Altrose 1,6-anhydro

If the data obtained on the dehydration of the 2-(aWo-polyhydroxy-alkyl)benzimidazoles31 is considered, it is to be expected that no inversion occurs in the configuration of the carbon atom next to the furan ring. If this is so, the anhydride should have formula XXXIV. With the object of deciding this question, researches are being carried out32 on the reaction of ethyl acetoacetate with 3,6-anhydro-n-glucose and with D-altrose. 

A. C. Richardson and H. O. L. Fischer, Cyclization of dialdehydes with nitromethane, Part VI. Preparation of 3- amino-1,6-anhydro-3-deoxy-p-D-gulose, -P-D-altrose and -p-D-idose derivatives and their characterization by means of inversion of mesyloxy groups,./. Am. Chem. Soc., 83 (1961) 1132-1139. 

The low reactivity of l,6-anhydro-2,3,4-tri-0-benzyl-/3-D-allopyra-nose is also of interest.106 This monomer has 1,3-interaction between substituents on C-2 and C-4 in the C4(d) conformation. However, when conversion into a boat conformation, as proposed, occurs on reaction with a propagating cation, eclipsed bonds develop at C-2, C-3, and C-4. It is, therefore, not surprising that the D-allo anhydride is less reactive than those of D-mannose, D-glucose, or D-galactose. The corresponding, D-altrose derivative has only one axial substituent in addition to the anhydro ring, and these are on opposite sides of the pyranose ring, and therefore do not interact it would be expected to be, and has proved to be, of very low polymerizability.106... 

Write the structural formulas for (a) 1,6 anhydro P-o-gl ucopyranose (b) 1,6 anhydro P-D-altrose. Compound (b) is many times more stable than compound (a). Explain this on stereochemical grounds. 

Anhydro-3,4-O-isopropylidene-2-O-toayl-/3-D-altrose Methyl 2,0-dideoxy-3-O-methyl-4-O-tosyl-a-D-xylo-hexoside Methyl 2,6-dideoxy-3-0-methyl-4-0-tosyl-/3-D- ct/lo-hexoside 0-Deoxy-2,3-O-isopropylidene-l-O-tosyl-L-sorhose 2,4 3,5-Di-0-methylene-l-0-tosyl-D-epirhamnitol... 

J. G. Buchanan and D. M. Clode, Synthesis and properties of 2,3-anhydro-D-mannose and 3,4-anhydro-D-altrose, J. Chem. Soc., Perkin Trans. 1, (1974) 388-394. 

Reeves has suggested that the spontaneous formation of 1,6-anhydro derivatives of idopyianose and altropyranose may be due to the conformational behavior of the aldoses his instability factors show that /3-Didose and /3-D-altrose will exist partly in the conformations favorable for closure of the 1,6-anhydro ring. This reasoning could lead to the further conclusions that D-talose, but probably not n-gulose, should fairly readily afford a 1,6-arihydro derivative of the pyranose form. 

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. ... 

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