Tropine Ladenburg formula

The results so far recorded are those upon which Ladenburg chiefly based his formulae representing tropine and tropidine as A-methyl-J -tetrahydropyridines, substituted in position 2 by the residues. CHa. CH OH (or. CHOH. CH3) for tropine (XIV) and, CH CH for tropidine (XV) thus ... 

This view of its structure has been confirmed by a synthesis of the acid (6). The question of the constitution of tropine is one which has presented far greater difficulties, but thanks to the researches of Ladenburg, Merling, Willstatter, and others, our knowledge of the constitution of this substance is as complete as that of any alkaloid, and there is no doubt that it is represented by the formula and this has been confirmed by Willstater s brilliant synthesis (7). 

M-Tropinic acid, CgHi304N. This oxidation product of tropine and 0-tropine, is a substance of great importance in this group, and its constitution and relation to tropine gave rise to much discussion. It crystallises in small needles, m.p. 248° (dec.), is soluble in water and almost insoluble in other media. It is a dibasic acid and yields salts, both with bases and acids. Its formation by the oxidation of tropine is not explicable in any simple manner by Ladenburg s tropine formula, and it was this difficulty which led Merling to propose his formula for this base. By crystallisation of the cinchonine salt, dl-tropinic acid can be resolved into d and 1-forms. 

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