The Five-membered N-hetero Ring Is 1,3-diazole, Which May Be Hydrogenated (e.g., 6-chloropurine Nucleoside, Nebularin, Etc.) Patents (Class 536/27.21)
- Additional nitrogen bonded directly to the 2-position of the purine ring system (Class 536/27.61)
- Nitrogen, chalcogen, or additional carbon bonded directly to the 6-position nitrogen (e.g., 6-position nitrogen is substituted, etc.) (Class 536/27.62)
- Chalcogen, halogen, or benzene bonded directly to carbon of the purine ring system (e.g., isoguanosine, 2-fluoroadenosine, etc.) (Class 536/27.7)