preferred_name: a purine nucleobase + D-ribose => a purine D-ribonucleoside + H2O
preferred_name_lc: a purine nucleobase + d-ribose => a purine d-ribonucleoside + h2o
label: a purine nucleobase + D-ribose => a purine D-ribonucleoside + H2O
label_lc: a purine nucleobase + d-ribose => a purine d-ribonucleoside + h2o