The first successful effort to replicate
the beginning of the Taxol
oxidase phase in the laboratory is reported, culminating in the total
synthesis of taxuyunnanine D, itself a natural product. Through a
combination of computational modeling, reagent screening, and oxidation
sequence analysis, the first three of eight C–H oxidations
(at the allylic sites corresponding to C-5, C-10, and C-13) required
to reach Taxol from taxadiene were accomplished. This work lays a
foundation for an eventual total synthesis of Taxol capable of delivering
not only the natural product but also analogs inaccessible via bioengineering.
Despite their outstanding antitumour activity in mice, the limited supply from the natural sources has prevented drug discovery/development based on intact halichondrins. We achieved a total synthesis of C52-halichondrin-B amine (E7130) on a >10 g scale with >99.8% purity under GMP conditions. Interestingly, E7130 not only is a novel microtubule dynamics inhibitor but can also increase intratumoural CD31-positive endothelial cells and reduce α-SMA-positive cancer-associated fibroblasts at pharmacologically relevant compound concentrations. According to these unique effects, E7130 significantly augment the effect of antitumour treatments in mouse models and is currently in a clinical trial. Overall, our work demonstrates that a total synthesis can address the issue of limited material supply in drug discovery/development even for the cases of complex natural products.
An asymmetric synthesis of (+)-lysergic acid methyl ester was accomplished through construction of the tetracyclic ergoline skeleton by double cyclization consisting of intramolecular aromatic amination and Heck reaction.
Process studies of E2212 (1) toward rapid clinical introduction are described. Through comprehensive routefinding studies and optimization of key condensation and cyclization steps, a racemate-based manufacturing route was established and successfully scaled-up to the hundred kilogram scale. For the rapid delivery of a drug substance containing the Z isomer for preclinical safety studies, the successful scale-up of the photoisomerization of an olefin in a flow system is also presented.
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