The composition of berberine phosphate : ead before the British Pharmaceutical Conference in London, July 1900 / by Frank Shedden.

  • Shedden, Frank.
Date:
[1900]
Catalogue details

Licence: In copyright

Credit: The composition of berberine phosphate : ead before the British Pharmaceutical Conference in London, July 1900 / by Frank Shedden. Source: Wellcome Collection.

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    num, corresponding to 0*1162 gramme or 60*52 per cent, of berberine. (1) (2) (3) (b Calculated for C20 H17 NO, '2 H;j P 04 + H„ O h2o 2-68 2-69 — — 3-28 per cent. h3po4 36-49 36-30 — —- 35.70 „ c20 H17 n o4 = 60-62 60-52 61-02 „ 100-00 From these results it will be seen that the berberine phosphate prepared by me, either by treating pure berberine-acetone with an excess of phosphoric acid, or by the interaction of mono- berberine sulphate and acid calcium phosphate, and subsequent purification of the product, has the composition C20H17NO4 *2H3P04, with varying amounts of water of crystallisation. It thus agrees with the results obtained b}^ Parsons in his analysis of a pure salt prepared by Willmarth, but, as was an¬ ticipated, disproves the formula C20 H17 N 04 *7 H3 P 04 + 4H2 0 assigned by Parsons and Wrampelmeier to a salt prepared by the interaction of berberine sulphate and acid calcium phosphate, notwithstanding the fact that one of my salts was prepared by the method followed by them, although carefully purified from calcium before analysis, and that we have employed the same methods for the determination of the base and the acid. The latter investigators had themselves remarked that “ this formula seems, at first sight, an improbable one,” and the support that was given to it by the subsequent experiments of Coblentz cannot be considered altogether satisfactory or conclusive, for although he worked with the pure alkaloid and an excess of phosphoric acid, he appears to have made no direct determination of the base, and only determined the amount of phosphoric acid present by indirect methods. It will be seen that my results also do not confirm the formula given by Schmidt, viz.: (C20 H17 N 04)3 (H3 P 04)2 + 5 H2 0, but, as previously noted, not having been able to find any record of analytical data relating to this formula, it can only incidentally be referred to. The accuracy of the determinations of the base by means of platinic chloride I have confirmed by control experiments with pure berberine salts of well-established composition, such, for example, as the nitrate and sulphate, which were likewise prepared by myself.