TRANSACTIONS OF SECTION B. 



617 



fluorescence. The subsequent researches of Graebe, Riedel, and others, led to the 

 view now adopted of its constitution as a heterocyclic anthracene derivative of the 

 formula 



The resources of synthetical chemistry were not long in bringing to light 

 methods for building up this interesting fluorophoric molecule from compounds of 

 simpler structure. A phenyl derivative was first obtained and the base itself by 

 Bernthsen and Bender in 1883. 



The numerous methods which have led to the formation of acridines may be 

 arranged into two classes — 1st, those starting from diphenylamine 



NH 



'H H~ 



and its derivatives ; and 2nd, those starting from o-amino-diphenylmethane 



CH2 



and its derivatives. 



As illustrations of the first method may be taken («) condensation by means of 

 aldehydes, for example formaldehyde : — 



NH 



NH 



+ H,0 + H, 



CH 



(Unstable dihydride) 



and (b) condensation by means of methylene diiodide ; a method discovered by 

 Mr. Goodwin and myself. For example, using -vlz-cumidine the following represents 

 the reactions which take place : — ■ 



Me 



NH 



NH.,H.,N 



