While ?diversity-oriented,? ?biology-oriented,? and ?analogue-oriented? syntheses have contributed to Wender?s call for ?function-oriented synthesis,? the simultaneous alignment of total synthesis efforts with structure activity relationship (SAR) studies has not been fully realized. This is particularly true with natural products where little to no SAR information exists. Bringing hypotheses regarding a targeted natural product's pharmacophore into the retrosynthetic planning stages of a total synthesis effort would dramatically accelerate the identification of simplified, bioactive derivatives as lead compounds for therapeutic intervention. Our chemical and biological studies of natural products possessing a broad range of cellular effects will be guided by the following inquiry: Can total synthesis efforts, in particular with limited SAR and unknown cellular targets, be more closely aligned to biological studies by targeting designed derivatives possessing a hypothesized pharmacophore during the retrosynthetic planning stages to enable SAR studies to be conducted en route to the natural product? Our study will develop a type of innovative retrosynthetic analysis that more closely aligns total synthesis efforts with concurrent biological studies. We term this strategy ?pharmacophore- directed retrosynthesis? (PDR) to emphasize the importance of considering hypothesized pharmacophores at the retrosynthetic planning stage of a total synthesis effort. This approach will importantly lead to the identification of simplified versions of the natural product with similar potency or potentially new functions in route to the natural product. While this approach increases the challenges of natural product total synthesis beyond important, contemporary goals, including atom-economy, step and redox efficiency, and protecting group avoidance, significantly it will greatly accelerate harvesting of the vast information content of natural products for basic cell biology and medicine. This strategy begins with a hypothesized pharmacophore for a bioactive natural product which informs and directs the retrosynthetic strategy. Stepwise, methodical introduction of complexity to the hypothesized pharmacophore enables concurrent SAR data collection which in turn informs cellular probe synthesis. A fruitful group of ongoing collaborators, including molecular, cell, and cancer biologists and chemical biologists will utilize our natural product-based probes to contribute to fundamental advances in cell biology. Overall, our proposed synthetic studies, combined with collaborative biological studies, will both open new avenues for novel therapeutics, and contribute to a greater understanding of basic cellular mechanisms involved in human disease including bacterial infection, inflammation, cardiovascular, Alzheimer?s disease, and cancer. The proposed research will demonstrate the importance of closely engaging total synthesis efforts with biological studies of natural products at the retrosynthetic planning stages. We will demonstrate the utility of PDR for reverse chemical genetic explorations of natural products towards identification of new drug leads and novel cellular targets critical to uncovering new avenues to impact human health.
Public Relevance Statement The proposed novel strategy for how the synthesis of natural products is approached will accelerate their exploration as new avenues for small molecule intervention against cancers of the brain and breast, Alzheimer?s, inflammation, and both cardiovascular and infectious disease. The structure-activity relationships derived from biological studies of simplified derivatives identified in route to the targeted natural products through our approach, along with derived cellular probes, will lead to identification of novel therapeutic targets impacting the treatment of human disease. The identification of novel small molecule-protein interactions is critical for the development of the next generation of human therapeutics and the proposed research will contribute significantly to this arena.
