| 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} | 
| 623 | DF | .~.~ Two oxygens bonded directly to the cyclopentanohydrophenanthrene ring system {5} | 
| 625 | DF | .~.~.~ The A ring is a benzene ring (e.g., estrones, estradiols, etc.) {5} | 
| 630 |  | .~.~.~.~ 17 alpha-position substituted {1} | 
| 631 | DF | .~.~.~.~.~> The 17 alpha-position substituent contains acyclic carbon-to-carbon unsaturation |