2 54 Willstätter's Researches on Chlorophyll [Jan. 



CH,— CH— CH— CH— CH— CH— CH— CH— C : C— CH^OH 



CH3 CH3 CH3 CH3 CH3 CH3 CH3 CH3 CH3 



The unsaturated nature of the alcohol is shown by the fact that it 

 adds one molecule of bromine and that it takes up one molecule of 

 hydrogen to form dihydrophytol, C20H42O. It is easily oxidized 

 by chromic acid or by ozone, forming a ketone, C17H34O. When 

 this ketone is treated with oxidizing agents, a series of ketones is 

 obtained by successive removal of pairs of carbon atoms, together 

 with saturated acids which contain one carbon less than the ketonic 

 products; this indicates the ketomethyl, — COCH3, arrangement. 

 These methyl ketones from phytol are interesting not only on ac- 

 count of their bearing upon the structure of that substance, but also 

 because of certain anomahes in their physical properties. An ex- 

 planation of the latter has been sought in the assumption that the 

 samples obtained consisted of the enolic isomerides. 



As an explanation of the natural synthesis of this substance, it 

 has been pointed out that the peculiar structure of the alcohol sug- 

 gests that it is formed by polymerization of a hydrocarbon such as 

 isoprene, four molecules being Condensed by the intervention of 

 water and hydrogen : 



4C5HS + H2O + 3H2 = C20H40O. 



In spite of the slender basis on which this hypothesis lies, it is par- 

 ticularly attractive on account of the genetic connection which it 

 reveals between phytol and the terpenes, rubbers and other groups 

 of Compounds. 



Oxidation of Chlorophyll derivatives. The only early ref- 

 erence to the oxidation of Chlorophyll derivatives is that of March- 

 lewskl,^^ who oxidized phylloporphyrine with chromic acid and ob- 

 tained hematinic acid : 



Me— C— CO2H 



II 



HO2C— CH2— CH2— C— CO2H 



Under the same conditions Küster^^ had previously obtained the 



23 Marchlewski : Bull, de l'Acad. des Sciences de Cracovie, 1902, i. 

 ** Küster: Zeitschr. f. physiol. Chem., 28, i (189g); 29, 185 (1900); 44, 391 

 (1905) ; 54, 501 (1908) ; 61, 164 (1909). 



