The Other Cyclo In The Bicyclo Ring System Is Five-membered Patents (Class 544/262)
- Chalcogen bonded directly to ring carbon of the purine ring system (Class 544/265)
- At 2-,6-, and 8-positions (Class 544/266)
- At 2- and 6-positions (e.g., theophyllines, etc.) (Class 544/267)
- Additional polycyclo ring system, which is not another purine, having a hetero ring as one of the cyclos (Class 544/268)
- Additional hetero ring which is unsaturated and is not one of the cyclos of a purine ring system (Class 544/269)
- Having -C(=X)-, wherein X is chalcogen attached directly or indirectly to the purine ring system by nonionic bonding or halogen bonded directly at 8-position (e.g., theophylline acetate, 8-chlorotheophylline, etc.) (Class 544/271)
- Nitrogen attached directly or indirectly to the purine ring system by nonionc bonding (Class 544/272)
- Positions other than 2- and 6- are unsubstituted or hydrocarbyl or hydro- carboyl substituted only (e.g., theophylline, etc.) (Class 544/273)
- Caffeine per se, theobromine per se, or salt thereof (Class 544/274)
- Nitrogen attached directly or indirectly to the purine ring system by nonionic bonding (Class 544/276)
- Nitrogen attached directly or indirectly to the purine ring system by nonionic bonding (Class 544/277)