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The transformation of glycals into 2,3-unsaturated glycosyl derivatives, reported by Ferrier in 1962, is supposed to involve an a,b unsaturated glycosyl cation, an elusive ionic species that has still to be observed experimentally. Herein, while combination of TfOH and flow conditions failed to observe this ionic species, its extended lifetime in superacid solutions allowed its characterization by NMR-based structural analysis supported by DFT calculations. This allyloxycarbenium ion was further exploited in the Ferrier rearrangement to afford unsaturated nitrogen-containing C-aryl glycosides and C-alkyl glycosides under superacid and flow conditions, respectively.

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Solketal is derived from the reaction of acetone with glycerol, a by-product product of the biodiesel industry. We report here the continuous reaction of solketal with anilines over a solid acid niobium phosphate (NbP), for the continuous generation of quinolines in the the well-established Skraup reaction. This study shows that NbP can catalyse all stages of this multistep reaction at 250 °C and 10 MPa pressure, with a selectivity for quinoline of up to 60%. We found that the catalyst eventually deactivates, most probably via a combination of coking and reduction processes but neverthless we show the promise of this approach. We demonstarted here the application of our approach to synthesize both mono-and bis-quinolines from the commodity chemical, 4,4'-methylenedianiline.

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No abstract

The transformation of glycals into 2,3-unsaturated glycosyl derivatives, reported by Ferrier in 1962, is supposed to involve an a,b unsaturated glycosyl cation, an elusive ionic species that has still to be observed experimentally. Herein, while combination of TfOH and flow conditions failed to observe this ionic species, its extended lifetime in superacid solutions allowed its characterization by NMR-based structural analysis supported by DFT calculations. This allyloxycarbenium ion was further exploited in the Ferrier rearrangement to afford unsaturated nitrogen-containing C-aryl glycosides and C-alkyl glycosides under superacid and flow conditions, respectively.

Poly(diphenyldithieno[3,2‐b;20,30‐d]thiophene) was synthesized by electropolymerization on Pt quartz crystal and on an indium tin oxide electrode by cyclic voltammetry. Ionic diffusion through the electronic conducting film (for the p‐doping process) was studied by cyclic voltammetry coupled to a quartz crystal microbalance (E‐QCM) and electrochemical impedance spectroscopy (EIS), using different electrolyte salts such as LiTFSI, LiClO4 or LiCF3CO2. The molar ratio of insertion/expulsion of anions and cations was estimated from E‐QCM. By comparison between E‐QCM and EIS, the intrinsic ionic diffusion mechanisms in the electronic conducting film were highlighted depending on the salts used in acetonitrile. Moreover, the different mechanisms are in good agreement with the molar ratio of anion/cation insertion/expulsion. © 2018 Society of Chemical Industry