x H^MATINIC ACIDS 515 



ammonia in a tube to 130, gives rise to a brown fluid, which on 

 exposure to the air becomes deep blue, while hsematinic acid itself 

 splits off C0 9 , and is converted into the imide of methylethyl-maleic 

 acid. After removal of the alcohol and the ammonia a watery solution 

 is obtained which shows two feeble" bands in the region of the oxy- 

 hsemoglobin bands. Another ester, resembling the one just described, 

 Kiister obtained from the haematinic acid C 8 H 9 4 N. 



All these reactions favour the view that hsemopyrrol is 3-methyl- 

 4-w-propylpyrrol, but by comparing the oxidation-product of hsemo- 

 pyrrol with the synthetically prepared imide, Kiister and Haas l have 

 shown that the two compounds are not identical, as the difference in 

 the melting-points amounts to 7. 



By reducing methylethyl-maleic anhydride, hsemotricarboxylic acids 

 are obtained : 2 



CH, C H CH CH 2 CH 9 COOH 



I i 



COOH COOH 



Haemotricarboxylic acid. 



These carboxylic acids are isomeric, although not identical, with the 

 synthetically prepared ethyltricarballylic acid : 



H 9 C CH CH . CH 2 . OH 3 



I I I 



COOH COOH COOH 



Ethyltricarballylic acid. 



And this fact supports the formula of butylpyrrol given above for 

 haemopyrrol. 



That hsemopyrrol is a pyrrol-derivative is proved 3 by the fact that 

 an ethereal solution of hsemopyrrol 4 combines with a freshly prepared 

 watery solution of benzene-diazonium 5 chloride to form an azo-dye- 

 compound, which is soluble in alcohol with a cherry-red and in 



1 Kiister and Haas, Ber. d. deutsch. chem. Oes. 37. 2470 (1904). 



2 M. Kolle, Dissertation, Tubingen, 1898 ; W. Kiister, Ber. d. deutsch. diem. Ges. 

 35. III. 2948 (1902). 



3 H. Goldmann and L. Marchlewski, Zeitschr. /. physiol. Chem. 43. 415 (1905). 



4 The hsemopyrrol was made according to Nencki-Zaleski's method : 5 grammes of 

 hiemin, 100 grammes of hydriodic acid, 100 grammes of glacial acetic acid, and about 

 8 grammes of phosphonium iodide. 



5 The discovery of the fact that pyrrol and some of its homologues react with 

 diazonium compounds was first made by Fischer and Hepp (Ber. der deutsch. 

 chem. Ges. 19. 2251 (1886). Pyrrol in acid solutions yields mono-azo-dyes, while in 

 alkaline solutions in the presence of two molecules of the diazonium-compound there are 

 formed di-azo-dyes. Both a and ^ hydrogen-atoms of pyrrol may be substituted. (See 

 p. 43 for formula of pyrrol.) 



2 L 



