Hexopyranosyl chloride

The Reactions of Nitrosyl Chloride and Dinitrogen Tetraoxide with Acetylated Glycals. Acetylated 2-Deoxy-2-nitroso-a-D-hexopyranosyl Chlorides and Nitrates and Acetylated 2-Nitroglycals, R. U. Lemieux, T. L. Nagabhushan, and I. K. O Neill, Can. J. Chem., 46 (1968) 413-418. 

Fig. 2.6 Quadripolar resonance frequency of peracetylated hexopyranosyl chlorides having configurations as indicated.

The Me2SO-oxalyl chloride method34 was successfully used13 to obtain2-(6-deoxy-2,3-0-isopropylidene-a-L-h/xo-hexopyranosyl-4-ulose)-8-nitro-t>-triazolo[l,5-fl]pyridine (49a) in 62% yield from the partially protected L-rhamnose nucleoside 48a. Treatment of 49a with formic acid gave the free ketonucleoside 50a. Hydrogenation over 10% Pd-C afforded the amino derivative 49b. 

In the case of hexopyranosyl derivatives, it is generally accepted that the tendency of the side-chain to adopt an equatorial position is dominating in solution, implying that the compounds adopt the4 i(D) or C L) conformations. This effect is observed even when it means that four (9-acetyl groups must adopt axial positions, as in the case of the penta-D-acetyl-a-D-idopyranosyl chloride (5). In the case of a-compounds,the presence... 

Nitrophenyl-a-L-fuco/galacto/rhamno/manno-pyranosides can be made by the reaction of the acetate protected sugar with p-nitrophenol and zinc chloride at 120 °C under vacuum [7]. p-Nitrophenyl-p-D-gluco/galactopyranoside can be generated from the reaction of the acetylated hexopyranosyl bromides with sodium p-nitrophenoxide in DMF [8], followed by deprotection, and /7-nitrophenyl-(3-D-mannopyranoside can be synthesised from mannose via 2,3 4,6-di-0-cyclohex-ylidene-a-D-mannopyranose [9]. 

The daunosaminyl (3-amino-2,3,6-trideoxy-L-/) xo-hexopyranosyl) analogue of the antibiotic puromycin and -daunosaminyl derivatives of adenine, thymine, and cytosine have been synthesized. " For example, 9-P-daunosaminyladenine was prepared by condensing 3-lV,4-0-bis(trifluoroacetyl)-a-daunosaminyl chloride with lV -benzoyl-9-chloromercuriadenine in refluxing xylene, or with IV -benz-oyladenine in dichloromethane at room temperature in the presence of a molecular sieve, and removal of the protecting groups from the product. 

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