178 



REPORT — 1902. 



give penta-broTno-/3-naphtha quinones under similar conditions ; in these 

 cases position 8 is unoccupied, and a transference of bromine takes place 

 from position 1, e.g., 



H Br\/N02 

 Bri^'^'^'^'No 



Br Hx/NOa 

 Brr'^^'N'''^^0 



Br O 



That a direct transference of bromine is effected, and that the product 

 is not formed by bromination of a tetra-bromo quinone formed in the 

 first instance, is proved by two facts : (1) that nearly a theoretical 

 amount is obtained, showing that none of the bromine can be eliminated 

 as hydrogen bromide ; (2) that the crude product is pure, showing the 

 entire absence of a tetra-bromo quinone. It is to be supposed that 

 if rebromination were to occur, a mixture of tetra-bromo and penta- 

 bromo quinones would be formed, as a mixture of 6-bromo and 

 4 : 6-dibromo-/?-naphtha quinones is obtained on decomposing the nitro- 

 keto compound of 1 : 6-di-bromo-/3-naphthol. 



Such a transference of bromine occurs only in the case of the penta- 

 bromo-naphthols, and has not been observed in the case of lower 

 brominated naphthols, in which position 8 is unoccupied. It should be 

 noted that whilst this position is free in 



Br 



OH 



the bromine atom in position 7 apparently prevents the transference of 

 bromine into position 8, although in the case of 



Br 



OH 



BrO) 



Br 



the presence of a bromine atom in position 7 does not prevent the forma- 

 tion of a penta-bromo quinone. 



The properties of 3 : 6-di-bromo-/3-naphtha quinone have been more 

 fully studied during the year. This substance is remarkable inasmuch as 

 it is far more unstable than any of the other brominated quinones. When 

 kept in the dry state for several months it is transformed by atmospheric 

 oxidation into 3 : 6-di-bromo-2-hydroxy-l : 4-naphtha quinone. 



