Page 69 - phytochemistry II -pharmD general

with ether). The residue (benzoyl ecgonine) is then washed with water, methylated
by treatment with methyl iodide and sodium in methanol to yield cocaine.
Identification of cocaine

Cocaine causes numbness of tongue and lips. Cocaine is negative Vitali-
Morine’s. Most of the tests for identification of cocaine depends on the
crystallographic characters of cocaine derivatives.
1- When few mg of cocaine HCl are dissolved in few drops of water and treated

with 1 ml of N/10 potassium permanganate, a violet crystalline precipitate is
formed which shows characteristic crystalline aggregates under the
microscope. This test is used also for differentiation of cocaine from cinnamyl
cocaine.
2- When cocaine HCl is mixed with a drop of platinic chloride solution, yellow
needles are obtained.
3- With aurichloride solution, crystals of stellate rods are obtained (very
sensitive 1:20 000).
3- When cocaine is heated with 0.1 ml sulphuric acid for 5 min, cooled

cautiously then 2 ml water added; an aromatic odour of methyl benzoate
is obtained. When the solution is cooled and allowed to stand for few
hours, crystals of benzoic acid is obtained. (B.P. 1998).

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