Heptulose phenylosazone

The dehydration of hexose, heptose, and octose phenylosazones in methanolic sulphuric acid has been studied. Each osazone gave rise to two 3,6-anhydrides epimeric at C-3 except 7-deoxy-D-wa no-heptulose phenylosazone which afforded only the 3,6-anhydro-7-deoxy-L- M/o-heptulose phenylosazone with... 

A reinvestlgatlon of the dehydration of D-galacto-heptulose phenylosazone showed the product to be a mixture of the 3,7-anhydrides (33) with a pyranosyl ring, and not the furanosyl 3>6-anhydro-counterparts as previously claimed (Vol.l4, p.88) further data on such dehydration reactions is detailed in Section 6. Further details on the dehydratlve cyclization of the phenylosazones of L-lyxo- and L-xylo-hexulose and 7-deoxy-L-manno-heptulose have been reported (Vol.liJ, p.88 V0I.15, p.ll2). ° ... 

LaForge and Hudson194 prepared an osone from the phenylosazone obtained from sedoheptulose (D-aZ(ro-heptulose). The osone reduced Fehling solution strongly, formed the original osazone with phenylhydrazine, and gave a crystalline derivative with o-phenylenediamine. 

Volemitol is also oxidized by A. xylinum, but the identity of the sirupy product, volemulose, remains obscure specificity requirements are again satisfied at both ends of the molecule. Thus, although Hudson and coworkers obtained only n-oZiro-heptulose from a slow and incomplete oxidation, it has been reported" that, in the later stages, o-madapted cultures, D-monno-heptulose predominated throughout." The melting point recorded for volemulose phenylosazone does not agree with either the individual, or mixed, melting points of the two heptulose osazones. ... 

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