The reaction of 2-phenyl-2,3,5,6,7,8-hexahydro imidazo[1,2-a]pyridine (I) with diphenyl sulfide (II) by means of n-butyllithium in THF gives 2-phenyl-8-(phenylthio)-2,3,5,6,7,8-hexahydroimidazo[1,2-a]pyridine (III), which is then oxidized with chloramine T in methanol and simultaneously ketalized.