A new highly diastereoselective synthesis of the polyhydroxylated pyrrolidine alkaloid (±)-codonopsinol B and its -nor-methyl analogue, starting from achiral materials, is presented. The strategy relies on the -stereoselective epoxidation of 2,3-dihydroisoxazole with in situ-generated DMDO, the -selective α-chelation-controlled addition of vinyl-MgBr/CeCl to the isoxazolidine-4,5-diol intermediate, and the substrate-directed epoxidation of the terminal double bond of the corresponding γ-amino-α,β-diol with aqueous hydrogen peroxide catalyzed by phosphotungstic heteropoly acid. Each of the key reactions proceeded with an excellent diastereoselectivity (dr > 95:5). (±)-Codonopsinol B was prepared in 10 steps with overall 8.4% yield. The antiproliferative effect of (±)-codonopsinol B and its -nor-methyl analogue was evaluated using several cell line models.
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http://dx.doi.org/10.3762/bjoc.17.188 | DOI Listing |
PLoS One
October 2024
Group «Mechanisms of DNA Repair and Carcinogenesis», CNRS UMR9019, Université Paris-Saclay, Gustave Roussy Cancer Campus, Villejuif Cedex, France.
Human thymine-DNA glycosylase (TDG) excises T mispaired with G in a CpG context to initiate the base excision repair (BER) pathway. TDG is also involved in epigenetic regulation of gene expression by participating in active DNA demethylation. Here we demonstrate that under extended incubation time the full-length TDG (TDGFL), but neither its isolated catalytic domain (TDGcat) nor methyl-CpG binding domain-containing protein 4 (MBD4) DNA glycosylase, exhibits significant excision activity towards T and C in regular non-damaged DNA duplex in TpG/CpA and CpG/CpG contexts.
View Article and Find Full Text PDFEJNMMI Res
August 2024
The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, 1550 Orleans St. CRB2 493, Baltimore, MD, 21228, USA.
Background: Reactive microglia and recruited peripheral macrophages contribute to the pathogenesis of Alzheimer's dementia (AD). Monocytes, macrophages and microglia all express the marker colony-stimulating factor 1 receptor (CSF1R). 4-Cyano-N-(4-(4-methylpiperazin-1-yl)-2-(4-methylpiperidin-1-yl)phenyl)-1H-pyrrole-2-carboxamide (1) is a high-affinity antagonist for CSF1R.
View Article and Find Full Text PDFJ Org Chem
July 2024
Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/163, 1060 Wien, Austria.
Our studies toward the total synthesis of the natural product euphosalicin () are presented. Different approaches targeting key intermediates are described, the synthesis of which includes findings on asymmetric dihydroxylations and ring-closing enyne metatheses (RCEYM). Their connection allowed the isolation of highly advanced precursors for studies on macrocyclizations.
View Article and Find Full Text PDFEur J Nucl Med Mol Imaging
October 2022
The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, USA.
Purpose: Macrophages represent an essential means of sequestration and immune evasion for Mycobacterium tuberculosis. Pulmonary tuberculosis (TB) is characterized by dense collections of tissue-specific and recruited macrophages, both of which abundantly express CSF1R on their outer surface. 4-Cyano-N-(5-(1-(dimethylglycyl)piperidin-4-yl)-2',3',4',5'-tetrahydro-[1,1'-biphenyl]-2-yl)-1H-imidazole-2-carboxamide (JNJ-28312141) is a reported high affinity, CSF1R-selective antagonist.
View Article and Find Full Text PDFBeilstein J Org Chem
November 2021
Institute of Organic Chemistry, Catalysis and Petrochemistry, Slovak University of Technology in Bratislava, Radlinského 9, 81237 Bratislava, Slovak Republic.
A new highly diastereoselective synthesis of the polyhydroxylated pyrrolidine alkaloid (±)-codonopsinol B and its -nor-methyl analogue, starting from achiral materials, is presented. The strategy relies on the -stereoselective epoxidation of 2,3-dihydroisoxazole with in situ-generated DMDO, the -selective α-chelation-controlled addition of vinyl-MgBr/CeCl to the isoxazolidine-4,5-diol intermediate, and the substrate-directed epoxidation of the terminal double bond of the corresponding γ-amino-α,β-diol with aqueous hydrogen peroxide catalyzed by phosphotungstic heteropoly acid. Each of the key reactions proceeded with an excellent diastereoselectivity (dr > 95:5).
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