Efficient, Solvent-Free, Microwave-Enhanced Condensation of 5,5-Dimethyl-1,3-cyclohexanedione with Aldehydes and Imines Using LiBr as Inexpensive, Mild Catalyst

p‐Dodecylbenzenesulfonic Acid: An Efficient Brønsted Acid‐Surfactant‐Combined Catalyst to Carry out Diverse Organic Transformations in Aqueous Medium

“…1,8‐Dioxo‐octahydroxanthene and 1,8‐dioxodecahydroacridine moieties, in particular, possess potent biological efficacies that include antimicrobial, anticancer and enzyme inhibitory activities . A number of methods are available in the literature for the synthesis of both 1,8‐dioxo‐octahydroxanthenes and 1,8‐dioxodecahydroacridines . These reported methods have certain drawbacks such as use of metal‐catalysts and organic solvents, harsh reaction conditions, prolonged reaction times etc .Jin and co‐researchers synthesized a series of 9‐aryl‐1,8‐dioxo‐octahydroxanthene derivatives ( 43 ) via one‐pot pseudo three‐componentreactions of one equivalent of aromatic aldehydes ( 8 ) and two equivalents of dimedone ( 31 ) using 10 mol% of p ‐dodecylbenzenesulfonic acid (DBSA) as catalyst in water under ultrasound irradiation at ambient temperature (Scheme ).…”

Recent developments on ultrasound-assisted organic synthesis in aqueous medium

“…N-Aryl-1,8-dioxodecahydroacridine moieties are important in drug design and discovery as they possesses potential pharmacological activities, such as antimicrobial, anticancer and enzyme inhibitory properties. [58][59][60][61][62][63] A large number of methods are already available in the literature for the synthesis of these important scaffolds employing various catalysts such as 1-methylimidazolium trifluoroacetate, 58 silica-supported N-propylsulfamic acid, 59 amberlyst-15, 60 ZnO nanoparticles, 61 LiBr 62 and NH 4 Cl. 63 Although these available methods possess notable merits they still suffer from some drawbacks, such as, use of organic solvents, longer reaction times, etc.…”

β-Cyclodextrin mediated synthesis of 1,8-dioxooctahydroxanthenes in water

“…Jin et al and Khosropour et al reported the synthesis of xanthene and benzoxanthene in presence of p-toluenesulfonic acid as a catalyst in organic solvent [17,18]. Other methods developed for the synthesis of 1,8-dioxooctahydroxanthenes include the use of NaHSO4-SiO2 (or) silica chloride [19], Amberlyst-15 [20], Dowex50w [21], Montmorillonite [22], cyanuric chloride [23], BiCl3 [24], Fe +3 -montmorillonite [25], polyaniline-p-toluenesulfonate [26], PMA-SiO2 [27], HClO4-SiO2 & PPA-SiO2 [28], ZrOCl2 [29], H3PW12O40 [30], LiBr [31], and proline triflate [32], as catalysts. Literature survey also indicates the role of ionic liquids [33,34], and acidic ionic liquids in aqueous media [35], in the synthesis of xanthenes.…”