1H-Purine-8-butanoic acid, 2,3,6,7-tetrahydro-1,3-dimethyl-2,6-dioxo- (9CI) 5438-71-1 8-(3-Carboxypropyl)theophylline 8-Theophyllinebutyric acid NSC 14374 Theophylline-8-butyric acid