0-n-Altrose

Page 77, lines 7, 8, and 9 from bottom. Between 3,6-Anhydro-n-allose phenyl-osazone and "2-methyl- insert the heading 3,6-Anhydro-n-altrose. ... 

It will be noticed that the future application of the Fischer cyanohydrin synthesis to n-altrose should lead to two heptitols, one of which (n-altro-D- luco-heptitol) should be the enantiomorph of the known D-gulo-L-talo-heptitol, while the other (o-altro-D-manno-heptitol) should be identical with natural volemitol (D-manno-D-[Pg.12]

The conversion of calcium o-altronate to n-altrose follows the standard procedure of Fischer, which consists in liberating the aldonic acid, heating it to effect lactonization, and reducing the sirupy lactone with sodium amalgam. Levene and Jacobs thus prepared n-altrose as a sirup, but did not record its rotation. It formed a crystalline phenylosazone, which is common to both n-altrose and n-allose, and a characteristic benzylphenylhydrazone. Pertinent data on these substances, and on ... 

It had been found that the equimolecular mixture of n-galactose and D-altrose resulting from the acid hydrolysis of neolactose had a negative rotation, calculated as hexose, of [ ]d —8.95° in water. Knowing the equilibrium rotation of n-galactose to be +80°, Kunz and Hudson" estimated that n-altrose would have [ajn —98° in water. 

Pigman has prepared crystalline u-altrose from neolactose by cleavage of the disaccharide with sweet almond emulsin, followed by removal of the D-galactose by fermentation with yeast. This procedure avoids the transformation of any n-altrose to u-altrosan, the non-reducing anhydride which is formed to the extent of 57% in the hydrolysis of neolactose by acids. 

Conversion of either pentaacetate to crystalline acetochloro-o-n-altrose was effected in good yield by the action of titanium tetrachloride in chloroform solution. Replacement of the chlorine atom by a hydroxyl group was accomplished by shaking the acetochloro compound with silver carbonate and aqueous acetone. The resulting tetraacetate appeared as the /3-modification, mutarotating from [ajo —6.0 to - -12.9° in chloroform solution. 

In addition to the transformations of n-glucose to n-altrose and its derivatives which have been described in most of the references between 53 and 67, similar transformations may be found in articles by Haworth, Hirst and Panizzon, by Peat and Wiggins," by Lake and Peat, " by Robertson and Myers, and by Young and Elderfield, Data on all these derivatives are reported in Table I. 

In the synthesis of n-altrose from D-ribose, first effected by Levene and Jacobs, the only crystalline intermediate was the characteristic calcium D-altronate -3.5 H2O. The sirupy lactone prepared from it was then reduced to n-altrose with sodium amalgam, as mentioned earlier in this review. Calcium n-altronate has been obtained from other sources also, such as the aluminum chloride rearrangement of the acetates of lactose, cellobiose and glucose and subsequent transformation of the neolactose, celtrobiose and altrose derivatives thus produced (see Section... 

Methyl 2,3-anhydro-4,6-di-O-methyl-a-D-allopyranoside MeMgl,Mgis 3-substituted p-glucose 2-substituted n-altrose a 54... 

Methyl 2,3-anhydro-a-D-allopyrano-side, dimethyl ether or diacetate HBF4 2-substituted n-altrose 3-substituted d-glucose a 65... 

Methyl 2,3-anhydro-4,6-0-benzylidene-a-D-mannopyranoside HCl 3-substituted n-altrose 2-substituted n-glucose a 70... 

The heptoses prepared from n-allose and n-altrose are of recent origin and merit further attention. B-glycero-D-allo-Reptose (40) crystallized readily, and was identified when (a) the configuration at C-2 of the parent... 

A study of the rates of hydrolysis of the 4,6-0-benzylidene acetals of several methyl hexosides showed that the trans-iused acetals (of n-glucose, D-mannose, and n-altrose) are hydrolyzed only about three times faster than the cis fused ones (of D-galactose and L-idose). It may be concluded, therefore, that the natiu-e of the ring fusion does not, in these fused, six-membered ring systems, greatly influence the rate. 

Subsequent to the synthesis of n-altrose in 1910, no further work on altrose was reported until 1926. In the preceding year, Hudson and Kunz had prepared acetochloro-a-lactose by boiling gently for one and one-half hours a mixture of 20 g. of octaacetyllactose in 100 ml. of chloroform with 10 g. of phosphorus pentachloride and 5 g. of anhydrous aluminum chloride the pure product, isolated in the usual way, consisted of needles, m. p. 120-121°, and [a]D +83.9° in chloroform. On one occasion, however, they noted that the addition of petroleum ether to the mother liquor of an original crystallization caused the separation of about 1 g. of a crystalline substance in the form of prisms, m. p. 160°, and [ ]d +71.7° in chloroform. 

The structure of celtrobiose was established through its oxidation to celtrobionic acid and subsequent cleavage with N sulfuric acid to n-glucose and D-altronic acid. Since the biose linkage should not be affected by the aluminum chloride rearrangement, celtrobiose was thus proved to be 4-/3-D-glucopyranosido-n-altrose. 

With a view to the ultimate production of n-altrose in the free condition, Robertson and Griffith in 1935 described the action of alkali upon methyl 2,3-ditosyl-4,6-benzylidene-a-D-glucoside (XXXIV), which is prepared readily from methyl a-n-glucoside (XXXIII). The action of... 

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