Synonyms for Propaedeutic (same or very similar meaning)
WordNet sense 1 (a course that provides an introduction to an art or science (or to more advanced study generally)):
propaedeutics
WordNet sense 2 (preceding and preparing for something):
preparatory, preparative
WordNet sense 3 (existing or coming before):
preceding
From the ODE community, based on WordNet
add/edit