Bicyclic azasugars containing a glycosidic heteroatom 2: D-lyxose analogues

Abstract Bicyclic azasugar analogues of D-lyxose containing a glycosidic heteroatom that is O, N, or S have been prepared from 5- O -tosyl-D-lyxose and characterized by NMR spectroscopy. The nitrogen analogue has an overwhelming preference to be the β-anomer, but the oxygen and sulfur compounds exist as mixtures of anomers with the α-anomer predominating in the latter case. The α-anomers undergo conformational equilibration with the sulfur analogue being fast at room temperature but the oxygen compound requiring 60°C to achieve fast exchange and a sharply resolved 1 H NMR spectrum at 500 MHz.