The alkaloids of ergot. [Pt. I] / by George Barger and Francis Howard Carr.
- George Barger
- Date:
- 1907
Licence: In copyright
Credit: The alkaloids of ergot. [Pt. I] / by George Barger and Francis Howard Carr. Source: Wellcome Collection.
Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.
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![through prolonged boiling. The solution saturated in the cold, and referred to above, was boiled under a reflux condenser. [a]D, originally + 338°, fell after five minutes to + 327°, after one hour to + 300°, after three hours’ boiling to + 242°. In another experiment a specimen of ergotinine, prepared from ergotoxine by acetic anhydride, had [a]D +388°, but after it had been boiled for half an hour the same solution gave [a]D +326°. The fall of rotatory power is accompanied by a disappearance of crystallisable alkaloid. We have frequently noticed a certain deficit when recrystallising a given quantity of pure ergotinine, however carefully the successive mother liquors were concentrated. The destructive action of hot alcohol is also shown by an experiment in which 0*1 gram of ergotinine was heated with 3 c.c. of alcohol in a sealed tube at 100° for twelve hours. More than half was destroyed. Tanret, in his recent publication, has also pointed out that a solution of the crystalline alkaloid always leaves a partially amorphous residue on evaporation. We further determined the specific rotation in other solvents and found higher values than in alcohol. In acetone : aD +0'86°; 1 = 1 dcm.; c = 0-234; [a]D +367°. In ethyl acetate : aD +0*64°; £=1 dcm.; c = 0T76; [a]D +363°. In chloroform: aD +2 '03°; 1=1 dcm.; c = 0*514; [a]D +396°. The lowering of the specific rotation of ergotinine, produced, as Tanret showed, by the addition of acids and alkalis to the solution, seems to depend in the first place on a transformation to ergotoxine and possibly also on racemisation. For instance, the addition of one molecular equivalent of phosphoric acid to an alcoholic ergotinine solution lowered [a]D from +328° to +319°, and after boiling for fifteen minutes to +195°. After boiling with fifteen molecular proportions of phosphoric acid the value was +41°. Under similai conditions sulphuric acid produced a much more rapid lowering of the rotatory power, which presumably depends on the concentration of hydrogen ions. So far we have not been able to prepare any undoubted ergotinine salts in the crystalline state. Even when crystals are obtained, there is the possibility of the formation of the corresponding ergotoxine salt as a result of hydrolytic action of the acid used. In an attempt to crystallise ergotinine phosphate we added the calculated quantity of phosphoric acid to an alcoholic solution of the base, and concentrated the solution in a vacuum desiccator. The salt which separated out was gelatinous and was filtered off; on decomposition with ammonia it readily yielded the characteristic prisms of ergotinine. The filtrate from the amorphous salt was concentrated further, and finally yielded](https://iiif.wellcomecollection.org/image/b22407479_0013.jp2/full/800%2C/0/default.jpg)
