Abstract
PROF. RUZICKA gave a brief sketch of the principal investigations conducted by Wallach in the domain of terpene chemistry. The work originated in a study of several samples of essential oils which had been kept untouched for fifteen years in a cupboard in Kekulé's private laboratory. It soon became evident that “a great many terpenes formerly designated differently and of supposedly varying constitution are undoubtedly identical”. In the first stages several simple reagents were caused to act on the separate fractions of natural terpene mixtures with the view of the separation of crystalline reaction products. In three years Wallach was able to list eight terpenes which obviously differed from one another, each being characterised without ambiguity: pinene, camphene, limonene, dipentene, sylvestrene, terpinolene, terpinene, and phellandrene. Later it appeared that dipentene is dl-limonene, and that pinene, terpinene, and phellandrene are mixtures of α-and β-compounds; moreover, it is now known that sylvestrene does not occur in Nature. Wallach also investigated oxygenated terpene derivatives and the sesquiterpenes, particularly cadinene and caryophyllene. After characterisation of the individual terpenes, he considered the elucidation of their innumerable mutual relations to be more important than the determination of their constitution. The real harvest from the persistent work of Wallach was reaped in 1895, when with a single stroke, the structure of an entire series of terpene compounds was elucidated. With the end, about this time, of the heroic period in terpene chemistry, Wallach ceased to play the part of pioneer. Of his later work, Prof. Ruzicka referred to that on bicyclic representatives of the terpene series, and that concerned with simple alicyclic compounds.
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Wallach's Chemical Investigations. Nature 129, 428 (1932). https://doi.org/10.1038/129428b0
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DOI: https://doi.org/10.1038/129428b0