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International audience; Tentacle-like polymers decorated with several copies of peptide antigens can be interesting tools to increase the ability to capture circulating antibodies in patient sera, using cooperative effects for stronger avidity. We previously showed that antibodies from multiple sclerosis (MS) patient sera preferentially recognize hyperglucosylated adhesin protein HMW1 of non-typeable Haemophilus influenzae (NTHi) . We selected the C-terminal HMW1(1347-1354) minimal epitope and prepared the diglucosylated analogue Ac-KAN(Glc)VTLN(Glc)TTG-K(N 3 )-NH 2 to graft a 40 kDa dextran scaffold modified with glycidyl-propargyl moieties to perform a copper catalysed alkyne-azide coupling reaction (CuAAC). Quantitative NMR measurements allowed to characterize the peptide loading (19.5%) on the multivalent dextran conjugate. This novel polymeric structure displayed optimal capturing properties of both IgG and, more interestingly, IgM antibodies in MS sera. Specific antibodies from a representative MS serum, were successfully depleted using a sepharose resin bearing the new glucosylated multivalent conjugate, as confirmed by ELISA. These results may offer a promising proof-of-concept for the selective purification of high affinity autoantibodies from sera of patients affected by autoimmune patients, in general, and of specific high affinity antibodies against a minimal glycosylated epitope Asn(Glc) from sera of multiple sclerosis (MS) patients, in particular.

Highly stable gold nanoparticles anchored on propynylcarbamate-functionalized silica (Au/SiO2@Yne) have been efficiently utilized for the heterogeneous hydroamination of phenylacetylene with aniline under different reaction conditions. In order to ascertain the eventual influence of surface silanol groups on the system activity and selectivity tailored modifications of Au/SiO2@Yne catalysts were pursued according to two different strategies, involving respectively functionalization with trimethylethoxysilane (Au/SiO2@Yne-TMS) or post-treatment with triethylamine (Au/SiO2@Yne-NEt3). The prepared materials were analysed by several complementary techniques such as Solid State NMR (SS NMR), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD). A comparison of the resulting catalytic activities with that of the pristine Au/SiO2@Yne revealed a significant improvement for Au/SiO2@Yne-NEt3 in terms of both conversion and selectivity. Recycling and stability studies showed a catalytic activity decrease after the first run, due to the formation of polyphenylacetylene (PPhA) oligomers shielding the active sites. PPhA removal by sonication in acetone fully restored the catalytic activity and empowered the system with a good operational stability, a very crucial issue in view of eventual practical applications.

The use of microflow reactors enabled dramatic improvements in the apparent rates of photochemical reactions. However, scaling-up of photomicroreactors remains a challenge due to the difficulties of distributing light and flow to all units of photomicroreactors. In this work, the mass and photon transfer limitations of an easily scalable micro-structured reactor, an aerosol photoreactor, was studied. In this reactor concept, each droplet works as a microreactor. The nature of aerosol light interaction enables good light distribution to all the droplets. A singlet oxygen mediated photosulfoxidation reaction was utilized as a model reaction to assess the reactor performance. The light transfer limitations were proven to be overcome in the aerosol photoreactor. The reaction rate constant was calculated as 0.12 s−1. A simple solution of the convection–diffusion equation for a droplet was presented to check for the mass transfer limitations in aerosol reactors. The Sauter mean diameters of the droplets at different pressures varied between 7 and 8 µm. The aerosol photoreactor was proven to overcome the mass transfer limitations at these droplet diameters. In addition, the highest volumetric mass transfer coefficient (kLa) was calculated as 1.2 s−1, which was at the same order of magnitude compared to other intensified photoreactors such as Corning Advanced Flow ReactorsTM or a gas–liquid microreactor. A discussion on increasing the throughput of aerosol photoreactors further is presented. This work paves the way for efficient and scalable photoreactors for industrial use.

