the linear and proximal benzo-separated derivatives of 8-phenyltheophylline , 1,3-diethyl-8-phenylxanthine , 1,3-dipropylxanthine , 1,3-dibutylxanthine , 3-isobutyl-1-methylxanthine , theophylline , caffeine , and isocaffeine have been synthesized and evaluated for affinity at the a1 and a2 adenosine receptors .
C0000096
3-isobutyl-1-methylxanthine
C0039771
theophylline