Hofmann-Löffler-Freytag reaction

The Hofmann-Löffler-Freytag reaction is a name reaction in organic chemistry that was named after August Wilhelm von Hofmann , Karl Löffler and Curt Freytag. In this reaction, cyclic amines synthesized from acyclic amines.

mechanism

An N -bromamine is used here as the acyclic amine . Iodine or chlorine can also be used as halogen . The radicals R ¹ and R ² are alkyl or aryl groups . Also, hydrogen is possible as the remainder. In an acidic medium, the nitrogen atom attacks a proton in an equilibrium reaction and an ammonium salt is formed. Under the condition of heat or UV radiation , a bromine radical splits off from the positively charged nitrogen. In the next step, the proton attaches to the nitrogen, whereupon a bromine radical binds to the alkyl radical. A proton is split off by a base , here with a hydroxide ion . The bromine is then split off and a cyclic molecule is formed. Another proton is split off by a further hydroxide ion and a cyclic amine is formed.

Individual evidence

↑ László Kürti , Barbara Czakó: Strategic Applications Of Named Reactions In Organic Synthesis. Background and detailed Mechanisms. 250 named reactions . Elsevier Academic Press, Amsterdam et al. 2005, ISBN 0-12-429785-4 , pp. 208 .

[1] László Kürti , Barbara Czakó: Strategic Applications Of Named Reactions In Organic Synthesis. Background and detailed Mechanisms. 250 named reactions . Elsevier Academic Press, Amsterdam et al. 2005, ISBN 0-12-429785-4 , pp. 208 .