658 



satisfactory manner that a resolution lias been effected of the racemic 

 «-sulphopropionic acid. 



The specific and molecular rotations of the compounds investigated 

 are united in the subjoined table. It should, however, be remarked 

 that the values of the /-acid and its derivatives are less trustworthy 

 because the acid has not been quite pure. 



It deserves notice that the molecular rotation of the «-sulphopropionic 

 acid (49°. 2) is certainly somewhat stronger than that of the «-bromo- 

 propionic acid \) (44°. 4) although the bromine atom (80) differs but little 

 in weight from the sulpho-group (81); still this may perhaps support 

 the view that the weight of the group influences the rotatory power. 

 If for instance, we compare with the rotation of «-ethylpropionic 

 acid^) (18°.2) we notice that both the rotation and the weight 

 of the group (29) are less. 



More interesting seems the fact that the rotation of the neutral 

 metallic salts is much less than, and of an op[)Osite sign to that of the 

 acid metallic salts and the acids tliemselves, particularly in connexion 

 with what has been stated at the commencement, namely that it 

 concerns here a dibasic acid with two groups of different ionisibility 

 which cause the acid functions. 



Although the phenomenon that salts of optically active acids 

 possess a rotatory power contrai'y to that of the acids themselves 

 was observed previously, for instance with lactic and glyceric 

 acids, the example now found seems a more simple one, because 

 there are not present any groups that can react on each other, and 

 because it may be called highly improbable that in the circumstances 

 stated the carboxyl- and the sulphoxyl-group should react on each 

 other. Consecpiently, the rotation will, probably, be less dependent 

 on concentration, temperature, age of solution etc. 



In conclusion, it may be remarked that the laevorotation of the 

 acid strychnine salt of the ^/-«-sulphopropionic^ acid as compared 

 with that of strychnine hydrochloride, amounts to about as much 

 less as the dextrorotation of the acid metallic salts. 



1) Ramberg. Liebig's Ann. 370. p. 23 i (1909) gives [:«] = 29°.0, whence [M] = U°A. 



~) ScnüTZ & Marckwald. Ber. d. D. ch. G. 29. p. 59 (1896) [«] = 17°.85, 

 hence [if] = i8\2. 



