(Z)-6-[3-[(N'-tert-butyl-N-cyanocarbamimidoyl)amino]phenyl]-6-pyridin-3-ylhex-5-enoic acid (Z)-6-[3-[(N'-tert-butyl-N-cyano-carbamimidoyl)amino]phenyl]-6-(3-pyridyl)hex-5-enoic acid (Z)-6-[3-[[tert-butylimino-(cyanoamino)methyl]amino]phenyl]-6-(3-pyridyl)hex-5-enoic acid (Z)-6-[3-[(N'-tert-butyl-N-cyano-carbamimidoyl)amino]phenyl]-6-pyridin-3-yl-hex-5-enoic acid