In the search for new anticancer drugs. 9. Synthesis and anticancer activity of spin-labeled analogues of N,N:N',N':N",N"-Tri-1,2-ethanediylphosphoric triamide and N,N:N',N':N",N"-tri-1,2-ethanediylphosphorothioic triamide.

A number of N,N:N',N':N",N"-tri-1,2- ethanediylphosphoric triamide (TEPA) and N,N:N',N':N",N"-tri-1,2- ethanediylphosphorothioic triamide (thio-TEPA) derivatives containing either two aziridine moieties (1a) or two (2-chloroethyl)amino functions (1b) and either a 2,2,6,6-tetramethylpiperidine, 1-oxy-2,2,6,6-tetramethylpiperidine or 1-hydroxy-2,2,6,6-tetramethylpiperidine component were synthesized and tested against lymphocytic leukemia P388 in mice. In a structure-activity comparison it was found that at optimum dose all compounds containing the nitroxyl radical were more active than the corresponding hydroxylamine derivatives. The open-chain compounds (1b) were less active than the corresponding aziridine ring compounds (1a). The replacement of the X = bridge in 1a with the X = N(CH3) group resulted in lowering of the anticancer activity.