| 552 / | HD | ORGANIC COMPOUNDS -- PART OF THE CLASS 532-570 SERIES |
| * | DD | ORGANIC COMPOUNDS (Class 532, subclass 1) {11} |
| 502 | DF | .~ Cyclopentanohydrophenanthrene ring system containing {21} |
| 612 | DF | .~.~ Three or more oxygens bonded directly to the cyclopentanohydrophenanthrene ring system {6} |
| 616 | | .~.~.~ Oxygen bonded directly at the 16-position {1} |
| 617 | DF | .~.~.~.~> The A ring is a benzene ring (e.g., estriols, etc.) |