[Et3NH][HSO4] catalyzed efficient and green synthesis of 1,8-dioxo-octahydroxanthenes

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.…”

Ionic Liquid-Catalyzed Green Protocol for Multi-Component Synthesis of Dihydropyrano[2,3-c]pyrazoles as Potential Anticancer Scaffolds

“…Ionic liquids have gained importance as green solvent for organic transformations [ 45 , 46 , 47 ] due to their special properties, including good solvating capability, negligible vapor pressure, non-inflammable, ease of recyclability, controlled miscibility and high thermal stability [ 48 , 49 ]. Use of the Brønsted acid ionic liquid (BAIL) triethylammonium hydrogen sulphate ([Et 3 NH][HSO 4 ] [ 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 ] as a catalyst should be advantageous due to its non-toxic nature, low cost, easy preparation from readily available starting materials, stability in water and air, easy separation and reusability [ 61 , 62 ].…”

AN ECO-FRIENDLY ONE-POT SYNTHESIS OF 4,4'-(ARYLMETHYLENE)BIS(1H-PYRAZOL-5-OLS) USING [Et3NH][HSO4] AS A RECYCLABLE CATALYST

“…Solvent-free conditions makes synthesis simpler, save energy, and prevent solvent waste, hazards, and toxicity [28][29] . Ionic liquids have been widely used as environmentally benign reaction media and catalysts in organic synthesis because of their unique properties of nonvolatility, nonflammability, and recyclability 30-31. Recently, the use of acidic ionic liquid [Et 3 NH][HSO 4 ] has received considerable attention as a cheap and easily available reagent in organic reactions [32][33][34][35][36][37] . In continuation of our work on the application of acidic ionic liquid for development of useful synthetic methodologies [37][38] , we report herein, an alternative protocol for the one-pot three-component synthesis of 4,4′-(arylmethylene)bis(1H-pyrazol-5-ols) derivatives starting directly from aldehydes, phenylhydrazine/hydrazine hydrate and ethyl acetoacetate using [Et 3 NH][HSO 4 ] as an efficient, costeffective and recyclable catalyst under solvent-free conditions (Scheme 1).…”