This ester, which is a characteristic constituent of many coniferous oils, also occurs in several other oils. The dextrogyrate acetate occurs in the needle oil of Callitris glauca, the lasvogyrate acetate in the needle oil of Abies alba, in the oil from the twigs of A. canadensis, A. balsamea and Siberian pine needle oil, also in the oils of coriander, valerian and kesso root. The acetate has likewise been found in the following oils but observations as to its direction of rotation are wanting, viz., in the oil from the cones of Abies alba (?), the oil of Pinus montana, the oils from the cones and needles of Picea canadensis and P. rubens, the oil from the twigs and needles of Larix americana, in German and Swedish oils of Pinus silvestris (?), in the needle oil of Picea nigra, and in the oils from Salureja Thymbra, Thymus capitatus and golden rod.
1) Bertram, G.I. P. 80711.
2) Bruylants, Berl. Berichte 11 (1878), 455.
3) Bertram and Walbaum, Journ. f. prakt. Chem. II. 49 (1894), 7.
4) Bertram and Walbaum, Arch, der Pharm. 231 (1893), 305.
5) Behal, Annal. de Chim. et Phys. VII. 20 (1900), 421.
6) Tschugaeff, Berl. Berichte 31 (1898) 1775.
7) Minguin and de Bollemont, Compt. rend. 1:54 (1902), 609.
The artificial preparation of bornyl acetate affords no difficulty. It can be obtained when borneol is acetylized in the ordinary manner, also by heating borneol with anhydrous acetic acid in the presence of some sulphuric acid.1)
It is the only bornyl ester of a fatty acid which has thus far been obtained in a crystalline state. From petroleum ether it is obtained in handsome hemiedric crystals, which melt to a colorless liquid at 29°.2) Molten bornyl acetate may remain in a liquid condition for a long time. Its aroma is typical of that of pine needles imparting to it its freshness and strength. The direction of rotation of the ester corresponds with that of the borneol. The following properties have been recorded:
M. p. 29°; b. p. 98° (10 mm.); d15o 0,991; aD - 38° 21'; nDl5o1,46635;3) b. p. 106 to 107° (15 mm.);4)
B. p. 107° (15 mm.); d 20o/4o 0,9855; [a]D - 44,40°;5) d15o 0,9908; aD-43°40'; nD20o 1,46387; dl5o0,9912; aD-43°40'; nD20o 1,46446; soluble in 2,7 vol. of 70 p. c. alcohol; m. p. 28,5°; d15o 0,9912; aD19o + 40° 28'; nD20o1,46397; soluble in 3 vol of
70 p. c. alcohol.6)
In connection with two liquid commercial products Schimmel & Co. observed the following properties: d15o0,9905; aD - 2° 22'; and d15o 0,9901; aD + 29°4'.
1) G.I.P. 80711.
2) Bertram and Walbaum, Arch, der Pharm. 231 (1893), 304.
3) Bertram and Walbaum, Ibidem 305.
4) Bertram and Walbaum, Journ. f. prakt. Chem. 11. 49 (1894), 7.
5) Tschugaeff, Berl. Berichte 31 (1898), 1775.
6) Observations made by Schimmel & Co.
For the identification of bornyl acetate, fraction 220 to 230° is employed. It is strongly chilled and inoculated with a little solid bornyl acetate. If the desired results are not thus obtained, the sample in question is saponified and the components identified.