Synthesis and characterization of oxygen and sulfur bridged aromatic macrocycles

The synthesis of nine 16–18–20–22 membered, oxygen and sulfur bridged aromatic macrocycles is reported, and reaction pathways to macrocycles formation are described. Molecular characterization of the nine compounds has been achieved by their mass spectra. Due to the cyclic nature of the compounds analyzed, the mass spectra are of particular interest. The 16–18-membered macrocycles, containing single oxygen and sulfur bridges, display very strong molecular ion intensities, while the 20–22-membered macrocycles, containing double bridges, show lower stability to electron-impact, and the molecular ion intensities are lower. Some of the salient features of the electron fragmentation processes are briefly discussed in the text.