One-pot three-component synthesis of some new azo-pyrazoline derivatives

3-(3,4-Dimethoxyphenyl)-5-(2-fluorophenyl)-1-phenyl-4,5-dihydro-1H-pyrazole

“…The absorption bands at ν 1119 in the FT-IR spectrum indicated the presence of C-F groups and they were confirmed by seven split signals at aromatic carbons area of δ 159.76, 129.13, 129.08, 127.55, 124.77, 115.62, and 57.64 in the 13 C NMR spectra. These splittings were due to the 1-4 bonds' J couplings of 13 C to 19 F [19,20]. In this case, the observed 1 J C-F (a) was 244 Hz; 2 J C-F (b) and (c) were 21.3 and 13.8 Hz, respectively; 3 J C-F (d), (e), and (f) were 8.75, 3.75, and 2.5 Hz, respectively; and 4 J C-F (g) was 3.1 Hz, as shown in presence of these two groups were also confirmed by aliphatic carbon signals at λ 42.39 and 57.64 in the 13 C NMR spectrum.…”

“…The synthesis of compound 1 was conducted by modification from previously original one-pot method under reflux condition [13,14]. In this work, the one-pot three-component reaction was performed in the presence of 2 mL of 10% sodium hydroxide solution as the catalyst in a sealed-vessel reactor, Monowave 50 at 80 • C for 10 min, as depicted in Figure 1.…”

“…1 H and 13 C-NMR spectrum were recorded on an Agilent ® (Agilent Technologies, Santa Clara, CA, USA) at 500 MHz and 125 MHz, respectively. The synthesis of compound 1 was conducted by a modification of previous methods [13,14]. 3 ,4 -dimethoxyacetophenone (0.5 mmol), 2-fluorobenzaldehyde (0.5 mmol), and phenylhydrazine (2 mmol) were dissolved in ethanol absolute (5 mL) in a pressure tube with a stirbar and 2 mL of 10% sodium hydroxide was added.…”

“…The first is the synthesis of fluorinated chalcone through Claisen-Schmidt condensation, then the second is the synthesis of fluorinated pyrazoline through intermolecular cyclization of fluorinated chalcone with a hydrazine or its derivatives [7] such as thiosemicarbazide [4], phenylhydrazine [8], hydrazine hydrate [9], halogenated phenylhydrazine [10], and 3,4,5-trimethoxybenzohydrazide [11]. Other researchers have also reported one-pot synthesis of pyrazolines from various starting materials and methods such as from 3-butynol and substituted phenylhydrazine under reflux condition [12], from substituted acetophenone, benzaldehyde, and phenylhydrazine under reflux condition [13,14] and through the formal [4 + 1] annulation reaction of 3-bromooxindoles and in situ-derived 1,2-diaza-1,3-dienes by stirring at room temperature [15]. In addition, it has also been reported that the one-pot synthesis of pyrazolines can be performed by reacting pyridine based chalcone and hydrazine hydrate under 300 W microwave irradiation [16]; by reacting substituted chalcone, hydrazine hydrate, and acetic anhydride under 550 W microwave irradiation [17]; and by reacting substituted pyrazole, formaldehyde, and β-diketone under 300 W microwave irradiation [18].…”

Syntheses, Experimental and Theoretical Studies on Absorption/Emission Properties of Pyrazoline-Containing Aryl/Methoxynaphthyl Substituents

“…[5][6][7][8] The building of these N-heterocycles systems, from simple reactions, using small molecules and compatible with multicomponent, regioselective, eco-friendly and efficient synthetic procedures, which include variations to conventional methods, allows to incorporate specific structural characteristics. [9][10][11][12][13][14] Substituents of different nature, electron withdrawing group (EWG) and electron releasing group (ERG), in aromatic aldehydes, ketones and hydrazines, make them versatile synthetic auxiliaries in classical organic synthesis. Reports in the literature [15][16][17][18] have attributed an increase in the biological properties of pyrazoline derivatives to the combined effect of ERG, aryl substituents and π-extended configuration.…”