Pilosine : a new alkaloid from Pilocarpus microphyllus / by Frank Lee Pyman.

  • Pyman, Frank Lee.
Date:
[between 1910 and 1919?]
Catalogue details

Licence: In copyright

Credit: Pilosine : a new alkaloid from Pilocarpus microphyllus / by Frank Lee Pyman. Source: Wellcome Collection.

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    O'1272, titrated with dilute sulphuric acid using methyl-orange, required 4'4 c.c. i\7’/10-H2SO4; whence equivalent = 289. C16H1S03N2 requires MAY. = 286. Pilosine is sparingly soluble in cold, fairly readily so in hot, water; sparingly soluble in cold, and easily so in hot, alcohol; and very sparingly soluble in boiling chloroform, ether, ethyl acetate, acetone, or benzene. It dissolves readily in dilute acids, but not in cold dilute alkalis; it is soluble in hot aqueous sodium hydroxide. It gives no coloration with sodium diazobenzene-p-sulphonate. Pilosine contains on© NMe but no OMe group, since, on heating with hydriodic acid, methyl iodide is not eliminated below about 280°: 0*4436 gave 0*3598 Agl. NMe = 10*0. C15H1503N(NMe) requires NMe = 10*l per cent. The presence of a lactonic grouping was shown as follows: A suspension of the base in cold water was rendered alkaline to phenolphthalein on the addition of a single drop of Nj 10-sodium hydroxide. After boiling, however, with excess of N/ 10-sodium hydroxide and titrating with Nj 10-sulphuric acid, it was found that 0*2328 required 8*1 c.c. A/10-NaOH, 8*1 c.c. being the required figure for one lactonic grouping, and the base was eventually recovered unchanged. Pilosine, like pilocarpine and isopilocarpine, is dextrorotatory, determinations of its specific rotation giving the following results: in chloroform: aB +0*94°; l—2 dcm.; c = 1*168; [a]D +40*2°; in absolute alcohol: aD +0*66°; l — 2 dcm.; c = 0*827; [a]D +39*9°. Pilocarpine is converted into its stereoisomeride isopilocarpine by prolonged boiling with aqueous sodium hydroxide, and in order to determine whether pilosine underwent a similar change a quantity was boiled with excess of 5 per cent, aqueous sodium hydroxide for half an hour, then acidified with hydrochloric acid, and pre¬ cipitated with ammonia. The base, which was obtained in nearly quantitative yield, was examined without further purification, when it melted at 187° (corr.), and gave the following result in chloro¬ form solution: aD +0*61°; l — 2 dcm.; c = 0*762; [a]D +40*0°. Pilosine, therefore, is not readily altered by treatment with alkali, behaving in this respect like isopilocarpine. The specific rotatory power of pilocarpine falls from +100*5° to + 31*5°, and that of isopilocarpine from +42*8° to nil after remain¬ ing with excess of alkali, owing to the formation of salts of the corresponding hydroxy-acids; a similar change occurs even more
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