|Named after||Cäsar Pomeranz
|Reaction type||Ring forming reaction|
The Pomeranz–Fritsch reaction, also named Pomeranz–Fritsch cyclization, is a name reaction in the organic chemistry. It is named after Paul Fritsch (1859–1913) and Cäsar Pomeranz (1860–1926). In general it is a synthesis of isoquinoline.
General Reaction Scheme
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.
- anesthetics such as dimethisoquin:
- vasodilators, a well-known example, papaverine, shown below.
- Pomeranz, C. (December 1893). "Uber eine neue Isochinolinsynthese". Monatshefte fur 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.
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