Structure elucidation successes 442 Subject

The structural elucidation of the secondary metabolites of Dictyosteiiium cellular slime molds was achieved by Y. Oshima et al. The total synthesis of a novel compound, dictyopyrone A, which possesses a unique a-pyrone moiety with a side-chain at the C3 position, was successfully carried out using the maionic ester synthesis. Meldrum s acid was acylated and the product was subjected to transesterification with an optically active did. Specific rotation of the final product was identical with that of the natural product, so the absolute configuration was established as (S). 

One year after the structure elucidation of alizarin, Heinrich Caro at BASF developed in collaboration with Graebe and Liebermann the following successful synthesis. Sulfonation of anthraquinone with oleum [56] gives in the absence of catalysts, on steric grounds, anthraquinone-2-sulfonic acid [57] as the main product. This intermediate is then subjected to an alkali melt under oxidative conditions. 

Electron diffraction may be successfully employed for the elucidation of more complicated structures. This is why the major part of the infonaation on the conformational properties of sulphone molecules originates from electron diffraction. It is also true, however, that the electron diffraction data are more subject to misinterpretation than rotational spectroscopic data owing to the possibility of reproducing the experimental data equally well with various models. 

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