216 



F'or tills purpose the jWtasslumsnU is first converted into the 

 hariumsa.\t, by adding a strong solution of 3 molecules of hariuin- 

 chloride to a concentrated solution of 2 molecules of the potassium- 

 salt : a yellow precipitate is formed, which dissolves i-ather easily 

 in hot water, but which can be almost completely precipitated from 

 its aqueous solution by the addition of 97 7o alcohol. This barium- 

 salt was now dissolved in water at 50° C, and then a solution of 

 one equivalent ciiichonine-sulphate ^), also heated to 50° 0, was added 

 to it. The solutions need not be too concentrated, because the 

 cinchonine-rhodium-malonate will otherwise partly precipitate, as it 

 is only sparingly soluble. The bariumsulphate formed is carefully 

 sucked off, and by washing with water of 45° C. all the 

 included yellow cmchouine-salt eliminated. On standing for 24 hours 

 in a large crystallising-disli, the liquid begins to deposit beautiful, 

 pale yellow and often in rosettes united needles of the cinchon'me- 

 salt of the laevo^yrsite. component, as will soon be shown. On 

 repeated partial evaporation of the mother-licjuid on the waterbath, 

 the successive fractions were separately collected and investigated. 

 The first three fractions appeared to contain the /<^/^handed com- 

 ponent; the fourth fraction gave the almost pure dextro^yva.{Q 

 antipode, the fifth and sixth fractions the pure dextrogyrate com- 

 ponent immediately. It is a remarkable fact that the cinflioiune- 

 l-malonate and the clnclionine-d-malonate are both r/^.r/ro-gyratory, 

 notwithstanding the very large rotation of opposite sign of the 

 complex ions present therein. This peculiar behaviour was checked 

 by us by a special control, namely by preparing the ivee potassium- 

 salts again from the cincho)ii?ie-8Si\ts used in the polarimetric measu- 

 rements. We could easily prove in this way, that the salts thus 

 obtained, really represented the right and left antipodes. From the 

 pure laevogyi'iiie po lass iu/u salt we once more prepared the corre- 

 sponding Glnchonine-s&\{ by means of the bariwu-saU; the rotations 

 determined with this especially prepared salt proved to be positive, 

 and they agreed very well with those formerly found. We have 

 also investigated the influence of the addition of three molecules of 

 cinclionine to a solution of the optically-active potassium-salts, and 

 the rotations found with these solutions were compared with those 



^) Originally we tried to reach our purpose by means of the stri/chnine-ssdt, 

 as in the case of the rhodium-oxalate. However, these experiments had no 

 result, the potassiumsdiW. prepared from the carefully fractionated strychynne-sah 

 by potassium-iodide being always optically-iT^active. It is difficult to say whether 

 racemisalion or partial racemism is the cause of this; but only after several 

 failures we passed to the use of cinclionine. 



