An easy synthetic access to new pyrazole spiro derivatives from 3-amino-1-phenyl-2-pyrazolin-5-one

Abstract

Pyrazole and pyrazolone moieties have shown important biological activities.

Catalytic Asymmetric Synthesis of Spiropyrazolones and their Application in Medicinal Chemistry

“…In 2015, the Khouili/Faustino group found that commercially available 5-amino-2-phenyl-2,4-dihydro-3H-pyrazol-3-one 90 can react with benzaldehyde 91 to provide access to the unexpected spiro derivative 92 containing two pyrazolone units under Knoevenagel conditions, in refluxing ethanol with the presence of a base (pyridine or triethylamine) (Scheme 38a). [48] Pyridine base had 45 % yield, whereas triethylamine had 35 %. Furthermore, an extra molecule of R D 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 benzaldehyde could continue the reaction, further obtaining a more complicated polycyclic system 93.…”

“…In 2015, the Khouili/Faustino group found that commercially available 5‐amino‐2‐phenyl‐2,4‐dihydro‐3 H ‐pyrazol‐3‐one 90 can react with benzaldehyde 91 to provide access to the unexpected spiro derivative 92 containing two pyrazolone units under Knoevenagel conditions, in refluxing ethanol with the presence of a base (pyridine or triethylamine) (Scheme a) . Pyridine base had 45 % yield, whereas triethylamine had 35 %.…”

Synthesis, Spectroscopic characterization and bactericidal valuation of some metal (II) complexes with new Tridentate Heterocyclic Azo Ligand Type (NNO) Donor

“…The peak at δ (163.74) ppm is due to C=C-N site linked of 2naphthol with azo group for pyrazolin ring [20], [27]. The signals at δ (47.34) ppm are assigned to the middle and terminal C-C carbon atoms of diaminobutane moiety in the ligand [12], [25], [27]. The mass spectrum data for azo ligand Figure ( 6) showed a molecular ion peak at (m/z =409.6) [25,27].…”

“…The infrared spectral data of azo ligand and its complexes have illustrated in Figures (12)(13)(14)(15) and Table (3). The IR spectra for complexes have compared with those of the free ligand with the intention of determining the coordination sites that can be included in chelation.…”

“…Pyrazolin-5-one and 5-Pyrazolones are very vital category of heterocycles attributable to their organic and pharmacological actions [10]. They are employed as main initial materials for the synthesizing viable aryl/hetarylazopyrazolone dyes [11], that are used as noble fastness dyes tuffs for wool, cotton, leather, silk, rubber and synthetic polymers (Nylons).On the other hand, many azopyrazolone dyes have been employed as indicators for complexometric titrations [12]. Within the subject of azo dyes, phenolic compounds have a foremost role for synthesizing the majority of viable dyes.…”