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 

 haBinin (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 341134^^605, 

 and from the recent investigations upon hasmin, 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/ haBmatin has the formula 

 CsoHs^sFeOs, 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 ). 



HaBmatin 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 haematoporphyrin 

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

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

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

 acetic acid with potassium bichromate or chromium trioxide, KUSTER 

 obtained the imide of the tribasic haBmatinic acid, CgHgNO^ which is 

 also produced on the oxidation of hasmatoporphyrin and bilirubin. On 

 reduction with phosphonium iodide it yields haBmopyrrol (see hasmato- 

 porphyrin) . 



The imide of the tribasic haematinic acid, which is a derivative of maleic acid 



NH, is readily transformed into 



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

 /O. On heating the imide with alcoholic ammonia to 



CH 3 .C.CO 

 COOH.CH 2 .CH 2 .C.CO/ 



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

 C T 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-ethvl maleic-acid 



C 2 H 5 .C.OK 

 anhydride, /O. 



CH 3 .C.CO/ 



On heating hoematinic 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 oxyhaemoglobin 

 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, Med.-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. iiber den Blut- 

 farbstoffe Dissert. Munchen, 1907. 



