2-Phenylcyclopentan-1-amine is a compound with two stereocenters. Thus, the following two enantiomeric pairs may exist:
(1RS,2SR)-trans-2-phenylcyclopentan-1-amine
(1RS,2RS)-cis-2-phenylcyclopentan-1-amine
The racemate (±)-trans-2-phenylcyclopentan-1-amine [1:1 mixture of (1R,2S)-trans-2-phenylcyclopentan-1-amine (box, left) and (1S,2R)-trans-2-phenylcyclopentan-1-amine (box, right)] is the active ingredient of cypenamine.[3] Furthermore, the kinetic resolution of (±)-trans-2-phenylcyclopentan-1-amine by lipase B from Candida antarctica may be effectively performed by an aminolysis reaction.[3]
Racemic cis-2-phenylcyclopentan-1-amine [1:1 mixture of (1R,2R)-cis-2-phenylcyclopentan-1-amine and (1S,2S)-cis-2-phenylcyclopentan-1-amine] has found no pharmacological application.[citation needed]
Homology
Cypenamine is a homolog of tranylcypromine, containing an expanded alicyclic ring that is two methylene units larger than the highly strained/reactive cyclopropane. The cyclohexane homologue has been reported, although the LD50s were all less than for plain amphetamine, it was still a functional stimulant.[citation needed]
^ abGonzález-Sabín J, Gotor V, Rebolledo F (2004). "Kinetic resolution of (±)-trans- und (±)-cis-phenylcyclopentanamine by CALB-catalyzed aminolysis of esters: The key role of the leaving group". Tetrahedron:Asymmetry. 15 (3): 481–488. doi:10.1016/j.tetasy.2003.11.013.