(E)-8-(2,5-Dimethylstyryl)-1,3-diethylxanthine hemihydrate 155271-26-4 1H-Purine-2,6-dione, 3,7-dihydro-1,3-diethyl-8-(2-(2,5-dimethylphenyl)ethenyl)-, (E)-, hydrate (2:1)