5-Acetamido-5-deoxy-L-arabinose

Acetamido-5-deoxy-L-arabinose A Sugar Derivative Containing Nitrogen as the Hetero-atom in the Ring, J. K. N. Jones and J. C. Turner,/. Chem. Soc., (1962) 4699-4703. 

For sugars in which the hetero-atom of the ring may be nitrogen, the infrared spectra show immediately which form has this structure. For example, for the two ring forms of 5-acetamido-5-deoxy-L-arabinose (Jones and Turner, 1962), one form exhibits bands at 3300, 1630, and 1555cm for OH and NH, NAc, and NH, respectively, and is therefore the furanose form (XXII), whereas the other form has bands at 3380 cm for OH, and 1616 and 1595 cm" for NAc, but no NH absorption near 1555 cm" and is therefore the pyranose (XXIII). 

Similar equilibrium relationships between pyranose and furanose forms apply to 5-acetamido-5-deoxy-l>lyxose. Its preparation, performed in a manner analogous to that of the D- or L-arabinose compound, by selective p-tolylsulfonylation of 0-5 of D-lyxose diisobutyl... 

Acetamido-5-deoxy-L-arabinopyranose, A-180 2-Acetamido-2-deoxy-D-arabinose, A-178 2-Acetamido-2-deoxy-L-arabinose, A-178 4-Acetamido-4-deoxy-D-arabinose, A-179... 

For 5-acetamido-5-deoxy-(D or L)-arabinose, the equilibrium is displaced in favor of the furanose form. Thus, l,2-0-isopropylidene-5-0-p-tolylsulfonyl-/8-L-arabinofuranose, on treatment with ammonia... 

Two of the most frequent monosaccharide components of bacterial polymers belonging to this group have been the subjects of articles in this Series. They are 3-deoxy-D-manno-2-octulosonic acid,247 a normal constituent of the core region of bacterial lipopolysaccharides that is also present in some other polymers, and N-acetylneuraminic acid,248 found in several capsular polysaccharides. Enolpyruvate phosphate serves as the precursor of the C-l-C-3 fragment of the monosaccharides, with D-arabinose 5-phosphate or 2-acetamido-2-deoxy-D-mannose 6-phosphate being an acceptor for transfer of the three-carbon unit. Characteristic, activated forms of these monosaccharides are the CMP derivatives. 

O-Methyl-A-acetylneuraminic acid was synthesized as shown in Scheme 2, and the C-4 epimer was also produced by the Wittig step of the sequence. The primary product was obtained crystalline, and characterized by mass spectrometry and by proton and n.m.r. spectroscopy. 5-0-(a-L-Rhamno-pyranosyl)-, (jS-o-glucopyranosyl)-, (2-acetamido-2-deoxy-j8-D-glucopyrano-syl)-, and (jS-D-glucopyranosyluronic acid)-3-deoxyoctulosonic acids were prepared in low yields by condensation between the four 2-0-glycopyranosyl-D-arabinoses and oxalacetic acid. "... 

Acetalation of the methyl P-furanoside of D-ribose with dimethoxymethane gave the new methylene derivative 3, whereas D-arabinose furnished the tri-C7-methoxymethyl ether 4 under the same conditions methyl p-D-arabinoside afforded a mixture of the two products 5 and 6. Treatment of L-sorbose with acetone and catalytic quantities of heteropolyacids HjPWjjO o or H4SiW,204o (0.1-0.35%) gave diacetonesorbose in 85% yield. The methyl glycoside monoacetonides 7 and 8 were obtained in the ratio 7 2 (90% combined yield) on exposure of 2-acetamido-2-deoxy-D-galactose to 2,2-dimethoxypropane and p-TsOH in dioxane at 60 °C When sucrose was heated in acetone... 

Amino-Alditols. - Aldose oximes, e.p... of mannose and arabinose, can be reduced electrochemically to 1-aminoalditols glucose oxime reacted differently, because, it is proposed, of its strong tendency to cyclize to an N-glucosyl hydroxylamine derivative. l-Amino-2-acetamido-1,2-dideoxy-D-alditols have been prepared by sodium cyano-borohydride reduction of 2-acetamido-2-deoxy-glycosylamines (D-Glc, D-Man, and D- lc-D-Glc).6-(5-deoxy-D-ribit-5-yl)amino-uracil has been condensed with 2-chloro-4-hydroxybenzaldehyde to give a flavin derivative which was further elaborated to Redox Coenzyme Factor 420. ... 

MacDonald and H. O. L. Fischer372 oxidized D-glucose diethyl dithioacetal pentaacetate (24) and its D-manno isomer with mono-peroxyphthalic acid in ether, isolating not the epimeric disulfones but a common product, to which they assigned the structure 3,4,5,6-tetra- O - acetyl -1,2- dideoxy-1,1 -bis (ethylsulfonyl)-D-arabtno-hex-1-enitol (176). Ammonolysis of 176 and reacetylation afforded 177, which was also prepared by oxidation of 2-acetamido-3,4,5,6-tetra-0-acetyl-2-deoxy-D-glucose diethyl dithioacetal, whereas the action of hydrazine in methanol on 176 produced a retroaldol reaction (and saponification) affording D-arabinose (179, 40% yield) and bis(ethyl-sulfonyl)methane (178). The latter reaction accords with earlier ob-... 

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