Carbon Nanotube-Supported Butyl 1-Sulfonic Acid Groups as a Novel and Environmentally Compatible Catalyst for the Synthesis of 1,8-Dioxo-octahydroxanthenes

Abstract

A novel multiwalled carbon nanotube catalyst with -SO 3 H functional groups was easily prepared from its starting materials and used as an efficient heterogeneous catalyst for one-pot Knoevenagel condensation, Michael addition, and cyclodehydration of 5,5-dimethyl-1,3-cyclohexanedione (dimedone) with various aromatic aldehydes. Using this method 1,8-dioxo-octahydroxanthenes were obtained in excellent yields at room temperature. The present method is superior in terms of reaction temperature, reaction time, easy work-up, high yields, and ease of recovery of catalyst.

Synthesis and Study of Catalytic, Anti–Bacterial, Anti–Oxidant, and DNA Cleavage Properties of Ag–Co and Ag–Ni Magnetic Nanoparticles

“…Then, dehydration of intermediate I a Yields refer to the isolated pure products, b All the products were identified by comparing the analytical data (the spectral properties and melting points) with those reported in the literature. [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] Scheme 1. The proposed mechanism for the synthesis of 1,8-dioxooctahydroxanthenes.…”

“…19 1,8-Dioxooctahydroxanthenes are one of the most important derivatives of xanthenes. A convenient method for the synthesis of 1,8-dioxooctahydroxanthenes is reac-tion between an aldehyde (1 equiv) and dimedone (2 equiv) in the presence of a catalyst such as p-dodecylbenezenesulfonic acid, 20 Amberlyst-15, 21 SmCl 3 , 22 carboxy functionalized ionic liquid, 23 SiCl 4 , 24 ceric ammonium nitrate (CAN), 25 [Et 3 NH][HSO 4 ], 26 CAN-supported HY-zeolite, 27 piperidine/HCl, 28 Mg-Al hydrotalcite, 29 thiourea dioxide, 30 hydroxylamine-O-sulfonic acid, 31 carbon nanotube-BuSO 3 H, 32 cellulose/Al 2 O 3 -[MeIm]Cl-XAlCl 3 , 33 sulfated zirconia, 34 and L-pyrrolidine-2-carboxylic acid sulfate (LPCAS). 35 Most of these catalysts, however, have numerous disadvantages such as waste production, corrosion problems, no catalyst recovery, low yields, high reaction temperature, long reaction times, tedious work-up, and the formation of the uncyclized product 2,2'-aryl-methylenebis(3-hydroxy-2-cyclohexene-1-one) derivatives.…”

Magnetically separable modified sulfuric acid (CuFe2O4@SiO2-OSO3H): Preparation, characterization and catalytic application for the synthesis of 1,8-dioxo-octahydroxanthenes

“…Furthermore, they are well-known as fluorescent and laser dyes [7][8][9]. Xanthenediones are generally synthesized by condensation of aromatic aldehydes with 1, 3-cyclohexanedione or 5, 5-dimethyl-1, 3-cyclohexanedione (dimedone) using various promoting agents such as sulfated zirconia [10], multiwalled carbon nanotube-supported butyl 1-sulfonic acid (MWCNT-BuSO3H) [11], β-cyclodextrin grafted with butyl sulfonic acid (β-CD-BSA) [12], ceric ammonium nitrate supported HY-zeolite (CAN/HY-zeolite) [13], silica-supported Preyssler nano particles (Silica/Preyssler NPs) [14], L-proline [15], ZnO nanoparticles [16], SmCl3 [17], nanosized MCM-41-SO3H [18], trimethylsilyl chloride [19], H3PW12O40/MCM-41 [20], and [Et3NC4SO3H][HSO4]/Al2O3 [21]. Some of these catalysts have disadvantages http://echemcom.com…”

Synthesis and Catalytic Application of Poly(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid‐co‐acrylamide) Grafted on Graphene Oxide

“…However many of the reported procedures need to relatively high temperature conditions or an additional energy (ultrasound or microwave) and are performed in toxic organic solvents. The synthesis of 1,8‐dioxo‐octahydroxanthenes from the reaction of aldehydes with dimedone at room temperature are relatively rare . Usually, in the absence of catalyst or at ambient temperature the uncyclized adduct 2,2’‐aryl‐methylene bis (3‐hydroxy‐2‐cyclohexene‐1‐one) is formed …”