Ab initio and Semiempirical Conformational and Configurational Analysis of N-2-(1,4-Dioxane)-Nʹ-(4-methylbenzenesulfonyl)-O-(4-methylphenoxy)isourea

The conformational, configurational behavior and the structure of N-2-(1,4-dioxane)-Nʹ-(4-methylbenzenesulfonyl)-O-(4-methylphenoxy) isourea 1 has been studied using ab initio and semiempirical calculations (AM1 and PM3). The endo-anomericeffect and hydrogen bonds control the population of dioxane ring conformers or anomers but not the configuration interconversion of the imine of imidoyl moiety. Ab initio and AM1 and PM3 calculations demonstrate that the dioxane ring adopts a chair conformation, that the imidoyl amino group prefers an axial conformation and that the tosyl and tolyl groups about the C=N bond retain an E configuration. The computational analysis of 1 complements the X-ray findings