Oleum Cupressi. - Cypressenol. - Essence de Cypres.
Origin and Production. Cypress oil is distilled from the leaves and young twigs of Cupressus sempervirens, L., (C. fasti-giata, DC). According to the season, the freshness of the material and the method of distillation, the yield varies from 0,2 to 1,2 p. c.
Properties. Cypress oil is a yellowish liquid with a pleasant odor of cypress, which, after evaporation leaves a distinct ambra-like odor reminding of labdanum. The physical constants of the oils distilled in Germany differ materially from those obtained in southern France, the German oils being denser than the French oils. This variation may be due partly to the difference in the freshness of material, but appears to be traceable principally to the difference in the method of distillation.
German distillates revealed the following constants: d15o0,88 to 0,90; aD + 4 to +18°; nD20o 1,474 to 1,480; A. V. 1,5 to 3,0; E. V. 13 to 22; E. V. after acetylation 36 to 51; soluble in 2 to 7 vol. and more of 90 p. c. alcohol, occasionally with slight turbidity.
In connection with French oils the following were observed: d15o 0,868 to 0,884; aD + 12 to +31°; nD20o about 1,471 to 1,476; A. V. up to 2; E. V. 3 to 14; E. V. after acetylation 9 to 32; soluble in from 4 to 7 vol. of 90 p. c. alcohol, occasionally with slight turbidity.
An Algerian oil had the following properties: d15o 0,8764; aD + 22° 18'. It did not yield a clear solution with 10 vol. of 90 p. c. alcohol.
Composition. As the result of a detailed investigation in the laboratory of Schimmel & Co.1) a considerable number of constituents have been isolated.
The oil that was subjected to examination had the following properties: d15o0,8922; aD + 16°5'; nD20o 1,7416; S. V. 25,3; E. V. after acetylation 50,5. These values correspond to an ester content of 8,8 p. c. computed as C10 H17 Ococh3 and of 14,4 p. c. of alcohols computed in C10H17OH. The oil did not yield a clear solution with 14 parts of 80 p. c. alcohol.
1) Report of Schimmel & Co. April 1904, 36; October 1904, 22; April 1910, 46.
Furfurol. When distilled in a vacuum (10 mm.), the first drops came over at 44°. With a solution of aniline hydrochloride in aniline they afforded the purple color reaction characteristic of furfurol.
d-a-Pinene. This terpene, the presence of which had previously been established1), was again identified in fractions possessing all of the properties of pinene (d15o 0,8587; aD + 28°4'). (M. p. of nitrosochloride 102 to 103°; of benzylamine derivative 122 to 123°).
d-Camphene. In all of the fractions between 160 and 170°, which constituted the bulk of the oil, this terpene was identified by means of the isoborneol reaction. Hence camphene is one of the principal constituents. The crude isoborneol isolated from the isobornyl actetate upon saponification, had a strong mouldy odor which was probably due to a small admixture of isofenchyl alcohol which, however, could not be isolated as such. Hence it is not improbable that fenchene also is contained in the oil since - analogous to camphene - it yields isofenchyl alcohol when treated with the mixture of glacial acetic acid and sulphuric acid. The isoborneol, after repeated purification from petroleum ether and sublimation, melted at 206 to 207°.
d-Sylvestrene. M. p. of the dihydrochloride 72°. The bromide, recrystallized from acetic ester, was obtained in flat, colorless prisms that melted at 134 to 135°.
Cymene is present in small amounts only. It was identified in fraction 174 to 180°. Oxidation with 5 p. c. permanganate solution yielded p-hydroxy isopropyl benzoic acid melting at 155 to 156°. When boiled with concentrated hydrochloric acid, it was changed to propenyl benzoic acid melting at 160 to 161°.
1) Report of Schimmel & Co., October 1894, 64.
Sabinol (?). Fraction 70 to 74° (3 to 4 mm.), which boiled between 208 and 212° under ordinary pressure, had the properties of sabinol: d15o 0,9433; aD +14°8'. Upon oxidation there resulted a mixture of acids, part of which melted between 130 and 140° and part of which did not melt at 250°. a-Tanacetogen dicar-boxylic acid, the oxidation product of sabinol, melts at 140°.
Alcohol. From fraction 90 to 95° (4 mm.) a few drops of an alcohol with a rose-like odor were obtained, when this was treated in benzene solution with phthalic acid anhydride at water-bath temperature. Its phenylurethane melted at 142 to 14401).
Esters of Terpineol. Fractions above 95° (3 to 4 mm.) were rather rich in esters. The S. V. of an oil which after repeated fractionation boiled between 96 and 98° (4 mm.) was 191,0 corresponding to an ester content of 66,85 p. c. computed as C10H17Ococh8. Saponification with alcoholic potassa yielded d- a-terpineol, m. p. 35° (d15o o0,938; aD22o+ 36°32'; m. p. of the phenylurethane 112°). The acids found in the several ester fractions were acetic acid, valeric acid, and an acid which boiled between 210 and 260° and crystallized in long silky needles that melted at 129°.
Free terpineol was not found in cypress oil.
Sesquiterpenes. In addition to appreciable amounts of cypress camphor, which can be removed by freezing and by washing out with dilute alcohol, the high boiling portions contain /-cadinene. It was identified by its dihydrochloride that melted at 117 to 11802).
Cedrol. The cypress camphor already referred to is found in the fractions above 135° (5 mm.). After recrystallization for 5 to 6 times from dilute alcohol and two subsequent purifications from petroleum ether it is obtained free from odor. It crystallizes in the rhombic system (0,98844:1:0,71772; well-defined cleavage in the direction of (001 J, less so in the direction of (110!); m. p. 86 to 87°; b. p. 290 to 292°. Its composition is that of a sesquiterpene alcohol (elementary analysis, molecular weight determination according to E. Beckmann). As the result of a false determination of its optical rotation, cypress camphor was at first regarded as the inactive modification of cedar camphor or cedrol. Later1) it was shown that cypress camphor is dextrogyrate ([a]D + 10° 5' in 10 p. c. chloroform solution) and that when treated with dehydrating agents it yields a lasvogyrate sesquiterpene (aD - 85° 57'), hence in no way differs from cedrol (Vol. I, p. 401) but is identical with it.
1) Report of Schimmel & Co., oct. 1904, 22.
2) Ibidem, October 1904, 22.
3) C. Blafi, Chem. Zentralbl. 1910, II. 872.
As distillation residue a tough, brown substance is obtained that has an odor reminding of labdanum and ambra.
Upon cohobation of the aqueous distillate of cypress oil a readily volatile, yellow distillate is obtained. In it the presence of methyl alcohol (acid oxalic acid ester), diacetyl (monophenyl-hydrazone) and furfurol (phenylhydrazone; m. p. of semicar-bazone 197°) were established2).
Medicinal Uses. In the Childrens Hospital, Leipzig, O. Soltmann3) has made extensive investigations of the use of cypress oil as a remedy against whooping cough. The remedy is applied by sprinkling an alcoholic solution of the oil (1 : 4) over the bedding, pillow and night gowns of the children four times daily.