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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    as the lactone of a /3-hydroxy-carboxylic acid, and it is well known that in certain circumstances /3-hydroxy-acids are capable of decom¬ position in this manner. Thus, /3-hydroxy-acids, in which the a-carbon atom is doubly alkylated, yield on distillation an aldehyde and a carboxylic acid, for instance, CH3*CH(0H)-CEt2-C02H = CH8-CHO + CHEt2-C02H (compare Schnapp, Annalen, 1880, 201, 70; Jones, ibid., 1884, 226, 287; and Blaise and Marcilly, Bull. Soc. chim., 1904, [iii], 31, 312). In the case of /3-hydroxy-a-methyl(and ethyl)-butyric acids, however (compare Rohrbeck, Annalen, 1877, 188, 229; and Wald- schmidt, ibid., 1877, 188, 240), where the a-carbon atom is attached to a hydrogen atom—as in the case of pilosine—distillation leads to the formation of the corresponding unsaturated acid: C'H3,CH(0n)*CHMe,C02H = CH3-CH:CMe-C02H + H20. It appears, nevertheless, that the mode of decomposition of /3-hydroxy-acids, of which the a-carbon atoms are attached to a hydrogen atom, is influenced by the presence of a negative sub¬ stituent such as the phenyl group; thus, Perkin (Trans., 1886, 49, 160) has shown that an odour of benzaldehyde is developed on heating /3-hydroxy-/3-phenyh’sobutyric acid. This indicates that the decomposition of this compound proceeds in some degree at least in accordance with the following equation: C6H5-CH(0H)*CHMe*C02H = C6H5*CHO + CH2Me-C02H. The formula for pilosine given above is thus established with some degree of probability, and it is interesting to note that the C6H5*CH(OH) group in this alkaloid occupies the same position with regard to the rest of the molecule that the C2H5 group occupies in the case of pilocarpine and wopilocarpine. This formula satisfac¬ torily accounts for all the known properties of pilosine, and leads to the following formula for anhydropilosine: C6H5-CH:C-CHL-CH2-C-NMe>CH CO CH2 CH—E \/ () Anhydropilosine. Specific Rotation of Pilosine and its Derivatives. Pilocarpine, zsopilocarpine, and pilocarpidine are dextrorotatory in the form of base or salts with acids, and less dextrorotatory in the form of the alkali salts of the corresponding hydroxy-acid. Pilosine and pilosinine are also dextrorotatory in the form of