- A concise approach to the synthesis of all twelve 5-deoxyhexoses: d-tagatose-3-epimerase-a reagent that is both specific and general
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2-Deoxy-d-glucitol and 2-deoxy-d-allitol, both prepared as crystalline polyols from d-erythronolactone, are oxidized by Gluconobacter thailandicus NBRC 3254 to 5-deoxy-d-threo-hexulose [5-deoxy-d-fructose = 5-deoxy-l-sorbose] and 5-deoxy-d-erythro-hexulose [5-deoxy-l-psicose = 5-deoxy-d-tagatose], respectively. d-Tagatose-3-epimerase (DTE) equilibrates 5-deoxy-d-fructose to 5-deoxy-d-psicose and 5-deoxy-l-psicose to 5-deoxy-l-fructose, providing substrates for the preparation of all eight d- and l-5-deoxy aldohexoses by aldose isomerases. This combination of chemical and biotechnological methods allows a concise approach to the synthesis of all twelve 5-deoxy hexoses and further demonstrates the range of deoxy sugar substrates on which DTE is active. NMR studies show that 5-deoxy-d-fructose exists solely as the β-pyranose form whereas both pyranoses of 5-deoxy-d-fructose [α:β. 22:78] are observed. [For the sake of clarity, all ketoses in this Letter are shown in blue, alditols in red and aldoses in purple.].
- Rao, Devendar,Best, Daniel,Yoshihara, Akihide,Gullapalli, Pushpakiran,Morimoto, Kenji,Wormald, Mark R.,Wilson, Francis X.,Izumori, Ken,Fleet, George W.J.
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scheme or table
p. 3559 - 3563
(2009/10/26)
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- Substrate Specificity and Carbohydrate Synthesis Using Transketolase
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This paper describes the use of the enzyme transketolase as a catalyst in organic synthesis.The properties of transketolase from both yeast and spinach were investigated.The yeast enzyme was found to be more convenient for routine use.Examination of the substrate specificity of yeast tansketolase demonstrated that the enzyme accepts a wide variety of 2-hydroxy aldehydes as substrates.A practical protocol for tansketolase-catalyzed condensation of hydroxypyruvic acid with these aldehydes has been developed and used for the synthesis of four carbohydrates: L-idose, L-gulose, 2-deoxy-L-xylohexose, and L-xylose.
- Kobori, Yoshihiro,Myles, David C.,Whitesides, George M.
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p. 5899 - 5907
(2007/10/02)
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- SYNTHESIS OF 2-DEOXY-D-arabino-HEXITOL AND ITS OXIDATION TO 5-DEOXY-D-threo-HEXULOSE ("5-DEOXY-D-FRUCTOSE") USING IMMOBILIZED CELLS OF Gluconobacter oxydans
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2-Deoxy-D-arabino-hexitol (6) was obtained by borohydride reduction of 2-deoxy-D-arabino-hexose (5).The synthesis of 5, starting from 2,3:4,5-di-O-isopropylidene-D-arabinitol (1), was achieved by one-carbon chain-elongation involving formylation of the Grignard reagent derived from 1-bromo-1-deoxy-2,3:4,5-di-O-isopropylidene-D-arabinitol (2), using lithium formate, followed by hydrolytic removal of the isopropylidene groups.Immobilized cells of Gluconobacter oxydans (ATCC) 15178) selectively oxidized 6 to give 5-deoxy-D-threo-hexulose (7) in 65percent yield (-9percent overall yield from 1).
- Tiwari, Kamal N.,Dhawale, Motiram R.,Szarek, Walter A.,Hay, George W.,Kropinski, Andrew M. B.
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- ENZYMATIC ALDOL REACTION/ISOMERIZATION AS A ROUTE TO UNUSUAL SUGARS
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Utilizing fructose diphosphate aldolase and glucose isomerase as catalysts, 3-, 5-, and 6-deoxy- and 6-O-methylhexoses have been synthesized from dihydroxyacetone phosphate or acetol phosphate and the corresponding hydroxypropionaldehydes.
- Durrwachter, J. Robert,Sweers, H. M.,Nozaki, K.,Wong, Chi-Huey
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p. 1261 - 1264
(2007/10/02)
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