The molecule is built on a piperidine ring (six-membered, fully saturated, with one ring nitrogen).
- At the carbon adjacent to the ring nitrogen: there is an ethyl substituent (-CH2-CH3).
- At the ring nitrogen: there is an exocyclic side chain that runs outward as follows:

Ring nitrogen substituent, from the ring outward:
1. The ring nitrogen is bonded to an sp2 carbon that bears a hydroxyl group and is double-bonded to a nitrogen, giving an -C(OH)=N- fragment (no E/Z specified for this C=N).
2. That imino nitrogen continues into a vinylene linkage (-CH=CH-), which is E-configured.
3. The terminal carbon of the vinylene group is bonded to one carbon of a cyclopropane ring (three-membered saturated carbocycle).