128 PRACTICAL ORGANIC AND BIO-CHEMISTRY 



from the dry residue with alcohol and precipitated as do ible salt with mercuric 

 or platinum chloride, from which its hydrochloride is obtained by decomposi- 

 tion with hydrogen sulphide. 



Synthetically choline has been prepared by the action of trimethylamine 

 upon ethylene oxide (glycol anhydride, p. 173) : 



CH 2 , CH 2 OH 



/0 + (CH,) 8 ; N + H 2 = | 

 CH 2 / CH 2 -N(CH 3 ) 3 



Properties. OH. 



Choline is a hygroscopic crystalline mass which has an alkaline 

 reaction. It forms salts with acids such as choline hydrochloride, 



CH 2 OH 



CH 2 -N(CH 3 ) 3 



Cl 

 and these salts form double salts with the salts of heavy metals. 



Choline has no peculiar reactions and must be isolated and 

 analysed in the-form of its salts for its identification. It is decomposed 

 by boiling with alkalies yielding trimethylamine and glycol. 



Esters of Choline. 



As an alcohol choline forms esters with acids : 



(1) Acetyl choline, CH.O OC.CH 3 



CH 2 -N(CH 3 ) 3 



OH, 

 has been found in ergot. 



(2) Palmityl choline, CH 2 O-OC. C 16 H 31 



iH 2 .N(CH 3 ) 3 



IP, 



has also been prepared. It is easily soluble in water and readily 

 hydrolysed by alkali. It has a powerful haemolytic action (Fourneau 

 and Page). 



(3) Choline nitrite, CH 2 O NO and choline nitrate, CH 2 O NO 2 



iHj-NfCH,), CH a -N(CH 3 ) 3 



OH, OH 



resemble the toxic constituents of the toad-stool (Amanita agarica). 

 The nitrite is formed by the action of nitric acid on choline and was 

 formerly supposed to be the aldehyde (pseudomuscarine), 



CHO 



CH 2 . N(CH 3 ) 8 



OH. 



The ethyl ether of choline resembles the action of natural mus- 

 carine still more closely (Ewins). 



Esters of choline have marked pharmacological actions. They 

 have only recently been isolated and prepared and will probably 

 account for many characteristic physiological actions. 



