608-66-2Relevant articles and documents
C3 Epimerization of Glucose, via Regioselective Oxidation and Reduction
Jumde, Varsha R.,Eisink, Niek N. H. M.,Witte, Martin D.,Minnaard, Adriaan J.
, p. 11439 - 11443 (2016)
Palladium-catalyzed oxidation can single out the secondary hydroxyl group at C3 in glucose, circumventing the more readily accessible hydroxyl at C6 and the more reactive anomeric hydroxyl. Oxidation followed by reduction results in either allose or allitol, each a rare sugar that is important in biotechnology. Also, N-acetylglucosamine is selectively oxidized at C3. These results demonstrate that glucose and N-acetylglucosamine, the most readily available chiral building blocks, can be versatile substrates in homogeneous catalysis.
Elucidating the effect of solid base on the hydrogenation of C5 and C6 sugars over Pt–Sn bimetallic catalyst at room temperature
Tathod, Anup P.,Dhepe, Paresh L.
, (2021/05/19)
Conversion of sugars into sugar alcohols at room temperature with exceedingly high yields are achieved over Pt–Sn/γ-Al2O3 catalyst in the presence of calcined hydrotalcite. pH of the reaction mixture significantly affects the conversion and selectivity for sugar alcohols. Selection of a suitable base is the key to achieve optimum yields. Various solid bases in combination with Pt–Sn/γ-Al2O3 catalysts were evaluated for hydrogenation of sugars. Amongst all combinations, the mixture (1:1 wt/wt) of Pt–Sn/γ-Al2O3 and calcined hydrotalcite showed the best results. Hydrotalcite helps to make the pH of reaction mixture alkaline at which sugar molecules undergo ring opening. The sugar molecule in open chain form has carbonyl group which can be polarized by Sn in Pt–Sn/γ-Al2O3 and Pt facilitates the hydrogenation. In the current work, effect of both; solid base and Sn as a promoter has been studied to improve the yields of sugar alcohols from various C5 and C6 sugars at very mild reaction conditions.
Selective and Scalable Synthesis of Sugar Alcohols by Homogeneous Asymmetric Hydrogenation of Unprotected Ketoses
Tindall, Daniel J.,Mader, Steffen,Kindler, Alois,Rominger, Frank,Hashmi, A. Stephen K.,Schaub, Thomas
supporting information, p. 721 - 725 (2020/10/19)
Sugar alcohols are of great importance for the food industry and are promising building blocks for bio-based polymers. Industrially, they are produced by heterogeneous hydrogenation of sugars with H2, usually with none to low stereoselectivities. Now, we present a homogeneous system based on commercially available components, which not only increases the overall yield, but also allows a wide range of unprotected ketoses to be diastereoselectively hydrogenated. Furthermore, the system is reliable on a multi-gram scale allowing sugar alcohols to be isolated in large quantities at high atom economy.
L-Xylo-3-hexulose, a new rare sugar produced by the action of acetic acid bacteria on galactitol, an exception to Bertrand Hudson's rule
Xu, Yirong,Chi, Ping,Lv, Jiyang,Bilal, Muhammad,Cheng, Hairong
, (2020/10/02)
Background: In acetic acid bacteria such as Gluconobacter oxydans or Gluconobacter cerinus, pyrroloquinoline quinone (PQQ) in the periplasm serves as the redox cofactor for several membrane-bound dehydrogenases that oxidize polyhydric alcohols to rare sugars, which can be used as a healthy alternative for traditional sugars and sweeteners. These oxidation reactions obey the generally accepted Bertrand Hudson's rule, in which only the polyhydric alcohols that possess cis D-erythro hydroxyl groups can be oxidized to 2-ketoses using PQQ as a cofactor, while the polyhydric alcohols excluding cis D-erythro hydroxyl groups ruled out oxidation by PQQ-dependent membrane-bound dehydrogenases. Methods: Membrane fractions of G. oxydans were prepared and used as a cell-free catalyst to oxidize galactitol, with or without PQQ as a cofactor. Results: In this study, we reported an interesting oxidation reaction that the polyhydric alcohols galactitol (dulcitol), which do not possess cis D-erythro hydroxyl groups, can be oxidized by PQQ-dependent membrane-bound dehydrogenase(s) of acetic acid bacteria at the C-3 and C-5 hydroxyl groups to produce rare sugars L-xylo-3-hexulose and D-tagatose. Conclusions: This reaction may represent an exception to Bertrand Hudson's rule. General significance: Bertrand Hudson's rule is a well-known theory in polyhydric alcohols oxidation by PQQ-dependent membrane-bound dehydrogenase in acetic acid bacteria. In this study, galactitol oxidation by a PQQ-dependent membrane-bound dehydrogenase represents an exception to the Bertrand Hudson's rule. Further identification of the associated enzymes and deciphering the explicit enzymatic mechanism will prove this theory.
