9,9a-Diphenyl-1,3,4,6,7,9a-hexahydro-2H-pyrazino[1,2-a]pyrimidine at 130 K

Abstract

The stereochemistry of the title compound, C19H21N3, has been confirmed by a single-crystal X-ray analysis. The bicyclic ring system adopts a cis-decalin-like conformation, which presumably minimizes steric repulsion involving the bridgehead phenyl substituent. The conformation of the amino group appears to be dictated by a nitrogen anomeric effect.