Survivin, a homodimeric member of the Inhibitor of Apoptosis Protein (IAP) family, is required for cancer cell survival and overexpressed in almost all solid tumors. However, targeting survivin has been challenging due to its "undruggable" nature. Recently, we used a novel approach to target the dimerization interface and identified inhibitors of two scaffolds that can directly bind to and inhibit survivin dimerization. One of the scaffolds, represented by the compound LQZ-7, contain an undesirable labile hydrazone linker and a potentially non-functional furazanopyrazine ring that we attempted to eliminate in this study. We found one compound, 7I, that is more active than the parent compound, LQZ-7, and when given orally effectively inhibits xenograft tumor growth and induces survivin loss in tumors. These findings indicate that 7I with a stable linker and a quinoxaline ring can be used as a lead for further optimization of this novel class of survivin inhibitors.
A nickel-catalyzed tandem Ueno–Stork
cyclization is developed
to enable stereoselective 1,2-dicarbofunctionalization of cyclic alkenes
and efficiently build various bicyclic products. This new protocol
does not involve any toxic or difficult-to-remove tin reagent and
is scalable and amenable to build all-carbon quaternary centers.
A concise and stereoselective total synthesis of the clinically relevant tricyclic prostaglandin D2 metabolite (tricyclic-PGDM) methyl ester in racemic form was accomplished in 8 steps from a readily available known cyclopentene-diol derivative. The synthesis features a nickel-catalyzed Ueno-Stork-type dicarbofunctionalization to generate two consecutive stereocenters, a palladium-catalyzed carbonylative spirolactonization to build the core oxaspirolactone, and a Z-selective cross metathesis to introduce the (Z)-3-butenoate side chain, a group challenging to introduce through traditional Wittig protocols and troublesome for the two previous total syntheses. A general Z-selective cross metathesis protocol to construct (Z)-β,γ-unsaturated esters was also developed that has broad functional group tolerance and high stereoselectivity. Additionally, our synthesis already accumulated 75 mg of valuable material for an 18 O tricyclic-PGDM based assay used in clinical settings for inflammation.
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