a) Halogenation of pyrrole

To avoid polyhalogenation, work with diluted halogen and at a low temperature should be used. Another option is to use NBS or NCS.


b) Sulfonation of pyrrole

The pyrrole sulfones via the pyridine-SO 3 complex, followed by slightly acidic water.


c) Friedel-Crafts alkylations and acylations
These reactions are not viable since the presence of Lewis acids produces the polymerization of pyrrole.