Taking into consideration the known mechanism of the drug action of cyclophosphamide (1), several analogs and related compounds 5, 6, 7, 9, 11, 12 and 27 were synthesized, and tested against lymphocytic leukemia P 388 in mice.
Moderate to high activity was found with 5 (T/C × 100 = 243 at a dose of 300 mg/kg), 7 (T/C × 100 = 155 at a dose of 55 mg/kg). None of these compounds was found to be more active than 1 (T/C × 100 = 339 at a dose of 65 mg/kg). Although the essential position C 4 for the enzymatic activation is completely blocked in 5, the compound possesses a high degree of activity. This result justifies a reevaluation of the proposed mechanism of drug action of 1 and its analogs.