Targeted sampling of natural product space to identify bioactive natural product-like polyketide macrolides

A sequential esterification-ring closing metathesis-Nozaki-Hiyama-Kishi strategy for constructing a natural product-like library of tetrahydrofuran-containing macrolides

Polyketide-like macrolides (pMLs) represent a privileged class of compounds with a high incidence of bioactivity, however their structural complexity challenges their synthesis and more general study. Here we report the synthesis of a library of tetrahydrofuran-containing pMLs underpinned by a robust and convergent build/couple/pair/couple synthetic approach. The library comprises 170 pMLs originating from 17 building blocks, 10 of which were synthesized using a proline-catalyzed α-chlorination aldol reaction. Northern and southern hemisphere building blocks were coupled using either an oxidation/Horner-Wadsworth-Emmons sequence or a saponification/Steglich esterification strategy. Coupled fragments were cyclized via ring closing metathesis to yield macrocycles 14-16 atoms in size, which we diversified using 3 eastern side chain vinyl iodides through a Nozaki-Hiyama-Kishi reaction.

Peripheral Evolution of Tanshinone IIA and Cryptotanshinone for Discovery of a Potent and Specific NLRP3 Inflammasome Inhibitor

Natural products (NPs) continue to serve as an invaluable source in drug discovery, and peripheral evolution of NPs is a highly efficient evolution strategy. Herein, we describe a unified "methyl to amide" peripheral evolution of Tanshinone IIA and Cryptotanshinone for discovery of NLRP3 inflammasome inhibitors. There were 54 compounds designed and prepared, while the chemoinformatic analysis revealed that these evolved NP analogues occupy a unique chemical space. Biological evaluation identified 5m as an NLRP3 inflammasome inhibitor, and 5m could directly bind to the NACHT domain of the NLRP3 protein and block the interaction of NLRP3 and ASC, thus suppressing ASC oligomerization and NLRP3 inflammasome assembly. Molecular dynamic stimulations revealed that the amide moiety played a vital role in the binding mode. Moreover, 5m exhibited therapeutical efficacy in sepsis and the NASH mouse model. In conclusion, this protocol provides a new vision of NPs' peripheral evolution and a novel NLRP3 inflammasome inhibitor.

Discovery of a Series of Macrocycles as Potent Inhibitors of Leishmania Infantum

Macrocycles are prominent among drugs for treatment of infectious disease, with many originating from natural products. Herein we report on the discovery of a series of macrocycles structurally related to the natural product hymenocardine. Members of this series were found to inhibit the growth of Plasmodium falciparum, the parasite responsible for most malaria cases, and of four kinetoplastid parasites. Notably, macrocycles more potent than miltefosine, the only oral drug used for the treatment of the neglected tropical disease visceral leishmaniasis, were identified in a phenotypic screen of Leishmania infantum. In vitro profiling highlighted that potent inhibitors had satisfactory cell permeability with a low efflux ratio, indicating their potential for oral administration, but low solubility and metabolic stability. Analysis of predicted crystal structures suggests that optimization should focus on the reduction of π-π crystal packing interactions to reduce the strong crystalline interactions and improve the solubility of the most potent lead.