Why are reactions of 2‐ and 8‐thioquinoline derivatives with iodine different?

The crystal structures of 1,2‐dihydro‐1,1′‐bi[thiazolo[3,2‐a]quinoline]‐10a,10a′‐diium diiodide hemihydrate, C₂₂H₁₆N₂S₂²⁺·2I⁻·0.5H₂O, and 1,2‐dihydro‐1,1′‐bi[thiazolo[3,2‐a]quinoline]‐10a,10a′‐diium iodide triiodide, C₂₂H₁₆N₂S₂²⁺·I⁻·I₃⁻, obtained during the reaction of 1,4‐bis(quinolin‐2‐ylsulfanyl)but‐2‐yne (2TQB) with iodine, have been determined at 120 K. The crystalline products contain the dication as a result of the reaction proceeding along the iodocyclization pathway. This is fundamentally different from the previously observed reaction of 1,4‐bis(quinolin‐8‐ylsulfanyl)but‐2‐yne (8TQB) with iodine under similar conditions. A comparative analysis of the possible conformational states indicates differences in the relative stabilities and free rotation for the 2‐ and 8‐thioquinoline derivatives which lead to a disparity in the convergence of the potential reaction centres for 2TQB and 8TQB.     

A facile synthesis of per (poly )fluoroalkyl substituted α-amino acid derivatives

Initiated by CrCl3/Fe redox couple, per(poly)fluoroalkyl iodides added to methyl a-acetylamino acrylate, giving B-per(poly)fluoroalkyl a-amino acid derivatives in good yields.     

Untersuchungen im System LaI2/H2: Phasenverhältnisse und Fehlordnung

Investigation of the LaI₂/H₂ System: Phase Relations and Stacking Disorder Heating of LaI₂ under 1 bar hydrogen pressure to 650 °C leads to light gray LaI₂H_0.95(3), accompanied by a structural change from tetragonal to hexagonal. Sharp reflections in the XRD pattern can be indexed in P6₃/mmc with a = 4.2158(7)Å and c = 15.508(3)Å, however, diffuse reflections indicate the presence of stacking faults in the structure, which correspond to a polytypic intergrowth of MoS₂ and NbS₂ type structural fragments. Increasing the reaction temperature to 730 °C results in a better defined diffraction pattern with the peak positions close to those of the 2H‐NbS₂ structure type. An X‐ray powder study of the samples LaI₂H_n proved the miscibility gap between LaI₂ and LaI₂H_n (0 ≤ n ≤ 0.5) in agreement with previous results. With decreasing H‐content of the homogeneous phase the lattice parameters change in opposite direction, a increasing to 4.236(1)Å and c decreasing to 15.39(2)Å for the lower limit.     

Copper-and Silver-Mediated Cyanation of Aryl Iodides Using DDQ as Cyanide Source

A new copper and silver‐mediated cyanation of aryl iodides with DDQ as a cyanide source is achieved, providing nitriles with good yields. This new approach represents a safe method leading to aryl nitriles.     

Silica Chloride (SiO2-Cl), a New Heterogeneous Reagent,for the Selective and Efficient Conversion of Benzylic Alcohols to Their Corresponding Chlorides and Iodides

Abstract

Structurally different benzylic alcohols were efficiently converted to their corresponding chlorides by silica chloride (SiO₂-Cl) in CHCl₃ at room temperature. Silica chloride is also able to convert benzylic alcohols to their iodides in the presence of NaI in a mixture of CH₃CN/CHCl₃ in excellent yields.     

An efficient copper-catalyzed N-arylation of amides: synthesis of N-arylacrylamides and 4-amido-N-phenylbenzamides

Copper-catalyzed intermolecular C–N bond-forming reactions between aryl iodides and amides are described using sodium ascorbate, which is both cheap and nontoxic, as the additive. A variety of functionalized amides including some practical, unique secondary amides, such as N-arylacrylamides and 4-amido-N-phenylbenzamides, which are difficult to obtain by the classical methods, are prepared. Furthermore, some tertiary amides are prepared by using copper thiophenecarboxylate.     

Palladium-catalyzed hydrodehalogenation of aryl halides using paraformaldehyde as the hydride source: high-throughput screening by paper-based colorimetric iodide sensor

Paraformaldehyde was employed as a hydride source in the palladium-catalyzed hydrodehalogenation of aryl iodides and bromides. High throughput screening using a paper-based colorimetric iodide sensor (PBCIS) showed that Pd(OAc)₂ and Cs₂CO₃ were the best catalyst and base, respectively. Aryl iodides and bromides were hydrodehalogenated to produce the reduced arenes using Pd(OAc)₂ and Pd(PPh₃)₄ catalyst. This catalytic system showed good functional group tolerance. In addition, it was found that paraformaldehyde is the hydride source and the reducing agent for the formation of palladium nanoparticles.     

Conductance studies of some ammonium and alkali metal salts in propylene carbonate

Conductance data are reported for NaI, KI, RbI, CsI, NH₄I, NaClO₄, and KClO₄ in propylene carbonate at 25°C in the concentration range 1×10^–4 –8.3×10^–3M. Analysis of the data with the current conductance theories indicates negligible ion-association, strong cation-solvent and weak anion-solvent interactions.     

Studies on ABX6 Compounds. V. Thermodynamics and kinetics of the high pressure transformations on ABX6 compounds (A = Ca,Dy, Ge,Sn, Pb; B = Th,U; X = I)

The results of high pressure experiments with ternary iodides of the general formula ABI₆ with A = Ca, Dy, Ge, Sn, Pb and B = Th, U are described. These compounds transform from a β- to a γ-SnThI₆-type structure, both variants of known trihalide structures (BiI₃- and PuBr₃-type). Trends and pecularities in the values for the minimal transformation pressures and in the velocities of transition are pointed out, and they are discussed in terms of geometric and electronic factors.     

Reductive mono- and diallylation of the bis(pyridine)dihydropyridyllithium dimer by triallylborane

Reductive allylation of the bis(pyridine)dihydropyridyllithium dimer containing the 1,2- and 1,4-dihydropyridine fragments by triallylborane results mainly in trans- and cis-2,6-diallylpiperidines (60—85%), their ratio depending on the nature of the solvent. The minor reactions products are 2-allyl-1,2,3,6-tetrahydropyridine and 4,10-diallyl-3,9-diazatricyclo[6.2.2.0^2,7]dodecane. The unexpected formation of the latter is due to hetero-Diels—Alder condensation of intermediate products formed in the allylboration of dihydropyridines. The stereochemistry of trans- and cis-2,6-diallylpiperidines was determined from the ¹H and ¹³C NMR spectra of the respective N,N-dimethylpiperidinium iodides. The structure of 4,10-diallyl-3,9-diazatricyclo[6.2.2.0^2,7]dodecane dipicrate was established by X-ray diffraction analysis.