Trityl Chloride (TrCl): Efficient and Homogeneous Organocatalyst for the Solvent‐Free Synthesis of 14‐Aryl‐14H‐dibenzo[a,j]xanthenes by in situ Formation of Carbocationic System

Abstract

Trityl chloride (triphenylmethyl chloride, TrCl, Ph3CCl) is utilized as an efficient and homogeneous organocatalyst for the synthesis of 14‐aryl‐14H‐dibenzo[a,j]xanthenes from β‐naphthol and arylaldehydes under solvent‐free conditions. Moreover, a plausible mechanism is suggested based on the literature and on in situ formation of trityl carbocation with inherent instability during the reaction.

Highly Efficient Synthesis of 1-Thioamidoalkyl-2-naphthols and 14-Aryl-14H-dibenzo[a,j]xanthenes using a Novel Ionic Liquid: Catalyst Preparation, Characterization and Performing the Reactions

“…A mixture of arylaldehyde (1 mmol), 2-naphthol (2 mmol) and [TEASA][TFA] (0.044 g, 0.15 mmol) was initially stirred by a magnet at 100 °C, and after the reaction was solidified, it was stirred with a small rod at that temperature. After the reaction was completed {as monitored by TLC) n-hexane/ethyl acetate: 3/1)} , the mixture was cooled to room temperature, and the solid residue (crude product) was purified by recrystallization from hot ethanol (95%) [8,[32][33][34][35][36][37][38][39][40].…”

“…Moreover, these compounds can be applied as pHsensitive fluorescent materials for visualization of biomolecules, as sensitizers in photodynamic therapy, and in laser technology [29][30][31]. The general method for synthesis of 14-aryl-14Hdibenzo [a,j]xanthenes, as a significant class of xanthenes, involves the reaction of arylaldehydes with 2-naphthol in the presence of a catalyst [8,[32][33][34][35][36][37][38][39][40].…”

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“…They have also been employed as potent biodegradable agrochemicals [25], cosmetics, and pigments [26]. Condensation of the arylaldehydes with 2naphthol, using Bronsted or Lewis acidic catalysts has been applied as the most useful protocol for synthesis of the 14-aryl-14Hdibenzo [a, j]xanthenes as an important class of benzoxanthenes [27][28][29][30][31][32][33][34][35]. Xanthene derivatives, especially benzoxanthenes are of importance since they have various biological activities such as antibacterial [36], anti-cancer [37], and anti-inflammatory [38] properties.…”

Alum as a Catalyst for the Synthesis of Bispyrazole Derivatives

“…Alum (KAl(SO 4 ) 2¨1 2H 2 O) has been widely used in organic methodology. This study introduces the term "dreamland catalyst" to denote a heterogeneous catalyst which is mild, efficient, safe, stable, low-cost, non-toxic, reliable, incorruptible, recyclable and easy to use [4]. The efficiency of alum has been reported for the synthesis of 1,4-dihydropyridines [5], cis-isoquinolic acids [6], mono-and disubstituted 2,3-dihydroquinazolin-4(1H)-ones [7], dihydropyrimidine using the Biginelli reaction [8], coumarins [9], 5-arylidene-2,4-thiazolidinedione [10], dibenzoxanthenes [7], 1,5-benzodiazepines [11], trisubstitutedimidazoles [5] and 4-substituted coumarins using the Pechmann reaction [9].…”

“…Compounds with pyrazolemoieties as nitrogen-containing heterocyclic systems have received attention owing to their diverse biological activities. These include anti-inflammatory, antipyretic and analgesic activities, uses as bactericides and fungicides, and promising inhibitory activity against monoamine oxidase for the treatment of Parkinson's and Alzheimer's diseases [1,4,[12][13][14]. More specifically, 4,4 1 -(arylmethylene)bis(3-methyl-1-phenyl-1H-pyrazol-5-ol)s is an important class of pyrazolones used as anti-inflammatories [15], antipyretics, gastric secretion stimulatories [16], antidepressants [17], and antibacterial and anti-filaria agents [11,[18][19][20].…”