... > SECTION VI - PRODUCTS OF THE CHEMICAL OR ALLIED INDUSTRIES > CHAPTER 29 - ORGANIC CHEMICALS > X. ORGANO-INORGANIC COMPOUNDS, HETEROCYCLIC COMPOUNDS, NUCLEIC ACIDS AND THEIR SALTS, AND SULPHONAMIDES > 2933 Heterocyclic compounds with nitrogen hetero-atom(s) only > Compounds containing in the structure a quinoline or isoquinoline ring-system (whether or not hydrogenated), not further fused > Levorphanol (INN) and its salts