136 THE SIMPLER NATURAL BASES 



hydrolysing the oxidation product (for details see Abderhalden and 

 Kautzsch [1912]). The free acid forms leaflets melting at 183-184 



/CH 2 . CH 2 

 with conversion into the anhydride pyrrolidone, NH. 



X CO . CH 2 . 



The hydrochloride crystallises in stout prisms; m.p. 135- 

 The platinichloride forms orange prisms; m.p. 220. 

 The aurichloride crystallises in glistening plates; m.p. 138. The 

 ethyl ester boils at 75-77/i2 mm - 



S-Amino-valeric Acid. 



E. and H. Salkowski obtained this substance from putrid blood 

 fibrin by evaporating the mixture repeatedly with water, adding barium 

 chloride to remove some fatty acids as soaps, acidifying the filtrate, 

 washing with ether, evaporating to dryness, and extracting the residue 

 with alcohol. On standing for a long time in a desiccator the residue 

 from the alcoholic solution gave the crystalline hydrochloride of B- 

 amino-valeric acid, from which the platinichloride and finally the 

 aurichloride was isolated. 



Formation from proline. Ackermann [1911, 2] obtained 3-6 grm. 

 of S-amino-valeric acid aurichloride from 34 grm. of proline after 

 putrefaction for nine days with glucose, peptone and salts. Neuberg 

 isolated the acid by means of o-naphthylisocyanate and obtained at 

 the same time n-valeric acid, which would result from the deamina- 

 tion of S-amino-valeric acid. Neuberg [1911, I] used a I percent, 

 proline solution, made and kept alkaline by repeated addition of 

 sodium bicarbonate, and containing a few drops of saturated magnes- 

 ium sulphate, potassium chloride and sodium phosphate solutions, but 

 no glucose or peptone; from 23 grm. of proline 12-1 grm. was re- 

 covered unchanged, together with 27 grm. S-amino-valeric acid hydro- 

 chloride, and 2-3 grm. of silver n-valerate. 



S-Amino-valeric acid crystallises in pearly leaflets, extremely soluble 

 in water, and melting at 1 57-1 58 when they undergo transformation to 

 piperidone. The aqueous solution is faintly acid and has an astringent 

 taste. The substance is precipitated in dilute solution by phospho- 

 tungstic acid, but not by cupric acetate or ammoniacal silver solution. 

 The hydrochloride, C 6 H U O 2 N . HC1, forms rhombic leaflets which on 

 heating distil for the most part without change. 



The platinichloride, (C 6 H u O 2 N)2H 2 PtCl 6 , forms long rhombic leaf- 

 lets, readily soluble in hot water but only slightly in cold water and 

 in alcohol. 



