80801-26-9 Antrimycin Antrimycin A Cirratiomycin B L-Serine, 2-(hydroxymethyl)seryl-L-alanyl-L-erythro-alpha,beta-diaminobutyryl-L-2,3,4,5-tetrahydro-3-pyridazinecarbonyl-L-alanyl-(E)-2,3-didehydroisoleucyl-