Maltose, osazone

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... 

Both maltose and lactose, being reducing sugars, give osazones which differ from one another and from glucosazone in crystalline form. Sucrose (G-r-r-F), having no potential aldehyde or ketone grouping, does not form an osazone. 

The approximate times of osazone formation in minutes are given in Table 111,139. The product from mannose is the simple hydrazone and is practically white. Arabinose osazone separates first as an oil, whilst that from galactose is highly crystalline. Lactose and maltose give no precipitate from hot solution. 

Maltose. This sugar is found in suybean. and is produced by the action of ihe enzyme diastase of germinated barley (mall) on starch at 50°C. and is thus an intermediate product in the transformation of starch into alcohol. Maltose CnHiaOn- ILO. melting point IOtf C. when rapidly heated, may be crystallized from the concentrated malt syrup after removal of proteins and insoluble material. Maltose reduces ammonio-cupric salt solulion. and forms osazone. 

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... 

Maltose reduces Fehling s solution and therefore probably contains an aldehyde group. The constitutional formula is probably the same as that given for lactose. It yields an osazone which crystallizes in tufts of needles which are more blunt than the crystals of glucosazone. Maltose, like the other di-saccharoses does not ferment with yeast zymase. 

Put 1-mL portions of phenylhydrazine reagent into each of four cleaned, numbered test tubes. Add 3.3-mL portions of 0.1 M solutions of glucose, fructose, lactose, and maltose and heat the tubes in the beaker of hot water for 20 min. Shake the tubes occasionally to relieve supersaturation and note the times at which osazones separate. If after 20 min no product has separated, cool and scratch the test tube to induce crystallization. 

Maltose a-D-glucose + a-D-glucose a(1 -+4) Germinating cereal and malt Forms osazone with phenylhydrazme. Fermentable by enzyme maltase present in yeast. Hydrolysed to two molecules of D-glucose. Undergoes mutarotation. 

Problem 35.4 When (4 )-maltose is subjected to two successive one-carbon do-gradations, there is obtained a disaccharide that reduces Tollens and Fehling s reagents but does not form an osazone. What products would be expected from the acidic hydrolysis of this disaccharide What would these facts indicate about the structure of (+)-maItosc ... 

Later, Machell and Richards and Whistler and BeMiller isolated the compound as a sirup (in yields of about 1%) by treatment of maltose with 0.05 N sodium hydroxide and of cellobiose with 0.05 N potassium hydroxide. There was a divergence in the reported specific optical rotations (in water), namely, —24.1° and -fll°, respectively, which might be attributable to degradation of this labile compound during isolation or storage. The crystalline (2,4-dinitrophenyl)osazone prepared in both investigations was further characterized as its crystalline triacetate. ... 

But a single case of maltosuria is reported in the literature (C2). The identification of maltose is based on the osazone, but the study is inadequate. The preliminary studies of Weijers et al. (W2) would suggest that maltosuria, secondary to maltase deficiency, exists and will be demonstrated conclusively in the near future. These patients can be expected to suffer from chronic diarrhea or vomiting or both. 

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. 

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. 

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