Preparation of various xanthene derivatives over sulfonic acid functionalized imidazolium salts (SAFIS) as novel, highly efficient and reusable catalysts

Abstract

In this work, some novel sulfonic acid functionalized imidazolium salts (SAFIS), as a new category of ionic liquids, are synthesized by eco-friendly and simple procedures, and used as highly efficient and reusable catalysts to promote the following one-pot multicomponent organic transformations under solvent-free conditions: (i) the synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes from b-naphthol (2 eq.) and arylaldehydes (1 eq.), (ii) the preparation of tetrahydrobenzo[a]xanthene-11-ones from b-naphthol, arylaldehydes and dimedone, and (iii) the synthesis of 1,8-dioxo-octahydroxanthenes from dimedone (2 eq.) and aromatic aldehydes (1 eq.). Environmentally benign, simple methodologies, easy workup procedure, clean reaction, short reaction time, high yield and easy preparation of the catalysts are some advantages of this work.ß 2012 Published by Elsevier Masson SAS on behalf of Acade ´mie des sciences.

p-Sulfonic acid calix[4]arene as an efficient and reusable catalyst for the synthesis of acridinediones and xanthenes

“…For the initial study, as a model, the condensation of dimedone (2 mmol) and benzaldehyde (1 mmol) was examined (Scheme 4) in the presence of different molar ratios of p-sulfonic acid calix [4]arene in ethanol at various temperatures ranging from 25 to 80°C ( Under optimized reaction conditions, different aromatic aldehydes (such as aldehydes bearing electron-withdrawing substituents, electron-releasing substituents, and halogens on their aromatic ring) were reacted with dimedone to furnish the corresponding products in high yields and in short reaction times ( Table 3, entries [11][12][13][14][15][16][17][18][19][20]. The aliphatic aldehyde underwent the reaction cleanly in excellent yield (Table 3, entry 20).…”

“…To obtain the optimized reaction conditions for the synthesis of this class of compounds, the reaction dimedone (2 mmol), benzaldehyde (1 mmol), and aniline (1.2 mmol) was selected as a model reaction (Scheme 5). The effect of different molar ratios of p-sulfonic acid calix [4]arene, p-Sulfonic acid calix [4]arene as an efficient and reusable… [19] p-Sulfonic acid calix [4]arene as an efficient and reusable… solvent, and temperature on the reaction was studied (Table 4). In order to optimize the reaction conditions, the model reaction was performed in various solvents such as H 2 O, CH 3 CN, EtOH, and CH 2 Cl 2 ( Table 4, entries 1-9).…”

“…Therefore, the synthesis of xanthenes is of great importance. Consequently, several methods have been developed for the synthesis of xanthene derivatives, which in general can be obtained by the condensation of aryloxymagnesium halides with triethyl orthoformate [15], the cyclization of polycyclic aryl triflate esters [16], and the reaction of dimedone or b-naphthol with aldehydes [17][18][19][20][21][22][23][24][25]. However, many of these existing methodologies suffer from one or more disadvantages, such as toxic metal ions and solvent, high cost, high catalyst loading, corrosive reagents, large amounts of solid supports, and cumbersome workup procedures.…”

Design, characterization and application of silica-bonded imidazolium-sulfonic acid chloride as a novel, active and efficient nanostructured catalyst in the synthesis of hexahydroquinolines

“…Recently, we introduced a new category of acidic ionic liquids (ILs) and solid salts, namely sulfonic acid-functionalized imidazolium salts (SAFIS) which published in this journal [30], and applied them as organocatalysts or organoreagents for preparation of 1-amidoalkyl-2-naphthols [30], N-sulfonyl imines [31], nitro aromatic compounds [32,33], bis(indolyl)methans [34], benzimidazoles [35], xanthenes [36], 1-carbamatoalkyl-2-naphthols [37], 4,4'-(arylmethylene)-bis(3-methyl-1-phenyl-1H-pyrazol-5-ol)s [38], t-butyl aryl carbamates [39], 1,2,4,5-tetrasubstituted imidazoles [40], β-acetamido ketones [41], and hexahydroquinolines [42].…”

2,6-Pyridinedicarboxylic acid as an efficient and mild organocatalyst for the one-pot synthesis of xanthene derivative

“…Different reagents have been employed for the synthesis of xanthenes and benzoxanthenes such as ZnO-NPs [15], PVPP-BF3 [16], H5PW10V2O40 [17], imidazol-1-yl-acetic acid [18], succinimide-N-sulfonic acid [19], ceric ammonium nitrate (CAN) [20], SAFIS [21] and 1,3-disulfonic acid imidazolium hydrogen sulfate [22] as catalysts. However, many of these methods, from certain drawbacks suffer including longer reaction times, unsatisfactory yields and conditions, use of high heat and the use of toxic catalysts [23][24][25][26].…”