DEVELOPERS AND THEORY OF DEVELOPMENT 



327 



The developing action of the tetrahydroquinolines has long been known. An 

 example of the earlier developers of this class is 



l,2,3,4-Tetrahydro-8-hydroxyquinoUne 

 OH H 



while recently the amino derivative 

 H. 



HoN 



\/\n 



H., 



H2 



6-Amino-l,2,3,4-tetrahydroquinohne 



H 



has been suggested as a fine-grain developing agent. 



Combinations of Developing Agents. — Various phenols, aminophenols and 

 phenylenediamines have been combined to produce, for instance, 



Metoquinone 

 Lumiere and Seyewetz 

 F. P. 325,385, (1902) 



The combination of 1 mole of chlorohydroquinone with 2 moles of the base of 

 metol 



Lumiere and Jugla 

 B. P. 1795 (1914) 



was known as Chloranol. 



The product resulting from the combination of 1 mole each of p-phenylenediamine 

 base and hydroquinone 



Hauff 



B. P. 11,306 (1896) 



Starnes 



B. P. 466,626 



appeared as the developing agent Hydramine. 



Recently the combination of apparently pyrocatechol, 1 mole, and 1 mole of 

 p-phenylenediamine base 



