Table 4.
Solubilities of Imidazo[2,1-i]purin-5-one Derivatives in Comparison with Xanthines1
![]() | |||
---|---|---|---|
compd | R1 | R2 | water solubility (μM)a |
Xanthines | |||
theophylline | H | H | 44 400b,37 |
8-phenyltheophylline | H | phenyl | 1038 |
8-styryltheophylline | H | styryl | 0.22 |
caffeine | methyl | H | 108 000b,37 |
8-phenylcaffeine | methyl | phenyl | 487 |
8-styrylcaffeine | methyl | styryl | 2.8 |
Imidazopurinonesc | |||
17 | methyl | H | 1 210 000 |
22 | methyl | phenyl | 1450 |
At 20 °C unless otherwise noted.
At 25 °C.
Hydrochlorides.