23491-45-4 HOECHST DYE 33258 Hoe 33258 NSC322921 Phenol, 4-[5-(4-methyl-1-piperazinyl)(2,5'-bi-1H-benzimidazol)- 2'-yl]-, trihydrochloride Phenol, p-[5-[5-(4-methyl-1-piperazinyl)-2-benzimidazolyl]-2- benzimidazolyl]-, trihydrochloride Pibenzimol HCl