Die Geburt einer Struktur: Zur 60. Wiederkehr der Aufstellung der Azulenformel durch Pfau und Plattner

The historical development of research on the blue color of certain fractions of distilled essential oils as such from chamomille, yarrow, wormwood, and many other sources is described. In 1863, Septimus Piesse suggested the name 'azulene', from azure blue, for this blue body which John Hall Gladstone as the first characterized by its Fraunhofer spectrum. However, it took additional 73 years of research of many famous chemists until Alexander Stanislaus Pfau and Placidus Andreas Plattner in their brilliant work, published in Helvetica Chimica Acta in 1936, could establish the right structure of vetivazulene and guaiazulene and develop the first synthesis for the parent molecule, nowadays called azulene.