A Facile and Efficient Synthesis of bis(Imidazo[1,2-a]pyridin-3-yl)methane and vinyl derivatives

An efficient synthetic route for the novel bis-imdizo[1,2-a]pyridine-3-yl)methane (2a-k) derivatives have been developed using acetic acid and two drops of trifluoroacetic acid at 40-45oC, resulting in 60-72% yields. An attempt to synthesize bis(Imidazo[1,2-a]pyridin-3-yl)methyl chloride derivatives by the reaction between two moles of imidazo[1,2-a]pyridine, one mole of chloroacetaldehyde in acetic acid, and two drops of trifluoroacetic acid was not successful, instead underwent dehydrohalogenation to yield vinyl derivatives (4a-d).

NiNPs@rGO Nanocomposites as Heterogenous Catalysts for Thiocarboxylation Cross-Coupling Reactions

A new type of ligand-free Ni-nanoparticles supported on rGO (size distribution average d = 9 ± 3 nm) is prepared and fully characterized via morphological (Fe-SEM), structural (P-XRD, HR-TEM) and spectroscopic (ICP-EOS, XPS) analysis tools. The metal composite was effectively employed in the unprecedented heterogeneously Ni-assisted cross-coupling reaction of aryl/vinyl iodides and thiocarboxylates. A range of sulphur-containing aryl as well as vinyl derivatives (15 examples) was achieved in high yields (up to 82%), mild reaction conditions and wide functional group tolerance.

Sustainable Hydrogenation of Vinyl Derivatives Using Pd/C Catalysts

The hydrogenation of unsaturated double bonds with molecular hydrogen is an efficient atom-economic approach to the production of a wide range of fine chemicals. In contrast to a number of reducing reagents typically involved in organic synthesis, hydrogenation with H2 is much more sustainable since it does not produce wastes (i.e., reducing reagent residues). However, its full sustainable potential may be achieved only in the case of easily separable catalysts and high reaction selectivity. In this work, various Pd/C catalysts were used for the liquid-phase hydrogenation of O-, S-, and N-vinyl derivatives with molecular hydrogen under mild reaction conditions (room temperature, pressure of 1 MPa). Complete conversion and high hydrogenation selectivity (>99%) were achieved by adjusting the type of Pd/C catalyst. Thus, the proposed procedure can be used as a sustainable method for vinyl group transformation by hydrogenation reactions. The discovery of the stability of active vinyl functional groups conjugated with heteroatoms (O, S, and N) under hydrogenation conditions over Pd/C catalysts opens the way for many useful transformations.

EMI Series Ruthenium-catalysed oxidative coupling of vinyl derivatives and application in tandem hydrogenation

The first ruthenium-catalyzed oxidative homo- and cross-coupling of exclusive vinyl derivatives giving highly valued 1,3-diene building blocks is reported. The catalytic system is based on readily available reagents and it...

Efficient labeling of organic molecules using 13C elemental carbon: universal access to 13C2-labeled synthetic building blocks, polymers and pharmaceuticals

Synthetic methodology enabled by 13C-elemental carbon is reported. Calcium carbide Ca13C2 was applied to introduce a universal 13C2 unit in the synthesis of labeled alkynes, O,S,N-vinyl derivatives, labeled polymers and 13C2-pyridazine drug core.

Synthesis of 1-(methylsulfonyl)-1-propene and N,N-dimethyl-1-propene-1-sulfonamide

Various vinylsulfones and vinylsulfonamides have a wide range of biological activities (mainly, inhibition of different types of enzymes) and are frequently used in synthetic organic chemistry (as active dienophiles, Michael acceptors and, generally, active agents in 1,4‑addition and electrocyclization reactions). However, despite numerous synthesized substances of this type, the synthetic protocols for the obtaining of the low molecular weight representatives of these compounds – 1‑(methylsulfonyl)-1-propene and N,N‑dimethyl-1‑propene-1-sulfonamide – seem to be still little known. In the present work we report a simple, efficient and general protocol for the dehydrative synthesis of 1‑(methylsulfonyl)-1‑propene and N,N‑dimethyl-1‑propene-1‑sulfonamide starting from corresponding 1-(methylsulfonyl)-2-propanol and N,N‑dimethyl-2‑hydroxypropanesulfonamide, respectively, using MeSO2Cl/organic base system basing on the preliminary experiment of 2‑(4‑bromophenyl)-N,N‑dimethylethenesulfonamide synthesis from 2‑(4‑bromophenyl)-2‑hydroxy-N,N-dimethylethanesulfonamide. The latter in its turn has been obtained starting from N,N‑dimethylmethanesulfonamide by lithiation with n-BuLi, subsequent action of 4‑bromobenzaldehyde and further workup. The applied protocol of vinyl derivatives synthesis allows to avoid isolation of intermediate mesyl derivatives, consisting of one-pot formation of leaving group and its elimination. Accordingly to coupling constants in 1H NMR spectra, synthesized N,N‑dimethyl-1-propene-1‑sulfonamide exists as mixture of E- and Z-isomers (in the ratio 88:12), while isolated 1‑(methylsulfonyl)-1‑propene and 2-(4-bromophenyl)-N,N‑dimethylethenesulfonamide are the most stable E‑isomers. The structures of the synthesized compounds are confirmed by the methods of 1H NMR-spectroscopy and mass-spectrometry.

A Review on Styrene Substitutes in Thermosets and Their Composites

In recent decades, tremendous interest and technological development have been poured into thermosets and their composites. The thermosets and composites with unsaturated double bonds curing system are especially concerned due to their versatility. To further exploit such resins, reactive diluents (RDs) with unsaturated sites are usually incorporated to improve their processability and mechanical properties. Traditional RD, styrene, is a toxic volatile organic compound and one of the anticipated carcinogens warned by the National Institute of Health, USA. Most efforts have been conducted on reducing the usage of styrene in the production of thermosets and their composites, while very few works have systematically summarized these literatures. Herein, recent developments regarding styrene substitutes in thermosets and their composites are reviewed. Potential styrene alternatives, such as vinyl derivatives of benzene and (methyl)acrylates are discussed in details. Emphasis is focused on the strategies on developing novel RD monomers through grafting unsaturated functional groups on renewable feedstocks such as carbohydrates, lignin, and fatty acids. This review also highlights the development and characteristics of RD monomers and their influence on processability and mechanical performance of the resulting thermosets and composites.