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} |
512 | DF | .~.~.~ The hetero ring is three-membered consisting of one oxygen and two carbons {7} |
550 | | .~.~.~.~ Cyano, nitrogen, or halogen bonded directly to the hetero ring |