Substituted xanthines CompoundStructure Substituted xanthines Paraxanthine Theobromine Theophylline Caffeine 8-Chlorotheophylline (8-CTP) 1-Propargyltheobromine (DMPX) Isobutylmethylxanthine (IBMX) 8-Cyclopentyltheophylline (CPX) Diprophylline 8-Phenyltheophylline 8-Bromotheophylline (8-BTP) Dipropylcyclopentylxanthine (DPCPX) Dimenhydrinate