o 



CHOLIN. 303 



The mercurochlorid, CjHj.NO.Cl+eHgClj, is difficultly soluble 

 even in hot water. On this account the mercury salt is very con- 

 venient for the separation of cholin from accompanying bases. It 

 is very difficult to separate cholin from cadaverin mercurochlorid 

 on account of the similarity in solubilities. Gulewitsch secured a 

 separation by fractional precipitation and fractional solution. It 

 forms small, short, cross-shaped prisms. It melts at 249°- 251° 

 (G.) ; at 242° (Morner). Its solubility in water is 1 : 56.6 at 24.5 

 (Gulewitsch); at 1 :66.6, 19.5° (Morner). Like creatinin it yields 

 a crystalline precipitate with alcoholic zinc chlorid (G.). 



Lactocholin, g'.llcHli^ci^CHfcH.O.Oc) C^-^S- This compound 



was obtained by Schmidt by heating an aqueous solution of cholin 

 lactate on a water-bath for six days. The platinochlorid forms long 

 prismatic crystals with roof-shaped ends. It is easily soluble in 

 water ; difficultly in alcohol. It has two molecules of water of 

 crystallization, and melts at 220°— 221°. The platinum compound 

 on decomposition with hydrogen sulphid or potassium chlorid and 

 precipitation with gold chlorid yields, instead of a gold salt, the 

 aurochlorid of cholin. All attempts to obtain the aurochlorid of 

 lactocholin failed. Lactocholin is formed from ethylidene, and not 

 from ethylene lactic acid (Nothnagel). 



Oxy-iso-butyro-cholin is produced in the same way as lactocholin. 

 The platinochlorid has the same form and melting-point — 221°. 

 The two molecules of water of crystallization are difficultly driven 

 off. The gold salt is not obtainable on account of reversion to 

 cholin. The formula corresponds to that of lactocholin (Noth- 

 nagel). 



Oxy-valero-cholin is also prepared the same as lactocholin. The 

 platinum salt crystallizes with two molecules of water of crystalliza- 

 tion, in long compact needles, which are rather easily soluble in 

 water, and melt at 223°- 224° (Nothnagel). Its composition also 

 corresponds to that of lactocholin. 



Oxy-acetic, ethylene lactic, and salicylic acids do not form anhy- 

 drid compounds. The above bodies result from the union of two 

 molecules of cholin and one molecule of acid with elimination 

 of two molecules of water. The platinum salts of all three anhy- 

 drides belong to the same system ; all have two molecules of water 

 of crystallization, difficultly expelled at 100°. The melting-point 

 is about the same in all. They do not yield gold salts. The free 

 anhydrids are not permanent. 



Acetyl cholin. The gold salt of this compound was studied first 

 by Baeyer, later by Nothnagel. Baeyer obtained the acetyl com- 

 pound by the action of acetyl chlorid on cholin chlorid in the cold, 

 but Nothnagel did not succeed in introducing the acetyl group short 



