Iodine(III)‐Catalyzed Rearrangements of Imides: A Versatile Route to α,α‐Dialkylated α‐Hydroxy Carboxylamides

A tertiary hydroxy group α to a carboxyl moiety comprises a key structural motif in many bioactive substances. With the herein presented metal‐free rearrangement of imides triggered by hypervalent λ³‐iodane, an easy and selective way to gain access to such a compound class, namely α,α‐disubstituted‐α‐hydroxy carboxylamides, was established. Their additional methylene bromide side chain constitutes a useful handle for rapid diversification, as demonstrated by a series of further functionalizations. Moreover, the in situ formation of an iodine(III) species under the reaction conditions was proven. Our findings clearly corroborate that hypervalent λ³‐benziodoxolones are involved in these organocatalytic reactions.     

Synthesis and Characterization of 5‐Cyanotetrazolide‐Based Ionic Liquids

New salts based on imidazolium, pyrrolidinium, phosphonium, guanidinium, and ammonium cations together with the 5‐cyanotetrazolide anion [C₂N₅]^? are reported. Depending on the nature of cation–anion interactions, characterized by XRD, the ionic liquids (ILs) have a low viscosity and are liquid at room temperature or have higher melting temperatures. Thermogravimetric analysis, cyclic voltammetry, viscosimetry, and impedance spectroscopy display a thermal stability up to 230 °C, an electrochemical window of 4.5 V, a viscosity of 25 mPa s at 20 °C, and an ionic conductivity of 5.4 mS cm^?1 at 20 °C for the IL 1‐butyl‐1‐methylpyrrolidinium 5‐cyanotetrazolide [BMPyr][C₂N₅]. On the basis of these results, the synthesized compounds are promising electrolytes for lithium‐ion batteries.     

Setting local rank constraints by orthogonal projections for image resolution analysis: Application to the determination of a low dose pharmaceutical compound

Raman chemical imaging provides chemical and spatial information about pharmaceutical drug product. By using resolution methods on acquired spectra, the objective is to calculate pure spectra and distribution maps of image compounds. With multivariate curve resolution-alternating least squares, constraints are used to improve the performance of the resolution and to decrease the ambiguity linked to the final solution. Non negativity and spatial local rank constraints have been identified as the most powerful constraints to be used.