| 568 / | HD | ORGANIC COMPOUNDS -- PART OF THE CLASS 532-570 SERIES |
| * | DD | ORGANIC COMPOUNDS (Class 532, Subclass 1) {4} |
| 18 | DF | .~ SULFUR CONTAINING {9} |
| 27 | DF | .~.~ Oxygen bonded directly to sulfur (e.g., sulfoxides, etc.) {3} |
| 28 | DF | .~.~.~ Plural oxygens bonded directly to the same sulfur (e.g., sulfones, etc.) {6} |
| 34 | | .~.~.~.~ Plural rings containing |