a D-5-monosubstituted hydantoin => a L-5-monosubstituted hydantoin
a d-5-monosubstituted hydantoin => a l-5-monosubstituted hydantoin
a D-5-monosubstituted hydantoin => a L-5-monosubstituted hydantoin
a d-5-monosubstituted hydantoin => a l-5-monosubstituted hydantoin