Oxirans and Oxetans; Reduced Furans; Reduced Pyrans; Furans and Benzofurans; Pyrans, Pyrones and Benzopyrones; Lactones and Cyclic Anhydrides; Compounds with Two or More Oxygen Atoms in the Same Ring; Saturated Heterocycles with One Sulfur Atom in the Ring; Unsaturated and Aromatic Sulfur Heterocycles; Heterocycles with Two or More Sulfur Atoms in the Ring; Compounds with Oxygen and Sulfur Atoms in the Same Ring; Saturated Heterocycles with One Nitrogen Atom in the Ring; Pyrroles, Indoles and Their Reduced and More Highly Condensed Analogs; Pyridine and Its Condensed Derivatives; Seven-Membered and Larger Unsaturated Heterocycles with One Nitrogen Atom in the Ring; Three-, Four-, and Five-Membered Two-Nitrogen Heterocycles; Six- Membered Ring Heterocycles with Two Nitrogen Atoms in the Ring; Five- and Six-Membered Ring Heterocycles with Three or More Nitrogen Atoms in the Ring; Seven-Membered and Larger Heterocycles with Two or More Nitrogen Atoms in the Ring; Heterocycles with Nitrogen and Oxygen; Nitrogen and Sulfur; or Nitrogen, Oxygen and Sulfur in the Same Ring.
