H^EMATOPORPHYRIN. 295 



to PILOTY two carboxyl groups are formed with the taking up of water and 

 these occur to a certain extent latent in lactam combination in the hsBmin. 

 According to KtisTER, 1 who admits of two already formed carboxyls in the hsemin, 

 two hydrox3 r ls are produced secondarily in the hsematoporphyrin, in that (by the 

 action of the glacial acetic acid and hydrobromic acid) primarily an attachment 

 of hydrobromic acid takes place and then from this as intermediary product, 

 by the action of water, bromine is split off and is replaced by hydroxyl. In the 

 formation of mesoporphyrin the procedure is still different because among others, 

 mesoporphyrin contains 2 oxygen atoms less than the hsematoporphyrin. 



On the gentle reduction of hsemin with glacial acetic acid, hydriodic acid 

 and red phosphorus, PILOTY and FINK obtained besides mesoporphyrin a second 

 body, phonoporphyrin, which differs from the mesoporphyrin by containing 

 more oxygen, a brown color and almost complete insolubility in dilute hydro- 

 chloric acid. It is not reduced to mesoporphyrin by hydriodic acid but yields 

 hsematinic acid and methyl-ethyl maleic imide on oxidation with chromic acid. 

 They obtained no other cleavage products from hsemin under the above men- 

 tioned experimental conditions. The two porphyrins were produced in about 

 equal quantities and they formed about 90 per cent of the calculated cleavage 

 products. They each represent one-half of the hsemin, whose formula corresponds 

 to CesHeiNsOsFeoClo which must be doubled. As these two porphyrins yield 

 methyl ethylmaleic imide, while this is not the case with either the hsemin or the 

 hsematoporphyrin, it is believed that both are combined together in the hsemin 

 or hsematoporphyrin with that part of their molecules which allow of the maleic 

 imide formation. 



By the action of glacial acetic acid, and hydriodic acid upon hsemin in the 

 cold (room temperature) in the presence of iodophosphonium, H. FISCHER and 

 BARTHOLOMAUS have obtained a beautiful crystalline, colorless product, por- 

 phyrinogen, whose formation and behavior have been further studied by RosE. 2 

 Porphyrinogen, CsJ^aN^ is formed from hsemin, the meso- and the hsemato- 

 porphyrin in acid, and from the meso- or hsematoporphyrin also in alkaline 

 reduction. Porphyrinogen can be transformed into mesoporphyrin by oxidative 

 action of various kinds. Like the latter it yields ha3matinic acid as well as methyl 

 ethyl maleic imide as oxidation products. 



Hsematoporphyrin is closely related to the bile pigment bilirubin 

 (see Chapter VII) and also stands in close relation with the urinary 

 pigment, urobilin. By action of reducing substances several investiga- 

 tors (HOPPE-SEYLER, NENCKI and SIEBER, LE NOBEL, MACMUNN and 

 others) have obtained pigments similar to urobilin, and by experiments 

 with rabbits, NENCKI and RoTSCHY 3 have proved that hsematoporphyrin 

 introduced into the animal body may in part be transformed into a 

 urobilin substance. 



In connection with the question of the behavior of hasmatoporphyrin in the 

 animal body, the poisonous action of this body, as discovered by HAUSMANN, 

 and which manifests itself as a photobiological sensibiliaation, is of interest. 

 HAUSMANN has found that white mice that have had hsematoporphyrin injected 



1 Piloty, 1. c.; Kiister, Ber. d. d. chem. Gesellsch., 45. 



2 Piloty and Fink, Ber. d. d. chem. Gesellsch., 46, 2021; H. Fischer and Bartholo- 

 maus, ibid., 46, 511; Rose, Zeitschr. f. physiol. Chem., 84. 



3 Hoppe-Seyler, Med. Chem. Unters. p. 533; Le Nobel, Pfliiger's Arch., 40; 

 Nencki and Sieber, 1. c.; MacMunn, Proc. Roy. Soc., 30, and Journ. of Physiol., 10; 

 Nencki and Rotschy, Monatsh. f. chem., 10. 



