Substituted pyrrolidines
Substituted pyrrolidines are a class of compounds that contain a pyrrolidine ring. Pyrrolidine features predominantly in Nicotine and its analogues that target the nicotinic acetylcholine receptor, in the racetam class of nootropics as part of the γ-lactam pyrrolidone, and in a group of compounds in the substituted cathinone class where the amine of the cathinone is integrated into a pyrrolidine ring.

Chemistry
Pyrrolidine is an organic, heterocyclic compound consisting of a five-membered ring containing one amine (nitrogen) constituent. Its ring is fully saturated, and contains no double bonds. Substitutions are know to occur at all positions around the ring.