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