Maytansine, N2'-deacetyl-N2'-[3-[[1-[[4-[[(2,5-dioxo-1-pyrrolidinyl)oxy]carbonyl]cyclohexyl]methyl]-2,5-dioxo-3-pyrrolidinyl]thio]-1-oxopropyl]-

Maytansine, N2'-deacetyl-N2'-[3-[[1-[[4-[[(2,5-dioxo-1-pyrrolidinyl)oxy]carbonyl]cyclohexyl]methyl]-2,5-dioxo-3-pyrrolidinyl]thio]-1-oxopropyl]-