112853-68-6 1H-Pyrido(4,3-b)carbazole, 2,3,4,4a,5,6,11,11a-octahydro-2-ethyl-, cis-, (E)-2-butenedioate (1:1) 4a-11a-cis-2-Ethyl-1,2,3,4,4a,5,11,11a-octahydro-6H-pyrido(4,3-b)carbazole fumarate cis-2,3,4,4a,5,6,11,11a-Octahydro-2-ethyl-1H-pyrido(4,3-b)carbazole (E)-2-butenedioate (1:1)