Palladium-catalyzed hydrogenolysis of azabicyclic peroxides. Quantitative transformation to 1-hydroxy-7-aza-2-oxabicyclo[3.3.0]octanes

Synthesis and antimalarial activity of novel bicyclic and tricyclic aza-peroxides

Bicyclic and tricyclic aza-peroxides were synthesized and assessed for theirin vitroandin vivoantimalarial activities againstPlasmodium falciparum(3D7 strain) andPlasmodium yoelii nigeriensisin Swiss mice by an oral route, respectively.

Systemic study on the biogenic pathways of yezo’otogirins: total synthesis and antitumor activities of (±)-yezo’otogirin C and its structural analogues

A systematic study of the biomimetic pathways to yezo’otogirin C under aerobic and anaerobic conditions has been investigated, and both are found to be feasible pathways to the natural product depending on the physiological conditions. Because of the lower activation energy, the aerobic process would be more favorable when the in vivo oxygen level is high. In the course of this study, a highly efficient synthetic route to (±)-yezo’otogirin C has been established in four steps (31% overall yield) from a readily available compound without using any protecting groups. The natural product and its structural analogues exhibited antitumor activities against several human cancer cell lines and appeared to arrest cell cycles in different phases.

Fusarisetin A: Scalable Total Synthesis and Related Studies

Fusarisetin A (1) is a recently isolated natural product that displays an unprecedented chemical motif and remarkable bioactivities as a potent cancer migration inhibitor. We describe here our studies leading to an efficient and scalable total synthesis of 1. Essential to the strategy was the development of a new route for the formation of a trans-decalin moiety of this compound and the application of an oxidative radical cyclization (ORC) reaction that produces fusarisetin A (1) from equisetin (2) via a bio-inspired process. TEMPO-induced and metal/O(2)-promoted ORC reactions were evaluated. Biological screening in vitro confirms the reported potency of (+)-1. Importantly, ex vivo studies show that this compound is able to inhibit different types of cell migration. Moreover, the C(5) epimer of (+)-1 was also identified as a potent cancer migration inhibitor, while (-)-1 and 2 were found to be significantly less potent. The optimized synthesis is applicable on gram scale and provides a solid platform for analogue synthesis and methodical biological study.