US PATENT SUBCLASS 549 / 483
.~.~.~.~ Having -C(=X)-, wherein X is chalcogen, bonded directly to the hetero ring

Current as of: June, 1999
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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}
483.~.~.~.~ Having -C(=X)-, wherein X is chalcogen, bonded directly to the hetero ring {5}
484  DF  .~.~.~.~.~> The -C(=X)- is part of a -C(=X)X- group, wherein the X's are the same or diverse chalcogens {2}
487  DF  .~.~.~.~.~> Nitrogen bonded directly to the -C(=X)- group
488  DF  .~.~.~.~.~> Additional chalcogen attached indirectly to the hetero ring by nonionic bonding
489  DF  .~.~.~.~.~> Preparation of furfural (i.e., furan-2-aldehyde)
490  DF  .~.~.~.~.~> Purification or recovery of furfural

DEFINITION

Classification: 549/483

(under subclass 429) Compounds in which a -- group, wherein X is chalcogen (i.e., oxygen, sulfur, selenium or tellurium), is bonded directly to the hetero ring.

(1) Note. An example of a compound provided for herein is: [figure]