(E)-8-(3-Chloro-4-fluorostyryl)-1,3-diethyl-7-methylxanthine 155271-98-0 1H-Purine-2,6-dione, 3,7-dihydro-8-(2-(3-chloro-4-fluorophenyl)ethenyl)-1,3-diethyl-7-methyl-,(E)-