The reaction is catalysed with weak base like piperidine or pyridine. Included are pyridine, thiophene, pyrrole, and furan. The pyridine analog is quinoline or isoquinoline. SO is a strong Lewis acid readily forming crystalline complexes with pyridine, dioxane, and trimethylamine. Chemists have long known of rings containing carbon, e.g. benzene, pyridine, and cyclohexane. It is freely soluble in chloroform, benzene, pyridine, and carbon disulfide. Like the related molecule pyridine and quinoline, acridine is mildly basic. Because of the decreased basicity compared to pyridine, electrophilic substitution of pyrimidine is less facile. The molecule is one of the three isomeric amines of pyridine. It is a weak Lewis acid, forming adducts with pyridine and methylamine. Despite the structural and bonding commonalities of benzene and pyridine, their reactivity differ significantly. One possible way to do a substitution on pyridine is nucleophilic aromatic substitution. Calculate the pH and percentage protonation of a .20 M aqueous solution of pyridine, CHN. Acetaldehyde is an important precursor to pyridine derivatives, pentaerythritol, and crotonaldehyde. The ring atoms in the pyridine molecule are sp-hybridized.