The physician-writer Gottfried Benn wanted amphetamines to be used by infantrymen but by students.

答案将not加在第一个by的前面，请问not可不可以加在to be used的前面呢？

将句子理解成

The physician-writer wanted amphetamines not to be used by infantrymen but( to be used) by students.

可以吗？