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.

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    original carbonyl compound from the crude extract by direct or steam distillation, or by the use of sodium hydrogen sulphite solution, failed. The total extract was therefore treated with excess of semicarbazide solution, and the mixture left for about 12 hours. The product was recrystallised until of constant melting point, 187° (corr.), from hot 95% alcohol. It had [a]y + 28-9 (c = 0*26 in alcohol or 1*96 in acetic acid), -f- 11-27° (c = 1-61 in alcoholic sodium ethoxide), or + 4-13° (c = 1-6 in aqueous sodium hydroxide) (Found for substance dried in a vacuum at 105° : C, 52-65; H, 7-7; N, 18-75. C10H17O3N3 requires C, 52-9; H, 7-5; N, 18-5%). The semicarbazone was hydrolysed by 15% hydrochloric acid in presence of ether, the ethereal solution washed with sodium carbon¬ ate solution and dried over anhydrous sodium sulphate, and the solvent distilled off, leaving a colourless oil, which crystallised. It had m. p. 48—50°, [a]g* -f 37-1° in water (c = 1-67) and -43-13° in benzene (c = 1-46) (Found : C, 63-4; H, 8-4. C9H1403 requires C, 63-5; H, 8-2%). An aqueous solution of the substance remains neutral for several days, but such solutions neutralise caustic alkalis and 6-1 c.c. of JV-sodium hydroxide were necessary to neutralise 1 g. of the substance. The amount of alkali required to convert a keto-lactone C9H1403 into the corresponding ketohydroxy- acid, C9H1604, is 5-9 c.c. Attempts to isolate the acid from solu¬ tions of the sodium salt by addition of weak acids and extraction with solvents merely led to the regeneration of the original keto- lactone. The keto-lactone (0-9 g.), dissolved in the calculated quantity of A-sodium hydroxide, was treated with a 4% solution of potassium permanganate until decolorisation no longer took place rapidly. The oil (0-8 g.) extracted from the acidified liquor by ether had a strong odour of acetic acid and crystallised on standing. The crystals had m. p. 93—95°, alone or mixed with Z-isopropylsuccinic acid prepared as described below; admixture with d-i<sopropyl- succinic acid raised the melting point to 110—117°. When the keto-lactone (3 g.), dissolved in the calculated quantity of aqueous sodium hydroxide, was added to excess of a freshly- prepared, ice-cold solution of sodium hypobromite, the mixture became cloudy and deposited bromoform. After 1 hour, the latter was extracted with ether and the aqueous liquor was freed from hypobromite by cautious addition of sodium hydrogen sulphite, acidified, and again extracted with ether. This removed an oil (2-3 g.), which on careful trituration with dry benzene deposited a crystalline substance, m. p. 225° (decomp.), which contained 31% of bromine but could not be obtained in sufficient quantity for