Specific Isotope Enrichment of Methyl Methacrylate

13 Cβ-Valine and 13 Cγ-Leucine Methine Labeling To Probe Protein Ligand Interaction

Precise information regarding the interaction between proteins and ligands at molecular resolution is crucial for effectively guiding the optimization process from initial hits to lead compounds in early stages of drug development. In this study, we introduce a novel aliphatic side chain isotope-labeling scheme to directly probe interactions between ligands and aliphatic sidechains using NMR techniques. To demonstrate the applicability of this method, we selected a set of Brd4-BD1 binders and analyzed 1 H chemical shift perturbation resulting from CH-π interaction of Hβ -Val and Hγ -Leu as CH donors with corresponding ligand aromatic moieties as π acceptors.

Synthesis of a 13C-methylene-labeled isoleucine precursor as a useful tool for studying protein side-chain interactions and dynamics

In this study, we present the synthesis and incorporation of a metabolic isoleucine precursor compound for selective methylene labeling. The utility of this novel α-ketoacid isotopologue is shown by incorporation into the protein Brd4-BD1, which regulates gene expression by binding to acetylated histones. High quality single quantum 13C-1 H-HSQC were obtained, as well as triple quantum HTQC spectra, which are superior in terms of significantly increased 13C-T2 times. Additionally, large chemical shift perturbations upon ligand binding were observed. Our study thus proves the great sensitivity of this precursor as a reporter for side-chain dynamic studies and for investigations of CH-π interactions in protein-ligand complexes.

Chiral Isochalcogenourea-Catalysed Enantioselective (4+2) Cycloadditions of Allenoates

Allenoates are versatile building blocks which are primarily activated and controlled using chiral tert. phosphine and tert. amine Lewis bases. We herein report the first example of allenoate activation by using chiral isochalcogenoureas (IChU) for formal (4+2) cycloaddition reactions. Compared to established phosphine and amine catalysis, the use of these easily available Lewis bases enables new stereoselective reaction pathways proceeding with high enantioselectivities, diastereoselectivities, and in good yields. In addition, the factors governing enantioselectivity and the origin of the observed differences compared to other commonly used Lewis bases are explained.

Chiral Isochalcogenourea-Catalysed Enantioselective (4+2) Cycloadditions of Allenoates

Allenoates are versatile building blocks which are primarily activated and controlled using chiral tert. phosphine and tert. amine Lewis bases. We herein report the first example of allenoate activation by using chiral isochalcogenoureas (IChU) for formal (4+2) cycloaddition reactions. Compared to established phosphine and amine catalysis, the use of these easily available Lewis bases enables new stereoselective reaction pathways proceeding with high enantioselectivities, diastereoselectivities, and in good yields. In addition, the factors governing enantioselectivity and the origin of the observed differences compared to other commonly used Lewis bases are explained.

Unexplored Vinylic-Substituted 5-Benzylidenethiazolidine-2,4-diones: Synthesis and DFT/NMR Stereochemical Assignment

By exploring an efficient and versatile method for the 6-functionalization of its scaffold, we investigated the opening of a new chemical space around benzylidenethiazolidine-2,4-dione (BTZD). The 6-chloro- and 6-formyl BTZD obtained in two steps starting from 5-lithioTZD were selected as key intermediates and involved in a Pd-catalyzed cross-coupling or Wittig olefination. A variety of aryl, heteroaryl, or alkenyl substituents was successfully introduced on the vinylic position of BTZD, and particular attention was paid to elucidate the stereochemistry of the benzylidene derivatives by using a combined DFT/NMR study.

Intramolecular Diels-Alder Reactions of Tethered Enoate Substituted Furans Induced by Dialkylaluminum Chloride

Gold(I)-catalyzed cycloisomerization of enynols 11 and 17, obtained by Sonogashira coupling, led to the tethered enoate-substituted furans 14 and 19. While attempts at thermal and several Lewis acid induced intramolecular Diels-Alder reactions remained fruitless, dialkylaluminum chloride led to the formation of hexahydroindene and octahydronaphthalene derivatives 20-23. Their formation can be explained by Lewis acid induced opening of the epoxy bridge with transfer of one alkyl group to the intermediate cycloadduct.

Synthetic use of the primary kinetic isotope effect in hydrogen atom transfer 2: generation of captodatively stabilised radicals

Using C-3 di-deuterated morpholin-2-ones bearing N-2-iodobenzyl and N-3-bromobut-3-enyl radical generating groups, only products derived from the more stabilised C-3, rather than the less stabilised C-5 translocated radicals, were formed after intramolecular 1,5-hydrogen atom transfer, suggesting that any kinetic isotope effect present was not sufficient to offset captodative stabilisation.

Concise syntheses of selective inhibitors against α-1,3-galactosyltransferase

Several iminosugar-based uridine diphosphate galactose (UDP-Gal) mimetics 1-4 including d- and l-epimers were designed and synthesized by concise routes, and these synthetic compounds were evaluated for the inhibition of α-1,3- and β-1,4-galactosyltransferases in vitro. The experimental data demonstrated that l-epimer 2 displayed the strongest inhibitory activity with moderate selectivity against α-1,3-galactosyltransferase.

Structure–activity relationship of anti-malarial spongean peroxides having a 3-methoxy-1,2-dioxane structure

In order to study the structure-activity relationship of anti-malarial spongean peroxides, several analogues concerning with the 6-methoxyacetyl moiety and the 3-pentyl residue in methyl 2-(3-methoxy-3-pentyl-1,2-dioxan-6-yl)acetate were synthesized and evaluated for anti-malarial activity. The tert-butyl ester analogue 14 showed stability in mouse serum and a high selectivity index against the malaria parasite, Plasmodium falciparum, and the citronellyl analogue 31 exhibited the strongest in vitro anti-malarial activity among them, and the imidazole analogue 25 showed desirable in vivo anti-malarial activity against P. berghei infected mice.