Racemates and enantiomers of basic substituted 5-phenylhydantoins. Syntheses and antiarrhythmic activity

The racemates and the enantiomers of 5-phenylhydantoins with basic substituents in 5-position are synthesized on two different routes via the Bucherer-Bergs-reaction. Using lanthanide-shift-reagents the enantiomeric excess for the enantiomers of 3-methyl-5-morpholinomethyl-5-phenylhydantion (3a) and 3-methyl-5-phenyl-5-(2-phthalimidoethyl) (6a) is found to be more than 98%. The enantiomers of 4d, 5b, 6b, 7a and 7b, derived from 3a and 6a, possess the same optical purity. The racemates and the enantiomers of 3a, 4d and 5b were tested at atrium of rat hearts on their antiarrhythmic activity. At the right atrium (+)-3a, (+)-4d, and (+)-5b reduce the spontaneous frequence dependent on the dosis. At the left atrium the enantiomers of 3a and 4d show a negative inotropic action (+)-3a is 4.1, (+)-4d is 1.5 more active as the corresponding (-)-enantiomers. Compound (+)-4d exceeds the reference substance diphenylhydantoin by the factor 1.3.