Synthesis and characterization of pyrazole derivatives

Pyrazole, a five-membered heterocyclic compound containing two nitrogen atoms, are interesting molecules due to their promising agrochemical, fluorescent and biological activities. Due to the wide variety of application areas, many studies are being done to find innovative ways to design and synthesize new pyrazole derivative compounds. Sonochemistry is the field of research that enables molecules to react chemically due to the application of powerful ultrasound radiation (20 kHz-10 MHz). The chemical effects of ultrasound are not caused by the direct attachment of the acoustic field to molecular species. Instead, they come from nonlinear acoustic phenomena, primarily acoustic cavitation. Acoustic cavitation can be divided into three different stages: (i) formation, (ii) growth, and (iii) bursting collapse of bubbles. Ultrasonic irradiation of liquids creates hot spots that can initiate chemical reactions. In this thesis study, the pyrazole derivatives were synthesized via the reaction of aromatic aldehydes, phenylhydrazine or benzohydrazide and malononitrile compounds in the presence of different solvents (H2O or Triton-x 100/H2O mixture) and non-toxic organocatalysts (camphor sulfonic acid (CSA), vitamin B1 (thiamine, Vit B1) under ultrasonic irradiation. The structures of the synthesized compounds were determined by spectroscopic methods.