Pharmacological Importance of Optically Active Tetrahydro-β-carbolines and Synthetic Approaches to Create the C1 Stereocenter

1,2,3,4-Tetrahydro-beta-carbolines (TH beta Cs) are a pharmacologically important group of compounds belonging to the indole alkaloids. C1-Substituted optically active TH beta Cs have been the target of extensive synthetic efforts due to the presence of the scaffold in numerous natural products and synthetic targets. This review briefly summarizes the methods to obtain the C1 stereocenter and concentrates on evaluating the pharmacological importance of optically active C1-substituted TH beta Cs, including their PDE5-inhibitory, antimalarial, antiviral and antitumor activities.