Hofmann–Löffler reaction

In the Hofmann -Löffler - Freytag reaction is a name reaction in organic chemistry, which was named after August Wilhelm von Hofmann, K. Löffler and C. Freytag. In this reaction, cyclic amines from acyclic amines are synthesized.

Mechanism

As an acyclic amine here an N- bromamine used. As well as halogen, iodine or chlorine can be used. The radicals R1 and R2 are alkyl or aryl groups. Hydrogen is also possible as the balance. In an acidic medium, the nitrogen atom is engaged with an equilibrium reaction of a proton and the result is an ammonium salt. Under the condition of heat or UV radiation, a bromine radical from the positively charged nitrogen is split off. In the next step, the proton superimposed on the nitrogen, whereupon a bromine radical binds to the alkyl radical. With a base, in this case with a hydroxide ion, a proton is eliminated. After the bromine is cleaved and forms a cyclic molecule. Through another hydroxide another proton is eliminated and there is a cyclic amine.