H^MATIN. 283 



The views in regard to the composition of hsematin are rather con- 

 tradictory, which seems to be due to the fact that the substance 

 hsemin (see below), from which the formula of hsematin is derived, has 

 a somewhat different composition, dependent upon various conditions. 

 According to HOPPE-SEYLER hsematin has the formula C3 4 H34X 4 FeO5, 

 and from the recent investigations upon hsemin, which will be mentioned 

 below, this formula seems to be now generally accepted. According to 

 this formula 1 atom of iron occurs with every 4 atoms of nitrogen. Ac- 

 cording to CLOETTA, and also ROSENFELD/ hsematin has the formula 

 C3oH 34 N 3 FeO3, with 1 atom of iron for every 3 atoms of nitrogen. The 

 question whether the hsematins obtained under different conditions 

 are identical or not is still undecided (v. ZEYNEK, EppiNGER 2 ). 



.Hsematin is very resistant toward boiling concentrated caustic 

 potash as well as toward boiling hydrochloric acid. It dissolves in 

 concentrated sulphuric acid, and is converted into hsematoporphyrin 

 with the splitting off of iron. On heating dry haimatin it yields abundant 

 pyrrol. On reduction with tin and hydrochloric acid a body similar 

 to urobilin is formed. As an oxidation product of hsematin in glacial 

 acetic acid with potassium bichromate or chromium trioxide, KUSTER 

 obtained the imide of the tribasic hsematinic acid, CgH 9 NO 4 , which is 

 also produced on the oxidation of hsematoporphyrin and bilirubin. On 

 reduction with phosphonium iodide it yields hsemopyrrol (see hsemato- 

 porphyrin) . 



The imide of the tribasic hsematinic acid, which is a derivative of malei'c acid 



and probably has the formula C 5 H 7 (COOHX /NH, is readily transformed into 



NXK 

 the anhydride of the tribasic haematinic acid, C 8 H 8 5 , having the probable formula 



CH 3 .C.C(X 



;O. On heating the imide with alcoholic ammonia to 

 COOH.CH 2 .CH 2 .C.CXK 



130 C. it splits off carbon dioxide, and the imide of the bibasic haBmaJinic acid 

 C 7 H 9 NO 2 is obtained. From this imide on saponificatiori with baryta-water we 

 obtain the barium salt of an acid whose anhydride is methyl-ethyl maleic-acid 



C 2 H 5 .C. 

 anhydride, 



CH..C.C 



On heating hrematinic acid ester with alcoholic ammonia in a tube to 130 

 KUSTER obtained a colored product whose bluish-violet aqueous solution gave 

 a spectrum with two bands which in position were similar to the oxyhffimoglobin 

 spectrum. He has also prepared and studied various salts, esters and aniline 

 derivatives of the haematinic acids and condensation products of their esters. 



1 Hoppe-Seyler, Msd.-chem. Untersuch., p. 525; Cloetta, Arch. f. exp. Path. u. 

 Pharm., 36; Rosenfeld, ibid., 40. 



2 v. Zeynek, Zeitschr. f. physiol. Chem.. 49; P. Eppinger, Unters. uber den Blut- 

 farbstoffe Dissert. Miinchen, 1907. 



