Maltose phenylosazone

Maltose, heptaacetate, I, 81 a-Maltose, octaacetate, III, 377 -Maltose, octaacetate, III, 377 Maltose, phenylosazone, reaction with KOH, III, 40... 

Although Fischer described a lactose phenylosazone anhydride in 1887, little attention was paid to substances of this type until 1935 when Diels and Meyer reported the isolation of monoanhydrides of D-glucose phenylosazone, D-galactose phenylosazone, D-xylose phenylosazone, L-arabinose phenylosazone, lactose phenylosazone, and cellobiose phenylosazone, as well as a dianhydride of maltose phenylosazone, by boiling the corresponding osazones in alcoholic solution with a little sulfuric acid. Because of the apparent identity of the D-glucose phenylosazone anhydride with the 3,6-anhydro-D-glucose phenylosazone of Fischer and Zach, Diels and Meyer formulated these compounds as 3,6-anhydrides. 

Maltose phenylosazone heptaacetate, on the other hand, yielded two isomeric maltose phenylosazone anhydrides " on deacetylation, both of which gave rise to pentaacetates like the other disaccharide anhydro-osazones, their precise structures are not known. It may be recalled that Diels and Meyer " isolated a dianhydride of maltose phenylosazone... 

Osazones can be cleaved in the same way. According to Fischer and Armstrong617 maltose phenylosazone (20 g) is dissolved in boiling water (1600 ml) and pure benzaldehyde (16 g) is added with vigorous stirring. If the benzaldehyde is kept well distributed the reaction requires about 20 min. After cooling, filtration gives benzaldehyde phenylhydrazone in almost theoretical yield, and the maltose is worked up as described above. 

XV. Proof of the Normal Character of the Phenylosazones of Turanose and Maltose... 

It has been assumed in the preceding section that the phenylosazones of turanose, maltose, and D-glucosyl-D-arabinose have structures like that of D-glucose pjienylosazone. This normal osazone structure is now proved40 by the following data for the turanose and maltose osazones, and there can be little doubt that it also holds for the osazone of d-glucosyl-D-arabinose. Turanose phenylosazone has been converted by... 

In 1896, Fischer developed the phenylhydrazine test" for the detection of hydrolytic scission of disaccharides, especially by enzymes this depends on the fact that the phenylosazones of disaccharides are soluble in hot water, whereas those of the monosaccharides are not. Lactose is hydrolyzed by emulsin (1894) and by lactase it is not fermentable by yeast, and is unaffected by invertase (1894). An extract of the small intestine of horses and cattle, especially from young animals, hydrolyzes lactose (1896). The action of enzymes on lactose allowed it to be classified, along with cellobiose and maltose, with the normal (and not the y-type of) methyl glucoside (1914). In the discussion of maltose, the relationship of lactose to the /9-series will be mentioned later. 

By the catalytic reduction of the phenylosazone from lactose, Kuhn and Kirschenlohr obtained both /3-n-gaIactopyranosyl-(l— 4)-l-amino-l-deoxy-D-fructose and /S-n-galactopyranosyl- (1- -4) -2-amino-2-deoxy-D-glu-cose. The A -acetyl derivative of the latter was found to be identical with a disaccharide obtained from the partial hydrolysis of a blood-group substance. The structure of a disaccharide obtained from the partial hydrolysis of heparin was likewise confirmed by comparison of the disaccharide with a synthetic product obtained by catalytic hydrogenation of the osazone from maltose. - Here, too, both the 1-amino-l-deoxy and the 2-amino-2-deoxy compounds were obtained. 

The rate of formation of osazones and their solubility, which differ substantially from case to case, can also serve as characteristic features useful in the identification of sugars. For example, osazones of glucose and fructose precipitate shortly after the heating of the solution, while saccharose requires 20 — 30 min of heating. Osazones of lactose and maltose precipitate only after cooling. In addition, phenylosazones of D-glucose, D-fructose, and D-mannose (which are identical) are insoluble in cold acetone, in contrast to phenylosazones of xylose, arabinose, rhamnose, and fructose. 

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