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.

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    The liquid remains colourless until about half the theoretical quantity of alkali has been added, and then gradually develops colour, but a decided red is not observed until practically the theoretical quantity of alkali has been added. This behaviour indicates the extraction of about 50 per cent, of the alkaloid from soda solution, as previously described. Barium Pilocarpate can be obtained, as stated by earlier workers, by evaporating to dryness equivalent proportions of pilocarpine or the nitrate with baryta water, and extracting the residue with 90 per cent, alcohol. I attempted to prepare free pilocarpic acid from this salt by decomposing it with exactly the right amount of dilute sul¬ phuric acid, and obtained a product having the following specific rotation : aD= +1*5°; ?=1; c = 8*73; [a]D = +17T80. The melting point of the nitrate of this base was 164°, showing that the treatment with baryta converted some of the pilocarpine into isopilocarpine. Copper Pilocarpate.—Hardy and Calmels stated that they prepared this salt by boiling a solution of barium pilocarpate to which a solu¬ tion of a copper salt has been added, when it separated as a green powder, and they gave it the formula B2Cu. I have obtained a similar result, but, on analysing the product, found it to be copper hydroxide : 0T982 gave 0T610 CuO. Cu = 64*90. B2Cu requires Cu = 13*2; Cu(OH)2 requires Cu= 65*1 per cent. Evidence, however, was obtained of the existence of copper pilocarpate, although the salt could not be isolated in a pure form. When freshly precipitated copper hydroxide in excess is boiled with a solution of pilocarpine, part of it dissolves, and a dark blue solution is formed, which, when filtered and evaporated to dryness, gives a dark blue varnish. On analysis, the following result was obtained : 0*1912 gave 0*0136 CuO. Cu = 5*67 per cent, A portion, well washed with chloroform to remove any free alkaloid, was also analysed : 0*1598 gave 0*019 CuO. Cu = 9*49. (CnH1503N2)2Cu requires Cu= 12*47 per cent. The product was therefore copper pilocarpate, with a little pilocarpine adhering to it. Silver Pilocarpate, as described by Hardy and Calmels, was silver oxide, but an impure salt may be obtained by treating pilocarpine with silver hydroxide, filtering, and evaporating the solution to dry-