A Method for the Racemization of 2-Methylpyrrolidine: A Histamine H3 Receptor Pharmacophore

This paper describes a method for the racemization of unwanted (S)-1 isomer arising from the resolution of (±)-1. The process of racemization involves thiyl radical-mediated reversible hydrogen abstraction at the chiral center, in the presence of AIBN in water. The racemized isomer was subsequently resolved by l-(+)-tartaric acid to get (R)-1, a histamine H3 receptor pharmacophore. We foresee that such an approach of racemization will be industrially useful for recycling waste (S)-1 enantiomer.