Hexahydro-dibenz[d, f]azecines : Existence of Two Conformational Isomers of the 6-Oxo Derivatives in Solution

Abstract

New hexahydro-dibenz[d, f]azecines, 11 and 12, were synthesized from the homoerythrinan-enone 3. Their 6-oxo derivatives were shown to exist in two conformations in solution due to the rotational isomerism of the ten-membered lactam group. An example of remarkably large separation of two methylenedioxy protons in the proton nuclear magnetic resonance spectrum due to their non-equivalence is also presented.