Stereo‐ and Regioselective Direct Multi‐Deuterium‐Labeling Methods for Sugars

Abstract

Deuterium-labeled sugars can be utilized as powerful tools for the architectural analyses of high-sugar-containing molecules represented by the nucleic acids and glycoproteins, and chiral building blocks for the syntheses of new drug candidates (heavy drugs) due to their potential characteristics, such as simplifying the (1)H NMR spectra and the stability of C-D bonds compared with C-H bonds. We have established a direct and efficient synthetic method of deuterated sugars from non-labeled sugars by using the heterogeneous Ru/C-catalyzed H-D exchange reaction in D(2)O under a hydrogen atmosphere with perfect chemo- and stereoselectivities. The direct H-D exchange reaction can selectively proceed on carbons adjacent to the free hydroxyl groups, and the deuterium labeling of various pyranosides (such as glucose and disaccharides), as well as furanosides, represented by ribose and deoxyribose was realized. Furthermore, the desired number of deuterium atoms can be freely incorporated into selected positions by the site-selective protection of the hydroxyl groups using acetal-type protective groups because the deuterium exchange reaction never proceeds on positions adjacent to the protected hydroxyl groups.

Photodynamic Activity of Fullerene Derivatives Solubilized in Water by Natural‐Product‐Based Solubilizing Agents

“…This finding suggests that the γ‐CDx ⋅ C 60 complex is present in equilibrium with free γ‐CDxs at room temperature. We showed the existence of an equilibrium by using 1 H NMR spectroscopy and deuterium‐labeled γ‐CDx (γ‐CDx‐[D]) . The binding ability of γ‐CDx‐[D] was the same as that of γ‐CDx.…”

“…We showedt he existence of an equilibrium by using 1 HNMR spectroscopy and deuterium-labeled g-CDx (g-CDx- [D]). [28][29][30] The binding ability of g-CDx-[D] was the same as that of g-CDx. Through 2D 1 H-1 He xchange spectroscopy (EXSY) NMR experiments, the intermoleculare xchange rate of g-CDx in the g-CDx·C 60 complexw as shown to be much slower than that in the g-CDx·C 70 complex (association rate:4 .3 s À1 , dissociation rate:0 .6 s À1 )a nd was on at imescale that could be directly measured.…”

Highlights of aliphatic C(sp3)‐H hydrogen isotope exchange reactions

“…The deuteration of the various sugars was achieved in a regioselective and stereoselective fashion without racemization. After simple work‐up, nearly quantitative deuterated sugars could be obtained ( 21 → 22 ; Scheme ) …”

New Gateways to the Platinum Group Metal-Catalyzed Direct Deuterium-Labeling Method Utilizing Hydrogen as a Catalyst Activator

“…Although all the reaction steps are in equilibria, the multideuterated products are preferentially obtained to circumvent the inverse reaction due to the stability of the C-D bond in comparison with the C-H bond. 21,22) Secondary and primary alcohols are deuterium-labeled site-selectively at the α-position of the hydroxy groups using Ru/C. 21) For example, 2-decanol efficiently undergoes Ru/C-catalyzed monodeuteration in D 2 O at 50°C under a hydrogen atmosphere for 3 h to give 2-decanol-d 1 with a 97% D content, along with the incorporation of a trace amount of deuterium atoms at the β-positions (Chart 3, top).…”