Discovery of Novel, Orally Bioavailable Pyrimidine Ether-Based Inhibitors of ELOVL1.

In our efforts to identify novel small molecule inhibitors for the treatment of adrenoleukodystrophy (ALD), we conducted a high-throughput radiometric screen for inhibitors of elongation of very long chain fatty acid 1 (ELOVL1) enzyme. We developed a series of highly potent, central nervous system (CNS)-penetrant pyrimidine ether-based compounds with favorable pharmacokinetics culminating in compound 22. Compound 22 is a selective inhibitor of ELOVL1, reducing C26:0 VLCFA synthesis in ALD patient fibroblasts and lymphocytes in vitro. Compound 22 reduced C26:0 lysophosphatidyl choline (LPC), a subtype of VLCFA, in the blood of ATP binding cassette transporter D1 (ABCD1) KO mice, a murine model of ALD to near wild-type levels. Compound 22 is a low-molecular-weight, potent ELOVL1 inhibitor that may serve as a useful tool for exploring therapeutic approaches to the treatment of ALD.

Discovery of Novel Thiophene-Based, Thumb Pocket 2 Allosteric Inhibitors of the Hepatitis C NS5B Polymerase with Improved Potency and Physicochemical Profiles.

The hepatitis C viral proteins NS3/4A protease, NS5B polymerase, and NS5A are clinically validated targets for direct-acting antiviral therapies. The NS5B polymerase may be inhibited directly through the action of nucleosides or nucleotide analogues or allosterically at a number of well-defined sites. Herein we describe the further development of a series of thiophene carboxylate allosteric inhibitors of NS5B polymerase that act at the thumb pocket 2 site. Lomibuvir (1) is an allosteric HCV NS5B inhibitor that has demonstrated excellent antiviral activity and potential clinical utility in combination with other direct acting antiviral agents. Efforts to further explore and develop this series led to compound 23, a compound with comparable potency and improved physicochemical properties.

Discovery and Characterization of a Water-Soluble Prodrug of a Dual Inhibitor of Bacterial DNA Gyrase and Topoisomerase IV.

Benzimidazole 1 is the lead compound resulting from an antibacterial program targeting dual inhibitors of bacterial DNA gyrase and topoisomerase IV. With the goal of improving key drug-like properties, namely, the solubility and the formulability of 1, an effort to identify prodrugs was undertaken. This has led to the discovery of a phosphate ester prodrug 2. This prodrug is rapidly cleaved to the parent drug molecule upon both oral and intravenous administration. The prodrug achieved equivalent exposure of 1 compared to dosing the parent in multiple species. The prodrug 2 has improved aqueous solubility, simplifying both intravenous and oral formulation.

Synthesis of (-)-(R)-pyrrolam a and studies on its stability: a caveat on computational methods.

The asymmetric synthesis of (-)-(R)-pyrrolam A was achieved in three operations from N-Boc pyrrolidine via an alpha-(N-carbamoyl)alkylcuprate vinylation reaction followed by N-Boc deprotection and cyclization. One-pot deprotection-cyclization procedures led to mixtures of pyrrolam A and its double bond isomers. These isomerization events could be circumvented by use of a two-step procedure. To guide aspects of the experiments, a series of computational energy evaluations and chemical shift predictions were performed with molecular mechanics, semiempirical, ab initio, and density functional methods. The relative stabilities of the double bond isomers, as estimated by experiment, challenged a number of computational methods, and only the MP2 model with its moderate degree of electron correlation came close to matching the experimental data. The MP2 method was further applied to an unusual aspect of the double bond migration between pyrrolam A and its isomer 9. The reaction (1 to 9) on neat samples is irreversible without racemization, and the alumina-mediated equilibration is accompanied by complete loss of enantiomeric excess. The source of the irreversibility was traced to asymmetric charge distribution in the intermediate dienolate anion. The analysis ultimately led to a semiquantitative sketch of the pyrrolam energy surface.

Reactivity and enantioselectivity in the reactions of scalemic stereogenic alpha-(N-carbamoyl)alkylcuprates.

Stereogenic 2-(N-carbamoyl)pyrrolidinylcuprates prepared from scalemic (i.e., enantioenriched) N-Boc-2-lithiopyrrolidine and THF soluble CuCN.2LiCl react with vinyl iodides, vinyl triflates, beta-iodo-alpha,beta-enoates, propargyl mesylates, and allyl bromide to afford the substitution products with excellent enantioselectivity. Excellent enantiomeric ratios are obtained in the conjugate addition reactions with methyl vinyl ketone while low enantiomeric ratios can be achieved with acrylate esters using HMPA/TMSCl activation. Enantiomeric ratios vary with substrate substitution patterns and the observed enantioselectivities appear to be more a function of cuprate-electrophile reactivities than of the reaction type (e.g., substitution, conjugate addition). Low enantiomeric ratios are obtained with the alpha-(N-carbamoyl)benzylcuprates. The lithium-copper transmetalation and cuprate vinylation reactions proceed with retention of configuration.