44 Proceedings of the Royal Irish Academy. 



catechin teti'amethyl ether necessarily requires the double bond linking in 

 the latter compound (m) to lie between the carbon atoms (8) and (4). A 

 synthesis of the compound oT -dimethoxy-2mp.-dimethoxy phenyl-1-4- 

 benzopyiuuol anhydrohydi-obromide has been commenced. In this way it is 

 hoped definitely to estabhsh the constitution of the above bromide derivative 

 of catechin. 



When excess of alcohol is poui'ed on some of the above bromide the led 

 colour gradually disappeare, a colourless solution resulting. Addition of 

 hydrochloric acid in excess., however, restores the colour to the solution. By 

 treating the bromide with dilute alcoholic ammonia, and then extracting the 

 mixture with ether, the expected colour-base was obtained on evaporation of 

 the ether. This method was fii-st described by Watson and Seun (Jour- 

 CheuL Soc., 1915, cvii, p. 1483). The colourless base so obtained ciystal- 

 lized from alcohol in colourless prisms, melting at ViZ" C. The results of 

 analyses of this compound agreed closely with the fonnula (v). 



^' 





3 r 



-.-^. 





^^^ 



yK / 



— >?S"5 





; V 



>°^3 



1 



/^\. 



^A 



Xoc^Hj 





>c„ \- 



/ 





N. /^ 



JCH V 



-V 



CXHj 



V. 







°S"s 



TI. 





vn. 



Watson and Senn (foe. at., p. 1,485) obtained a very closely allied com- 

 pound as the colour-base of the pyranol salt got from the action of magne- 

 sium-ethyl iodide on luteolin tetra-ethyl ether. These anthoi-s, in their 

 paper, do not mention any results of analysis of their compound, to which 

 they gave the formula (vi). From the very close analogy of the colour- 

 base (¥) with that obtained by Watson and Senn from 5-7-dietlioxy-2mp- 

 diethoxy phenyl-l'4:-benzopjTanol anhydrohydriodide, it woidd seem that 

 the latter, in reality, had the constitution represented by formirla (vn). 



The colour-base (v) on treatment with hydrochloric acid immediately 

 r^ains the bright-red colour of the anhydrohydrochloride. The anliydro- 

 hydroehloride was prepared in a pure condition, as described in the experi- 

 mental part of this paper. The results of analysis of this chloride agreed 



