Synthesis of spiropyrazoline [5.3′] 4′-chromanones

Synthesis of a series of novel 1,3-diphenyl-4-aryl spiropyrazolines [5.3′] 4′-chromanones has been accomplished in good yields by regioselective 1,3-dipolar cycloaddition of diphenylnitrilimine to 3-arylidene-4-chromanones. X-ray crystal structure analysis of one of the products 4a confirms the structure and the regiochemistry of cycloaddition. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:327–332, 1998     

An Expedient Approach for the Synthesis of Bioactive Pyrazole,Isoxazole and Benzodiazepine‐Substituted Quinolin‐2(1H)‐one Derivatives

A sequence of functionalized pyrazole, isoxazole and benzodiazepine‐substituted quinolone derivatives were synthesized in good yield starting from readily available starting precursors. These approaches lead to the synthesis of hitherto unknown compounds with a varied substitution pattern by both conventional and microwave‐assisted method. A good number of analogues were evaluated for their in vitro cytotoxicity against human cervical and colon cancer cell lines by MTT protocol. Almost all the selected compounds showed remarkable cytotoxic activities. Among them, compound 4g and 4i emerged as the most promising scaffolds. These scaffolds will be used for further molecular level studies.     

Transformation of Metallic Ti to TiH2 Phase in the Ti/MgH2 Composite and Its Influence on the Hydrogen Storage Behavior of MgH2

The current work explores the in-situ formation of TiH₂ additive in a Ti/MgH₂ nanocomposite system. Mild mechanical milling leaves Ti chemically unchanged, while formation of stable TiH_2–x occurs upon strong mechanical milling. TiH_2–x further transforms to TiH₂ upon recycling the powder (dehydrogenation and subsequent hydrogenation) and lowers the activation energy of MgH₂ to 89.4 kJ (mol H₂)⁻¹ [E_a of as-received MgH₂ is 153 kJ (mol H₂)⁻¹]. This work also reiterates that metallic Ti additive mixed MgH₂ requires strong mechanical milling for better H₂ ab/de-sorption performance. The current observations support the view that lattice strain may be an important factor in the catalysis of additives incorporated MgH₂ hydrogen storage systems.     

Effects of material strain on triboelectric charging: Influence of material properties

We address electrostatic charging of unstrained and strained latex rubber sheets contacted with a series of materials: polytetrafluoroethylene (PTFE), polyurethane (PU) and stainless steel (SS). For PTFE, strain causes a reversal in the direction of charge transfer. For PU, the direction of charge transfer is reversed after repeated contacts due to material transfer, and strain increases the number of contacts needed for this reversal. For SS, strain reduces the frequency of electrical discharges occurring. These effects may be explained by strain either changing material properties relevant to triboelectric charging, or changing the nature of contact between the surfaces.     

Catalysis of Ethanol Decomposition over Rare Earth Oxide Supported Vanadia

Supported vanadia systems synthesized by the excess solvent technique were characterized by different analytical methods. The selective oxidation activity of the system was examined towards the decomposition of ethanol.     

Surface properties and catalytic activity of sulfated rutile

The present work reports an investigation of physico-chemical properties and catalytic activity of the pure, sulfated and iron containing sulfated rutile. The catalysts were characterized by X-ray Diffraction, FT-IR, BET surface area, TG and NH₃-TPD measurements. The catalytic activity of the prepared catalysts towards liquid phase Friedel-Crafts alkylation of toluene with benzyl chloride was tested. This revised version was published online in June 2006 with corrections to the Cover Date.     

NiO-Al2O3 Prepared From A Ni-Al Hydrotalcite Precursor As An Efficient Catalyst For Transfer Hydrogenation Reactions

NiO-Al₂O₃ catalyst prepared by calcining a Ni-Al hydrotalcite precursor efficiently reduces nitroarenes and carbonyl compounds in presence of propan-2-ol and KOH. Presence of two different reducible groups in the substrate leads to chemoselective reduction.