| 549 / | HD | ORGANIC COMPOUNDS -- PART OF THE CLASS 532-570 SERIES |
|
| * | DD | ORGANIC COMPOUNDS (Class 532, Subclass 1) {1} |
| * | DD | .~ HETEROCYCLIC CARBON COMPOUNDS CONTAINING A HETERO RING HAVING CHALCOGEN (I.E., OXYGEN, SULFUR, SELENIUM, OR TELLURIUM) OR NITROGEN AS THE ONLY RING HETERO ATOMS (Class 540, subclass 1) {2} |
| 200 | DF | .~.~ Oxygen containing hetero ring (e.g., dioxirane, etc.) {16} |
| 429 | DF | .~.~.~ The hetero ring is five-membered {14} |
| 472 |  | .~.~.~.~ Plural hetero rings {1} |
| 473 | DF | .~.~.~.~.~> Acyclic -C(=X)-, wherein X is chalcogen, attached directly or indirectly to the hetero ring by nonionic bonding |