The resolution of hyoscine and its components, tropic acid and oscine / by Harold King.

  • King, Harold
Date:
1919]
Catalogue details

Licence: Public Domain Mark

Credit: The resolution of hyoscine and its components, tropic acid and oscine / by Harold King. Source: Wellcome Collection.

    26/34 (page 501)
    d-Hyoscine. The starting material for the isolation of ^-hyoscine consisted of 75 grams of well-crystallised hydrobromides obtained as a by¬ product in the manufacture of /-hyoscine. It was slightly laevo- rotatory, having [a]D —4*1° (c = 2-3, anhydrous), and contained 9 per cent, of water of crystallisation, which was lost over sulphuric acid. It was regenerated to base, using sodium hydrogen carbonate and chloroform for the purpose, the weight of base being about 55 grams. This was converted into its salt with c?-a-bromo-7r- camphorsulphonic acid, and crystallised from a mixture of dry ethyl acetate and absolute alcohol. In a few days there was a copious, crystalline separation, which was collected, and amounted to 38-5 grams. It was deliquescent and had [a]D+4640 (c = 2), and on two more crystallisations gave 8'8 grams of pure meteloidine bromocamphorsulphonate. Meteloidine d-a-bromo-T:-camphor sulphonate crystallises exceed¬ ingly well from absolute alcohol, in which it is soluble to the extent of about 1 part in 10 (boiling), or from a mixture with dry ethyl acetate in clusters of prisms. It also crystallises well from water. It melts at 224—227° (228-5—23T50 corr.), and is anhydrous: 0*1410 gave 0'2547 C02 and 0-0808 H20. C = 49'3; H = 6-4. Ci3H2iO4N,Ci0H15O4BrS requires C = 48'75; 11 = 6*4 per cent. Its specific rotatory power was determined in water: c = 2-039; / = 2-dcm.; aD +1°56'; [a]D + 47-42°; [M]D +268-7°. This value for the molecular rotation is somewhat smaller than that given by Pope and Read for the bromocamphorsulphonic acid ion (T., 1910, 97, 2200). That the meteloidine was inactive was confirmed in two ways: (1) A small quantity of the above salt was converted into base, avoiding conditions which might favour racemisation by using sodium hydrogen carbonate and chloroform. The base crystallised readily, and was identical in appearance and other properties with a sample of meteloidine kindly supplied by Dr. Pyman, and which was known to be inactive (Pyman and Reynolds, T., 1908, 93, 2077). (2) One-half a gram of /-meteloidine base was converted into its bromocamphorsulphonate, and the solution evaporated to dry¬ ness with absolute alcohol. The crystalline residue was triturated with a little dry ethyl acetate, in which the crystals are practically insoluble, and collected. The rotation of this salt, representing