669-90-9Relevant articles and documents
Expanding the reaction space of aldolases using hydroxypyruvate as a nucleophilic substrate
De Berardinis, Véronique,Guérard-Hélaine, Christine,Darii, Ekaterina,Bastard, Karine,Hélaine, Virgil,Mariage, Aline,Petit, Jean-Louis,Poupard, Nicolas,Sánchez-Moreno, Israel,Stam, Mark,Gefflaut, Thierry,Salanoubat, Marcel,Lemaire, Marielle
, p. 519 - 526 (2017/08/14)
Aldolases are key biocatalysts for stereoselective C-C bond formation allowing access to polyoxygenated chiral units through direct, efficient, and sustainable synthetic processes. The aldol reaction involving unprotected hydroxypyruvate and an aldehyde offers access to valuable polyhydroxy-α-keto acids. However, this undescribed aldolisation is highly challenging, especially regarding stereoselectivity. This reaction was explored using, as biocatalysts, a collection of aldolases selected from biodiversity. Several enzymes that belong to the same pyruvate aldolase Pfam family (PF03328) were found to produce the desired hexulosonic acids from hydroxypyruvate and d-glyceraldehyde with complementary stereoselectivities. One of them was selected for the proof of concept as a biocatalytic tool to prepare five (3S,4S) aldol adducts through an eco-friendly process.
METHOD FOR SELECTIVE CARBOHYDRATE OXIDATION USING SUPPORTED GOLD CATALYSTS
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Page/Page column 40-42, (2010/02/09)
The invention relates to a method for the selective oxidation of a carbohydrate in the presence of a gold catalyst comprising gold particles distributed in a nanodispersed manner on a metal oxide support, and to a method for the selective oxidation of an oligosaccharide in the presence of a gold catalyst comprising gold particles distributed in a nanodispersed manner on a carbon or metal oxide support. The invention also relates to aldonic acid oxidation products produced using said method.
Regio- and stereo-selectivity in homogeneous catalytic hydrogenation of 2,5-diketo-D-threo-hexonic acid
Hamersak, Zdenko,Pavlovic, Nediljko,Delic, Vladimir,Sunjic, Vitomir
, p. 245 - 249 (2007/10/03)
2,5-Diketo-D-threo-hexonic acid (2,5-diketo-D-gluconic acid, 1), a crucial intermediate in the microbial production of L-threo-hex-2-enono-1,4-lactone (L-ascorbic acid, vitamin C), was isolated from the fermentation broth of bacterium Erwinia citreus ATCC 31623, and its regio- and stereo-selective hydrogenation, catalyzed by the water-soluble Ru(II) complex of tris(m-sulfophenyl)phosphine (TPPTS), was performed, The effect of hydrogen pressure, temperature, pH, and catalyst-to-substrate ratio on regio- and stereo-selectivity of the process was studied, at low pH, over 90% regioselectivity in favor of the reduction of the 5-keto group in 1 was achieved, affording L-xylo-2-hexulosonic acid (2-keto-L-gulonic acid, 2) as the main product. Maximal diastereoselectivity, i.e. ratio between 2 and 2-keto-n-gulonic acid (3) expressed as diastereomeric excess (d.e.%), amounted to ca. 50% and was not influenced by any of the above reaction parameters.