Abstract
W-doped ZnO nanocomposite was easily prepared by sol–gel method. The sample was characterized using a variety of techniques including X-ray diffraction, scanning electron microscopy, transmission electron microscopy, inductively coupled plasma and BET surface area measurement. This reagent can be used as an efficient and heterogeneous catalyst for the preparation of 1, 8-dioxo-octahydroxanthenes from aldehydes in ethanol under mild conditions. The structures of the products were characterized by their physical constants, comparison with authentic samples and IR, 1H NMR and 13C NMR spectroscopy. Easy preparation of the catalyst, mild reaction conditions, easy workup procedure, excellent yields and short reaction times are some advantages of this work. In addition, in this article and for the first time the preparation of 1, 8-dioxo-octahydroxanthenes from the protected derivatives of aldehydes including oximes, semicarbazones and 1,1-diacetates is reported.
Highlights
Xanthenes and their derivatives have received special attention due to their diverse array of biological activities such as anti-inflammatory, antibacterial and antiviral activities [1,2,3]
The sample was characterized using a variety of techniques including X-ray diffraction, scanning electron microscopy, transmission electron microscopy, inductively coupled plasma and BET surface area measurement
Easy preparation of the catalyst, mild reaction conditions, easy workup procedure, excellent yields and short reaction times are some advantages of this work
Summary
Xanthenes and their derivatives have received special attention due to their diverse array of biological activities such as anti-inflammatory, antibacterial and antiviral activities [1,2,3] These compounds can be used as leuco dyes [4], in laser technology [5] and as pH-sensitive fluorescent materials for the visualization of biomolecular assemblies [6]. Various catalysts were reported for the promotion of this reaction including SbCl3/SiO2 [7], SiO2-R-SO3H [8], MCM-41SO3H [9], p-dodecylbenzene sulfonic acid [10], triethyl benzyl ammonium chloride [11], diammonium hydrogen phosphate [12] and silica-supported Preyssler nanoparticles [13], silica sulfuric acid [14], Amberlyst-15 [15] and trichloroisocyanuric acid (TCCA) [16] are examples. It is important to find more efficient catalysts and methods for the synthesis of these types of compounds
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