A facile approach to anhydrogalactosucrose derivatives from chlorinated sucrose.

Three new anhydrosucrose derivatives: 1,4:3,6-dianhydro-beta-D-fructofuranosyl 4-chloro-4-deoxy-alpha-D-galactopyranoside (4), 1,4:3,6-dianhydro-beta-D-fructofuranosyl 3,6-anhydro-4-chloro-4-deoxy-alpha-D-galactopyranoside (6) and 1,6-dichloro-1,6-dideoxy-beta-D-fructofuranosyl-3,6-anhydro-4-chloro-4-deoxy-alpha-D-galactopyranoside (8) were prepared from chlorinated sucrose. The structures of these anhydrides were confirmed by their (1)H and (13)C NMR spectra, ESIMS and elemental analysis. The crystal structures of 6 and the acetate of 4 (5) are presented. The relative reactivity of the chloromethyl groups towards S(N)2 reactions in 1,6-dichloro-1,6-dideoxy-beta-d-fructofuranosyl 4,6-dichloro-4,6-dideoxy-alpha-D-galactopyranoside was found to be in order 6>6'>1'.