US PATENT SUBCLASS 548 / 421
.~.~.~.~.~ Plural ring hetero atoms in the tetracyclo ring system


Current as of: June, 1999
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548 /   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) {4}
400  DF  .~.~ Hetero ring is five-membered consisting of one nitrogen and four carbons (e.g., halopyrrolidines, etc.) {20}
416  DF  .~.~.~ Polycyclo ring system having the five-membered hetero ring as one of the cyclos {5}
420  DF  .~.~.~.~ Tetracyclo ring system having the five-membered hetero ring as one of the cyclos {3}
421.~.~.~.~.~ Plural ring hetero atoms in the tetracyclo ring system {2}
422  DF  .~.~.~.~.~.~> Three-membered nitrogen containing hetero ring is cyclo in the tetracyclo ring system (e.g., mitomycin C, etc.)
423  DF  .~.~.~.~.~.~> Plural chalcogens bonded directly to ring carbons of the five-membered hetero ring (e.g., cyclic imides, etc.)


DEFINITION

Classification: 548/421

(under subclass 420) Compounds wherein the tetracyclo ring system contains at least one ring hetero atom in addition to the ring nitrogen of the five-membered hetero ring.