Action of Beckmann's chromic acid mixture on some monocyclic terpenes / by T.A. Henry and H. Paget.

  • Henry, Thomas Anderson, 1873-1958
Date:
[1928.]
Catalogue details

Licence: Public Domain Mark

Credit: Action of Beckmann's chromic acid mixture on some monocyclic terpenes / by T.A. Henry and H. Paget. Source: Wellcome Collection.

    12/16 (page 79)
    The quinidine salt also crystallised well, but, like the quinine salt,, only furnished a partly deracemised acid. The strychnine salt separated from alcohol in long needles. On drying in a vacuum at 100°, or on boiling with alcohol, this salt partly dissociated and free strychnine was obtained as a first crop, [a]ff — 140*9° in chloro¬ form (c = 1*884). The second crop also contained free strychnine, and no accurate constants could be obtained for the salt. From the second and other early fractions, however, an acid was recovered, m. p. 94°, [ag* + 22*99° in water (c — 5*64). When no more of the sparingly soluble strychnine salt could be induced to separate, the acid was recovered from the residues and converted into the brucine salt, which crystallised well from acetone; m. p. 144° (decomp.), [a]ff — 15*9° in chloroform (c = 1*929). The acid recovered from this melted at 94° and had [a]ff — 23*46° in water (c = 12*866). This Z-acid showed no depression of melting point when mixed with the Z-acid, C7H1204, obtained directly (p. 78) and indirectly (p. 76) from phellandrene; admixture with the d-acid raised the melting point to 115—117°, and this was not depressed by further addition of the dl-acid. The anilic acid pre¬ pared from the anhydride of the d-acid obtained by distillation melted at 129°, and a mixture of this with the anilic acid of tho Z-acid from phellandrene at 142—144°. The remainder of the extracts B and C consisted of oily acids from which no well-defined product could be isolated, either by fractional precipitation with metallic salts or by fractional dis¬ tillation of the ethyl or methyl esters. Recovered Oil (D).—The colour of the unoxidised oil varied from pale yellow to dark brown. It was separated by distillation into four fractions : (1) b.p. 70°/25 mm. or 172—180°/760 mm. (60%) (2) b. p. 70—110°/25 mm. (25%); (3) b. p. 115—120°/25 mm. (8%); and (4) a black, tarry residue, distilling with decomposition at 200°/15 mm. (7%). Fraction (1) had a strong odour of cineole, due, no doubt, to the presence of this substance in the phellandrene used, and cineole- equivalent to 8% by weight of extract D was isolated from it by repeated agitation with a 50% solution of resorcinol. The residue of fraction (1), after removal of cineole and repeated distillation over metallic sodium, had b. p. 176—180°/760 mm., [a]D ± 0°, and consisted principally of 39-cymene, identified by oxidation to hydroxy- tsopropylbenzoic acid, m. p. 157°, with a hot aqueous solution of potassium permanganate. The yield of p-cymene amounted to about 25% of the a-phellandrene used. An attempt to estimate- the amount of p-cymene originally present was made by removing the phellandrene as nitrosite in the way described by Smith, Hurst,