Purine (including Hydrogenated) Patents (Class 514/263.1)
- The additional hetero ring is a 1,3-diazine ring (including hydrogenated) (Class 514/263.21)
- The additional hetero ring is six-membered consisting of one nitrogen and five carbons (Class 514/263.22)
- The additional hetero ring consists of carbon and chalcogen as the only ring members (Class 514/263.23)
- With perservative, stabilizer, or an additional active ingredient (Class 514/263.31)
- Chalcogen bonded directly to the 2-,6-, and 8-positions of the purine ring system (Class 514/263.33)
- Chalcogen bonded directly to the 2-and 6- positions of the purine ring system (e.g., theophylline, etc.) (Class 514/263.34)
- Nitrogen bonded directly to a ring carbon of the purine ring system (e.g., guanine, etc.) (Class 514/263.37)