Introduction of a new high yielding method for the synthesis of 1, 8-dioxo-octahydroxanthenes using W-doped ZnO nanocomposite

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, 1 H NMR and 13 C 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.

Natural phosphate-supported Cu(ii), an efficient and recyclable catalyst for the synthesis of xanthene and 1,4-disubstituted-1,2,3-triazole derivatives

“… 27 For the synthesis of xanthenes, Knoevenagel condensation has been employed followed by the Michael addition of carbonyl compounds to 1,3-dicarbonyl compounds along with using a wide range of solid catalysts and inorganic salts. Various catalysts have been reported to promote the synthesis of xanthene, including ICl 3 /SiO 2 and In(CF 3 SO 3 ) 3 , 28 lactic acid, 29 2,6-pyridinedicarboxylic acid, 30 poly( N , N ′-dibromo- N -ethylnaphtyl-2,7-sulfonamide) (PDNES), 31 W-doped ZnO, 32 silica-supported Preyssler nanoparticles, 33 ceric ammonium nitrate-supported HY-zeolite, 34 and Fe 3 O 4 @SiO 2 -imid-H 3 PMo 12 O 40 nanoparticles. 35 However, these catalysts possess several disadvantages, such as less availability, difficult preparation process, containing toxic organic solvents and harsh reaction conditions (microwave irradiation and high temperature).…”

Study on the Effect of the Three-Dimensional Electrode in Degradation of Methylene Blue by Lithium Modified Rectorite

“…One of the most environmental concerns is dyes in wastewater from industries producing paper, leather, textiles, and so forth. However, several of dyes and their derivatives not only are toxic and carcinogenic to mankind, cause allergy and dermatitis [1, 2], and even provoke cancer [3], but also are nonbiodegradable; methylene blue (MB) is a sort of typical dyes [4]. Therefore, how to remove such dye from effluents for avoiding adverse health hazards and protecting the ecosystem is a matter of great urgency.…”