1-(5,6,7,8-Tetrahydro-2-naphthalenyl)piperazine (Z)-2-butenedioate 1-(6-Tetralyl)piperazine maleate 57537-11-8 Piperazine, 1-(5,6,7,8-tetrahydro-2-naphthalenyl)-, (Z)-2-butenedioate (1:1)