THE CONDENSATION PRODUCTS OF AMINO ACIDS 

 ANHYDRIDES. 



Condensation products of amino acids have been obtained by various 

 investigators by simply heating the amino acids to a temperature of 

 about 200 C. 



Leucinimide. Hesse, in 1857, obtained by distilling a substance, 

 which was called pseudoleucine and was isolated from the products 

 resulting from the putrefaction of yeast, small quantities of a compound 

 termed " leucinsaurenitril ". This compound was also obtainable from 

 leucine. A better yield resulted if the compounds were heated in a 

 current of carbon dioxide. Hesse and Limpricht three years later 

 showed that this compound was identical with a crystalline compound 

 isolated by Bopp in 1849 from amongst the products of hydrolysis of 

 caseinogen. Kohler, in 1 865, again prepared this compound by heating 

 leucine to 220-230 C. in a current of hydrogen chloride and showed 

 that it lost 20 per cent, by weight in the process. The resulting 

 crystalline mass was insoluble in water, but soluble in hot alcohol from 

 which it crystallised out on cooling. This substance was identical 

 with that of Bopp and of Hesse and Limpricht and from a study of 

 its properties he gave it the more appropriate and correct name of 

 leucinimide. 



Lactimide. A similar experiment was made by Preu with alanine 

 and an anhydride lactimide of the formula C 6 H 7 N,O 4 was ob- 

 tained. 



