preferred_name: penilactone B => penilactone D + o-quinone methide + H(+)
preferred_name_lc: penilactone b => penilactone d + o-quinone methide + h(+)
label: penilactone B => penilactone D + o-quinone methide + H(+)
label_lc: penilactone b => penilactone d + o-quinone methide + h(+)