Possible locations for modifications of the parent ring include the tricyclic structure, (22) C-2 methylene, (15) C-3 carbonyl, (23) C-8 methylene, (17) C-13 methylene, (24) and C-19 double bond.
CONNECT: parent ring modification of pleuromutilin relates to the synthesis of thyroid hormone (T3 and T4) through parent ring modification. The parent ring undergoes ionization which adds either three or four iodines onto the benzene ring.