Transposition de l'atome d'azote de dialkylaminopentopyranosides; mise en evidence de sels d'aziridinium intermediaires

Abstract

Methyl pyranosides with dimethylamino and sulfonyloxy groups in trans relationship undergo rearrangement with participation of the dimethylamino group. This rearrangement results in a 1,2-shift of the nitrogen function which is assumed to be concerted in apolar solvents such as benzene. On the contrary, in water the shift proceeds via an aziridinium ion (observed by NMR) which is opened in a second step, with water or nucleophiles in good yields. The opening of the aziridinium ion has the same regioselectivity as that of corresponding epoxides.