The conformational analysis of saturated heterocycles. Part 89. Conformational analysis of trans-1,2,3,4,5,6-hexamethyl-1,2,4,5-tetra-azacyclohexane

Abstract

Variable-temperature 13C n.m.r. shows the title compound to be the trans-isomer which adopts a symmetric conformation with the C-methyl groups diequatorial and the N-methyl groups symmetrically diaxial diequatorial (aeae). The N-inversion barrier (ΔGc‡ 7.7 kcal mol–1) provides strong evidence for the three conformational sets previously postulated for 1,2,4,5-tetra-azacyclohexanes.