New Synthesis of Azulene
Heinz Langhals presents a new way to synthesize azulene.
A Convenient Synthesis of Azulene: H. Langhals, M. Eberspächer
Synthesis 2018, DOI: 10.1055/s-0036-1591906
Azulene is a bicyclic hydrocarbon characterized by a distinctive deep blue color. Its hydrophobicity renders it an ideal dye for staining non-hydrophilic materials which are otherwise difficult to stain, such as perfluorinated hydrocarbons, greasy polymers and silicon oil. The group of Professor Heinz Langhals (Ludwig-Maximilians-Universität Munich, Germany) has recently reported a new, convenient and scalable entry to azulene, using pyridine and 2,4-dinitro-chlorobenzene as starting materials.
Professor Langhals said: “The use of pyrrolidine gave an improvement and simplification compared to the preparation for azulene described in Organic Syntheses, by becoming less problematic. The easy scaling favors applications such as in cosmetics and for the coloration of perfluorated compounds and silicone oil.”
