THEORETICAL STUDIES ON CONFORMATION OF ALDOPYRANOSES

The potential energy of non-bonded interactions for sixteen aldoheopyranoses and eight aldopentopyranoses have been calculated using the Kitaigorodsky type functions. It has been shown that the C1 (chair) conformation has the lowest energy for all the aldohexoses and most aldopentoses. Only for α-D-arabinose and α-D-ribose does the 1C conformation have the lowest energy. The energy difference between C1 and 1C conformations of β-D-arabinose and α-D-lyxose is small and it is likely that these molecules exist in C1[larr2] equilibrium. The differences in the preferred conformations assigned by the earlier instability schemes and the present energy calculations are also discussed. © 1977.