On 17 Jan 1996 cotegl at ncaur1.ncaur.gov wrote:
> In article <FE03E646A2 at CIS.EPM.BR>, TAKAHASHI.BIOQ at EPM.BR says...
> >Hello All,
> >Does anybody know how to prepare methyl- alpha and beta
> > glucofuranose?
> >Helio K. Takahashi
> >takahashi.bioq at epm.br>> The classical method is by a modification of the method used for
> preparation of the methyl glucopyranosides. Reacting a solution of the
> free sugar in methanol in the cold with less than 1% HCl (dissolved by
> bubbling HCl gas into the cold methanol) should give a mixture containing
> mainly alpha and beta methyl glucofuranosides. For details, consult
> Pigman & Horton, or try looking in Meth. in Carbohydr. Chem.
The reference in Methods in Carbohydrate Chem. is pg.349, Vol. II. It
uses cyclic carbonates to prepare glycofuanoses. Unfortunetly, it also
uses phosgene and a few other nasty reagents. I don't think the MeOH/HCl
route would be viable synthetically, but I could be wrong. I've never
tried stopping it at the furanoside stage. You can also prepare a
MeOH/HCl solution by mixing acetyl chloride and methanol. This
avoids dealing with HCl cylinders.
Angela R. Karash
carbchem at mcs.com