Origin. Paracoto bark of commerce is the bark of an unknown species of the Monimiacead from Bolivia1). The oil, which is obtained as a byproduct in the production of cotoin, was first examined by ). jobst and O.Hesse2), later by O.Wallach and T. Rheindorff3).
Properties. Paracoto bark oil is a very mobile, colorless liquid of an extremely pleasant odor. Sp.gr. 0,9275; aD - 2,12°-).
Composition. 1. According to jobst and Hesse, fraction 160° (d 0,8727; [a]d + 9,34°) consists of a hydrocarbon C12H18 which they named u-paracolene.
2. Fraction 170 to 172° (d 0,8846; [a]D - - 0,63°) yielded upon elementary analysis figures for the formula C11H18 This hydrocarbon was named B-paracotene.
Both these fractions, which evidently consisted of not quite pure terpenes, were lacking almost entirely in the oil examined by Wallach and Rheindorff.
3. The bulk of paracoto bark oil consists of laevogyrate cadinene3) (m.p. of dibromhydrate 121°, of dichlorhydrate 118°).
According to Wallach, the or-, B- and ;'-paracotol of jobst and Hesse, to which they assigned the formulas C15H240 and C28H2402, are not chemical units but essentially mixtures of lasvogyrate sesquiterpenes and inactive methyleugenol. As to the a-paracotol, the possibility of its being a natural hydrate of cadinene is not excluded. In this case, however, its formula should be C15H26O and not C15H240.
1) Moller (Anatomie der Baumrinden) is of the opinion that the bark belongs to a tree of the Monimiaceae, whereas Vogl (Kommentar zur Osterreich. Pharmakopoe) believes that it belongs to a lauraceous plant.
2) Liebig's Annalen 199 (1879), 75.
3) Ibidem 271 (1892), 300.