| 534 / | HD | ORGANIC COMPOUNDS -- PART OF THE CLASS 532-570 SERIES |
| * | DD | ORGANIC COMPOUNDS (CLASS 532, SUBCLASS 1) {8} |
| 573 | DF | .~ Azo {51} |
| 682 | DF | .~.~ Plural hydroxy groups or esters thereof bonded directly to a monocyclic benzene ring (H of hydroxy may be replaced by a substituted or unsubstituted ammonium ion or metal) {1} |
| 683 | DF | .~.~.~ Azo bonded directly to the benzene ring {3} |
| 685 | DF | .~.~.~.~ At least three azo groups attached indirectly to each other by nonionic bonding {2} |
| 686 | | .~.~.~.~.~ Hetero ring containing |