757 



Chemistry. — "N'dro-derivntiües of alkylhenzidin.es" . B}' G. van 

 RoMBURGH. (Communicated by Prof. P. van Rombürgh). 



(Communicated in the meeting of October '30, 19i5). 



Mertkns') lias obtained in J 877 as a byproduct in the nitration 

 of dimethyiaiiiiine an orange-yellow compound soluble witli difliculty 

 in aleoliol, which he named isodinitrodimelhylaniline. From this was 

 obtained on boiling with concentrated nitric acid a product which 

 he again investigated a few years later') and took it for dinitro- 

 phenylmethylnitramine. From this was formed on boiling with 

 phenol a splendid red coloured compound which was described as 

 tetranitrodimethylazobenzene. Shortly afterwards P. van Romburgh ') 

 showed that these compounds found by Mertkns are derivatives of a 

 tetranitrobenzidine without, however, determining the position of the 

 nitro-groups. 



I resolved to endeavour to elucidate the structure of these products, 

 and at the same time to study also a number of nitro compounds in 

 the alkylbenzidine series in addition to some reduction products thereof. 



The tetranitrotetramethylbenzidine, which in the circumstances, is 

 formed only in small quantity, in the above nitration is obtained 

 in a yield of about 35"/„ of the dimefhylaniline employed, when 

 we operate as follows : 



30 grams of dimethylaniline are dissolved in 900 c.c. of nitric acid 

 D. 1.11, wliicii are cooled in ice-water to about 5°. After thorough 

 shaking and leaving it for some time in the ice-water it is left at 

 tiie ordinary temperature. The product that has formed over night 

 is collected, boiled with alcohol and filteied through a hot water- 

 funnel. The substance so obtained is already very pure and, when 

 recrystailised from phenol, it decomposes at 272°. 



Aqueous potassium hydroxide is supposed not to act on this 

 compound. I could, however, ascertain that on prolonged boiling 

 some formation of dimethylamine takes place. 



The manner iu which the product is formed justifies the belief that 

 the nitro-groups occupy the positions 3. 3'. 5. 5'. For in the nitration 

 of dimethylaniline, as shown by Pinnow *) there is formed, at least 

 in diluted sulphuric acid solution, some orthonitrodimethylaniline, 

 which product is not readily nitrated any further. As nitric acid of 



1) Diss. Leiden, 1877. 



-) Ber. d D. Ghem. Ges. 19, 2123 (1886). 



8) Rcc. d. Trav. Ghim. 5, 240 (1886). 



*) Ber. d. D. Ghem. Ges. 32, 16G6 (1899). 



