Polyhalogenonitrobenzenes and derived compounds. Part 3. Reactions of 1,2,3,4-tetrachloro-5,6-dinitrobenzene with bidentate nucleophiles

Abstract

1,2,3,4-Tetrachloro-5,6-dinitrobenzene (TCDNB) has been treated with a number of bidentate nucleophiles, all of which contained at least one amino or methylamino group. Diamines of the type H₂N(CH₂)_nNHR (R = H or Me, n= 2, 3, or 5), reacted via the primary amino group displacing a nitro group from TCDNB. The resulting products were inert to further reaction, i.e. cyclisation or further nucleophilic substitution. Both 2-hydroxyethylamine and ethyl glycinate behaved similarly, although ethyl diazoacetate was a by-product in the latter reaction.

The reaction of TCDNB with hydrazine hydrate was very sensitive to the conditions employed, i.e. rapid addition of excess of reagent (2.2 : 1 molar ratio) gave 3,4,5,6-tetrachloro-o-phenylenediamine (reduction had occured). Slow addition of an equimolar amount yielded 2,3,4,5-tetrachloro-6-nitrophenylhydrazine, i.e. nucleophilic substitution. N,N′-Dimethylethylenediamine and 2-hydroxy-N-methylethylamine reacted with TCDNB to give cyclised products, i.e. both nucleophilic centres reacted. The course of these reactions was investigated. In contrast 2-acetoxyethylamine, glycine, urea, 2,2′-iminodiethanol and butane-1,1,4,4-tetra-amine were all unreactive towards TCDNB.