Chenopodium oil / by Thomas Anderson Henry and Humphrey Paget.

  • Henry, Thomas Anderson, 1873-1958
Date:
[1921.]
Catalogue details

Licence: Public Domain Mark

Credit: Chenopodium oil / by Thomas Anderson Henry and Humphrey Paget. Source: Wellcome Collection.

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    these in succession. On treatment with sodium nitrite in presence of acetic acid at 0°, the mixture gave a nitrosite, which, after recrystallisation from ethyl acetate, had m. p. 155° and showed no depression of melting point on admixture with a-terpinene nitrosite made from terpinene, prepared from either turpentine oil or terpineol. The formation of a-terpinene nitrosite had already been recorded by Nelson (loc. cit. Compare Caius and Mhaskar, loc. cit.), who, however, failed to obtain any other evidence of the presence of a-terpinene. Caius and Mhaskar state that phellandrene is also present. Phellandrene gives even in small quantities an excellent yield of a nitrosite of unmistakable appearance, and the present authors were unable to find any evidence of the formation of phellan¬ drene nitrosite along with the a-terpinene derivative in the reaction. Baeyer has shown (Ber., 1894, 27, 815) that small quantities of terpinene can be removed from its mixtures with other terpenes by repeated agitation in the cold with Beckmann’s chromic acid mixture. Two hundred c.c. of the hydrocarbon fraction were treated repeatedly with small quantities of chromic acid mixture until no further absorption, and no increase in the specific rotation of the recovered oil, took place. The recovered oil, after distillation over sodium, had b. p. 176-5—177°/758 mm., d23° 0-8545, [a]f^ —23*08°, wg* 1-48637 (Found : C = 89-08, 88-92, 88-80; H = 10-86, 10-59, 10-65. A mixture of terpene, C10H16, with cymene, C10H14, in the proportion of about 40 : 60 requires C = 89-04; H = 10-96 per cent.). The recovered oil gave no crystalline nitrosite on treatment with sodium nitrite in acetic acid at 0°, but still gave the characteristic bluish-red coloration with sulphuric acid in presence of acetic anhydride, and on oxidation with potassium permanganate (see below) yielded no trace of the characteristic crystalline oxidation products of a-terpinene, whence it appears that the latter terpene had been completely eliminated by the treatment. The chromic acid mixture recovered yielded, on extraction with ether, a small quantity of a crystalline acid melting at 189°, which proved to be one of the forms of a8-dihydroxy-a-methyl-S-^sopropyladipic acid produced by the oxidation of a-terpinene (see below). Action of Bromine. Isolation of a New Terpene Tetrabromide.— Bromine, in excess of that required to form a tetrabromide, was added to either the original mixture of hydrocarbons or the a- terpinene-free mixture (see preceding paragraph) dissolved in its own volume of chloroform and cooled to 0°. After standing for one hour, the chloroform and excess of bromine were removed by a current of dry air, leaving a viscous, dark grey oil; this, on standing for six to eight weeks, deposited a solid tetrabromide.