596 SCIENCE PROGRESS 



Tafel's electro-reduction process as a preparative method, though 

 the physical researches to which he was thereby forced have 

 revealed much that is theoretically of considerable importance. 

 The electric current has been most prolific in the preparation 

 of products which cannot be obtained by other reducing agents. 

 A few of these may be mentioned as typical examples : 

 Strychnine, 1 the first of these substances to be submitted to 

 electrolytic reduction, yielded strychnidine and tetrahydro- 

 strychnine, both these substances possessing in a less degree 

 the same physiological action as strychnine. 



// N ^ N //, N 



C 20 H 22 O #~|CO C 20 H 22 O ^-rCH 2 QoHJD <^-CH 2 OH 



N N NH 



Strychnine. Strychnidine. Tetra-hydro-strychnine 



As an example from the ureides, barbituric acid 2 may be 

 cited, this substance yielding on reduction a mixture of hydro- 

 uracil and trimethylene-urea. 



NH-CO NH-CH 2 NH-CH 2 



II II II 



CO CH 2 CO CH, CO CH, 



II II" II 



NH-CO NH-CO NH-CH 2 



Barbituric acid Hydro-uracil Trimethylene urea 



The behaviour of di-ethyl-barbituric acid, 3 which is now 

 being used somewhat extensively as a soporific under the name 

 of Veronal, is very remarkable. Instead of being reduced in 

 a manner analogous to barbituric acid, the hydrogen attacks 

 the urea residue thus : — 



NH CO NH CO 



II II 



CO C(CHo), -» CH, C(C,H 5 ) 2 



II" I " I 

 NH CO NH CO 



Up to the present this is the only observed instance in which 

 the carbonyl (CO) group of the urea chain has been electro- 

 lytically reduced. 



Of particular interest are the electro-reduction products 

 of uric acid, 4 inasmuch as this physiologically important body 

 has not been directly reduced by any other means, if one leaves 

 out of account the breaking down of the molecule by hydriodic 



1 Annalen, 301 (1898), 285. 



3 Ber. d. deut. chetn. Gesell. 33 (1900), 3383. 



3 Tafel and Thompson, Ber. d. deut. chetn. Gesell. 40 (1907), in press. 



4 Ibid. 34 (1901), 258. 



