The molecule is built on a decalin framework, a bicyclic system formed by two fused saturated six-membered carbon rings sharing two adjacent carbons at the ring junctions.

At one of the carbons in the decalin framework, specifically, a carbon that is neither a junction carbon nor adjacent to a junction carbon, there is an exocyclic methine substituent.

This exocyclic methine carbon bears three substituents:
  - one hydrogen atom,
  - one unsubstituted phenyl ring,
  - one primary amino group (-NH2).