Synthesis of new morpholine-connected pyrazolidine derivatives and their antimicrobial, antioxidant, and cytotoxic activities.

A simple and convenient one-pot four-component synthesis of morpholine-connected pyrazolidine derivatives 2a-f and 4a-f was developed using direct metal-free catalysis, with the identities of the synthesized compounds confirmed by IR, NMR (1 H and 13 C), mass spectrometry, and elemental analysis. The prepared compounds were inspected for antimicrobial, antioxidant, and cytotoxic activities. Antimicrobial and antifungal activities against five bacterial and four fungal pathogens, respectively, were investigated using the disc diffusion technique. In antibacterial activity, compounds 2d and 2f (MIC=2μg/mL) exhibited significantly higher activity than the standard ciprofloxacin. The results of antifungal assay showed that the activity of compound 4a (MIC=0.5μg/mL) was significantly higher than the standard clotrimazole. Antioxidant activity was screened based on ABTS+ radical scavenging and linoleic acid peroxidation performance. Compound 4a showed substantial antioxidant (91.3%) activities, as compared with the Trolox standard. Cytotoxicity was evaluated using HepG2 (liver), HeLa (cervical), and MCF-7 (breast) cancer cell lines, with high toxicities observed for 2b (GI50 =12.2μm) and 4a (GI50 =07.8μm).