Publications by authors named "Lieven Meerpoel"

Cyclopropane fusion of the only rotatable carbon-carbon bond in furanosyl nucleosides (i.e., exocyclic 4'-5') is a powerful design strategy to arrive at conformationally constrained analogues.

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Novel C-4',C-5' cyclobutane-fused spirocyclic ribonucleoside analogues were prepared. Thermal [2 + 2] cycloaddition between dichloroketene and readily derived 4'--methylene furanoses afforded a first entry to the required constrained ribofuranoses, relying on a carbonyl transposition sequence. Alternatively, an unusual stereoselective ionic [2 + 2] cycloaddition using methyl propiolate promoted by methylaluminoxane gave a complementary, more direct approach to such ribofuranoses.

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The protein arginine methyltransferase 5 (PRMT5) methylates a variety of proteins involved in splicing, multiple signal transduction pathways, epigenetic control of gene expression, and mechanisms leading to protein expression required for cellular proliferation. Dysregulation of PRMT5 is associated with clinical features of several cancers, including lymphomas, lung cancer, and breast cancer. Here, we describe the characterization of JNJ-64619178, a novel, selective, and potent PRMT5 inhibitor, currently in clinical trials for patients with advanced solid tumors, non-Hodgkin's lymphoma, and lower-risk myelodysplastic syndrome.

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Androgen receptor (AR) transcriptional reactivation plays a key role in the development and progression of lethal castration-resistant prostate cancer (CRPC). Recurrent alterations in the AR enable persistent AR pathway signaling and drive resistance to the treatment of second-generation antiandrogens. AR F877L, a point mutation in the ligand binding domain of the AR, was identified in patients who acquired resistance to enzalutamide or apalutamide.

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Numerous mechanisms of resistance arise in response to treatment with second-generation androgen receptor (AR) pathway inhibitors in metastatic castration-resistant prostate cancer (mCRPC). Among these, point mutations in the ligand binding domain can transform antagonists into agonists, driving the disease through activation of AR signaling. To address this unmet need, we report the discovery of JNJ-63576253, a next-generation AR pathway inhibitor that potently abrogates AR signaling in models of human prostate adenocarcinoma.

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Persistent androgen receptor (AR) activation drives therapeutic resistance to second-generation AR pathway inhibitors and contributes to the progression of advanced prostate cancer. One resistance mechanism is point mutations in the ligand binding domain of AR that can transform antagonists into agonists. The AR F877L mutation, identified in patients treated with enzalutamide or apalutamide, confers resistance to both enzalutamide and apalutamide.

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Protein arginine methyltransferase 5 (PRMT5) is an enzyme that can symmetrically dimethylate arginine residues in histones and nonhistone proteins by using -adenosyl methionine (SAM) as the methyl donating cofactor. We have designed a library of SAM analogues and discovered potent, cell-active, and selective spiro diamines as inhibitors of the enzymatic function of PRMT5. Crystallographic studies confirmed a very interesting binding mode, involving protein flexibility, where both the cofactor pocket and part of substrate binding site are occupied by these inhibitors.

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A novel class of substituted spiro[3.4]octanes can be accessed via a [2 + 2]-cycloaddition of dichloroketene on a readily prepared -methylene cyclopentane building block. This reaction sequence was found to be robust on a multigram scale and afforded a central spirocyclobutanone scaffold for carbocyclic nucleosides.

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Liquid crystals (LCs) undergo fast phase transitions, almost without hysteresis, leading to the notion that it is difficult to bypass LC transitions. However, recent work on itraconazole has shown that a nematic-to-smectic phase transition can be frustrated or avoided at moderate cooling rates. At each cooling rate, the highest smectic order obtained is determined by the kinetic arrest of the end-over-end molecular rotation.

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We describe a series of potent and highly selective small-molecule MALT1 inhibitors, optimized from a High-Throughput Screening hit. Advanced analogues such as compound 40 show high potency (IC: 0.01 µM) in a biochemical assay measuring MALT1 enzymatic activity, as well as in cellular assays: Jurkat T cell activation (0.

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Despite the large variety of modified nucleosides that have been reported, the preparation of constrained 4'-spirocyclic adenosine analogues has received very little attention. We discovered that the [2+2]-cycloaddition of dichloroketene on readily available 4'-exo-methylene furanose sugars efficiently results in the diastereoselective formation of novel 4'-spirocyclobutanones. The reaction mechanism was investigated via density functional theory (DFT) and found to proceed either via a non-synchronous or stepwise reaction sequence, controlled by the stereochemistry at the 3'-position of the sugar substrate.

