SEARCH Articles Figures Tables Heteroatom heterocycles Heteroatoms Heterocycles Heteroatoms, three-membered Heterocycles with Three Heteroatoms Heterocycles with heteroatoms Heterocyclics six-membered Peri-Heterocycles with Six-Membered Heteroring and Three Heteroatoms Six-Membered Heterocycled Six-membered heterocycles Three heteroatoms Three-membered Three-membered heterocycles