I9I4] Clarence J. West 255 



same acid from hemin, but in the form of the Imide : 



Me— c— c==o 



li >NH 

 HO2C— CH2— CH2— c— c=o 



Willstätter^^ has shown that, by the oxidation of Chlorophyll 

 derivatives (phyllo-, pyrro-, and rhodo-porpliyrines, and phytochlo- 

 rine) with either lead peroxide and sulfuric acid, chromic acid, 

 or Caro's acid, there results a mixture, which, apart from minor de- 

 composition products, such as carbon dioxide and acetic acid, con- 

 sists of two princpial products : hematinic acid imide and methyl- 

 ethyl maleinic imide. 



Me— c— c^=o 



II /NH 

 Et— C— C=0 



The latter Compound had been obtained by Küster^^ by Splitting 

 off carbon dioxide from the hematinic acid imide, and had also been 

 prepared synthetically by him. It was not obtained by the oxida- 

 tion of hemin. 



The oxidation is best carried out by dissolving the Chlorophyll 

 derivative in about 50 percent sulfuric acid, cooling to 0°, adding a 

 Solution of chromic acid in water with stirring and holding the 

 temperature at 5-7°. The next day the sol. is filtered, extracted 

 with ether, the mixture dissolved in water after the removal of the 

 ether, neutralized with sodium carbonate and extracted with ether, 

 when the two substances are obtained crystalline. Five gm. of 

 phylloporphyrine gave about 3.3 gm. of the mixture, of which 1.67 

 gm. was methyl-ethyl maleinic acid and 1.3 gm. hematinic acid 

 imide. This is approximately one molecule of each. Willstätter 

 supposes, however, that since the yield of methyl-ethyl maleinic 

 imide is always a little larger than that required for one molecule, 

 and since there is always a certain amount of loss connected with 

 the purification, two pyrrole nuclei are concerned in the formation 

 of this Compound. 



Since methyl-ethyl maleinic imide is not formed in the oxidation 

 of hemin, at least two of the four pyrrole nuclei in Chlorophyll are 

 different from those of hemin. 



35 Willstätter and Asahina : Ann. d. Cheni., 373, 227 (1910). 



36 Küster: Ibid., 315, 174 (1900). 



