Mesotoinisation of Diamuiinc-diuitrc-oxalc-cobalt Complex. 7 



standing the insoluble free alkaloid gradually sei:>arated out from 

 the solution. However, by working rapidly but cautiously we 

 were able to effect its further fractional crystallisation and purifica- 

 tion, and ultimatel}^ a crop of crystals which had as high a specific 

 rotation as 



[a]g-5»=-70-7° 



•was obtained, a \'alue which has not been increased by further 

 recrystallisation. These crystals we have designated as fraction la.^ 

 Fractions II, III and IV, having been ascertained to show 

 comparatively small differences in their rotatory power, were now 

 together dissolved in the mother liquor from fraction la, and this 

 solution was again kept in a vacuum in order to repeat the fraction- 

 ation. Two more fractions were thus obtained, fractions Y and 

 VI, which had the following specific rotations: 



V [«?i>°=0' 



VI [a]l°=+45° 



Fraction VI was once more dissolved in a small quantity of water 

 and refractionated by partial crystallisation in a vacuum (fractions 

 VII and VIII), Fraction VIII, which was most easily soluble in 

 water, had a specific rotation of [«]d°= + 68-3. As this value 

 remained unchanged even after further recrystallisations, it was 

 concluded that the fractions la and VIII were essentially the l- 

 brucine salt of /-and <^-diammine-dinitro-oxalo-cobalt complex 

 respectively. 



Elimination of the brucine molecule from these fractions 

 was then proceeded with. For this purpose, the example set 

 by A. Werner, who mesotomised trioxalo-chromium complex 

 {Cr(C204)3)]"' Me'3 (loc. cU.) as str^^chinine salt and subsequently 

 decomposed it by means of potassium iodide in order to eliminate 

 str3''chinine as its insoluble iodide, was followed. 



The operation was carried out in tlie following manner: the 

 brucine complex was first dissolved In a small quantity of water, 

 and to this solution a calculated amount of solid potassium iodide 

 was then added. On vigorous agitation the hardly soluble brucine 

 hydroiodide completely separated out from the solution, and the 



