Pilocarpine and the alkaloids of jaborandi leaves / by Hooper Albert Dickinson Jowett.

  • Jowett, H. A. D. (Hooper Albert Dickinson)
Date:
[1900?]
Catalogue details

Licence: In copyright

Credit: Pilocarpine and the alkaloids of jaborandi leaves / by Hooper Albert Dickinson Jowett. Source: Wellcome Collection.

    9/28 (page 481)
    [a]D= +85-40°. [a]D= +62-47°. [a]D= +32-21° [a]D= + 33-62°. (1.) 4 mols. of base to 1 mol. caustic soda. aD= +5-08°; 1=1 dcm.; c = 5-949 (2.) 2 mols. of base to 1 mol. caustic soda. aD = +3-716°; 1 = 1 dcm.; c = 5*949 (3.) 1 mol. of base to 1 mol. caustic soda. aD = +1-916°; 1=1 dcm.; c = 5*949 (4.) 1 mol. of base to 4 mols. caustic soda. aD= +1°; 1=1 dcm.; c = 2-9745 This, after standing one month, gave [a]D = +31’5°. aD — +0-6°; 1=1 dcm. ; c = 2*8376; [a]D= +21-15°. (5.) Boiled with excess of caustic soda for 10 minutes. These experiments show that the specific rotation of pilocarpine with excess of the alkali is +31*5°, and that the figure obtained by- Petit and Polonowsky, namely, +23*8°, is due to a slight decompo¬ sition into isopilocarpine. It was also found that this conversion of pilocarpine into the acid of lower specific rotation may take place, to a limited extent, in aqueous solution in the absence of alkali. Thus the specific rotation of pilocarpine in aqueous solution, after standing for 3 weeks, was : aD= +5-5°; 1=1 dcm.; c = 7*094 ; [a]D = +77*53°. This solution gave a nitrate of melting point 178° (corr.), so that the base was pure pilocarpine. An attempt was made to determine the rotation of free pilocarpic acid by preparing it from the barium salt, but low figures were obtained, which were found to be due to the partial conversion of pilocarpine into isopilocarpine by the alkali. Compounds of Pilocarpine with Metals. Hardy and Calmels stated that pilocarpine might be regarded as the anhydride of a hypothetical pilocarpic acid, and described the sodium, potassium, barium, copper, and silver salts. Petit and Polo¬ nowsky confirm this statement, describing, however, only the sodium and barium salts and the acid, which rapidly passed into the anhydride. Sodium Pilocarpate is formed as a varnish by evaporating to dryness a solution of pilocarpine in water, to which a molecular proportion of soda has been added. As stated by Petit and Polonowsky, chloro¬ form does not dissolve this salt or extract any alkaloid from it when dry; if, however, it is dissolved in water, an appreciable amount of the alkaloid can be removed by shaking with chloroform. The alkaloid can be titrated with alkali by boiling, and using phenol- phthalein as an indicator; the end reaction, however, is not sharp.