Quininae Ethylcarbonas. Quinine Ethylcarbonate.
C23H28N2O4 = 396.244.
Quinine ethylcarbonate, C2H5CO3C20H23N2O, is prepared by the action of ethyl chloro-carbonate on quinine. It occurs in the form of white, slender, odourless, and almost tasteless, crystalline needles, or in masses of silky, acicular crystals, which are lighter than quinine sulphate. Quinine ethylcarbonate is also known under the trade-name Euchinin or Euquinine. The sulphuric or nitric acid solutions are as strongly fluorescent as the corresponding quinine solutions, but are much less bitter. Solutions of quinine ethylcarbonate yield the usual alkaloidal reactions. Melting-point, 95°; on ignition, it burns without leaving any residue. In its chemical behaviour quinine ethylcarbonate has a strong resemblance to quinine, having basic properties, turning red litmus blue, and forming crystalline salts with acids; it gives the thalleioquin reaction but not the Herapath reaction, and is more stable towards the action of light than quinine. On mixing about 2 decigrams of quinine ethylcarbonate with 2 to 3 mils Of sodium hydroxide solution, adding a fragment of iodine, and warming, a slight odour of iodoform is developed (showing presence of the ethyl group). The nitric acid solution is not affected by solution of silver nitrate or barium nitrate (absence of quinine hydrochloride, or sulphate, especially when taken in conjunction with absence of marked bitterness). Aristochin or Aristoquinine is the carbonic ester of quinine, a white almost tasteless powder, insoluble in water, containing 96 per cent. of quinine; dose, ½ to 2 decigrams (1 to 10 grains).
Sparingly soluble in water; easily soluble in alcohol, ether, or chloroform; soluble in acids, forming well-defined crystalline salts which are easily soluble in water.
Action and Uses.—Quinine ethylcarbonate is employed as It substitute for quinine sulphate or hydrochloride, on account of its freedom from taste, in whooping cough, influenza and malaria, especially in children. Solutions in acid or alcohol are much more bitter than the undissolved substance. It may be administered in powders, which are best given in milk , or in cachets.
Dose.—½ to 6 decigrams (1 to 10 grains).