549 / | HD | ORGANIC COMPOUNDS -- PART OF THE CLASS 532-570 SERIES |
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* | 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} |
223 | DF | .~.~.~ Xanthene ring system having a benzene ring bonded directly thereto para to the xanthene ring oxygen, wherein the carbon of a -COO- group is bonded directly to the benzene ring ortho to its position of attachment to the xanthene ring system, and spirolactone derivatives thereof (e.g., fluoresceins, chlorofluorans, etc.) {2} |
224 | | .~.~.~.~ The xanthene ring system is three cyclos of a polycyclo ring system having at least four rings (e.g., benz(c)fluorans, etc.) |