2-Chloro-3,5-dinitropyridine, amination

As an extension of this work, the aminodechlorination of 2-chloro-3,5-dinitropyridine was studied (85JOC484). Because of the high 77-electron deficiency of this compound, it appears that the amination does not require the presence of a strong nucleophilic amide ion liquid ammonia is already... 

Amination of 2-chloro-3,5-dinitropyridine in liquid ammonia at —40°C and potassium permanganate gave 2,6-diamino-3,5-dinitropyridine. Its formation indicates that besides SNH at C-6, a SN(AE) amino-dechlorination occurs at C-2 (Scheme 6). 

NMR studies on a-adduct formation between 2-chloro-3,5-dinitropyridine and liquid ammonia show that the site of covalent addition is temperature dependent at — 60 °C the C-4 adduct is formed, at —40°C the C-6 adduct is obtained (85JOC484). Apparently, at — 60 °C the C-4 adduct is the kinetically favored one, and at —40°C the thermodynamically more stable C-6 adduct is obtained. The results are in agreement with those of the amination at —40 °C (Scheme 6). 

Since these early studies, numerous derivatives of 2-chloro- and 2-bromo ia, 672 and 4-chloro- and 4-bromo-pyridine 73 have been converted into amino- or alkylamino-pyridines under conditions differing little from those mentioned above. Modifications which have been used include the addition of copper sulphate as a catalyst a, 672a reaction in the presence of pyridine 64 and also, in the case of 4-chloropyridine, reaction with primary and secondary aliphatic amines in benzene 4 at 140-180 . The qualitative data from these numerous examples show the effect of other substituents upon 2- and 4-halogen atoms to be as expected. GarboxyM oa, 675, 9i8 and nitro-groups24ia markedly augment reactivity, and in a compound such as 2-chloro-3,5-dinitropyridine, much milder conditions than usual can be used for amination e ... 

---