Sorbose 6-deoxy

Not able to reproduce a previously reported approach [30] to (5) from D-galactose, Tyler and co-workers designed an efficient sequence starting from L-sorbose [46], via a partially protected 6-azido-6-deoxy-L-tagatose derivative, and obtained an overall yield of 20%. Ogawa and co-workers [47] prepared D-galactonojirimycin as well as 1-deoxygalactonojirimycin from L-quebrachitol (11), a natural product found in the serum of the rubber tree. 

Dideoxy-2,5-imino-D-mannitol (26), a nattural product found in Derris elip-tica as well as Lonchocarpus sp. [126], was obtained from L-sorbose via 5-azido-5-deoxy-D-ffuctopyranose (82) by Card and Hitz [127] and characterized as a very potent inhibitor of /3-D-fructofuranosidase (invertase). 

Thus, the reaction of 1,3,4,5,6-penta-O-acetyl-keto-L-sorbose (33) with 24% aqueous ammonia36 afforded 6-(l-deoxy-L-threo-tetritol-l-yl)-2-(L-xylitol-l-yl)pyrazine (34) in 11% yield and 2,5-bis(L-xylitol-l-yl)pyrazine (35) in 0.4% yield. In this reaction mixture, the follow-... 

The protonated amino group, however, has no nucleophilic activity, and does not form a hemiacetal an amino sugar can, therefore, be obtained, as a salt, in an otherwise unfavorable form. For example, 6-amino-6-deoxy-L-sorbose can be isolated as the hydrochloride of a furanose form (22) (presumably a). In alkaline solution, immediate ring-expansion to the pyranose form (23) occurs127 this reaction can be reversed under strongly acidic conditions. 4-Amino-4,6-dideoxy-D-glucose hydrochloride forms a 35 65 mixture of the a- and / -pyranose forms in solution.128... 

In contrast, the 6-tosyloxy group of l,6-di-0-tosylketohexofuranose derivatives is more readily replaced by iodine. Thus, by reaction during 24 hours at 90-100°, 2,3-0-isopropylidene-l,6-di-0-tosyl-L-sorbose gives264 the corresponding 6-deoxy-6-iodo-l-0-tosyl derivative (possibly accompanied by some unisolated l,6-dideoxy-l,6-diiodo derivative) and 2,3-0-isopropylidene-l,6-di-0-tosyl-D-fructose behaves266 similarly (16 hours at 100°). 

Ishizu et al.29H found that D-xylose and D-fructose react with aqueous calcium hydroxide to produce 13 lactonizable saccharinic and other acids. These were identified after separation by cellulose column and gas-liquid chromatography, and the Cs-saccharinic acids, 2-C-methyl-D-threonic acid (117) and 2-C-methyl-D-erythronic acid (118), were among those isolated. These authors299 later reported that L-sorbose reacts similarly, to generate 14 lactones, including the 2-C-methyl-L-xr/o o-l,4-lactone and 2-C-methyl-L-lyxono-1,4-lactone, which were also prepared from 1-deoxy-L-threo-pentulose via the cyanohydrin reaction. 

The Synthesis of Sugars from Simpler Substances. Part IV. Enzymic Synthesis of 6-Deoxy-u-fructose and 6-Deoxy-L-sorbose, L. Hough and J. K. N. Jones,/. Chem. Soc., (1952) 4052-4055. 

Scheme 5.57. TK catalyzed synthesis of 6-deoxy-L-sorbose, precursor to furaneol, was prepared from the readily available reagents acetaldehyde, HPA, and serine.

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