CHAPTER III 



PORPHYRIN CHEMISTRY 



1. INTRODUCTION 



1.1. Historical 



"Iron-free hematin" was first mentioned by Scherer in 1841 (2440) 

 and Mulder and van Goudoever in 1844 {2003). In 1871 Hoppe- 

 Seyler {1337) obtained a purple pigment by the action of concen- 

 trated sulfuric acid on hemoglobin which he called hematoporphyrin; 

 a similar product, "Dichromatinsaure," resulted from the action 

 of alkali on chlorophyll {1339). This was later recognized by Will- 

 statter {3091) as a mixture of porphyrins. Porphyrin in pathologic 

 urine was observed in 1874 by Baumstark {195). 



The first pure product was hematoporphyrin hydrochloride, 

 which Nencki and co-workers {2032-203 Jf.,2036) obtained by treat- 

 ment of hemin with hydrobromic acid in glacial acetic acid. Shortly 

 afterward (1901) they isolated another porphyrin, mesoporphyrin, 

 by treatment of hemin with hydriodic acid. Although Saillet {2^14) 

 had noted spectroscopic differences between the urinary porphyrin 

 and hematoporphyrin, the prosthetic group of hemoglobin and also 

 the porphyrin found in pathological urines by Salkowsky, Garrod, 

 and Saillet (1891-1893) were prematurely identified with hemato- 

 porphyrin, and until very recent times were still thus described in 

 most medicine and physiology textbooks {cf. 2). 



Our knowledge of the variety of porphyrins was developed later, 

 first by Willstatter's work on chlorophyll porphyrins, and then 

 rapidly in the years after 1923 by the work of Fischer and Schumm 



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