Synthesis and biological evaluation of an indanone-pyrazoline hybrid compound and its synthetic intermediates

Pyrazoline and indanone scaffolds are two important skeletal motifs widely used in medicinal chemistry for their broad biological activities. In the current investigation, a novel indanone-pyrazoline hybrid compound was prepared in a three-step synthetic sequence. Synthesis consisted of the formation of a Schiff base via reaction with indanone, Claisen-Schmidt condensation to obtain the indanone chalcone, and phenylhydrazine cyclization to yield the desired pyrazoline. The synthesized compounds were evaluated using 1H NMR spectroscopy, while 13C NMR data were additionally obtained for compounds 1 and 3. Antimicrobial testing using the agar diffusion test produced inhibition zones of 11–12 mm against E. coli and S. aureus. The hybrid compound showed a 12 mm inhibition zone, whereas the intermediates produced an 11 mm inhibition zone; however, the biological relevance of this small numerical difference should be interpreted cautiously. For antifungal activity, C. albicans showed inhibition zones of 10–11 mm, with the Schiff base intermediate producing a slightly larger inhibition zone than the hybrid compound. At the same time, no inhibition was observed for A. flavus.