| 568 / | HD | ORGANIC COMPOUNDS -- PART OF THE CLASS 532-570 SERIES |
| * | DD | ORGANIC COMPOUNDS (Class 532, Subclass 1) {4} |
| 18 | DF | .~ SULFUR CONTAINING {9} |
| 38 | DF | .~.~ Thioethers {5} |
| 39 | DF | .~.~.~ Oxygen containing {6} |
| 51 | DF | .~.~.~.~ Oxygen bonded directly to a ring {2} |
| 52 | | .~.~.~.~.~ Plural rings containing {1} |
| 53 | DF | .~.~.~.~.~.~> Plural rings bonded directly to the same sulfur |