Ecgonine-obtained from the leaves of Erythroxylum coca Lam.

D. Ecgonine

Biological Source It is also obtained from the leaves of Erythroxylum coca Lam. (Erythroxylaceae) (Coca) as its l-form.

Chemical Structure

[1R-(exo, exo)]-3-Hydroxy-8-methyl-8-azabicyclol [3, 2, 1] octane-2-carboxylic acid; (C₉H₁₅NO₃). It is the principal part of the cocaine molecule.

Isolation Ecgonine may be obtained by the hydrolysis of cocaine as given below:

Cocaine -------Hydrolysis----à  Ecgonine + Benzoic acid + Methanol

Characteristic Features

1. The l-form ecgonine monohydrate is obtained as triboluminescent, monoclinic prisms from ethanol having mp 198°C (anhydrous substance gets decomposed at 205°C).

2. Its specific optical rotation [α ]_D¹⁵  -45⁰ (C = 5); dissociation constants are: pK_a 11.11, and pK_b 11.22.

3. Solubility Profile: 1 g dissolves in 5 ml water, 67 ml ethanol, 20 ml ethanol, 75 ml ethyl acetate; sparingly soluble in ether, acetone, benzene, chloroform and petroleum ether.

Identification Tests

1. Ecgonine Hydrochloride (C₉H₁₅NO₃.HCl): It is obtained as the triclinic plates obtained from water having mp 246°C; [α]_D¹⁵-590 (C = 10); soluble in water and slightly in ethanol.

2. dl-Ecgonine Trihydrate: It is obtained as plates from 90% ethanol having mp 93-118°C (anhydrous substance gets decomposed at 212°C).

Uses It is mostly used as a topical anaesthetic.