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.

    28/34 (page 503)
    d-Hyoscine hydrobromide crystallises exceedingly well from water in rectangular-shaped tablets with bevelled edges. It crystallises with three molecules of water, the hydrate melting in a capillary tube at 54‘5—55° (54*5—55° corr.). It is rendered anhydrous by drying over sulphuric acid in a vacuum. The behaviour of the anhydrous salt on heating is very varied. It sometimes melts sharply at 168°, resolidifies, and melts at 193—194° (197—198° corr.). Occasionally, the intermediate melt¬ ing point is not observed at all, or is only indicated by a slight shrinking. If the anhydrous salt is dried for half an hour at 120°, only the higher melting point, 193—194°, is observed. The probable explanation is that the product, which melts at 168°, is either an amorphous form or a metastable, crystalline form of the anhydrous salt, and the transformation of one form into the other is accelerated by rise of temperature. Z-Hyoscine hydrobromide behaves similarly: 0T842, dried over H2S04, lost 0*0228. H20 = 12*38. 0*1813, dried at 100°, lost 0*0226. H20 = 12*47. 0*1587, „ 100° gave 0*0778 AgBr. Br=20*85. C17H2104N,HBr,3H20 requires H20 = 12*33 per cent. Ci7H2i04N,HBr requires Br = 20*80 per cent. The specific rotatory power of the hydrated salt was determined in water: c = 2*842; Z = 2-dcm.; a+l°18*5/; [a]D + 23*02°. c = 2*525; Z|=2-dcm.; a+l^O7; [a]D + 23*10°. The mean of these values gives for the anhydrous salt [a]D +26*3° and for the <7-hyoscinium ion [a]D +33*2°. The latter value is in approximate agreement with that calculated from the molecular rotation of the bromocamphorsulphonate (p. 502), namely, + 30*2°. di-Hyoscine Aurichloride.—eZ-Hyoscine bromocamphorsulphonate (0*3 gram) was dissolved in 5 c.c. of warm water, and 5 c.c. of 10 per cent, hydrochloric acid were added, followed by 7 c.c. of gold chloride solution (1 in 30). The aurichloride separated, partly in isolated, minute, rectangular plates, but for the most part in fern-like growths or spangles. It melted at 202—203° and weighed 0*32 gram. It was twice recrystallised from 2*5 per cent, hydrochloric acid, the melting point each time remaining at 204—205° (208—209° corr.) (decomp.). The recrystallised solid separated in long, flattened, orange-yellow needles with both edges serrated: 0*1266, air-dried, gave 0*0387 Au. Au = 30*6. CiyHgiO^NjAuClgjHCl requires Au = 30*7 per cent.