Synthesis and antioxidant activity study of carbothioamide and their corresponding thiazole derivatives

Abstract

A novel series of 5‐(p‐(prop‐2‐ynyloxy)phenyl)‐3‐aryl‐4,5‐dihydropyrazole‐1‐carbothioamides 2a‐f and functionalized 2‐(3‐(aryl)‐5‐(4‐(prop‐2‐ynyloxy)phenyl)‐4,5‐dihydropyrazol‐1‐yl)‐4‐(3‐arylsydnone‐4‐yl)thiazoles 4a‐l were synthesized. The newly synthesized compounds were elucidated by analytical and spectral analysis. From the single‐crystal X‐ray diffraction method, it was observed that 2d crystallizes in a monoclinic crystal system with P21/n space group. The compounds 2d crystallized with cell parameters a = 15.0614 (19) Å, b = 6.0805 (7) Å, c = 20.903 (7) Å, α = 114.136 (6)o, β = 110.709 (14) o, γ = 96.553 (5) o, V = 1790.6 (4) Å3, Z = 4. From the Hirshfeld surface computational method, the major intercontacts present in these molecules are H…H (31.6%), C…H (18.2%) and S…H (12.2%), respectively. The newly synthesized compounds were tested for their ability to bleach 2,2'‐diphenyl‐1‐picrylhydrazyl (DPPH) radical using DPPH scavenging assay. Among the synthesized compounds carbothioamide compounds 2c (90.7%) and 2b (89.8%) exhibited good DPPH scavenging activity compared to the rest of the compounds. Most of the synthesized carbothioamide molecules (2a‐f) found to be potent compared to the thiazole derivatives (4a‐l).

Synthesis of chalcone precursor via Cu(I) catalyzed 1,3‐dipolar reaction of functionalized acetylene and pyrazole embedded dipole

“…Synthesis of various dipolarophiles (acetylene) ( 4a‐h ) was carried out as per the procedure reported in the literature. [ 35–38 ]…”

Two isostructural 3-(5-aryloxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-1-(thiophen-2-yl)prop-2-en-1-ones: disorder and supramolecular assembly

“…The synthetic route to compounds (I) and (II). (Asma et al, 2017) to provide the 5-aryloxy intermediates (C). Condensation with 2-acetylethiophene then gave the products (I) and (II) in yields of 86% and 84%, respectively.…”

“…Condensation with 2-acetylethiophene then gave the products (I) and (II) in yields of 86% and 84%, respectively. Thus the appropriate 3-methyl-5-aryloxy-1-phenyl-1H-pyrazole 4-carbaldehydes (Asma et al, 2017) [1.7 mmol; 445 mg for (I), or 469 mg for (II)] and 2-acetyl thiophene (1.7 mmol, 214 mg) were dissolved in ethanol (20 ml) at 273 K; a solution of potassium hydroxide (2.1 mmol, 112 mg) in ethanol (5 ml) was then added dropwise, and the resulting mixtures were then stirred for 4 h. When the reactions were complete, as judged by thin-layer chromatography, the resulting solid products were collected by filtration, washed with water, dried in air and then recrystallized from ethanol-dimethylformamide (9:…”

Four 1-aryl-1H-pyrazole-3,4-dicarboxylate derivatives: synthesis, molecular conformation and hydrogen bonding

“…Pyrazole derivatives have been shown to exhibit a wide range of biological activities including analgesic (Girisha et al, 2010), anticonvulsant (Owen et al, 1958), antimicrobial (Satheesha & Kalluraya, 2007;Asma et al, 2018), antitumour (Park et al, 2005), and insecticidal and larvicidal activity (Yang et al, 2018). Pyrazole carboxylic acids and their derivatives are versatile precursors for the synthesis of numerous substituted analogues (Asma et al, 2018;Devi et al, 2018) and, with these considerations in mind, we have now synthesized a series of new pyrazole carboxylate derivatives as intermediates for the synthesis of new pharmacologically active products. Here we report the syntheses, and the molecular and supramolecular structures of four such compounds, namely 1-phenyl-1Hpyrazole-3,4-dicarboxylic acid (I), dimethyl 1-phenyl-1Hpyrazole-3,4-dicarboxylate (II), dimethyl 1-(4-methylphenyl)-1H-pyrazole-3,4-dicarboxylate (III) and 1-(4-methoxyphenyl)-1H-pyrazole-3,4-dicarbohydrazide (IV) (Figs.…”