| 552 / | HD | ORGANIC COMPOUNDS -- PART OF THE CLASS 532-570 SERIES | 
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| * | DD | ORGANIC COMPOUNDS (Class 532, subclass 1) {11} | 
| 208 | DF | .~ Polycyclo ring system containing anthracene configured ring system having at least one double bond between ring members and having oxygen single bonded or any atom double bonded directly at the 9- and 10-positions (e.g., anthraquinones, etc.) {19} | 
| 234 | DF | .~.~ Sulfur bonded directly at alpha position (i.e., 1-, 4-, 5- or 8-position) {1} | 
| 235 |  | .~.~.~ Nitrogen or halogen bonded directly to the anthracene configured ring system |