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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    Pilocarpine Platinichloride is obtained by adding platinic chloride to a solution of pilocarpine hydrochloride; it forms silky plates, which can be recrystallised from hot acidified water. The recrystal¬ lised salt melts with decomposition at about 218° (corr.). On analysis: 0*0594 gave 0*0144 Pt. Pt = 24*24. (CnH1602N2)2,H2PtCl6 requires Pt = 23*58 per cent. No compound of the composition (CnH1602N2)2PtCl4, as described by Hardy and Calmels, could be isolated. Pilocarpine Methiodide is formed on dissolving dry pilocarpine in excess of methyl iodide, when the clear solution gradually deposits an oil, which, however, could not be crystallised. Pilocarpine Ethiodide is obtained by dissolving pure dry pilocarpine in excess of ethyl iodide and allowing to stand, when an oil separates which slowly becomes crystalline. The compound may be recrystal¬ lised from alcohol and ether. It forms cubical crystals, very soluble in water or alcohol, and melts at 114° (corr.). On analysis : 0*3742 required 10*4 c.c. JV/IO AgN03 for precipitation. 1 = 35*25. c1)h16o2n2,o2h6i requires I = 34*84 per cent. A determination of the specific rotation gave the following result : aD= +2*71°; 1= Idem.; c = 4*158; [a]D= +65*2°. Properties of Pilocarpine. Pilocarpine is best obtained by adding excess of ammonia to an aqueous solution of one of its salts, and extracting two or three times with chloroform; after washing to remove ammonia, the chloroform solution, on evaporation or distillation, yields a colourless oil, which can be freed from the last traces of the solvent by leaving it in an open dish for several days. As thus obtained, pilocarpine is a thick oil, freely soluble in water, alcohol, or chloroform, but almost insoluble in ether or light petroleum. All efforts to crystallise it by ordinary methods failed. It can be distilled in a vacuum, but during this process undergoes change into isopilocarpine : thus, pure pilocarpine, after distillation at about 260° under 5 mm. pressure, was found to form a nitrate, which melted at 146°, this being the melting point of a mixture of pilocarpine and isopilocarpine, containing chiefiy the latter. Petit and Polonowsky state that pilocarpine and isopilocarpine are not extracted by chloroform from a solution of the salt rendered alkaline with caustic soda. The following experiment shows that it is possible