Design, Synthesis, and Evaluation of Tetrasubstituted Pyridines as Potent 5-HT2C Receptor Agonists
摘要:
A series of pyrido[3,4-diazepines that are potent and selective S-HT2C receptor agonists is disclosed. Compound 7 (PF-04781340) is identified as a suitable lead owing to good 5-HT2C potency, selectivity over 5-HT2B agonism, and in vitro ADME properties commensurate with an orally available and CNS penetrant profile. The synthesis of a novel bicyclic tetrasubstituted pyridine core template is outlined, including rationale to account for the unexpected formation of aminopyridine 13 resulting from an ammonia cascade cyclization.
Chemistry and Biology of Deoxynyboquinone, a Potent Inducer of Cancer Cell Death
摘要:
Deoxynyboquinone (DNQ) is a potent antineoplastic agent with an unknown mechanism of action. Here we describe a facile synthetic route to this anthraquinone, and we use this material to determine the mechanism by which DNQ induces death in cancer cells. DNQ was synthesized in seven linear steps through a route employing three palladium-mediated coupling reactions. Experiments performed on cancer cells grown in hypoxia and normoxia strongly suggest that DNQ undergoes bioreduction to its semiquinone, which then is re-oxidized by molecular oxygen, forming superoxide that induces cell death. Furthermore, global transcript profiling of cells treated with DNQ shows elevation of transcripts related to oxidative stress, a result confirmed at the protein level by Western blotting. In contrast to most other antineoplastic agents that generate reactive oxygen species (ROS), DNQ potently induces death of cancer cells in culture, with IC50 values between 16 and 210 nM. In addition, unlike the experimental therapeutic elesclomol, DNQ is still able to induce cancer cell death under hypoxic conditions. This mechanistic understanding of DNQ will allow for a more comprehensive evaluation of the potential of direct ROS generation as an anticancer strategy, and DNQ itself has potential as a novel anticancer agent.