CHEMISTRY OF EPINEPHRINE 77 



Synthetic epinephrine prepared as just described is optically 

 inactive. To obtain the levo-rotary form which occurs natur- 

 ally, the racemic compound is resolved by Flacher's 199 method 

 in which the d-tartaric acid salt of ^^-epinephrine is extracted 

 with methyl alcohol in which the dextro-rotary salt is soluble, 

 leaving behind the insoluble /-epinephrine-d-tartrate, from 

 which in turn the /-epinephrine is liberated by treatment with 

 alkali. In this way a compound identical with the natural 

 product is obtained. 



Since d-epinephrine has little pharmacological activity, it is 

 also converted to the Z-form in the synthetic preparation of 

 epinephrine. This is accomplished by racemizing the cZ-form 

 by heating with mineral acid and then repeating the above 

 described process for resolving the racemic mixture into its 

 /-and d-rotatory constituents. 35 



At present both the natural and synthetic sources are utilized 

 in the manufacture of the epinephrine of commerce. 



PREPARATION OF EPINEPHRINE 



Epinephrine is prepared in large quantities for medicinal 

 use either synthetically or by extraction from adrenal glands. 

 Its preparation from glandular material is relatively simple 

 and consists in extraction of the minced glands with dilute 

 acid, removal of proteins (after concentrating the aqueous ex- 

 tract) with alcohol, and precipitation of the free base by the 

 addition of ammonia after evaporation of the alcohol. In 

 manufacture on a large scale the theoretical yield, about 0.2 

 per cent of the weight of the fresh glands, is obtained. 35 



A convenient laboratory method for preparing pure epi- 

 nephrine, as described by Bertrand, 53 is as follows: 600 grams of 

 finely minced defatted adrenal glands are mixed with 5 grams 

 of oxalic acid and sufficient 95 per cent ethyl alcohol to fill a 

 two liter flask. The flask should be well filled to exclude air, 

 stoppered, and shaken at intervals for two days. The con- 

 tents are then filtered through muslin and well pressed. The 

 filtered extract is concentrated in vacuo until the alcohol is re- 



