SEARCH Articles Figures Tables 3- Membered rings synthesis Five-Membered Heterocycled Five-membered heterocycles Five-membered heterocyclic rings Five-membered heterocyclics Five-membered ring Heterocycle, five ring Heterocyclic 5- membered ring Heterocyclic synthesis five-membered rings Heterocyclic synthesis five-membered rings Nitrogen-containing heterocycle synthesis five-membered ring heterocycles Ring synthesis 9-membered rings Ring synthesis five-membered rings Synthesis of Five-Membered Ring Heterocycles