The constitution and synthesis of damascenine, the alkaloid of Nigella damascena / by Arthur James Ewins.

  • Ewins, Arthur James.
Date:
1912
Catalogue details

Licence: In copyright

Credit: The constitution and synthesis of damascenine, the alkaloid of Nigella damascena / by Arthur James Ewins. 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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    structure (II) was suggested, which involves a quinquevalcnfc nitrogen atom linked in a manner which is without analogy, and is, as will be shown below, also without experimental foundation. I he suggested relationship for the supposed three compounds is shown by the following scheme: ( No Me 1 *NHMe CO,H (I) Daiiiasceninic acid. Ag satt+ >- Mcl / ,OMe v /NHMe (JO., Me (III) Mcthyldauiascenine. co-o Me (II) Damasceninc. It was the doubt attaching to Keller’s “ betaine ” formula which first suggested the present investigation. Since damasceninic acid could be converted into damascenine, the synthesis of the former was first attempted. Keller, starting from 3-nitromethylanthranilic acid, failed to achieve the synthesis; but it was accomplished with very little difficulty in the present instance by starting from m-hydroxybenzoic acid. The successive reactions employed will be referred to later. It was then somewhat unexpectedly found that the methyl ester of damasceninic acid was in all respects identical with the alkaloid damascenine as described by Schneider, and found by the author to be the only alkaloid obtainable from Nigdla damascena. In view of this result it was only necessary to explain some of the results obtained by Pommerehne and by Keller. The explana- tion becomes obvious if it is borne in mind that damascenine, now shown to be the methyl ester of an amino-acid, is very readily hydrolysed. Pommerehne himself {Arch. Pharm., 1899, 23 7, 475) emphasised the similarity of damascenine to the ester of anthranilic acid. Nevertheless, in the preparation of the hydrochloride of the alkaloid he evaporated a hydrochloric acid solution of the base at temperatures as high as 80° to 90°. The salt which he thus obtained, and which both he and Keller considered to be the hydrochloride of damascenine, was in reality a mixture consisting largely of the hydrochloride of damasceninic acid, and their conclusion that both damasceninc and damasceninic acid had the same formula is conse- quently not surprising. That this is the explanation of many of