Phosphoramide derivatives of the general formula: ##STR1## are disclosed wherein X and Y each represents a hydrogen atom or X and Y are removed to form a double bond between the respective adjoining carbon atoms, and n represents an integer of 0 to 2. A process for the preparation of these compounds and pharmaceutical compositions containing these phosphoramide derivatives are also disclosed. The phosphoramide derivatives of the invention are used to treat urethral calculosis and pyelonephritis.