| 546 / | 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) {1} |
| 1 | DF | .~.~ Hetero ring is six-membered consisting of one nitrogen and five carbons {24} |
| 15 | | .~.~.~ Spiro {1} |
| 16 | DF | .~.~.~.~> The spiro includes the six-membered hetero ring {2} |