274 



the chloro-succinic acid, or during the transformation of the last 

 acid into the final dextrogyrate malic acid. Moreover, it is most 

 remarkable that the inversion is evidently intimately connected 

 with the particular nature of the substance by which the chloro- 

 succinic acid is finally transformed into the malic acid; for if 

 silver-oxide or silver-carbonate be used for this purpose, the final 

 product is the dextrogyratory malic acid, while, when potassium- 

 hydroxide or ammonia is used in the reaction, the original laevo- 

 gyratory acid is reproduced. 



Quite independently of the question, as to whether or not a 

 re-arrangement of the groups round the asymmetric carbon-atom 

 takes place in the transformation of l-malic acid into d-chloro- 

 succinic acid, or in that of the latter into one of the enantio- 

 morphous malic acids, an "inversion" must obviously have occur- 

 red during the process. 



It is possible, as has been pointed out by several investigators '*), 

 to pass through a complete cycle of such changes, if the corresponding 

 reactions be only suitably chosen. As an example of this the 

 following cycle may be mentioned: 



+ KOH 



^ dextrogyrate 



malic acid 



aspartic acid 

 /aevogyr&te 



bromo-succinic .acid 



+ Ag 2 



Y 



laevo gyrate 

 malic acid 



-f PBr 3 



KOH 



+ Ag 2 



dextrogyrate 

 bromo-succinic acid 



If laevogyrsitory aspartic acid be treated with nitrosyl-bromide, 

 it is changed into the laevogyr&tory bromo-succinic acid; this 

 however will be changed by an aqueous solution of ammonia 

 into the dextrogyrate aspartic acid. By the same succession of 

 reactions the latter will now be transformed into the original 

 laevogyrzte acid, etc. 



These highly remarkable "inversions" have been observed almost 



i) P. Wa Iden, loco cit.; Journ. de Chim. phys. , 9. 164. 176. (1911); A. Mac 

 Kenzie and G. W. CJough, Journ. Chem. Soc. London, 93. 811. (1908) ; 95. 777. 

 (1909); 97. 1016, 2564. (1910); 101. 390. (1912); P. F. Frankland, Journ. Chem. 

 Soc. London, 103. 713. (1913). 



