BICYCLIC DIAZASUGARS 2 - SYNTHESIS AND STRUCTURES OF L-ARABINOSE AND D-RIBOSE ANALOGS

Bicyclic diazasugar analogues of L-arabinose and D-ribose have been pr epared and characterized by x-ray crystallography and NMR spectroscopy . The crystalline arabinose analogue is the beta-anomer in the ring-fl ipped C-1(4) conformation (7), but in D2O solution this is a minor com ponent with the major being the cr-anomer in the C-4(1) conformation(6 ). The crystalline ribose analogue is the beta-anomer in the C-4(1) co nformation (10) which is also the major component in D2O solution and is accompanied by a minor form which is probably the alpha-anomer in t he ring-nipped C-1(4) conformation (11). (C) 1998 Elsevier Science Ltd . All rights reserved.