1,3,5-Tris(hydrogensulfato) Benzene: A New and Efficient Catalyst for Synthesis of 4,4′-(arylmethylene)bis(1H-pyrazol-5-ol) Derivatives

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

“…The results showed that reactions in solvents take more time and also the yields are low compared to the solvent-free conditions (Table 1, entries [13][14][15][16][17][18]. Water has been identified as an ideal solvent because it is abundant, inexpensive, non-flammable and environmentally benign 40,41 .…”

“…The condensation of aldehydes with two equivalents of 3-methyl-1-phenyl-5-pyrazolone is a conventional chemical approach to 4,4′-(arylmethylene)bis(1H-pyrazol-5-ols). Many catalysts have been used for this transformation such as xanthan sulfuric acid 4 , phosphomolybdic acid 5 , silica sulfuric acid 6 , 3-aminopropylated silica gel 7 , sodium dodecyl sulfate 8 , [Cu(3,4-tmtppa)](MeSO 4 ) 4 9 , PEG-SO 3 H 10 , cellulose sulfuric acid 11 , lithium hydroxide monohydrate 12 , 1,3,5-tris(hydrogensulfato) benzene 13 , sulfuric acid ([3-(3-silicapropyl)sulfanyl]propyl)ester 14 , ethylenediammonium diacetate 15 , [Sipmim]HSO 4 16 , TEBA 17 , ceric ammonium nitrate 18 , silica-bonded S-sulfonic acid 19 , 2-hydroxyethylammonium acetate 20 , 1,3-disulfonic acid imidazolium tetrachloroaluminate 21 and 1-sulfopyridinium chloride 22 . Catalyst-free protocol and the electrocatalytic procedure were also applied to the preparation of 4,4'-(arylmethylene)bis(1H-pyrazol-5-ols) [23][24][25][26] .…”

Synthesis and characterization of two novel biological-based nano organo solid acids with urea moiety and their catalytic applications in the synthesis of 4,4′-(arylmethylene)bis(1H-pyrazol-5-ol), coumarin-3-carboxylic acid and cinnamic acid derivatives under mild and green conditions

“…Synthesis of 4,4'-(arylmethylene)bis(1H-pyrazol-5-ol) derivatives using 10 mol% of 2-carbamoylhydrazine-1-sulfonic acid and carbamoylsulfamic acid as a nano structure organocatalyst. 37 We offer the probable mechanism to explanation for the synthesis of 4,4'-(arylmethylene)bis(1H-pyrazol-5-ol) derivatives 3. Initial step includes the creation of benzylidene intermediaite 8 via the nucleophilic addition of 1-phenyl-3-methyl-5-pyrazolone 2 to aromatic aldehyde 5 1 followed through dehydration.…”

Alum as a Catalyst for the Synthesis of Bispyrazole Derivatives

“…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]. These compounds have been also useful as fungicides, pesticides, dyestuffs [19] and as chelating and extracting reagents for metal ions [21].…”