SEARCH Articles Figures Tables 14-membered ring structures 3- Membered rings three heteroatoms 4- Membered rings with three heteroatoms 5-Membered rings heteroatoms Heteroatomic Rings Heteroatomic structures Heteroatoms, three-membered Of three-member rings Ring structure heteroatoms Ring structures Ring structures 5- membered rings Three heteroatoms Three structures Three-membered Three-membered rings Three-membered rings with two heteroatoms