Origin. All parts of the mountain laurel of California, Umbellularia californica, Nutt. (Oreodaphne californica, Nees, Tetranthera californica, Hook, et Am., also known as California bay tree)1), contain volatile oil. This is particularly true of the leaves which upon distillation yield from 2,4 ) to 5,17 p.c.) of oil.
Properties. The oil is light yellow in color. Its odor is pungently aromatic, reminding one of nutmeg and cardamom. If breathed in deeply it attacks the mucous membranes and causes tears to flow. Its taste is warm and camphor-like. d15o 0,936 to 0,948; aD - 22 to - 24°; A.V. 4,7; E.V. 5,5; E.V. after acetylation 50,8 (but one determination in each case); soluble in 1,5 to 2,2 vol. of 70 p.c. alcohol.
Composition. Older investigations have been carried out by j. P. Heaney4) and by Stillman5). Our present knowledge of the oil, however, we owe to F. B. Power and F. H. LeesG). According to these investigators the oil contains traces of formic and higher fatty acids in the free state, small amounts of eugenol (m. p. of benzoyl eugenol 69 to 70°), l-a-pinene (m. p. of nitrol piperidine 119 to 120°; of nitrol benzylamine 124 to 125°), cineol1) (m. p. of iodol compound 115°), very little safrol (m.p. of piperonal 35°), methyleugenol (m. p. of bromeugenol methyl ether dibromide 78 to 79°; of veratric acid 177°). The principal constituent, however, is umbellulone which is present to the extent of from 40 to 60 p.c.
1)W. Busse, Ober die Blatter des kalifornischen Lorbeers. Berichte d. deutsch. pharm. Ges. 6 (1896), 56.
3) J. M. Stillmann, Berl. Berichte 13 (1880), 630.
3) Report of Schimmel &Co. November 1908, 126.
4) Americ. Journ. Pharm. 47 (1875), 105. - Pharmaceutical Journ. III. 5 (1875), 791.
5) Berl. Berichte 13 (1880), 630.
6) Journ. chem. Soc. 85 (1904), 629.
Umbellulone is a ketone C10H14O which, in the pure condition when regenerated from its semicarbazide-semicarbazone, has the following properties: b. p. 219 to 220° (749 mm.)-), 92,5 to 93° (10 mm.)3); d20.0,9503); aD-36°30'3); nD 1,483253). It yields a semicarbazide-semicarbazone (m. p. above 200°) and a normal monosemicarbazone which melts between 240 to 243°, according to the mode of heating. Umbellulone yields a solid dibromide which melts at 119°. Upon oxidation it yields umbellulonic acid, C9H14O3, m. p. 102°, an unsaturated keto acid. Upon distillation this is converted in part into an unsaturated lactone C9H1202 b. p. 218 to 221°.
Based upon the results of Power and Lees2), Lees4), as well as F. Tutin5), in connection with the preparation of numerous derivatives, the action of bromine on umbellulone and its oxidation with permanganate, Tutin proposed the following formula for this ketone: -
Semmler3) reduced umbellulone with sodium to dihydro-umbellulol C10H18O which, upon oxidation with chromic acid, yielded , B-dihydroumbellulone C10H16O. Upon oxidation with permanganate, the benzylidene compound of this ketone yielded homotanacetone dicarboxylic acid. From this Semmler concluded that in dihydroumbellulone the same arrangement of carbon atoms prevails as in tanacetone. However, whereas in tanacetone the keto group is in carvone position, in dihydroumbellulone it is in menthone position. A further proof for the grouping assumed by Semmler is found in the quantitative change of umbellulone to thymol when the ketone is heated in a sealed tube to 280° for 18 hours. These changes are illustrated by the following structural formulas.
1) Report of Schimmel & Co. October 1893, Table in supplement, p. 26. 2) Journ. chem. Soc. 85 (1904), 629.
3) F. W. Semmler, Berl. Berichte 40 (1907), 5017 and 41 (1908), 3988.
4) Journ. chem. Soc. 85 (1904), 644.
5) Ibidem 89 (1906), 1104; 91 (1907), 271, 275; 93 (1908), 252.