PANTOTHENIC ACID 



isopropyl ether and with acetone from pyridine solution. About 3 g. 

 of crude (40 %) calcium salt was obtained from 250 kg. of liver. 



In an improved process the charcoal eluate was heated with barium 

 hydroxide to pK 8 and the precipitate containing the barium panto- 

 thenate was dissolved in absolute alcohol and filtered. The filtrate 

 was concentrated, and acetone was added, giving a precipitate con- 

 taining barium pantothenate. The free acids were liberated by the 

 addition of sulphuric acid, giving a concentrate containing 20 to 25 % 

 of pantothenic acid. 



Y. SubbaRow and G. H. Hitchings ^ also used liver as starting 

 material. This was freed from fat by extraction with solvent, the 

 aqueous extract was then treated with mercuric acetate to remove 

 impurities, the filtrate treated with charcoal and the adsorbate eluted 

 with pyridine-methanol-water. Impurities were removed from the 

 eluate by precipitation with phosphotungstic acid, and uridine (uracil- 

 D-riboside) was removed by crystallising the concentrated filtrate 

 from methanol. Pantothenic acid was then precipitated from the 

 methanol solution by means of barium hydroxide, and impurities were 

 removed from the precipitate by repeated treatment with phospho- 

 tungstic acid. Finally, the pantothenic acid was adsorbed on acid- 

 activated alumina, and recovered by elution. 



The isolation of pantothenic acid from molasses and rice bran was 

 described by Mohammad et al.^ 



References to Section 2 



1. R. J. WiUiams, J. H. Truesdail, H. H. Weinstock, E. Rohrmann, 



C. M. Lyman and C. H. McBurney, /, Amer. Chem. Sac, 1938, 

 60, 2719 ; H. K. Mitchell, H. H. Weinstock, E. E. Snell. S. R. 

 Stanbery and R. J. Williams, ibid., 1940, 62, 1776. 



2. Y. SubbaRow and G. H. Hitchings, ibid., 1939, 61, 1615. 



3. A. Mohammad, O. H. Emerson, G. A. Emerson and H. M. Evans, 



/. Biol. Chem., 1940, 133, 17. 



3. CHE2VUCAL CONSTITUTION AND SYNTHESIS OF 

 PANTOTHENIC ACID 



The presence of a carboxyl group in pantothenic acid was proved 

 by esterification,^ whilst the presence of two hydroxyl groups was 

 indicated by a determination of active hydrogen. ^ The observation 

 that pantothenic acid condensed with acetaldehyde, acetone or 

 benzaldehyde indicated the presence of an a^-, ay- or aS-glycol. 



The details of the degradation experiments that finally established 

 the constitution of pantothenic acid were given in two papers by 



352 



