A combined microwave and Raman system offers the possibility of controlled heating together with in situ reaction monitoring. Thus, it enables a fast process optimization of chemical reactions like a Gould-Jacobs reaction.
To demonstrate the potential of Anton Paar’s combined microwave synthesis reactor and Raman spectroscopy setup, this report shows in situ monitoring of a solvent free Gould-Jacobs reaction of aniline and ethoxymethylenemalonate (EMME) toyield an ethylanilino methylenemalonate as intermediate and a 4-quinolone as final product. Quinolones, especially fluoroquinolones such as ciprofloxacin or norfloxacin, are antibacterial agents. Therefore, the Gould-Jacobs reaction is an important procedure in the production of raw materials for a number of pharmaceuticals. As shown for the coumarin reaction presented in another application report, live monitoring gives the opportunity to follow the intermediate in a two-step reaction, which usually has to be run without supervision leaving only the final product. More importantly, this reaction shows how such an organic synthesis can be sped up using the combination of Anton Paar’s Cora 5001 Raman spectrometer with the Monowave 400 R for fast and target-oriented process optimization.