Researches on the constitution of physostigmine. Pt. 1 / by Arthur H. Salway.
- Salway, Arthur H. (Arthur Henry)
- Date:
- [1912?]
Licence: Public Domain Mark
Credit: Researches on the constitution of physostigmine. Pt. 1 / by Arthur H. Salway. Source: Wellcome Collection.
6/16 page 981
![The empirical formula assigned to eseroline by Ehrenberg (loc. cit.) is thus confirmed. The molecular weight of eseroline was next determined by the cryoscopic method in benzene: 0*2058 in 22*53 benzene gave —0*116°. M.W. = 394. 0*1792 „ 24*40 „ „ A£-Q*093°. M.W. = 395. (C13H18ON2)2 requires M.W. = 436. It appears from these results that eseroline either possesses twice the molecular weight previously assigned to it, or is associated in benzene solution. A determination of the molecular weight of the base in nitrobenzene gave the following results: O'1251 in 31*25 nitrobenzene gave A^ —0*094°. M.W. =298. 0*2459 „ 31*25 „ „ A*-0*164°. M.W. = 336. C13H18ON2 requires M.W. — 218. It is to be inferred from these determinations that the simplest molecular formula of eseroline is C13H18ON2, but that the base is associated in benzene solution and to a less extent also in nitro¬ benzene. Physostigmine, on the other hand, was found to give normal results, both in benzene and nitrobenzene. A determination of the specific rotatory power of eseroline resulted as follows: 0*2736, made up to 20 c.c. with methyl alcohol, gave, in a 2-dcm. tube, aD — 2°56/, whence [a]D —107*2°. Eseroline is readily soluble in alcohol, ether, chloroform, or benzene, but only sparingly so in light petroleum. The free base is quite stable when pure, and can be kept for a long time exposed to the air without change. In neutral or acid solutions it is slowly oxidised, whilst in the presence of alkalis the oxidation is extremely rapid. On account of the ease with which it oxidises, eseroline possesses strong reducing properties, silver nitrate, gold chloride, and platinic chloride being reduced by it to the metallic state. Eseroline possesses a strongly alkaline reaction. Its basicity was ascertained by dissolving it in N /10-sulphuric acid, and titrating the excess of acid with barium hydroxide in the presence of ether, using iodeosin as indicator: 0*1791 required for neutralisation 8*15 c.c. A/10-H2SO4, whereas a monacidic base, C13H18ON2, requires 8*2 c.c. It is evident from this result that eseroline contains only one basic nitrogen atom. Eseroline Hydrochloride.—This salt was prepared by passing dry hydrogen chloride into an ethereal solution of the base. The colourless precipitate which formed was collected and purified by crystallisation from a mixture of alcohol and ethyl acetate, when](https://iiif.wellcomecollection.org/image/b30619427_0006.jp2/full/800%2C/0/default.jpg)
