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Relevant academic research and scientific papers

NHC-Stabilized Iridium Nanoparticles as Catalysts in Hydrogen Isotope Exchange Reactions of Anilines

The preparation of N-heterocyclic carbene-stabilized iridium nanoparticles and their application in hydrogen isotope exchange reactions is reported. These air-stable and easy-to-handle iridium nanoparticles showed a unique catalytic activity, allowing selective and efficient hydrogen isotope incorporation on anilines using D2 or T2 as isotopic source. The usefulness of this transformation has been demonstrated by the deuterium and tritium labeling of diverse complex pharmaceuticals.

Multiple Site Hydrogen Isotope Labelling of Pharmaceuticals

Radiolabelling is fundamental in drug discovery and development as it is mandatory for preclinical ADME studies and late-stage human clinical trials. Herein, a general, effective, and easy to implement method for the multiple site incorporation of deuterium and tritium atoms using the commercially available and air-stable iridium precatalyst [Ir(COD)(OMe)]2 is described. A large scope of pharmaceutically relevant substructures can be labelled using this method including pyridine, pyrazine, indole, carbazole, aniline, oxa-/thia-zoles, thiophene, but also electron-rich phenyl groups. The high functional group tolerance of the reaction is highlighted by the labelling of a wide range of complex pharmaceuticals, containing notably halogen or sulfur atoms and nitrile groups. The multiple site hydrogen isotope incorporation has been explained by the in situ formation of complementary catalytically active species: monometallic iridium complexes and iridium nanoparticles.

Synthesis of Some Deuterated Aromatic Mesomorphic Compounds Used in Broad-Line 2H-NMR Studies

Twenty-one deuterated mesogens of the following types: HOAB (perdeuterated chains), 4-alkoxybenzoic acids (perdeuterated chain and acid deuteron), 7S5 and 8S5 (perdeuterated alkoxy chain), 4-alkoxybenzylidene-4'-alkylanilines (2 or 4 deuterons in the aniline ring, 2-α-deuterons on the alkyl chain and perdeuterated alkyl or alkoxy chain) and TBBA (perdeuterated alkyl chains or anil deuterons) were prepared for use in broad-line 2H-NMR by using standard literature methods.The required 4-alkoxybenzoic acids, aldehydes and anilines with perdeuterated chains were prepared by alkylation of the appropriate 4-substituted phenol.The acid proton in the 4-alkoxybenzoic acids were replaced with a deuteron either by basic hydrolysis of the ester or acid chloride or by base-catalyzed exchange on the acid.Two deuterons were incorporated into the aniline ring ortho to the amino group by exchange in dilute H2SO4.Four ring deuterons, two α-chain deuterons or a perdeuterated chain were incorporated into 4-alkylanilines by the following sequence of steps: Friedel-Crafts acylation of benzene with an acid chloride, catalytic reduction, Friedel-Crafts acylation with oxalyl chloride, hydrolysis in base and a Schmidt rearrangement in H2SO4.New deuteration equipment was designed for the catalytic reduction using deuterium.IR NMR and MS were used to determine the deuterium content of these compounds.Small differences in mesophase transition temperatures were observed for mesogens containing perdeuterated alkyl or alkoxy chains.