Some properties of the ecgonines and their esters I

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Abstract
The specific rotation of l‐ecgonine in different solutions is discussed. The decomposition of 0.5g of cocaine in 20 cm3 of 2 n.hydrochloric acid is complete in 5 hours, as is also that of 0.25 g in 20 cm3 of n/2 acid. A method is indicated for the determination of the quantity of l‐ecgonine in a mixture containing a compound with leavo rotation, which is not altered by boiling with 20% caustic potash solution. The following principle results were obtained with this method. The quantity of ecgonidine formed by boiling l‐ecgonine, l‐benzoylecgonine and l‐cocaine with hydrochloric acid is greater the stronger the acid and the longer the time of boiling. The esters are split up first into ecgonine and this is then partly transformed into ecgonidine. d‐Φ‐Ecgonine is not converted by boiling for 12 hours in a strong solution of hydrochloric acid. The l‐ecgonine of the esters is partly converted into ecgonidine by boiling with 20% potash. At ordinary temperatures the esters of l‐ecgonine are partially converted into d‐Φ‐ecgonine by alkalis in alcohol or acetone. This is a result of their easy conversion into their d‐isomers while they are still undecomposed and in contact with an alkali. By boiling with water benzoylecgonine and also cocaine form only small quantities of ecgonidine. l‐Cocaine heated at 115°–120° is converted first to the extent of 50% into ecgonidine methylester and benzoic acid; this acid then forms a benzoate with the remaining 50% of l‐cocaine, which is transformed on heating into l‐ecgonine methyl ester and benzoic acid anhydride, while the latter ester is changed on longer heating into its d‐isomer. d‐Cocaine is also transformed by heating at 115–120° into ecgonidine but with much more difficulty. The ecgonines and the cocaines are all converted on heating with excess benzoic acid at 115–120° into ecgonidine. l‐Ecgonine forms a compound with barium chloride (2 mol. of ecgonine + 1 mol. of BaCl2) which is slightly soluble in boiling absolute alcohol, but insoluble in boiling benzene.

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