Synthetic studies on naphthoxylosides - labeled compounds and mechanistic studies on acetals

Abstract: Labeled analogs to an antiproliferative naphthoxyloside have been synthesized and evaluated. Our investigations have shown that the fluorescently labeled analogs are poor structural analogs, and the physical and biological properties are altered to a large extent. Instead, a radioactively labeled compound was synthesized, which made it possible to follow the pathway in the cell. The results showed a difference between a normal and a transformed cell line based on accumulation of the naphthoxyloside and it appears that the transformed cells process the naphthoxylosides faster than the normal cells do. This work also involved mechanistic studies for regioselective openings of benzylidene acetals with boranes and a new mechanism has been proposed. As it turns out, the regioselectivity can be controlled by the choice of borane, Lewis acid and solvent. When the borane is activated by a Lewis acid, the reaction rate is increased and the borane is the most electrophilic species, thus directing the regioselectivity. In contrary, when the borane is not activated, the Lewis acid is the most electrophilic species that directs the regioselectivity.