648 



logy with that of picijlmethjlamide C,B, (N0,)3 NHMe, and that thé 

 latter spectrum is not much changed by alkali. 



We then concluded, that the coloration of picrylalkjlnitramines 

 with alkalies had a similar cause as the colour of nitranilines {vicl. 

 Franchimont, Rec. irav. chim. 1910, 29, 298, 313), which is ascribed 

 by Hantzsch {Ber. 1910, 43, 1669) to an action between the nitro 

 and amino groups attached to the benzene nucleus. The coloration 

 of the nitramines would thus be produced by nitro groups of the 

 nucleus reacting with the base, the nitro group attached to nitrogen 

 playing only a secondary part. 



In order to test this hypothesis, we have now examined several 

 derivatives of picryhnethylaniide, compounds of the formula Pier. 

 -NMeX'). For X we have chosen the nitroso group, the organic 

 acyl groups COC]^,, CO.Me, CO„Et and finally the phenyl group 

 as example of a negative group being no acylgroup. The compounds 

 investigated were thus picrylmethylnitrosamine Pier. NMe(NO), picryl- 

 methylacetamide Pier. NMe(C0CH3), methylpicrylmethylaminoformiate 

 Pier. N Me (CO^Me) and the ethylester Pier. NMe (CO^ Et), and picryl- 

 phenylmethylamide Pier. NMe Ph. 



In the tirst place it should be observed that, like the nitrogroup, 

 also the acyl groups NO, COOH.,, CO.Me, CO^Et strongly diminish 

 the. colour of the picrylmethylamide. Compared with this deeply 

 yellow coloured amide, the nitramine, nitrosamine, acetyl derivative 

 and both the urethanes are only palish yellow. 



These differences are clearly shown by the absorption curves. 



1 

 Both the absorption bands of picrylmethylamide at —2390 and 2875 



(see curve 15) disappear wholly; the acyl derivatives give for the 

 concentrations examined, only a continuous absorption in the ultra- 

 violet (curves 3, 5, 8, 10), just as it was found for the nitramine 

 {Rec. tmv. chim. 1913, 32, 332). 



It must be admitted, that the presence of acyl groups in the 

 aminogroup of picrylmethylamide so strongly diminishes the basic 

 properties of this group, that it loses the power to act with a nitro- 

 group, and thus to produce colour. 



If this hypothesis is correct, it must be possible to prevent this 

 reaction also by addition of a strong acid combining with the 

 amine group. 



Indeed, picrylmethylamide dissolves perfectly colourless in strong 



1) In this paper Pier, means the group 2, 4, 6trinilrophenyl. 



