Cytotoxic compounds. XVII. O-, m-, and p-(bis-2-chloroethylamino)phenol, p-(N-(2-chloroethyl)methylamino)phenol, NN-bis-2-chloroethyl-p-phenylenediamine, and NN-bis-2-chloroethyl-N'-methyl-p-phenylenediamine as sources of biologically active carbamates.