Synthesis and characterization of novel 2‐(1‐benzyl‐3‐[4‐fluorophenyl]‐1H‐pyrazol‐4‐yl)‐7‐fluoro‐4H‐chromen‐4‐one derivatives

Abstract

Novel 1‐benzyl‐3‐(4‐fluorophenyl)‐1H‐pyrazole‐4‐carbaldehydes 3a to 3e were synthesized via Vilsmeier‐Haack reaction of the appropriate 1‐benzyl‐2‐(1‐(4‐fluorophenyl)ethylidene)hydrazines, derived from 4‐fluoroacetophenone 1 with substituted 2‐benzylhydrazines 2a to 2e. The base catalyzed condensation of 1‐benzyl‐3‐(4‐fluorophenyl)‐1H‐pyrazole‐4‐carbaldehydes 3a to 3e with 1‐(4‐fluoro‐2‐hydroxyphenyl)ethanone 4 gave (E)‐3‐(1‐benzyl‐3‐(4‐fluorophenyl)‐1H‐pyrazol‐4‐yl)‐1‐(4‐fluoro‐2‐hydroxyphenyl)prop‐2‐en‐1‐ones 5a to 5e. On cyclization with dimethyl sulfoxide (DMSO)/I2, compounds 5a to 5e gave 2‐(1‐benzyl‐3‐(4‐fluorophenyl)‐1H‐pyrazol‐4‐yl)‐7‐fluoro‐4H‐chromen‐4‐ones 6a to 6e. Structures of all novel compounds were confirmed by infrared (IR), proton nuclear magnetic resonance (1H NMR), carbon nuclear magnetic resonance (13C NMR), and mass spectral data. All the synthesized compounds were screened for their antibacterial activities.

Unravelling the synthetic and therapeutic aspects of five, six and fused heterocycles using Vilsmeier–Haack reagent

“…In 2020, Hon et al 43 described the cyclization and formylation of 1-benzyl-2-(1-(4-fluorophenyl)ethylidene)hydrazones to synthesize 1-benzyl-3-(4-fluorophenyl)-1 H -pyrazole-4-carbaldehydes using V. H. reagent (DMF-POCl 3 ) in cold condition and stirred further at 70 °C for 5 to 6 hours, in good yield. The synthesized compounds were screened against anti-bacterial efficacy.…”

Recent advances in the synthesis of 4H-chromen-4-ones (2012 − 2021)

“…4-Oxo-4H-chromen-2-carboxylic acid arise in 70% yield from the cyclodehydrogenation reaction of (E)-4-(2-hydroxyphenyl)-4-oxobut-2enoic acid using iodine in DMSO at 120 °C for 30 min. 86 The same catalytic system was used for the synthesis of 2-(pyrazol-4-yl)-4H-chromen-4-ones starting from 1-(2-hydroxyaryl)-3-(pyrazol-4-yl)prop-2-en-1-ones at 100-140 °C for 1.5-2.5 h [87][88][89][90] and for the synthesis of 2-(thiazol-4-yl)-4H-chromen-4-ones starting from 1-(2-hydroxyaryl)-3-(thiazol-4-yl) prop-2-en-1-ones at 160 °C for 3-4h. 91 Oxidative cyclization reaction of 3-(furan-3-yl)-1-(2-hydroxyphenyl)prop-2-en-1-one and of 1-(2hydroxyphenyl)-3-(indol-3-yl)prop-2-en-1-one using a catalytic amount of iodine in DMSO led to, respectively, 2-(furan-3-yl)-4H-chromen-4-one and 2-(indol-3-yl)-4H-chromen-4-one.…”

Synthesis of 3‐(trifluoromethyl)‐1‐(perfluorophenyl)‐1H‐pyrazol‐5(4H)‐one derivatives via Knoevenagel condensation and their biological evaluation

“…From our study, the results demonstrated that green methodologies are less hazardous than classical synthesis methods, as well more efficient and economical and environmentally friendly; short reaction times and excellent yields are observed for those reactions in which conventional heating is replaced by microwave irradiation. Keeping in mind the 12 principles of green chemistry, in continuation of our research work, [ 26 ] and the advantages of microwave irradiation and activities associated with pyrazole and fluorine, we construct pyrazole and fluorine in one molecular framework as new 3‐(trifluoromethyl)‐1‐(perfluorophenyl)‐1 H ‐pyrazol‐5(4 H )‐one derivatives under conventional, as well as microwave, irradiation and ultrasonication and evaluated their anti‐inflammatory and antioxidant activity. In addition to this, we have also performed in silico absorption, distribution, metabolism, and excretion (ADME) predictions for the synthesized compounds.…”