Synthesis and Antimicrobial Activity of Some New Spiropyrazoline Derivatives of 9 alpha- and 9 beta-Hydroxyparthenolide

In the present study, we efficiently synthesized two new series of spiropyrazoline derivatives from 9 alpha- and 9 beta-hydroxyparthenolide (isolated from the aerial parts of Anvillea radiata). The compounds were obtained by modifications at the C-13 and C-9 positions via 1,3-dipolar cycloaddition followed by O-H acylation at the C1-C10 using epoxidation with metachloroperoxybenzoic acid (m-CPBA) followed by 1,3-dipolar cycloaddition on the double bond alpha-methylene-gamma-lactones. The structures and stereochemistry of the cycloadducts were established by spectroscopic methods, including X-ray diffraction data. Some compounds were tested for antibacterial activity. Several spiropyrazoline derivatives showed good to moderate activity against bacteria.