preferred_name: a L-5-monosubstituted hydantoin => a D-5-monosubstituted hydantoin
preferred_name_lc: a l-5-monosubstituted hydantoin => a d-5-monosubstituted hydantoin
label: a L-5-monosubstituted hydantoin => a D-5-monosubstituted hydantoin
label_lc: a l-5-monosubstituted hydantoin => a d-5-monosubstituted hydantoin