Oxyacanthine dimethiodide

Dimethyl -d-isochon-dodendrine dimethiodide Oxyacanthine dimethiodide 0-Methyloxyacanthine Dimethiodide... 

Since in this series mixed melting points were not wholly satisfactory as a means of establishing the identity of compounds, Bick and Todd employed X-ray powder photography. They found that the powder photographs of 0-methylrepandine methine dimethiodide and 0-methyloxy-acanthine methine dimethiodide were identical. This showed that repandine corresponds to oxyacanthine rather than berbamine in structure. An examination of the X-ray photographs and optical rotations revealed that repandine and oxyacanthine (XXVI) are optical isomers. 

In an attempt to determine the position of the phenolic hydroxyl in daphnandrine, Bick, Ewen, and Todd (112) ethylated i T-methyldaphnan-drine dimethiodide with ethyl iodide and ethanolic sodium ethoxide and then subjected the resulting V-methyl-O-ethyldaphnandrine to the Hofmann degradation. A methine base was obtained which on ozonolysis yielded 2-methoxy-4, 5-diformyldiphenyl ether (XXXIV) as before. This showed that the phenolic group in daphnandrine must be attached to one of the tetrahydroisoquinoline nuclei and cannot occupy a position in the benzyl residue as it does in oxyacanthine and repandine (XXVI). 

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