Bioreductively activatable prodrug conjugates of phenstatin designed to target tumor hypoxia.

A variety of solid tumor cancers contain significant regions of hypoxia, which provide unique challenges for targeting by potent anticancer agents. Bioreductively activatable prodrug conjugates (BAPCs) represent a promising strategy for therapeutic intervention. BAPCs are designed to be biologically inert until they come into contact with low oxygen tension, at which point reductase enzyme mediated cleavage releases the parent anticancer agent in a tumor-specific manner.

Synthesis of a 2-aryl-3-aroyl indole salt (OXi8007) resembling combretastatin A-4 with application as a vascular disrupting agent.

The natural products colchicine and combretastatin A-4 are potent inhibitors of tubulin assembly, and they have inspired the design and synthesis of a large number of small-molecule, potential anticancer agents. The indole-based molecular scaffold is prominent among these SAR modifications, leading to a rapidly increasing number of agents. The water-soluble phosphate prodrug 33 (OXi8007) of 2-aryl-3-aroylindole-based phenol 8 (OXi8006) was prepared by chemical synthesis and found to be strongly cytotoxic against selected human cancer cell lines (GI₅₀ = 36 nM against DU-145 cells, for example).

Regioselective synthesis of water-soluble monophosphate derivatives of combretastatin A-1.

The natural products combretastatin A-4 (CA4) and combretastatin A-1 (CA1) are potent cancer vascular disrupting agents and inhibitors of tubulin assembly (IC₅₀ = 1-2 μM). The phosphorylated prodrugs CA4P and CA1P are undergoing human clinical trials against cancer. CA1 is unique due to its incorporation of a vicinal phenol, which has afforded the opportunity to prepare both diphosphate and regioisomeric monophosphate derivatives.

Development of synthetic methodology suitable for the radiosynthesis of combretastatin A-1 (CA1) and its corresponding prodrug CA1P.

Synthetic methodology has been established suitable for the preparation of combretastatin A-1 (CA1) and its corresponding phosphate prodrug salt (CA1P) in high specific activity radiolabeled form. Judicious selection of appropriate phenolic protecting groups to distinguish positions on the A-ring from the B-ring of the stilbenoid was paramount for the success of this project. Methylation of the C-4' phenolic moiety by removal of the tert-butyldimethylsilyl protecting group in the presence of methyl iodide was accomplished in excellent yield without significant Z to E isomerization.