618 



EEPOKT — 1903. 



+ HCHL 1:3:4:6:7:9- 



Hexamethyl acridine. 



The related acridones and thio-acridones furnish an instance of ketonic and 

 enolic tautomerism which it would be interesting to investigate by spectroscopic 

 methods as described by Professor Hartley in his Address to this Section. 



Another class of compounds formed from the acridines by the addition of two 

 atoms of hydrogen — acridine hydrides or ' hydro-acridines ' — are very unstable, 

 and on oxidation, even by boiling with water, in some cases lose their hydrogen 

 and revert to the original base. They are not fluorescent, a property characteristic 

 of the acridine ring with its para linking, and may therefore have the struc- 

 ture : — 



NH 



Mr. Goodwin and I, in an inquiry not yet quite completed, have obtained a 

 similar class of dihalides. We have prepared chlorides, bromides, and iodides of 



/3N/3 aNa 



hexamethylacridine, | -naphtbacridine, and | -naphthacridine (for notation 



aCa /3C3 



see Naphthacridines, below). Like their hydrogen analogues, these compounds 

 are unstable and are not fluorescent. Their constitution is therefore in the case 

 of simple acridines : — 



NCI NBr 



CH CI 



CHBr 



CHI 



The salts and alkhaloids of the acridines are fluorescent, and may he regarded, 

 following Bernthsen and Bender, as true acridines with pentavalent nitrogen, 

 thus : — 



/H H 



^Cl \l 



CH 

 Me 



N— O.SO,.OMe 



CH 



