Stannate(II) reduction of the beta -D-glucopyranosylnitromethane derivative
4 affords aldoxime 5, which provides access to the nitrile oxide 7, either
on treatment with aq. hypochlorite, or via conversion to the hydroximoyl c
hloride 11 followed by base-mediated dehydrohalogenation. D-Galactose-, D-m
annose- and D-xylose-derived nitrile oxides are generated similarly. The ni
trile oxides either dimerise to 3,4-dipyranosyl-1,2,5-oxadiazole N-oxides o
r are trapped as cycloadducts in the presence of dipolarophiles. (C) 2001 E
lsevier Science Ltd. All rights reserved.