Anomeric Effects in Sulfamides

Sulfamides, together with their simpler sulfonamide analogs, are common functional groups in a significant number of biologically active compounds. This is partly due to their unique electronic structure and conformational behavior, which mimics the tetrahedral intermediate involved in many proteases, esterases, and related enzymes. Here, the origin of these unique structural elements are analyzed in the context of a coupled, double anomeric effect using DFT calculations, including conformational scans, and NBO analysis. It is shown that these coupled interactions can be implicitly parametrized in MM3* type force fields using the quantum-guided molecular mechanics (Q2MM) method, yielding accurate force field parameters for molecular mechanics studies of sulfamides and sulfonamides.