An efficient and convenient approach for the synthesis of novel 2‐hydroxy‐12‐aryl‐8,9,10,12‐tetrahydrobenzo[a]xanthene‐11‐ones using p‐toluenesulfonic acid in ethanol and ionic liquid

A novel series of 2‐hydroxy‐12‐aryl‐8,9,10,12‐tetrahydrobenzo[a]xanthene‐11‐ones were synthesized by the one‐pot multicomponent condensation of 2,7‐dihydroxynaphthalene, aromatic aldehydes, and cyclic 1,3‐dicarbonyl compounds in the presence of a catalytic amount of p‐toluenesulfonic acid in ethanol and in ionic liquid butyl methyl imidazolium tetrafluroborate ([bmim]BF₄). The newly developed protocol is operationally convenient, widely applicable, and gives excellent yields of the diversely substituted title compounds in high purity by easy workup. J. Heterocyclic Chem., (2011).     

Identification of selective oxidation of TiC/SiC composite with X-ray diffraction and Raman spectroscopy

Open cell 3D titanium carbide/silicon carbide (TiC/SiC) composite was oxidised to titanium oxide/silicon carbide (TiO₂/SiC) following different temperature profiles in a thermal gravimetric analysis (TGA) instrument in continuous air-flow and static air (oven) environments. The TiC oxidation to anatase, starting at temperatures over 450°C, was confirmed by Raman spectroscopy and X-Ray diffraction (XRD). By increasing the temperature, the mass fraction of anatase diminished, while the mass fraction of rutile increased. SiC oxidation started at 650°C when a mixture of TiO₂/SiO₂/SiC could be observed by Raman, XRD and HRTEM.     

One‐pot four component condensation for the synthesis of novel dispirooxindole pyrrolidine linked 1,2,3‐triazoles via stereo‐ and regioselective [3 + 2] cycloaddition reaction in PEG‐400

A one‐pot four component condensation of isatin, sarcosine, 2‐[2‐oxo‐1‐(prop‐2‐ynyl)indolin‐3‐ylidene]malononitrile and aryl azides has been reported for the synthesis of novel dispirooxindole pyrrolidine linked 1,2,3‐triazole conjugates using Cu(I) as a catalyst in PEG‐400 by stereoselective [3 + 2] azide‐alkyne cycloaddition followed by [3 + 2] azomethine ylide and alkene cycloaddition. Structures have been confirmed by spectral and X‐ray studies. Crystal packing of 5a has also been reported. Rapid reaction, easy work‐up and high yields are the salient features of the present protocol.