Semi-Synthesis of C-Ring Cyclopropyl Analogues of Fraxinellone and Their Insecticidal Activity Against Walker.

Fraxinellone () is a naturally occurring degraded limonoid isolated from Meliaceae and Rutaceae plants. As a potential natural-product-based insecticidal agent, fraxinellone has been structurally modified to improve its activity. Furan ring of fraxinellone is critical in exhibiting its insecticidal activity, but with few modifications.

Furan-site transformations of obacunone as potent insecticidal agents.

Furan ring is a key pharmacophore for insecticidal activity of limoninoids. To develop natural-product-based insecticidal agents, a series of furan-site transformations (, and -) of obacunone were synthesized by selective bromination and following coupling reactions without altering other functional groups. Bioassays indicated that derivatives and displayed more potent insecticidal activity than obacunone and toosendanin against the instar larvae of Walker.

Furan-Site Bromination and Transformations of Fraxinellone as Insecticidal Agents Against Mythimna separata Walker.

Furan ring of limoninoids is critical in exhibiting insecticidal activity. Herein, fraxinellone (1) was used as a template of furan-containing natural products and a series of its derivatives was synthesized by selective bromination in good yields on gram-scale and following Suzuki-Miyaura or Sonogashira coupling reactions in moderate to good yields. Bromination of limonin (9) was also accomplished without altering other functional groups in high yield.

Constructing novel dihydrofuran and dihydroisoxazole analogues of isocombretastatin-4 as tubulin polymerization inhibitors through [3+2] reactions.

[3+2] reactions play a key role in constructing various pharmaceutical moleculars. In this study, using Mn(OAc) mediated and 1,3-dipolar [3+2] cyclization reactions, 38 novel dihydrofuran and dihydroisoxazole analogues of isoCA-4 were synthesized as inhibitors of tubulin polymerization. Among them, compound 6g was found to be the most potent cytotoxic agents against PC-3 cells with IC value of 0.