We report the structural dependency of long range scalar J-coupling constant across four bonds as function of the dihedral angles Φ1 and Φ3. The calculated homonuclear coupling constants 4 J(H,H ), obtained at a density functional theory level, were measured between C(1)─X(2) and X(2)─C(3) bonds in three-term models, where C, N, O, and S were systematically used as the second atom of the alkyl structures (1-4). The 4 J(H,H) calculated values, tabulated for variation of 30° for both Φ1 and Φ3, have disclosed an unexpected detectable coupling constant (4 J(H,H ) ≥ 1 Hz) across heteroatoms, useful to provide valuable structural information. A 2-methyl-1,3-dithiane sulfide (5) was used as a case study to prove the applicability and reliability of the calculated values to real issues. The 4 J(H,H ) values obtained at density functional theory for the system 4 have reproduced with good accuracy an unexpected experimental 4 J(H2ax-H4ax ) = 1.01 Hz of sulfide molecule (5), suggesting these calculated coupling constant values as a new powerful tool for the organic synthesis and stereochemical analysis.

Docosahexaenoic acid (DHA) is a semiessential polyunsaturated fatty acid (PUFA) for eukaryotic cells that is found in natural sources such as fish and algal oils and widely used as an ingredient for omega-3 containing foods or supplements. DHA effects are connected to its natural structure with six cis double bonds, but geometrical monotrans isomers can be formed during distillation or deodorization processes, as an unwanted event that alters molecular characteristics and annihilates health benefits. The characterization of the six monotrans DHA regioisomers is an open issue to address for analytical, biological, and nutraceutical applications. Here we report the preparation, separation, and first identification of each isomer by a dual approach consisting of the following: (i) the direct thiyl radical-catalyzed isomerization of cis-DHA methyl ester and (ii) the two-step synthesis from cis-DHA methyl ester via monoepoxides as intermediates, which are separated and identified by nuclear magnetic resonance spectroscopy, followed by elimination for the unequivocal assignment of the double bond position. This monotrans DHA isomer library with NMR and GC analytical characterization was also used to examine the products of thiyl-radical-catalyzed isomerization of a fish oil sample and to evaluate the trans isomer content in omega-3 containing supplements commercially available in Italy and Spain.

Gold nanoparticles (AuNPs) were anchored on alkynyl carbamate-functionalized support materials having the suitable features for application as catalysts in continuous-flow packed bed reactors. The functionalization step was carried out by grafting with the difunctional organosilane [3-(2-propynylcarbamate)propyl]triethoxysilane (PPTEOS) three commercial micrometer-sized oxide supports, i.e. silica, alumina, and titania. The alkynyl-carbamate moieties were capable of straightforwardly reducing the gold precursor HAuCl4 yielding the supported AuNPs systems Au/SiO2@Yne, Au/Al2O3@Yne, and Au/ TiO2@Yne. A comparison among the three materials revealed that silica allowed the highest organic functionalization (12 wt %) as well as the highest gold loading (3.7 wt %). Moreover, a TEM investigation showed only for Au/SiO2@Yne the presence of homogeneously distributed spherically shaped AuNPs (average diameter 15 nm). Au/ SiO2@Yne is an efficient catalyst, both in batch and flow conditions, in the oxidation of a large variety of alcohols using H2O2 as the oxidizing agent at a temperature of 90 °C. Furthermore, under flow conditions, the catalyst worked for over 50 h without any significant decrease in the catalytic activity. The catalytic activity of the three catalysts was evaluated and compared in the oxidation of 1-phenylethanol as a model substrate. We found that the flow approach plays a strategic role in preserving the physical and chemical integrity of the solid catalysts during its use, with remarkable consequences for the reaction conversion (from 2% in batch to 80% in flow) in the case of Au/TiO2@Yne.

An efficient enantioselective aryloxylation of cyclic β-keto esters with a selection of substituted o-quinones catalyzed by a bifunctional cinchona alkaloid derivative, giving entry to tricyclic dioxin adducts with high enantio- and diastereoselectivity, is described. © Georg Thieme Verlag Stuttgart - New York.