asynthesisoftropinone托品酮合成(參考版)
2024-08-25 16:29本頁面
【正文】 A Synthesis of Tropinone（托品酮的合成） Robert Robinson Among the noteworthy achievements of Willstatter in connexion with his investigation of the chemistry of tropine, there was nothing that contributed a greater share to the final solution of constitution of tropinone, a ketone first produced in 1896 (Willstatter, Ber., 1898, 31, 2655). This substance has bee the central figure in the atropine group of the alkaloids, and, as shown below, may be regarded as the natural starting point in the synthetical preparation of a number of bases of great value in the practice of medicine and surgery. An examination of the details of the reactions involved in the above shows that it is improbable that cocaine would be synthesised from artificial tropinone, and that the feasibility of the prepration of atropine would depend on the elaboration of improved methods for the production of tropic acid . On the other hand, given readily accessible tropinone, the technical preparation of homatropine and tropacocaine would be a paratively simple matter. By reason of the richness of the field of chemistry explored, the synthesis of tropine by Willstatter (Annalen, 1901, 317, 204。 1903, 326, 1) is classical, but the method employed, which it is unnecessary to recall in all its details, appears to be of too plicated a character to admit of development into an economical process. It is first of all necessary to obtain suberone, which is then conberted through several stages into cycloheptatriene, and finally into tropidine, ?tropine, tropinone, and tropine. Nevertheless, an inspection of the formula of tropinone (I) discloses a degree of symmetry and an architecture which justify the hope that the base may ultimately be obtained in good yield as the product of some simple reaction and from accessible materials. By imaginary hydrolysis at the points indicated by the dotted lines, the substance may be resolved into succindialdehyde, methylamine, and acetone, and this observation suggested a line of attack of the problem which has resulted in a direct synthesis. In searching for a method of synthesis of any substance, it is always convenient to be able to recognise the formation of traces of the desired product, and in the present instance none of the derivatives of tropinone already prepared was found to be so suitable for its detection as the dipiperonyhlidene derivative(II), which does not appear to have been hitherto described. With the aid of this highly characteristic pound it was proved that tropinone is obtained in small yield by the condensation of succindialdehyde with
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