Background: Up-regulated pyruvate dehydrogenase kinase isoforms (PDKs) are associated with impaired glucose homeostasis in diabetes. Results: Novel PDK inhibitors were developed using structure-based design, which improves glucose tolerance with reduced hepatic steatosis in diet-induced obese mice. Conclusion: Obesity phenotypes are effectively treated by chemical intervention with PDK inhibitors. Significance: PDKs are potential drug targets for obesity and type 2 diabetes.
A possible biosynthetic link between atropurpuran, the hetidine diterpenoid alkaloids and the alkaloid arcutine and congeners is proposed. The feasibility of aspects of this biosynthesis, especially key 1,2-rearrangements, have been examined computationally.
An approach to construct enantiopure complex natural product-like frameworks, including the first reported synthesis of a C17 oxygenated taxoid scaffold, is presented. A palladium-catalyzed C-C activation/cross-coupling is utilized to access these structures in a short sequence from (+)-carvone; the scope of this reaction is explored.
The
full details of a synthesis of the hetidine framework of the
C20-diterpenoid alkaloids and its conversion to the atisine
core structure are reported. The application of the hetidine framework
to the synthesis of dihydronavirine, which is the formal reduction
product of the natural product navirine, is also described. Key to
the success of these studies is the use of a Ga(III)-catalyzed cycloisomerization
reaction of alkynylindenes to prepare a [6–7–6] framework
that was advanced to the hetidine skeleton. Furthermore, a Michael/aldol
sequence was developed for the construction of the bicyclo[2.2.2]
framework that is characteristic of the hetidines and atisines.
Arcutinidine and other arcutinidine-type diterpenoid alkaloids feature an intricate polycyclic, bridged framework with unusual connectivity. A chemical network analysis approach to the arcutane skeleton enabled the identification of highly simplifying retrosynthetic disconnections, which indicated that the caged structure could arise from a simpler fused ring system. On this basis, a total synthesis of arcutinidine is reported herein, featuring an unprecedented oxopyrrolium Diels− Alder cycloaddition which furnishes a key tetracyclic intermediate. In addition, the synthesis utilizes a diastereoselective oxidative dearomatization/cycloaddition sequence and a SmI 2 -mediated C−C coupling to forge the bridged framework of the natural products. This synthetic plan may also enable future investigations into the biosynthetic relationships between the arcutanes, the related diterpenoid atropurpuran, and other diterpenoid alkaloids.Communication pubs.acs.org/JACS
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