N-Psicose

Melibiose, n-mannose, o-ribose, 3,6-anhydro-n-glucitol, n-psicose... 

The powdered-cellulose, flowing chromatogram of an unfermentable residue from the mixture obtained by the action of heat on n-fructose yielded a sirup containing a ketose having a mobility greater than that of D-fructose it may be n-psicose. D-Psicose (identified as the phenylosazone... 

An instance of osazone formation in which substitution takes place on the second and third carbon atoms (in l-desoxy-n-psicose) has been reported. This case is of interest since the possibility arises that with other ketoses, as psicose, 2,3- as well as 1,2-osazones might be produced side by side. The commonest ketose, D-fructose, gives n-glucose phenyl-osazone with such extreme ease, that it is just possible the phenomenon may have escaped observation. 

It will be recalled that Lobry de Bruyn and Alberda van Ekenstein claimed that pseudofructose (n-psicose) was one of the products formed as a result of a transformation of D-fructose and n-glucose in mildly alkaline solution. The doubt that one can have about its presence in the glutose mixture rests on their observation that D-psicose is fermentable. Synthetic D-psicose prepared by Steiger and Reichstein is... 

A eto-D-n6o-Hexulose (n-psicose) 1-chloro-l-deoxy-tetra-O-acetyl- 89-91 -26.0 C 96... 

Four sugars quite frequently occur as furanose residues in Nature. These sugars are D-fructose, n-arabinose, D-ribose, and 2-deoxy-n-erytAro-pentose D-Galactose, L-fucose, and D-psicose have also been found naturally in the furanose form. 

The presence of D-psicose (D-n o-hexulose, D-allulose) in distillery slop (from the fermentation of cane molasses) is claimed,96 but sharp experimental support is lacking. 

Another n-2-ketohexose, psicose, yields a mixture of allitol and altritol when reduced with NaBH4. What is the structure of psicose ... 

CHjOH CHjOH n-Glucose n-Mannose CHjOH n-a-Glutose CHjOH D-/3-Glutose (DHjOH D-Psicose... 

From 3,6-Anhydromonosaccharide OsotriazdlesA —The osotriazoles of the 3,6-anhydro derivatives of D-psicose and L-tagatose gave the same dialdehyde monohydrate, to which the hemialdal structure (33) was assigned. The mirror-image product (34) was obtained from oxidation of the HC=N... 

The tautomeric equilibria of aldopentoses, aldohexoses and hexuloses in DMSO have been examined by C-n.m.r. spectroscopy the mutarotation kinetics of aqueous D-glucose have been investigated by i.r. methods, and Raman spectroscopic data on the tautomeric transformations of glucose in aqueous solution over a wide pH range confirmed that the ring-chain tautomerism depends on pH." The ring shapes of the two fiiranose and two pyranose forms of psicose in aqueous solution, riiown by n.m.r. spectroscopy to be present in almost equal proportions, have been analyzed by MM3."... 

On the other hand, the product from glucose is an exceedingly complex mixture, the composition of which varies with the conditions of treatment. D-Psicose (from treatment with ammonia) (55) and (dl + n)-sorbose (from treatment with a strong base resin) 90) have been identified definitely in the mixture. D-Glucose is readily converted to D-fructose. From the latter has been isolated after treatment with potassium hydroxide (dl + D)-sor-... 

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