Racemization and asymmetric transformation processes used in the manufacture of levobupivacaine and analogues thereof

A process for the racemisation of an optically-enriched N-containing heterocyclic compound having 3 to 7 ring atoms and a carboxanilide group attached to the ring at a carbon atom in the 2-position adjacent to the N-atom, said carbon atom being the chiral center to be racemised, wherein said N-atom is substituted with an R.sub.1 substituent and said R.sub.1 substituent is not H, said method comprising heating the compound in a wholly or substantially non-aqueous system comprising an acid selected from the group consisting of alkanoic acids, arylalkanoic acids and acids having a pKa of -1 to +6, relative to water.