Polycyclo Ring System Having The Cyclic Anhydride As One Of The Cyclos Patents (Class 549/234)
- Plural bicyclo ring systems each having the cyclic anhydride as one of the cyclos (Class 549/241)
- Nitrogen or additional chalcogen bonded directly to the bicyclo ring system (Class 549/243)
- Having -C(=X)-, wherein X is chalcogen, bonded directly to the bicyclo ring system (Class 549/244)
- Halogen bonded directly to the bicyclo ring system (Class 549/246)
- Phthalic anhydride per se (Class 549/247)