The Pomeranz–Fritsch reaction, also named Pomeranz–Fritsch cyclization, is a named reaction in organic chemistry. It is named after Paul Fritsch (1859–1913) and Cäsar Pomeranz (1860–1926). In general it is a synthesis of isoquinoline.
|Named after||Cäsar Pomeranz |
|Reaction type||Ring forming reaction|
General Reaction SchemeEdit
In the archetypical reaction sulfuric acid was used as proton donor, but Lewis acids such as trifluoroacetic anhydride and lanthanide triflates have been used occasionally. Later, a wide range of diverse isoquinolines were successfully prepared.
A possible mechanism is depicted below:
First the benzalaminoacetal 1 is built by the condensation of benzaldehyde and a 2,2-dialkoxyethylamine. After the condensation a hydrogen-atom is added to one of the alkoxy groups. Subsequently, an alcohol is removed. Next, the compound 2 is built. After that a second hydrogend-atom is added to the compound. In the last step a second alcohol is removed and the bicyclic system becomes aromatic.
- topical anesthetics such as dimethisoquin:
- vasodilators, a well-known example, papaverine, shown below.
- Pomeranz, C. (December 1893). "Uber eine neue Isochinolinsynthese". Monatshefte für Chemie. 14 (1): 116–119. doi:10.1007/BF01517862.
- Fritsch, Paul (January 1893). "Synthesen in der Isocumarin- und Isochinolinreihe". Berichte der Deutschen Chemischen Gesellschaft. 26 (1): 419–422. doi:10.1002/cber.18930260191.
- Wang, Zerong (2009). Comprehensive organic name reactions and reagents. Hoboken, N.J.: John Wiley. pp. 2256–2259. ISBN 978-0-471-70450-8.
- Kürti, László; Czakó, Barbara (2007). Strategic applications of named reactions in organic synthesis : background and detailed mechanisms ; 250 named reactions (Pbk. ed., [Nachdr.]. ed.). Amsterdam [u.a.]: Elsevier Academic Press. pp. 358–359. ISBN 978-0-12-429785-2.
- Li, Jie Jack (2006). Name reactions : a collection of detailed reaction mechanisms ; [more than 300 reactions] (3., expanded ed.). Berlin [u.a.]: Springer. pp. 472–474. ISBN 978-3-540-30030-4.