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.
