Synthesis, NMR and X-ray characterization of dibenzoannulated dimeric steroid spiroketals. Evaluation of cytotoxicity and anti-inflammatory activity

Two dibenzoannulated dimeric steroid spiroketals were obtained from cholesterol and 1,4-phenylenedimethanol. The key step in synthetic protocol is a Pd-catalyzed double spiroketalization in an adduct obtained from the double Sonogashira coupling of the 5α and 5β diastereomers of 4,5-secocholestan-5-ol. A detailed NMR characterization supported by Single Crystal X-ray Diffraction studies corroborated the obtained structures. While no cytotoxic effect was observed, the obtained compounds produced a significant reduction in the production of nitric oxide in macrophages stimulated with Lipopolysaccharide (LPS), indicating a potential anti-inflammatory activity.