The constituents of the bark of "Prunus serotina" / by Frederick B. Power and Charles W. Moore.
- Frederick Belding Power
- Date:
- [1909?]
Licence: In copyright
Credit: The constituents of the bark of "Prunus serotina" / by Frederick B. Power and Charles W. Moore. Source: Wellcome Collection.
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![substance which, after repeated crystallisation from water, melted at 196— 198°: 0-1252 gave 0*2510 C02 and 0*0470 H20. C = 54*7 ; H = 4*2. C7H604 requires C = 54*5 ; H = 3*9 per cent. This substance was thus identified as protocatechuic acid. Examination of the Aqueous Liquid (C). This liquid, as already indicated, represented that portion of the original alcoholic extract of the bark which was soluble in cold water, and from which the previously-described resins (A) and (B) had been removed. Isolation of Benzoic Acid. The aqueous liquid was extracted many times with ether, the com¬ bined ethereal liquids being washed, dried, andlthe solvent removed. A quantity of a crystalline product was thus obtained, which was subjected to vigorous distillation with steam. The distillate had a distinctly acid reaction, and, on extraction with ether, yielded 9 grams of a crystalline substance melting at 120—121°: 0*1432 gave 0*3608 C02 and 0 0661 H20. C = 68*7; H = 5*l. > C7H602 requires C = 68*8 ; H = 4*9 per cent. This substance thus proved to be benzoic acid, and its identity was further confirmed by the formation of its methyl ester, boiling at 197— 198°. Isolation of Trimethylgallic Acid. After completely removing the benzoic acid from the crystalline product by distillation with steam, as above described, the contents of the distillation flask were extracted with ether, and the ethereal liquid shaken with eight successive portions of a dilute solution of ammonium carbonate. The liquids obtained by the first three ex¬ tractions with alkali gave, on acidification, a distinctly crystalline precipitate, and these were therefore united. The liquids obtained by the subsequent five extractions, when acidified, yielded a more or less amorphous precipitate, and this was separately examined, as described below. The precipitate obtained by acidifying the liquids from the first three ammonium carbonate extractions was crystallised from ethyl acetate, when it yielded 10 grams of a crystalline compound melting at 165—169°. After several recrystallisations from the same solvent, the melting point remained constant at 167—169° : 0*1647 gave 0*3424 C02 and 0*0865 H.,0. C = 56*7 ; H = 5*8. Ci0H]2O5 requires C = 56*6; H = 5*6 per cent. This substance is evidently trimethylgallic acid, and its isolation is](https://iiif.wellcomecollection.org/image/b30614375_0013.jp2/full/800%2C/0/default.jpg)
