The article, that George prepared for you today is a great review on morpholines. It is a versatile moiety, a privileged pharmacophore, and an outstanding heterocyclic motif with a wide range of pharmacological activities due to different mechanisms of action.
The review covers synthetic medicinal chemistry, SAR, and the pharmacological significance of morpholine derivatives. Besides that, the authors give a summary on drugs under clinical trial, containing such fragments. The full text is available here!