Researches on the constitution of physostigmine. Pt. 1 / by Arthur H. Salway.

  • Salway, Arthur H. (Arthur Henry)
Date:
[1912?]
Catalogue details

Licence: Public Domain Mark

Credit: Researches on the constitution of physostigmine. Pt. 1 / by Arthur H. Salway. Source: Wellcome Collection.

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    were deep blue by transmitted light, but purple-red by reflected light; from these no pure substance could be isolated, and they evidently contained a mixture of bases. The final extracts, however, were deep blue, both by transmitted and reflected light. They were united, then evaporated to dryness under diminished pressure, and the residue dissolved in a little hot alcohol, when, on cooling, a crystalline hydrochloride separated in deep blue needles. The yield of this compound was equivalent to about 8 per cent, of the physostigmine employed in the reaction: 0*0708 gave 0*1419 C02 and 0*0465 H20. 0 = 54*7; H = 7*3. 0*0913 „ 8*7 N2 at 18° and 764 mm. N = ll*2. 0*0888 „ 0*0686 AgCl. 01 = 19*1. Another preparation of the blue hydrochloride gave the following numbers: 0*1120 gave 0*2247 0O2 and 0*0694 H20. 0 = 54*7; H = 6*9. C]7H2502N3C12 requires C = 54*5; 11 = 6*7; N = ll*2; Cl = 19*1 per cent. The free base corresponding with this hydrochloride was prepared by treating the latter with dilute sodium hydroxide, and extracting the alkaline liquid with chloroform. On the addition of light petroleum to the dry chloroform solution the base separated as a dark blue powder, which was not obtained in the crystalline condition: 0*0310 gave 0*0766 C02 and 0*0222 H20. C = 67*4; H = 8*0. C'^H^OgNg requires 0=67*8; 11 = 7*6 per cent. An attempt was made to determine the molecular weight of the above base by the microscopic method, but owing to the intensity of the blue colour a satisfactory determination was not possible. It is evident, however, from the above analyses, that the simplest formula for the compound is C17H2302N3. Eserine blue is a dark blue powder, which is readily soluble in water, chloroform, or alcohol with the formation of intensely blue solutions. When the aqueous solution is heated with alkali hydroxides, an insoluble black powder separates. Eserine blue is a strong base, which forms salts with two equivalents of an acid. The hydrochloride, C17H2302N3,2HC1, prepared as described above, crystallises in blue needles, which by reflected light have a bronze-like lustre. It is readily soluble in water, yielding a deep blue solution, but on the addition of a little acid a beautiful carmine-red fluorescence is produced. The aurichloride was prepared by the addition of gold chloride to a solution of the base in hydrochloric acid. The violet precipi¬ tate thus obtained crystallised from hot alcohol containing a little
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