TWO CHEMICAL CONSTITUENTS FROM THE EUCALYPTS. 67 



Continuing the investigation upon his own Osyritrin he 

 found that this substance also has the same formula, and 

 that it is identical with Myrticolorin and with Viola- 

 quercitrln. 1 These three glucosides are thus identical 

 substances, although obtained from three different natural 

 orders ; they all have the formula C 2 7H 28 0i 6 and all give 

 identical substances chemically. 



In the original paper it was shown that the osazone 

 formed with the sugar of myrticolorin melted at 190° 0., 

 thus suggesting galactose, but from subsequent investiga- 

 tions I find that this sugar is not present and evidently 

 the osazone was not pare, as later determinations on several 

 different portions of material gave identical osazones melt- 

 ing at 204 — 205° 0., so that the osazone formed with the 

 sugar of myrticolorin is glucosazone. The same melting 

 point is obtained with the osazones from the sugars of both 

 osyritrin and violaquercitrin. 



The glucoside, myrticolorin, undergoes the following 

 reaction when decomposed with acid, quercetin and glucose 

 being formed : — 



GfrHasOie + 3 H 2 = O 15 H 10 O 7 + 2 6 H 12 6 . 

 Quercetin is a member of the flavone group and contains 

 five hydroxyls, two of which are in the ortho position rela- 

 tively to each other. It appears probable that the location 

 of the hydroxyls in the molecule of the several members 

 of this group decides the tinctorial peculiarities of these 

 bodies, although it does not appear necessary for the 

 hydroxyls in the several members of the flavone series to 

 take up the ortho position to form true dyestuffs. 



In the members of the anthraquinone series (alizarin or 

 dihydroxyanthraquinone for instance) the two hydroxyls 

 are in the ortho position relatively to each other, and it is 



1 Trans. Chem. Soc, 1902, p. 477. 



