1H-Purine-2,6-dione, 3,7-dihydro-1,3-dimethyl-7-(2-hydroxy-3-(5-(2-(4-methyl-1-piperazinyl)ethyl)-1,2,4-oxadiazol-3-yl)propyl)-, (Z)-2-butenedioate (1:2) (salt) 88338-43-6