322 PIGMENTS 



The constitution of this alcohol phytol has been studied by 

 Willstatter and his pupils,* who find it to be an unsaturated 

 primary alcohol with a double bond between the second and 

 third carbon atoms of the chain, probably represented by the 

 formula — 



-CH 



I 

 -CH3 



CH3- 



-C = C— CHgOH 



CHo CHo 



RELATIONSHIP BETWEEN CHLOROPHYLL AND 



HAEMOGLOBIN. 



With a view to the further elucidation of the constitution 

 of the chlorophyll molecule, especially in regard to the com- 

 plex to which the carboxyl groups are attached, the oxidation 

 of the porphyrins by means of chromic acid in the presence 

 of sulphuric acid has been studied by Marchlewski f and by 

 Willstatter and Asahina.J These investigations point to the 



C— C. 



existence of the grouping 



"/N in the molecule, since 

 ~C 



the two chief oxidation products are found to be pyrrole 

 derivatives of the formulae — 



CH3 . C— COv CH3 . c— CO\ 



ll /NH II >NH 



COOH CH2 . CH2 . C— CO/ CH3 . CHj, . C— CO/ 



Haematinic acid imide Methylethylmaleinimide 



The former substance, which is the imide of a tricarboxylic 

 acid known as haematinic acid, of the formula — 



CH3 . C— COOH 

 COOH . CH2 . CH2 . C— COOH 



has also been obtained from haemoglobin, the red colouring 

 matter of the blood, and a connection between haemoglobin 

 and chlorophyll is thereby established. 



The relationship between this haematinic acid imide and 

 haemoglobin is as follows : — 



* Willstatter, Schuppli, and Mayer : " Annalen," 1919, 418, 121. 



t Marchlewski : " Chem. Zentralbl.," 1902, i, 1017. 



X Willstatter and Asahina : " Annalen," 1910, 373, 227. 



