Iso amygdalin and the resolution of its hepta-acetyl derivative / by Frank Tutin.

  • Tutin, Frank.
Date:
[1909?]
Catalogue details

Licence: In copyright

Credit: Iso amygdalin and the resolution of its hepta-acetyl derivative / by Frank Tutin. Source: Wellcome Collection.

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    LXXX.—iso Amygdalin and the Resolution of its Hepta- acetyl Derivative. By Frank Tutin. It was shown by J. W. Walker (Trans., 1903, 83, 472) that, under certain conditions, amygdalin yields inactive mandelic acid on ydrolysis, instead of the lsevo-isomeride. If, for example, amygdalin be directly hydrolysed with concentrated hydrochloric acid, ^-mandelic acid is formed, but if it be first hydrolysed to amygdalinie acid and the latter subsequently treated with hydrochloric acid, the resulting mandelic acid is optically inactive. Walker also demonstrated that the racemisation of the mandelic part of the molecule does not occur unng hydrolysis, but that this takes place whenever amygdalin is dissolved in dilute solutions of an alkali. He concluded, therefore, that amygdalinie acid is partially racemic, but did not ascertain ehmtely the nature of the product formed by the action of dilute alkalis on amygdalin. The subject in question was studied more fully by H. D. Dakin ■^jX1904’ 85’ 1512>’ Wh° showed that amygdalin, when treated wi dilute aqueous alkalis, is converted into an optically isomeric product, which was designated fsoamygdalin. He confirmed the observation of Walker that amygdalinie acid, on hydrolysis, yields inactive mandelic acid, but found that the mandelic acid prepared bv the acid hydrolysis of isoamygdalin always had a small dextro-rotation. ese facts have also been confirmed by the present author, akin, however, considered it highly improbable that the pre¬ ponderance of rf-mandelic acid yielded by fsoamygdalin was due to the a er eing a mixture of z'-mandelonitrile maltoside and d-mandelo- nitrile maltoside.” He, therefore, offered the explanation that it was due to the occurrence of both racemisation and hydrolysis, the derivative of the d-mandelonitrile undergoing the latter change more rapidly than that of the f-nitrile. During the course of hydrolysis, therefore, the unchanged part of the material would contain a preponderance of the latter derivative, and this, he considers, would undergo some racemi-ation, the final result being the production ol more d-mandelic acid than of its optical antipode. It appears to the present author, that of these two explanations the one preferred by Dakin is not the correct one. When an optically active compound is completely racemised, the resulting optical antipodes are, of course, formed in equal proportions, but when one asymmetric carbon atom suffers racemisation in a molecule containing
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