4-(Glycosyl) isoxazoline N-oxides were synthesized directly from aldehydo sugars by one- step cyclization with double mole of methyl nitroacetate in a satisfactory yield. 2, 3-O- Isopropylidene-D-glyceraldehyde reacted with methyl nitroacetate to give 4-(1, 2-O- isopropylidene-D-glycero-dihydroxyethyl)-3, 5-bis (methoxycarbonyl) isoxazoline N-oxide. The same treatment of 2, 3: 4, 5-di-O-isopropylidene-aldehydo-L-arabinose and penta-O- ...