Chemical structures of lobeline, lobelane, and N-1,2-diol analogs. For clarity of presentation, compounds are grouped according to structural similarity of substituent additions to the phenyl rings: lobeline, lobelane, and N-1,2-diol; N-1,2-diol analogs containing 1-naphthyl or 4-biphenyl substituents; N-1,2-diol analogs containing aromatic methoxy or methylenedioxy substituents; N-1,2-diol analogs containing aromatic halogeno substituents.