The constitution of pseudo-muscarine ("synthetic muscarine") / by A.J. Ewins.

  • Ewins, Arthur James.
Date:
[1914?]
Catalogue details

Licence: In copyright

Credit: The constitution of pseudo-muscarine ("synthetic muscarine") / by A.J. Ewins. Source: Wellcome Collection.

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    As a preliminary step it was decided to attempt to confirm the above formula. The platinichloride was obtained “ air dry ” by standing in an ordinary desiccator over calcium chloride. The salt then remained unaltered in weight when placed in vacuo in a desiccator over sulphuric acid, and when heated under ordinary pressure in a steam bath (98°). Loss of weight occurred when the salt was heated to a temperature of about 115°, but it was found that by heating to 130-135° the loss of weight was considerably greater than that required for the loss of two molecules of water, and it was evident that the salt was undergoing decomposition. Finally it was found that the air dry platinichloride could be heated in vacuo at 100° for some hours without undergoing any loss of weight; a fact which afforded conclusive evidence of the absence of water of crystallisation. An examination of the analytical data recorded by Schmiedeberg and Harnack, as well as by Nothnagel, further showed that there was no record of a determination of the nitrogen content of the molecule, although an otherwise complete analysis had been carried out. The platinichloride was accordingly analysed for nitrogen according to Dumas’ method, when figures were obtained showing the presence of four nitrogen atoms in the molecule, i.e. two atoms of nitrogen in each molecule of free base. Accepting the remaining analytical data as more or less accurate for the supposedly hydrated platinichloride the actual formula for this salt was presumably the following: (C5H1302N2)2 PtCl6. Subsequently complete analysis proved this to be correct. For the constitution of this base the two most probable formulae were the following: (OH) N (CH3)3 CH2. CH2. N02, (OH) N (CH3)3 CHa. CH2.0. NO. i ii Formula (I) is that of an aliphatic nitro-derivative, the nitrogen being directly linked to a carbon atom while (II) represents the base as the choline ester of nitrous acid. That formula (II) correctly represents the constitution of the base is shown by the following facts: In the first place the base gives a typical Liebermann’s nitroso-reaction with phenol and sulphuric acid, which would not be the case if it were a nitro derivative. In the second place, on hydrolysis of the base by means of dilute acid or alkali, nitrous acid is very readily liberated, and choline may be recovered from the solution. This base was actually obtained and recognised as such by Nothnagel
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