Please keep in mind the following Graduate School restrictions on  undergraduate student enrollment in 60000-level courses. 

Here’s the language from Policies and Procedures for Administering Graduate Student Programs (https://catalog.purdue.edu/content.php?catoid=16&navoid=19700#graduate-level-courses )

Courses at the 60000-level generally are restricted to graduate students to facilitate the preservation of the highest course quality and, thereby, to help maintain strong graduate programs.

However, some exceptional senior undergraduate students may be allowed to register for a 60000-level course under the following conditions:
a.The student has a cumulative index of at least 3.4 or has been admitted to a graduate program for asubsequent session; and
b.The student’s semester (session) load is no more than 16 credit hours; and
c.Inclusion of 60000 credits is not more than 33% of the semester (session) load.

Graduate School approval is required if the requested 60000-level course is not offered in a subject field administered by the academic college/school in which the student is enrolled. The Course Request (Registrar’s Form 23) should contain a brief justification in the “comments” section and should bear the additional signature of the course instructor.