[[2-(amino-3,4-dioxo-1-cyclobuten-1-yl) amino]alkyl]-acid deriva
[[2-(Amino-3,4-dioxo-1-cyclobuten-1-yl)amino]alkyl]-acid...
[[4 -[4-(4-phenyl-1-piperazinyl)phenoxymethyl]-1,3-dioxolan-2-yl
[[4-[4-(4-phenyl-1-piperazinyl)phenoxymethyl]- 1,3-dioxolan-2-yl
[[4-[4-(4-phenyl-1-piperazinyl)phenoxymethyl]-1,3-diox olan-2-yl