N-Substitution Effects on the Conformations of Iminosugar Analogues of 1-Deoxy-L-Idose and 1-Deoxy-L-Iduronic Acid

We herein report the synthesis and complete conformational analysis of a focused library of iminosugar analogues of l-idose and l-iduronic acid designed to probe the impact of N-substitution on ring dynamics. Molecular modelling, supported by experimental 1H NMR data, reveals that introducing alkyl or acyl substituents on the ring nitrogen profoundly alters the conformational equilibrium, inducing a clear shift from the preferred 1C4 chair to the 4C1 conformation. These findings highlight how targeted nitrogen functionalisation can be used to modulate the conformational landscape of iminosugars, offering new opportunities for the rational design of glycomimetic scaffolds.