N1‐substituted 3,5‐dimethoxy‐4‐halogeno‐1H‐pyrazoles: Synthesis and NMR study

Abstract

The synthesis of 1‐methyl‐ and 1‐benzyl‐3,5‐dimethoxy‐4‐halogeno‐1H‐pyrazoles is described. Moreover, detailed nmr spectroscopic studies with the title compounds are presented. The highly shielded pyrazole C‐4 atom in the corresponding 4‐iodo congeners was found to have a 13C‐chemical shift of only −27 ppm.

Electrophilic Iodination of Organic Compounds Using Elemental Iodine or Iodides

“…Pyrazole derivatives were iodinated using the iodine-iodide method (I 2 , KI), 167 oxidative iodination by molecular iodine and iodic acid 168 or the molecular iodine with lead(IV) acetate 34 combination, but the efficiency as well as the selectivity of these efforts were poor. Better results resulting in efficient formation of the desired 4-iodo-sub-…”

Molecular properties and In silico bioactivity evaluation of (4-fluorophenyl)[5)-3-phen-(4-nitrophenyl yl-4,5-dihydro-1H-pyrazol-1-yl]methanone derivatives: DFT and molecular docking approaches

“…Pyrazole derivatives are heterocyclic compounds recognized to possess a wide range of biological and pharmacological activities. 1 , 2 The unique properties of pyrazoles have been attributed to the electrophilic substitution reactions that occur specially at position 4, and nucleophilic attacks that occur at positions 3 and 5, thus leading to diverse pyrazole structures with broad potential applications in areas such as medicine, agriculture and technology. 3 , 4 , 5 In addition, compounds containing a pyrazole nucleus have been reported to be anti-inflammatory, antiviral, anticancer, antiparasitic, antibacterial, antirheumatoid, antidepressant, analgesic, antinociceptive, antihypertensive, antipyretic and antifungal agents.…”

Theoretical investigation of the chemoselectivity and synchronously pyrazole ring formation mechanism from ethoxymethylenemalononitrile and hydrazine hydrate in the gas and solvent phases: DFT, meta-GGA studies and NBO analysis

“…12 In addition the reaction of dimethyl dithiomalonate with methyl hydrazine afforded 1-methylpyrazole. 13 However, the syntheses of the pyrazole derivatives have been reported by other precursors such as ethyl ethoxymethylenecyanoacetate, 14 acetylenedicarboxylates 15 and many other compounds. 16,17 Ethoxymethylenemalononitrile is another precursor, which gives 5-aminopyrazole-4-carbonitrile in the presence of hydrazine hydrate.…”