(S-(R*,R*))-N1-(16,21-Diamino-21-imino-15-oxo-6,10,14,20-tetraazaheneicos-1-yl)-2-(((2,4-dihydroxyphenyl)acetyl)amino)butanediamide 108687-79-2 AR 636 Butanediamide, N1-(16,21-diamino-21-imino-15-oxo-6,10,14,20-tetraazaheneicos-1-yl)-2-(((2,4-dihydroxyphenyl)acetyl)amino)-, (S-(R*,R*))- argiotoxin 636