1H, 13C 2D NMR and X-ray studies of the products of the reaction between dibenzylidencyclohexanone and 6-amino-1,3-dimethyl uracil

Abstract

The reaction of the 6-amino-1,3-dimethyl uracil with the dibenzylidencyclohexanone ( 1 ), provided three adducts whose structures result from nucleophilic attack yielding the monoadduct 3 and two isomeric bisadducts ( 4 and 5 ) in moderate yields (50–60%). The structures obtained in this study were elucidated with 2D high resolution NMR experiments, variable temperature NMR and X-ray crystallographic studies. In compound 3 , the tricyclic skeleton is essentially planar and the cyclohexane ring addopts an envelope conformation. The structures 4 and 5 correspond to two isomeric spiro compounds.