Hexosid-4-ulose

Methyl-3,6-di-0-benzoyl-2-deoxy-a-D- Methyl-3,6-di-0=-benzoyl-2-deoxy-a-D-t/ reo-hexosid-4-ulose S [317]... 

On treatment with sodium ethoxide in ethanol, methyl 2,4,6-tri-O-methyl-a- (72) and -/3-D-ribo-hexosid-3-ulose yielded l-deoxy-2-methoxy-4,6-di-0-methyl-D-hex-l-en-3-ulose (73) and several isomeric ethyl 2,3,6-tri-0-methylhexosid-3-uloses (74) (see Scheme 10).133 On alkaline degradation of methyl 2,3-di-0-ethyl-6-0-pro-pyl-a-D-xy/o-hexosid-4-ulose (75) with sodium 1-butoxide in 1-butanol, one mole of ethanol was released per mole of 75, indicating that the substituent at C-2 was preferentially eliminated. On mild, acid hydrolysis of the product, methanol, ethanol, and some 1-propanol were formed, consistent with fission at C-l, C-3, and, to some extent, C-6 (see Scheme 10).134... 

Rearrangement of methyl 4,6-0-benzylidene-3-deoxy-3-phenylazo-aldohexopyranosides with alkali provides a new route to hexosid-3-uloses (18). 

Most compounds of this type are derived from methyl hexosides methyl 2,6 3,4-dianhydro-a-D-altropyranoside309 398 400 516 and methyl 2,5 3,6-dianhydro-a- and /J-n-mannol iiranosides.517 From hexuloses, the synthetically useful l,5 3,6-dianhydro-D-<2raZ)i o-hex-2-ulose (172) has been prepared by regioselective monobenzylation of l,5 3,6-dianhydro-D-mannitol at C-4 (171a — 171b) followed by oxidation with tetrapropylammonium perruthenate.518... 

A compound having a related structure, namely, methyl 4,6-0-benzylidene-2,3-dideoxy-3-phenylazo-a-D-en/fhro-hex-2-enopyrano-side, was obtained on treatment of methyl 2-0-benzoyl-4,6-0-benzyl-idene-a-D-rifco-hexosid-3-ulose with phenylhydrazine, followed by a molar proportion of sodium methoxide. It was found to undergo additions similar to those reported for the 3-nitro anologs.112b... 

These pyranoid compounds offer a means of obtaining 1-deoxy-ketoses (seep. 259), and continue to provide a source ofaldos-5-uloses the sugar component of hygromycin A has thus been prepared by hydrolyzing methyl 6-deoxy-a-D-arafcino-hex-5-enopyranoside.149 In related fashion, methyl 6-deoxy-2,3-0-isopropylidene-a-D-Zyxo-hex-5-enopyranoside (81) was isomerized150 in the presence of an acid to methyl 6-deoxy-2,3-0-isopropylidene-a-D-Zyxo-hexosid-5-ulose (82). 

C. F. J. Chittenden, R. D. Guthrie, and M. Oki, Nitrogen containing carbohydrate derivatives. Part XI. Reduction of methyl 4,6-0-bezylidene-ct-D-hexoside-3-ulose phenylhydrazones, J. Chem. Soc., (1966) 1508-1510. 

Treatment of 2,3,4,6-tetra-O-methyl-0 ,j3-D-glucopyranose with 30% hydrogen peroxide in the presence of potassium hydroxide yields the products (2)-(7), thought to arise by decomposition of the hydroperoxide (8), Mechanistic schemes were proposed.The formation of reductic acid from methyl -D-ribo-hexosid-3-ulose by sulphuric acid treatment has been studied by -tracer... 

Urginea rubella has been found to contain the hexosid-3-ulose acetal structure (38). ... 

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