| 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} |
| 633 | DF | .~.~.~ Carbon bonded directly at the 10- and 13-positions (e.g., androstenes, etc.) {5} |
| 635 | ![]() | .~.~.~.~ Carbon or halogen bonded directly at the 2- or 4-position |