| 540 / | HD | ORGANIC COMPOUNDS -- PART OF THE CLASS 532-570 SERIES |
|
| * | DD | ORGANIC COMPOUNDS (Class 532, Subclass 1) {1} |
| 1 | DF | .~ HETEROCYCLIC CARBON COMPOUNDS CONTAINING A HETERO RING HAVING CHALCOGEN (I.E., OXYGEN, SULFUR, SELENIUM OR TELLURIUM) OR NITROGEN AS THE ONLY RING HETERO ATOMS {6} |
| 2 | DF | .~.~ Cyclopentanohydrophenanthrene ring system containing {10} |
| 6 |  | .~.~.~ Spiro {3} |
| 7 | DF | .~.~.~.~> Plural spiro atoms {4} |
| 15 | DF | .~.~.~.~> The cyclopentanohydrophenanthrene ring system is part of a polycyclo ring system having at least five cyclos {1} |
| 28 | DF | .~.~.~.~> The spiro includes the cyclopentanohydrophenanthrene ring system and a hetero ring {6} |