Deoxyhydroxyamino analogs of sugars : derivatives of methyl 2,3-dideoxy-2-hydroxyamino-α-D-arabino-and -lyxo-hexopyranosides

Abstract N -Substituted hydroxylamines reacted both regio- and stereo-specifically with ethyl 2,3-dideoxy-α- d - glycero -hex-2-enopyranosid-4-ulose ( 1 ) to give N -substituted ethyl 2,3-dideoxy-2-hydroxyamino-α- d - threo -hexopyranosid-4-uloses ( 2 – 7 ), whereas O -methylhydroxylamine gave a mixture of O -methyloximes ( 8 – 10 ), including the product of both stereospecific conjugate addition and oximation ( 10 ). Sodium borohydride reduction of ethyl 2,3-dideoxy-2-( N -hydroxy- N -methylamino)- and 2,3-dideoxy-2-( N -hydroxy- N -isopropylamino)α- d - threo -hexopyranosid-4-uloses proceeded stereoselectively, and the major product had the α- d - arabino configuration. The conformations of these compounds were established using n.m.r. spectroscopy and X-ray diffraction for 3 and 19 . The major interest of these deoxyhydroxyamino sugars was their easy oxidation into spin-labelled sugar analogs whose conformation could be studied by e.s.r. spectroscopy.