CAFFEINE

Brand Names : Thein, Guaranine; Methyltheobromine, NODoz; Coffeine.


Caffeine is a purine which occurs in tea, coffee, male leaves; also in guarana paste and cola nuts. It is usually extracted from tea dust or damaged tea. It can be prepared from uric acid which occurs in abundant amounts in guano. Uric acid is first converted into 1,3,7,8-tetramethylxanthine as described under theophylline. Finally, the methyl group originally introduced e in the 8 position is eliminated by chlorination, followed by heating with water or alkali.

Caffeine, m.p. 230°, sublimes at 1789, occurs as odourless, silky white, usually matted together, or white crystalline powder. Iteffloresces in air; is soluble in water (1 in 60); freely soluble in boiling water and chloroform; slightly soluble in alcohol and in ether. It dissolves in concentrated solutions of alkali benzoate, litol salicylates, citrates and cinnamates. It is a weak base. Its aqueous solutions are neutral to litmus. Caffeine is stored in airtight containers. A cup of coffee or tea contains about 60 mg of caffeine.



Caffeine can be identified by murexide test by treating it with concentrated nitric acid. The mixture is dried on a waterbath, cooled and treated with a drop of dilute ammonia to produce deep-purple colour. This test is also positive for uric - acid, theophylline, and many other purine derivatives.


Uses

Caffeine is a central nervous stimulant. It is used as a cardiac and respiratory stimulant and as a diuretic

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