An Effective Bismuth Trichloride-Catalyzed Synthesis of 1,8-Dioxo-Octahydroxanthenes

ZnO nanoparticles: an efficient and reusable catalyst for one-pot synthesis of 1,8-dioxo-octahydroxanthenes

“…As a matter of fact, substrates having an electron-withdrawing at the aryl ring benzaldehyde give a higher yield of desired products (3) in shorter reaction times ( Table 2, entries 2-10) compared with one having an electrondonating substituent ( Table 2, entries [11][12][13][14]. Aromatic aldehydes possessing two groups on the aryl ring such as 3,4-dimethoxybenzaldehyde and 4-hydroxy-3-methoxybenzaldehyde reacted with dimedone under reaction conditions to give the corresponding xanthenes in good yields ( Table 2, entries [15][16].…”

“…In addition, because of their useful spectroscopic properties, they have been widely used as dyes in laser technology [7], sensitizers in photodynamic therapy [8], and pH-sensitive fluorescent materials for visualization of biomolecules [9]. There are several methods for the synthesis of 1,8-dioxooctahydroxanthenes; these compounds conventionally prepared using condensation of aromatic aldehydes with 5,5-dimethyl-1,3-cyclohexanedione (dimedone) in the presence of catalysts such as InCl 3 Á4H2O [10], FeCl 3 Á6H 2 O [11], NH 2 SO 3 /SDS [12], NaHSO 4 /SiO 2 [13], PPAÁSiO 2 [14], ZnO-acetyl chloride [15], BiCl 3 [16], (L)-proline [17], trimethylsilyl chloride [18], amberlyst-15 [19], p-dodecylbenzene sulfonic acid [20], and tetrabutylammonium hydrogen sulfate [21].…”

Synthesis of 1,8-Dioxo-octahydroxanthenes Catalyzed by Acidic Ionic Liquids in Aqueous Media

“…-montmorilonite [9], NaHSO 4 -SiO 2 or silica chloride [10], Amberlyst-15 [11], silica sulfuric acid [12], (NH 4 ) 2 HPO 4 [13], Dowex-50 W [14], SbCl 3 /SiO 2 [15], cyanuric chloride [16], and BiCl 3 [17] as catalysts, as well as with the assistance of microwave [18] or ultrasound irradiation [19,20]. However, the search for the new readily available and green catalysts is still being actively pursued.…”

Manganese Perchlorate–Catalyzed Greener Synthesis of 12-Aryl or 12-Alkyl-8,9,10,12-tetrahydrobenzo[α]xanthen-11-one Derivatives Under Ultrasonication

“…[2][3][4] These compounds are being utilized as antagonists for paralyzing action of zoxazolamine [5] and in photodynamic therapy. [6] Xanthenes have also been employed as dyes [7] and pH-sensitive fluorescent material for visualization of biomolecules [8] and in laser technologies.…”