Palladium-catalyzed carboxamidation reaction and aldol condensation reaction cascade: a facile approach to ring-fused isoquinolinones

Palladium-catalyzed carboxamidation reaction and aldol condensation reaction cascade are very useful for the synthesis of various ABC ring substituted fused isoquinolinones.     

Sequence of intramolecular carbonylation and asymmetric hydrogenation reactions: highly regio- and enantioselective synthesis of medium ring tricyclic lactams

The intramolecular cyclocarbonylation reaction with palladium-complexed dendrimers on silica is a very effective method for the regioselective synthesis of methylene 8-, 9-, and 10-membered rings. The heterogeneous dendritic catalysts are easily recovered by simple filtration and reused for up to 10 cycles with only a slight loss of activity. Asymmetric hydrogenation of the resulting unsaturated heterocycles affords optically active tricyclic lactams in excellent yields and in high enantiomeric excess. This process can tolerate a wide array of functional groups, including halide, ether, nitrile, ketone, and ester. Moreover, the variation of heteroatom on the rings does not have any influence on the efficiency and enantioselectivity of the reaction.     

Stereoselective hydroxycarbonylation of vinyl bromides to alpha,beta-unsaturated carboxylic acids in the ionic liquid [BMIM]PF6

(E/Z)-isomers containing vinyl bromides were stereoselectively carbonylated to the corresponding (E)-alpha,beta-ethylenic carboxylic acids in the ionic liquid [BMIM]PF6. Vinyl dibromides also underwent hydroxycarbonylation to give monoacids. The products are pure by proton NMR spectroscopic determination without purification by silica gel column chromatography or recrystallization.     

Electric-field induced strain in biological tissues

This paper reports a new effect whereby a physiological-level direct-current electrical field (at 1.4 V/cm) can induce time-varying mechanical strain in various types of biological tissues and gel phantoms. This effect cannot be explained by the piezoelectric effect, tissue contraction, temperature changes, and electrorestriction. The induced strain in tissues was analyzed by processing ultrasound echo signals. The sample expanded perpendicularly to the applied electric field. The expansion rate depended on the history of the applied electric field. The speed of sound changed little compared with the expansion. The new effect might be related to electrokinetic effects.     

Numerical solutions of the Gardner equation by extended form of the cubic B-splines

The extended definition of the polynomial B-splines may give a chance to improve the results obtained by the classical cubic polynomial B-splines. The optimum value of the extension parameter can be determined by scanning some intervals containing zero. This study aims to solve some initial boundary value problems constructed for the Gardner equation by the extended cubic B-spline collocation method. The test problems are derived from some analytical studies to validate the efficiency and accuracy of the suggested method. The conservation laws are also determined to observe whether the test problems remain constant as expected from the theoretical aspect. The stability of the proposed method is investigated by the von Neumann analysis.     

Hydrogen Bonded Supramolecular Network from a Mixed Valence Cobalt System: Synthesis and Crystal Structure of [Co(H2O)6][Co(pydc)2(en)]2·14H2O

Abstract  

The [Co(H₂O)₆][Co(pydc)₂(en)]₂·14H₂O (1) compound (H₂pydc = Pyridine-2,3-dicarboxylic acid and en = ethylenediamine) was synthesized and characterized by elemental analysis, magnetic and spectroscopic measurements (UV–Vis and IR spectra) and single crystal X-ray diffraction technique. There are two coordination spheres with different charges inside this aqueous compound of ionic character. The cationic part is composed of Co(II) encircled by six aqua ligand. Whereas the anionic part contains two anions complex unit each with −1 charge and have Co(III) ions in the centre. As a result different coordination spheres have cobalt ions with different states. The crystallographic analysis revealed that 1 consists of both discrete one-cationic and two-anionic entities, [Co(H₂O)₆]²⁺ and [Co(pydc)₂(en)]₂⁻ and fourteen crystal water molecules. Two water molecules within the water cluster act as hydrogen-bonding acceptors, whereas one water molecule acts as a hydrogen-bonding donor to form a discrete water trimer. These water molecules have stabilized the crystal structure by strong hydrogen bonding interactions.     

A simple synthesis of thioketonemolybdenum carbonyl complexes. An example of geometric isomerism

Thioketones react with molybdenum hexacarbonyl in tetrahydrofuran (60–65°C, 2–3 h) to give molybdenum pentacarbonyl complexes in 52–80% yield. Geometric isomers were isolated in the case of thiocamphor.     

Style goods pricing with demand learning

For many industries (e.g., apparel retailing) managing demand through price adjustments is often the only tool left to companies once the replenishment decisions are made. A significant amount of uncertainty about the magnitude and price sensitivity of demand can be resolved using the early sales information. In this study, a Bayesian model is developed to summarize sales information and pricing history in an efficient way. This model is incorporated into a periodic pricing model to optimize revenues for a given stock of items over a finite horizon. A computational study is carried out in order to find out the circumstances under which learning is most beneficial. The model is extended to allow for replenishments within the season, in order to understand global sourcing decisions made by apparel retailers. Some of the findings are empirically validated using data from U.S. apparel industry.     

Rhodium(I) catalyzed carbonylation reactions of halides and ethers

Benzylic bromides and methyl iodide react with ethers, carbon monoxide, potassium iodide, and the dimer of chloro(1,5-hexadiene)rhodium($\text{I}$) to give esters in good yields.     

Photoinduced Rearrangement of Dienones and Santonin Rerouted by Amines

The photoinduced rearrangement pathways of simple 2,5‐dienones and the natural product santonin were found to be effectively rerouted by amines, giving rise to unprecedented products. Either cis olefins or cyclobutenes were obtained from 4,4‐disubstituted 2,5‐dienone upon irradiation (365 nm) in the presence of various amines depending on the solvent. Previously undescribed [4.4.0] and [5.3.0] fused‐ring‐containing products were obtained when santonin was irradiated (365 nm) in the presence of methylamine. The amines present in these reactions were incorporated into the products by means of amide‐group formation.