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A new three-component reductive arylation of amides with stable reactants (iPrOH and arylboronate esters), making use of a 2-pyridinyl (Py) directing group, is described. The N-Py-amide substrates are readily prepared from carboxylic acids and PyNH , and the resulting N-Py-1-arylalkanamine reaction products are easily transformed into the corresponding chlorides by substitution of the HN-Py group with HCl. The 1-aryl-1-chloroalkane products allow substitution and cross-coupling reactions.

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The development of a general, mild, and functional-group-tolerant direct functionalization of N-heteroarenes by C-H functionalization with N-protected amines, including azetidines under Minisci-mediated photoredox conditions, is reported. A broad scope of substituted azetidines, including spirocyclic derivatives, and heterocycles were explored. This reaction enables the production of sp3-rich complex druglike structures in one step from unactivated feedstock amines and heterocycles.

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We designed and synthesized a new series of fatty acid synthase (FASN) inhibitors with potential utility for the treatment of cancer. Extensive SAR studies led to highly active FASN inhibitors with good cellular activity and oral bioavailability, exemplified by compound 34. Compound 34 is a potent inhibitor of human FASN (IC = 28 nM) that effectively inhibits proliferation of A2780 ovarian cells (IC = 13 nM) in lipid-reduced serum (LRS).

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An iron-catalyzed synthesis of sulfur- and sulfone-containing heterocycles is reported. The method is based on the cyclization of readily available substrates and proceeded with high efficiency and diastereoselectivity. A variety of sulfur-containing heterocycles bearing moieties suitable for subsequent functionalization are prepared.

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Article Synopsis
  • - A new method is introduced for creating silylated heterocycles that could be valuable in medicinal chemistry, focusing on bromophenyl trimethylsilyl pyrazole intermediates.
  • - These intermediates can be converted into two types of regioisomeric iodoaryl substrates using arylzinc or aryllithium chemistry, where the TMS group can either stay on the pyrazole or move to the aryl.
  • - The resulting compounds can be transformed into benzo silino pyrazoles through a single-step process that activates a C(sp(3))-H bond near a silicon atom, suggesting a specific reaction mechanism called concerted metalation-deprotonation (CMD).
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The construction and subsequent orthogonal functionalization of a hitherto unknown oxazolo[5',4':4,5]pyrano[2,3-b]pyridine are reported. A palladium-catalyzed direct C-H bond functionalization methodology was used to build the tricyclic scaffold as well as to achieve the subsequent C-H bond functionalization at the C-2 position of the oxazole unit with various (hetero)aryl iodides. Remarkably, selective C-H construction and functionalization procedures preserve the chorine atom on the pyridine moiety offering a late-stage substitution site to progress drug design.

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An iron-catalyzed cyclization of hydroxy allylic derivatives into tetrahydropyrans possessing an N-heteroaryl at C2 is disclosed. The reaction proceeds with good yield and in high diastereoselectivity in favor of the more stable isomer. The diastereoselectivity results from an iron-induced reopening of the tetrahydropyrans, allowing a thermodynamic equilibration.

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Maternal embryonic leucine zipper kinase (MELK), a serine/threonine protein kinase, has oncogenic properties and is overexpressed in many cancer cells. The oncogenic function of MELK is attributed to its capacity to disable critical cell-cycle checkpoints and reduce replication stress. Most functional studies have relied on the use of siRNA/shRNA-mediated gene silencing.

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Article Synopsis
  • A new Type II kinase inhibitor has been developed specifically for maternal embryonic leucine zipper kinase (MELK) using a method known as structure-based ligand design.
  • This approach involved detailed structural analysis of the protein-ligand interactions through techniques like X-ray crystallography, which helped identify a unique pocket for the inhibitor to bind.
  • The optimized inhibitor is highly effective, operating at low nanomolar concentrations and able to easily enter cells, making it a promising tool for researching MELK's biological functions.
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Article Synopsis
  • Fragment-based drug design was used effectively to target maternal embryonic leucine zipper kinase (MELK).
  • Researchers identified an initial low-affinity fragment that bound to MELK's hinge region in a unique way.
  • This fragment was then optimized into a potent, cell-penetrating inhibitor with low nanomolar affinity, making it a valuable tool for studying MELK's biological roles.
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A simple access to silylated and germylated binuclear heterocycles, based on an original anionic rearrangement, is described. A set of electron-rich and electron-poor silylated aromatic and heteroaromatic substrates were tested to understand the mechanism and the factors controlling this rearrangement, in particular its regioselectivity. This parameter was shown to follow the rules proposed before from a few examples.

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Background: Pyrrolo[1,2-α][1,4]benzodiazepines (PBDs) have been described as a novel class of antifungal compounds with activity against dermatophytes and Aspergillus fumigatus. The initial structure-activity relationship showed that compounds with a chlorine substitution at position 7 have a higher activity compared with regioisomers or other substituents.

Methods: The present study evaluated more analogues with a 7-chlorine-substitution in vitro against a broad panel of clinically relevant fungal species.

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