metabolites presented here have not been described to date and are presumably biosynthesised via deamination products of amino acids, such as phenylalanine, valine, tyrosine, and alani…

Functionalization of Active Ester-Based Polymersomes for Enhanced Cell Uptake and Stimuli-Responsive Cargo Release

2016

Poly(2,3-dihydroxypropyl methacrylamide) (P(DHPMA))-based amphiphilic block copolymers have recently proven to form polymer vesicles (polymersomes). In this work, we further expand their potential by incorporating (i) units for pH-dependent disintegration into the hydrophobic membrane and (ii) mannose as targeting unit into the hydrophilic block. This last step relies on the use of an active ester prepolymer. We confirm the stability of the polymersomes against detergents like Triton X-100 and their low cytotoxicity. The incorporation of 2-(2,2-dimethyl-1,3-dioxolane-4-yl)ethyl methacrylate into the hydrophobic block (lauryl methacrylate) allows a pH-responsive disintegration for cargo rele…