120 ILLINOIS STATE ACADEMY OF SCIENCE 



located. For instance, iodi-p-phenylenediamine lost 

 iodine less rapidly than o-iodoaniline, while 2, 4-diamino- 

 iodobenzene reacted more rapidly than either, as did 

 also the corresponding iodoresorcinol. 



It might be well to emphasize the fact that halogens 

 not in favored positions show no sign of reacting under 

 any of the conditions used. This is shown, for in- 

 stance, by the fact that 2, '4, 5, 6-tetrabromo-m-dinitro- 

 benzene, warmed with a stannous chloride and acid, loses 

 three of its four bromines quantitatively, giving 1, 3- 

 diamino-5-bromobenzene. One might choose an even 

 more decisive case; 2-iodi-3,5-dibromo-4-aminotoluene, 

 after refluxing for 8-10 hours with the same reagents, 

 loses all of its bromine, without the formation of a de- 

 tectible amount of iodide ion. The product, 2-iodo-4- 

 aminotoluene, should not lose iodine if the considera- 

 tions already advanced are correct. 



