Synthesis of chiral primary amines: diastereoselective alkylation of N-[(1E)-alkylidene]-3,5-bis[(1S)-1-methoxyethyl]-4H-1,2,4-triazol-4-amines and N4–Nexocyclic bond cleavage in the resulting 1,2,4-triazol-4-alkylamines
作者:Muriel Serradeil-Albalat、Christian Roussel、Nicolas Vanthuyne、Jean-Claude Vallejos、Didier Wilhelm
DOI:10.1016/j.tetasy.2008.12.015
日期:2008.12
Enantiomerically pure 3,5-bis[(1S)-1-methoxyethyl]-4H-1,2,4-triazol-4-amine 14a and 3,5-bis[(1S)-1-ethoxyethyl]-4H-1,2,4-triazol-4-amine 14b were used as chiral auxiliaries to obtain enantiomerically enriched alpha-aminoacetals, primary alkyl and arylalkyl amines (ee ranging from 40% to 90%). The different stages of the process were imine formation from the corresponding aldehydes, diastereoselective addition of a Grignard reagent, quaternization of the triazole auxiliary and cleavage of the N-4-N-exocylic bond by LiBH4. The mechanism of the cleavage of the N-4-N-exocyclic bond is supported by the use of deuterated metal hydride. The absolute configurations of the new stereogenic centres were established by X-ray analyses of the enantiomerically pure stereomers isolated by semi-preparative liquid chromatography on a chiral support. (C) 2008 Elsevier Ltd. All rights reserved.
Anderson, D. Keith; Sikorski, James A.; Reitz, David B., Journal of Heterocyclic Chemistry, 1986, vol. 23, p. 1257 - 1262
作者:Anderson, D. Keith、Sikorski, James A.、Reitz, David B.、Pilla, Linda T.
DOI:——
日期:——
Site-Selective Silver-Catalyzed C–H Bond Deuteration of Five-Membered Aromatic Heterocycles and Pharmaceuticals
作者:Adrian Tlahuext-Aca、John F. Hartwig
DOI:10.1021/acscatal.0c04917
日期:2021.2.5
pharmaceutical ingredients that have been resistant to catalytic H/D exchange. The reactions occur with CH3OD as a low-cost source of the isotope. The silver catalysts react with five-membered heteroarenes lacking directing groups, tolerate a wide range of functional groups, and react in both polar and nonpolar solvents. Mechanistic experiments, including deuterium kinetic isotope effects, determination of kinetic