APPENDIX TO CHAPTER III BETAINES 147 



TrigoneUine. 



Jahns extracted Trigonella seeds with 70 per cent alcohol, purified 

 with basic lead acetate, concentrated to a syrup and precipitated with 

 potassium bismuth iodide. The precipitate was decomposed with 

 soda, and after filtration the solution was exactly neutralised ; mer- 

 curic chloride was then added until mercuric iodide appeared. This 

 precipitates only choline, but on acidification the crystalline double 

 salt of trigonelline separates. 



Schulze [1909; Ch. IV, choline] used phosphotungstic acid and 

 alcoholic mercuric chloride for approximately quantitative estimation 

 of trigonelline. 



Trigonelline, C 7 H 7 O 2 N. H 2 O, becomes anhydrous at 100, when the 

 crystals become opaque without losing their shape. The hydrated 

 base melts at about 130, the anhydrous at 218. 



The platinichloride, hardly soluble in alcohol, crystallises from 

 water. There are two characteristic aurichlorides ; one, of normal 

 composition, C 7 H 7 O 2 N . HAuCl 4 , leaflets, m.p. 198, changes on re- 

 crystallisation from water to the basic salt (C 7 H 7 O 2 N) 4 . 3HAuCl 4 , 

 needles, m.p. 186, which recrystallised in the presence of gold chloride 

 and hydrochloric acid, may be reconverted to the normal salt. 



Butyrobetaine. 



Brieger precipitated the alcoholic mother liquors of putrescine 

 hydrochloride with alcoholic mercuric chloride and extracted the pre- 

 cipitate with boiling water. On cooling cadaverine mercurichloride 

 crystallised out, while the butyrobetaine salt remained in solution. 

 After removal of the mercury with hydrogen sulphide and concen- 

 tration to a syrup, the butyrobetaine was precipitated as sparingly 

 soluble aurichloride. 



According to Willstatter the free &w<? crystallises from dilute alco- 

 hol in leaflets, probably with three molecules of water. Dried over 

 sulphuric acid, the composition is C 7 H 15 O 2 N ; the crystals begin to 

 soften at 130 and froth up at 222, decomposing into trimethylamine 

 and 7-butyrolactone. 



The hydrochloride^ C 7 H 15 O 2 N. HC1, forms needles, almost or quite 

 insoluble in absolute alcohol ; m.p. 200 (Takeda), 203 (Engeland and 

 Kutscher). 



The aurichloride, C 7 H 15 O 2 N . H AuCl 4 , is precipitated on adding gold 

 chloride to an aqueous solution of the hydrochloride ; it crystallises 

 in needles and leaflets and melts at 176 (Brieger; his formula con- 

 tains two more hydrogen atoms). 



10* 



